| Change gears (Feb 6,
2001) |
9 Inch Change Gears (Feb
1, 2003) |
| Looking for gears (Feb
11, 2001) |
Gear pitch (Feb 5, 2003) |
| Need a 48 tooth change gear for 9
inch lathe. (May 28, 2001) |
Gear (Mar 2, 2003) |
| End Gearing for 9" Model A
(Jun 17, 2001) |
9" SB Gears questions
(Mar 23, 2003) |
| Question about SB 9" Mod A
Gearing Setup (Jul 8, 2001) |
Change gears (Apr 19,
2003) |
| How Many Gears? (Sep 3,
2001) |
Leadscrew gear (Jul 4,
2003) |
| Odd Change gears (new)
(Sep 10, 2001) |
Gear alignment (Jul 8,
2003) |
| Of gears and such (Jan
14, 2002) |
9-C Change gears pressure angle
(Jul 8, 2003) |
| SB 9" gear spec.s? (Feb
18, 2002) |
40 Tooth stud gear (Jul
19, 2003) |
| Change gears (Feb 19,
2002) |
Change gear diameter
(Aug 14, 2003) |
| 20t gears (Mar 18, 2002) |
Old 13" gears (Oct 3,
2003) |
| How to run my SB without the
change gears (Jun 2, 2002) |
Diametrical pitch (Oct
13, 2003) |
| 16 pitch gears on SB 9
(Jul 11, 2002) |
Change gear question
(Nov 22, 2003) |
| Reverse gear (Jul 11,
2002) |
16 Tooth Stud gear (Dec
12, 2003) |
| Pitch and pressure angle of
gears (Sep 30, 2002) |
Calculating DP on Gears
(Jan 25, 2004) |
| Gears (Nov 11, 2002) |
9" B or C change gears
(May 11, 2004) |
| Lathe gear (Nov 15,
2002) |
How much is a set of Change
gears? (Jun 11, 2004) |
| Change gear question
(Nov 17, 2002) |
9 Inch Model "C" Gears
(Nov 12, 2004) |
| Change Gears (Nov 22,
2002) |
Gearing for threading
(Feb 4, 2005) |
| Change Gears 9" (Dec 24,
2002) |
What gears come with SB Lathe
(Feb 21, 2005) |
| |
| Change gears |
| I have a
model b workshop from 1951 that needs change gears. What's the
cheapest source? Anyone know if Boston Gear still makes them?
Charles
(193) |
| I bought some gears from Boston Gear
5 years ago and they have worked well on my Model C, which uses pick
of gears. You may have to bore or ream the hole in the gear to
conform to your machine. I'm no expert on gears, but make sure you
order the right kind of gear. If I am not mistaken the key word is
the gear "pitch". Some SBs use 14 degree gears and some 21 degree
gears. (194) |
| Does
anyone know the pitch of the change gears on a 9 C. I believe it is
18 but I'm not sure. Rick (223) |
| Rick, No question about it, the
diametral pitch for the 9" SBL change gears is 18, and not carried
in the standard Boston Gear catalog. I am still looking for a used
16T one but no luck yet. (229) |
| Looking for
gears |
| I have a 9" 1939 Mod C with
standard change gears and two gear idler arms. I need 16T, 54T idler
gears. I could use a shaft bolt for the 2nd arm. An original tool
post wedge would also help. Looking for inexpensive sources. Any
suggestions?
(210) |
| Here's what I've
found: Dave Sobel of Sobel Machinery in Closter, New Jersey, will
probably have anything you want. He's not on the web. Try
201-768-9645. Dave Ficken at Meridian Machinery also has some parts,
though it seems not as many. Try his web site at
www.Mermac.com I'm
looking for change gears as well. It's looking like Dave Sobel is
the best bet. charles (213) |
| When you guys
purchase stuff from these places, please let us know how things
went. I'm sure we'll all want to patronize the good ones and avoid
the bad ones. Paul R. (214) |
| Paul. I bought a
bunch of gears for an Atlas Lathe from Mr. Sobel and could not have
been happier. Very quick service, Salty old gentleman, but he
definitely knew his stuff! And his prices were very fair. Dee (215) |
| Need a 48 tooth
change gear for 9 inch lathe. |
| I have a non quick
change South Bend Lathe. I need a 48 tooth change gear for it. I
would like to pay for the order over the phone as I need it
immediately. Does anyone know of a good source? Jayson (731) |
| I recommend you try
Joe Berganmo, Plaza Machinery, 802 2349673, fax 802 234-6325, He was
recommended to me by SB group member, Karl, and I have bought several items
from him. He is a wealth of information on parts, prices are fair,
stuff is nice, you know what you are getting. Have bought several
$100s worth of SB stuff from him and borrowed a large tap to chase a
few backing plates. big tom (734) |
| MSC has 48 tooth
spur gears in Browing and Boston Gear brands. Grainger has it in
Boston Gear. ~$23. 0.5" thick with 0.5" bore. You can easily modify
it for your needs. Your local power transmission warehouse/jobber
will also have generic change gears in any tooth count you need. Be
sure to verify the pitch and pressure angle of the mating gears
before you order. Machinery's Handbook has the formulas. Ken
(738) |
| End Gearing for
9" Model A |
| I recently acquired a 9" Model A and discovered in trying to
cut threads that there is no correspondence between what I'm setting
the quick change gearbox to, and the number of threads that are
actually cut. I'm thinking my problem may lie in the end gearing. Can
someone tell me what the setup should be so that the threads I cut
will correspond with those on the gearbox plate? Currently, my setup
is a 40 tooth gear (stud) on the leadscrew/gearbox shaft in mesh
with the idler gear (4 1/2" diameter). The idler gear then is in
mesh with a 20 tooth stud gear on the reverse handle. Over the 40
tooth gear on the leadscrew/gearbox shaft, is a 56 tooth gear that
is not being used. I removed the 40 tooth gear from the
leadscrew/gearbox shaft and tried to put the 56 tooth gear in it's
place, so that it would mesh with the idler gear. The idler gear
will not fit then between the 56 tooth gear and the 20 tooth stud
gear on the reverse handle, unless the end gear bracket can be moved
somehow. I loosened the socket screw holding the bracket, but it
seems immovable. Is this bracket meant to move, or are gears meant
to be placed in the two flanged areas of this bracket. Am I missing
a gear?
(877) |
| Do you have
the book that came with the machine? I would contact the company for
a copy. Start with if you can. Next, set up a piece of 1" round
stock in your lathe. Get a pitch-gage and register every thread
setting on the plate regardless of what you get. Using a thread bit
of course. If nothing else it'll keep you occupied until the manual
arrives. Ron (881) |
| It sounds
like you have a couple gears mixed up. I've attached a picture of
the way the gear train should be set up. The stud gear (the
removable gear on the tumbler assembly) is either a 20T or a 40T
(see the plate on the QC gearbox for choice). From there we go to
the 80T idler gear on the banjo. Finally, we go to the QC gearbox
gear which is 56T. The unused stud gear (typically the 40T) is just
stored on top of the 56T QC gear, but is not involved in the
gearing. The 20T stud gear is used for the bulk of threading and
feeding, while the 40T provides for very coarse threads and fast
feeds. You've got all the gears, just get them in the proper
positions and everything should be fine. Paul R.
(882) |
| Paul, Much thanks
for the setup info for the end gear train, and especially for the
pic. It confirmed my thinking in my original post about how the
gears should be arranged. Trying this arrangement again, I found
when my idler is in mesh with the 56T QC gear, there is no way it
will mesh with the 20T stud gear which is on the tumbler assembly.
In fact, it is off enough so that the teeth of the idler almost
reach the shaft that the stud rides on. As I indicated in my
original post, it seems that the bracket (banjo?) needs to be
rotated slightly counterclockwise in order to allow the idler to
mesh with the stud. Is it possible to rotate the bracket by
loosening the socket screw, or is the bracket keyed to the gearbox
shaft? If so, any thoughts on how I can correct this situation and
get my gears in alignment, anyone? Any thoughts on how things got
this way? I should add that the lathe is wonderful except for this,
and is in good overall alignment. Al (884) |
| Danny: Yes, just
loosen the socket head cap screw and adjust the banjo so that they
mesh right. Randy (885) |
| Question about
SB 9" Mod A Gearing Setup |
| I've been cutting threads using the
chart on the quick change gear box and I'm getting roughly double
the number of threads per inch as per the chart. The lathe came with
this gearing set up: 20 tooth stud gear 80 tooth idler 40 tooth gear
attached to the gear box (with 56 tooth gear riding on the same axle
but not driven). Question: Which gear should be driven on the gear
box? The 40T or the 56 T? I suspect the two have been reversed for
some reason, however the 56T gear rubs on the back guard when I try
to switch the two. Any idea what's wrong with my setup? Jim
(1045) |
| Jim, Here's a
what I posted before about the gearing setup for a 9" model A SB:
I've attached a picture of the way the gear train should be set up.
The stud gear (the removable gear on the tumbler assembly) is either
a 20T or a 40T (see the plate on the QC gearbox for choice). From
there we go to the 80T idler gear on the banjo. Finally, we go to
the QC gearbox gear which is 56T. The unused stud gear (typically
the 40T) is just stored on top of the 56T QC gear, but is not
involved in the gearing. The 20T stud gear is used for the bulk of
threading and feeding, while the 40T provides for very coarse
threads and fast feeds. You've got all the gears, just get them in
the proper positions and everything should be fine. Paul R.
(1046) |
| Paul,
Thanks for the reply and picture, much appreciated. Apparently the
previous owner reversed the 56T and 40T gears on the gear box shaft.
I changed them back as they should be. I did find that the aluminum
guard disk behind the gears had been bent enough to rub on the 56T
gear. I simply bent it back into shape. I think the gearing is back
to normal now! Now all I have to do is figure out how to make some
decent threads. (1049) |
| How Many Gears? |
| Does anyone
have a list of all the gears that should go with (or fit, whatever
the correct expression is...) a SB9C? I thought I had a complete set
until a couple weeks ago, when I went to set up a particular
threading operation. Turns out I am missing at least one gear. Drat!
Would like to get a list of all the gears and only have to call
Plaza or Meridian one time to cure my machine of it's missing gear(s).
Bubba (1435) |
| Bubba: Here is the
list from the South Bend parts manual: PT32NK116
(1436) |
| Bubba, If you
you need a gear that is no longer available you're not out of luck.
Here's a post from Earl who foud a gear shop in Portland Oregon. I
wouldn't be so sure about Meridian selling you the gears you need. I
visited Dave while I was in N.Y. last week. I was looking for a 80
tooth gearbox gear, Morse spindle nose sleeves, 5-C spindle nose
adapter and a quill for my heavy 10. I walked out of there empty
handed. Dave told me that he likes to sell his machines complete and
rarely parts them out. On the up side though, for those that may be
in the market for a new tail stock quill, Dave told me that he gets
a lot of request for them and he may be selling newly manufactured
quill's within 3 to 4 months. By the way, Delray Beach Florida is a
long way from Meridian in N.Y. I think I'll call first next time.
Chris (1437) |
| Gears for
many of these machine were originally manufactured by Boston Gear
and you can usually find the gear you need from them.
http://www.bostgear.com/
Yasmiin (1438) |
| By going through
"How to Run a Lathe" and tallying each gear noted for each thread
specified on the Model C chart I came up with the following:
16-18-18-24-32-32-36-40-44-46-48-52-54-56-60-72-80 (note the extra
18 and 32). This is for the standard specified inch threads between
4 and 160 TPI plus feeds down to .0021" per rev. It does not cover
unusual threads, such as 19 TPI used for British pipe threads, nor
does it cover Metric, DP, or Modular threads. I have not seen a list
of "standard gears", as noted I created the above list from reading
the book. If anybody has different or additional information, please
make your contribution to our collective knowledge. Anthony
(1441) |
| Anthony, your list is complete except for the 127/100 metric
transposition gear. With this and the gears you list you can cut
most any thread there is plus a few there aren't. (I do this to be a
stinker on special parts I make)
(1442) |
| Looks like the question
is not 100% straight forward as Anthony came up with two 18s and a
72 tooth gear and Randy's list from the SB parts manual didn't have
them. Interesting? Bubba (1476) |
| My list is not an "official" South
Bend list. I created it by reading the C-model change gear chart in
"How to Run a Lathe" and tallying each gear specified. I do not
guarantee that it matches any "official" South Bend data but I do
guarantee that it covers all the set-ups covered by the published
chart without any extras that were not required somewhere in that
chart. There is a possibility that one of the 18s and the 72 are a
permanently joined compound gear, similar to the 127/100 used for
metric threads. The purpose would be to have a compact 4 to 1
reduction for fine feeds or threads. Anthony
(1477) |
| Anthony, I
thought I had a full set with all the items you specified except as
follows: My 72 is part of a compound 72/18 gear I have no loose 18s
Given a compound 72/18, what thread or feed is the loose 18 tooth
gear used on? I don't see it on my change gear listing (but then I
may have missed something) Bill (1479) |
| As there's no way I
would remember this I looked it up in "How to Run a Lathe". It's
used for all the fine feeds (Fig. 4 on the Chart for Threads and
Feeds). Feeds listed are .0063 (160 TPI), .0052, .0042, .0031, and
.0021". Anthony
(1481) |
| This is
starting to get really interesting! In my copy of "How to run a
lathe" (1942 version reprinted), I don't have a "fig 4" in the
screws threads and power feeds chart!. 160 TPI is given as fig 3
(uses 72/18 compound), 16 stud, 80 screw and yields .0021 long feed
.0063 long feed is NOT there closest is 0.0060 or .0062 .0052 long
feed is there, 16 stud, 32 screw (fig 3) .0042 long feed is there,
16 stud, 40 screw (fig 3) .0031 long feed is NOT there, closest is
0.0030 or 0.0032 .0021 long feed is there, 16 stud, 80 screw WOW!
What configuration does figure 4 show? I can see how a completely
different gear train setup might give a new bunch of feeds (the ones
missing above). What bothers me is the 160 TPI which my table shows
as long feed of 0.0021 and you have 0.0063 - I can't see how that
could be different. Bill (1483) |
| My notes were made from the 1966 Edition, p. 72, which illustrates
both the 9" Model B and 9" Model C lathes. At a glance the two
charts are identical for gear trains through 120TPI but they result
in different feeds because when you set up for feeds on the "B" you
aren't using the split nut. Instead you drive a gear train from the
keyway on the leadscrew which results in a longitudinal feed 1/3
(approx.) of the same thread pitch and the cross feed is reduce by
another factor of 1/3. As an example, the "C" set up for an 80 TPI
thread results in a .0125" longitudinal feed (two values meaning the
same thing) but the "B", using the same set up as the "C" to produce
80 TPI, results in a .0043" longitudinal feed and a .0013" cross
feed. I also have a 1941 Edition. The chart on p. 72 is for a 10"
Series "S" lathe. In this one the feeds for 80 TPI are slightly
different, .0042" and .0015" respectively, obviously slightly
different gearing in the apron. WOW! What configuration does figure
4 show? I can see how a completely different gear train setup might
give a new bunch of feeds (the ones missing above). You're right, no
Fig. 4 in the 1942 Edition. In the 1966 Edition Fig. 4 is like so:
Stud | 18---54 (Individual gears) | 72---18 (Permanently joined
compound gear) | 80---Leadscrew All of thes are mounted on the long
arm of the banjo. What bothers me is the 160 TPI which my table
shows as long feed of 0.0021 and you have 0.0063 - I can't see how
that could be different. On the Model C, which has no gearing in the
apron, the feeds are simply the equivalent pitch of a TPI thread. To
get longitudinal feed divide 1 by TPI (1/80 = .0125"). Stud gear 48
gives .0063" or 160 TPI, 40 gives .0052", 32 gives .0042", 24 gives
.0031", and 16 gives .0021". Hope the above clarifies the situation
and is useful to you. Anthony P.S. I'm not certain
if you're aware, the gearset for a 9" Model B is slightly different
than that for a 9" Model C.
(1499) |
| I had no idea
that some of the 9s did not use a split gear for threading and the
info on how they are setup is appreciated. Bill (1507) |
| Anthony I
reread your post and a light blinked ON this time. The essential
thing I missed in my reply was that the model C FEEDS use the same
split nut as for threading and that's why they are different than my
model B list. I think I have the picture now. Bill (1508) |
| Odd Change
gears (new) |
| Pete writes: Can anyone advise me
of a source of gears for my 9"SB. I need a 35 and a 55 to cut an odd
thread for a project. Can you sub a 28 and 44 respectively? Send us
a copy of the set-up you were planning and whether you're running a
gearbox or not. Anthony
(1517) |
| I hadn't thought of that possibility. This change gear
setup stuff is new to me, I have a quick change. The setup is for
cutting an odd acme thread for a dividing device. I'll dig out the
instructions and get back to you. Pete (1519) |
| The setup is for
cutting an odd acme thread for a dividing device. I'll dig out the
instructions and get back to you. Sounds like you should also tell
us the pitch you want to cut and any gears you already have that can
be used in the setup. Anthony (1520) |
| Anthony: I
want to cut a worm to match a 16dp 76 tooth wheel, I have a 9"SB
with a quick change. Here is the instruction I spoke about. Any
other Ideas would be appreciated. From " Using The Small Lathe" by
L.C. Mason, Model and Allied Publications . 7th printing 1980, page
98 "Suppose you want to cut a worm to mesh with a 16 dp gear; a
wheel 1in diameter will have 16 teeth. Imagine the 1in. disc with a
line across its diameter marked of into 16. The marks will be 1/16
in apart. Now the circumference of the disc measures pi times the
diameter. ie., 1in x 22/7. So that it follows that if we divide the
edge of the disc in 16, the distance between the marks will be 22/7
times the distance between those across the diameter. From that we
can now say that the distance between our 16 teeth will be 1/16 x
22/7 in. Now suppose we set up the lathe to cut 16 tpi. To get the
correct pitch for the worm , we need to multiply that pitch by pi or
22/7. If we treat that 22/7 as a wheel ratio required in the change
wheels, we could call it 220/70 or 110/35. Now we are getting
somewhere! Few lathes have a 110 wheel , and its a hefty beast
anyway, so lets fiddle a bit and make it half that - 55/35 There's a
convenient pair of wheels, but as th 55 is the driver, we've only
got half the ratio that we need. So we compensate elsewhere by
setting up the wheels to cut 8 tpi instead of 16. Half the required
leadscrew speed at half the pitch comes to the same thing. So
there's the rule for cutting worms to match wheels; set up to
screwcut half the nominal dp number of the wheel and introduce a
55/35 pair of wheels somewhere in the train. Accurate for the most
awkward circular pitch dimension, yet you need to do no calculations
at all". Pete (1521) |
| Firstly, a 76/1
ratio is a bad choice. Usual choices would be 40, 60, 72, 80, or 90
to 1. If you have any of these gears you could use the same
procedure. If you're simply working without enough information,
explain to us the purpose of your indexing mechanism. On the other
hand, if 76/1 has a special value for the indexing you need to
perform, that's okay too. From " Using The Small Lathe" by L.C.
Mason, Model and Allied Publications . 7th printing 1980, page 98
--- You need to understand that this is a British publication. As
it's quite common for British hobbyist lathes to use change gears
"by 5s" most of their published gear trains use this convention. In
most cases (not all) if you multiply their gears by 0.8 you can
substitute those values in the gear train which are more applicable
to American (read North American) equipment which usually uses
change gears "by 4s". Converting Diametral Pitch to TPI by
*dividing* by Pi is the exactly correct method. 22/7, as proposed by
Mason is reasonable for this purpose on an amateur basis ( [22/7] /
Pi = 1.000402499--- ). His suggestion of using 44/28 (was 55/35) and
engaging 8 TPI on the QC Box is also correct but you'll need to no
where to mount the gears. As I don't know the original gear train on
your lathe I will do my best to clarify the situation. If your
original setup has a stud gear "X". an idler gear "I" (often 80),
and a screw gear "Y", set up the following: X | 44--28 | Y----8 TPI
on gear box This should result in 5.09090909---- TPI. Correct for 16
DP is 5.092958179--- TPI. If for any reason the above isn't
practical for you tell us something about your limitations or other
parameters. Anthony
(1528) |
| Anthony, the dividing device that I an
proposing to build is a version of the one designed to attach to the
headstock of a Myford lathe. My lathe (9"SB) has a bull gear with 76
teeth, and I have been pondering the practicality of using such on
my lathe. I realize that 76 teeth will not give many direct
divisions, but with an appropriate division plate more should be
possible. I have also toyed with the idea of making an attachment to
fit on the outboard end of the spindle, incorporating the 40 tooth
stud gear (which is included with the lathe, but only used to cut
coarse threads) As you suggest this give better ratios, and it would
perhaps be able to use existing (surplus) division plates. I believe
that the change gears for the SB lathe are 18dp, would the method we
are discussing work in cutting a worm to match this gear by setting
up the gearbox for 9 tpi? What do you think? is a device like this
practical? Pete(1530) |
| 15, 16, 17, 18,
19, 20, 21, 23, 27, 29, 31, 33, 37, 39, 41, 43, 37, 49. Cincinnati:
24, 25, 28, 30, 34, 37, 38, 39, 41, 42, 43, 46, 47, 49, 51, 53, 54,
57, 58, 59, 62, 66. Cincinnati also offered a set of High Number
Index Plates, with numbers going up to 199 holes. If you want I can
cite those numbers as well, but I think if you start out with the B
S numbers you'll have a very good start on your indexing needs. Hope
this is useful, maybe even interesting to some of the others in the
group. Anthony
(1535) |
| Of gears and
such |
| I've finished my
research. We don't know if this is coarse-tooth or fine-pitch for
starts. I'm assuming it is coarse-pitch, 14.5-degree pressure angle
just because of the age of the lathe. The 20-degree-pressure-angle
gear standards I think were developed AFTER 1937 when my dinosaur
was built. Working from Machinery's Handbook, 25th Ed, p.1922: Do =
outside diameter D = pitch diameter N = number of teeth pi = 3.1416
p = circular pitch [distance from one tooth to the same point on the
next tooth] P = diametral pitch [the number we're interested in] PA
= pressure angle Formulas given for full-depth teeth: Do = [(N + 2)
* p]/pi p = (pi * D)/N P = (pi)/p My 32-tooth stud gear measures
1.990 Do and 1.657 root diameter [diameter measured across bottom of
between-teeth grooves]. Let us assume for the moment a D of 1.780
[eyeballed with a vernier over the wear points on two opposite
teeth]. It would follow that for this gear: p=(pi * 1.780)/32 which
equals .153 so that P=3.14/p which equals (3.1416/.153) or 20.43
This is a 20-pitch gear. I measure the bore at .563[9/16] The
McMaster-Carr website catalog, p.892, lists their p/n 6325K83,
semi-finished 3/8 bore for $9.68. To save $58 over SBL's price I'll
risk the $10. Will let the list know when I get it.
(2730) |
| Lurch, I have
some formulas in my machining books. But I think something is wrong
in your figures. The Outside Diameter (OD) of a gear is equal to the
Number of teeth (N) + 2 divided by the Diametral Pitch (DP); or in
formula form: OD = (N + 2) / DP By using this formula and a little
algebra, it can be shown that: DP = (N + 2) / OD Now using your
dimensions, a 32 tooth gear that has an OD = 1.990 should be: DP =
(32 + 2)/ 1.990 = 17.054. And a 32 tooth gear with a Diametral
Pitch of 20 should have an OD of: OD = (32 + 2) / 20 = 1.7 inches
And a 32 tooth gear with a Diametral Pitch of 17 should have an OD
of: OD = (32 + 2) / 17 = 2.0 inches And this is very close to the
diameter of the 32 tooth gear you described in your post. Anyway, I
would double check your math and formulas.
Webb
(2733) |
| Two things: 1]
I typo'ed right from the git-go and didn't catch
it. the OD is 1.890, not 1.990 2] Your formulas
are for full-depth teeth. According to Machinery's Handbook, for
American Standard Stub Teeth the formulas are: OD = (N + 1.6) / DP
hence DP = (N + 1.6) / OD or (N + 2) / OD DP = (32 + 1.6) / 1.890 or
(32 + 2) / 1.890 DP = (33.6)/1.890 or (34)/1.890 DP = 16.88 or 17.98
Thanks for the heads-up. The numbers work out a lot closer for 18-DP
full-depth teeth than for 16-DP stub teeth. I thought I had found
the hot cheap deal there. Measuring the chordal thickness at the
pitch line [actually the wear line] measures out to .089 which is
very close to the .0872 listed on p.1941 for a 18-DP
gear...comparing the gear to the pix in the book on p.1923 I'm
inclined to believe these are 14.5-deg PA teeth...crap! OK, let me
try this again with a 16t gear, OD=.994 DP=[16+2]/.995 or 18/.995 or
18.09 And with a 40t gear, OD=2.333 DP=42/2.333 or 18.00 I stand
corrected, sir...and my sincere thanks to you. Never should have
ditched my 10-year-old $2 plasticium vernier for a dial caliper. An
18-DP gear. Well, I am off on a quest to find a vendor for same for
under sixty bucks. If anyone else knows anything more, I'd love to
hear it...feeling a bit lost and confused at the moment. (2734) |
|
http://www.ohiogear.com/spur.html
has charts for every common size of gear including outside diameter.
a 20-DP, 40t gear is 2.100 OD and a 16-DP 40t is 2.625 OD per these
charts. My 40t gear off my 9" is 2.33 OD which falls right in the
middle. Webb was right. 18DP apparently is NOT a common size.
Checked many vendors, they all stock 16 and 20 but not 18.
(2735) |
| I have uploaded a
pic of a 9" "A" headstock clearly showing the 'reverse gear' to *picture no longer available* it looks like the same 24t
gear as on a "C", anyone with better eyes see it different? which
I
HOPE only leaves the 20t, 18DP stud gear as an issue in the "C" to
"A" conversion for some of us.
(2737) |
| After all the
screwing around and calls to a multitude of vendors with bad
attitudes about small runs of non-standard parts, I bought the 18DP
gear tooth cutter today for twenty bucks and change. I'll make a 20T
gear by putting the blank on a shaft in v-blocks with my 40T gear
and indexing every-other-tooth on the 40. (2744) |
| Well, now that I
went ahead and ordered the cutter, it looks like I may have a
reasonable-price source for the 20t stud gear. [isn't that how it
usually goes?] Waiting on a quote. I may have to go in quantity to
get the price. Anyone else who might be interested, drop me an
email. Lurch (2745) |
| SB 9" gear
spec.s? |
| Anyone know the
pressure angle associated with the gears in the SB 9" gear train?
(3307) |
| All the 9"
SB lathes I have had used 18 DP, 14-1/2 PA. Walt (3312) |
| Change gears
|
| Would like to know
if anyone knows the tooth pitch on a 9 inch south bend model c
change gears.
(3316) |
| My South
Bend a is 16 diametral pitch. If you are not sure, divide the pitch
diameter( midway point where the teeth of two gears mesh) into the
number of teeth. i.e.- a 56 tooth gear divided by It's diameter of 3.5
inches equals 16.
(3317) |
| If you look
back through previous posts, there was quite a thread on this topic
about a month and a half ago where it was finally concluded these
are 18DP full-tooth-depth gears...included early in the thread are
my original miscalculations which led me to believe they're 16DP
stub-tooth. (3322) |
| Mine are 18,
this is a 1939 Workshop C. The 60 tooth has a PD of 3.332 (found by
taking the minor diameter + (major_diameter - minor_diameter)), so
using 60/3.332 you get 18.007. Close enough to 18 for me, a PD of
3.333 would be perfect, but I was using calipers on old gears. If
there wasn't a thou of combined wear and error due to original gear
making tolerances, caliper accuracy + quick and dirty method used, it
would be unbelievable. In truth, I'm shocked the results came out so
darn close! I'm not sure if these gears are 14 1/2 or 20 PA though,
I'll have to take a closer look and some measurements later.
Stan (3324) |
| I have a set
of gear pitch gages for both 14-1/2 and 20 PA. The South Bend 9"
lathes I have had the 18 DP and 14-1/2 PA fits. The 20 does not. Walt
(3329) |
| I think my
lathe might predate the 20PA standard anyway. (3331) |
| 20t gears |
The best quote I
have so far for 20t, 18DP gears for the 9-inch C-to-A conversion, in
quantity of 10 or more, is $24 apiece. Seriously now, how much
interest is there in terms of people willing to hard-commit [i.e.
"put money up"] to buying one?
(3636) |
| It was my
understanding the SBL 9" gears are 16DP, from both prior postings on
this group and from info I received from Scott Logan. Do I have bad
info, or is your 18DP spec. a misprint? My concern is I'm getting
ready to cut my metric compound adapter gear and don't want to screw
up. Also, have you checked Boston gear? Or with Dave Sobel? (3639) |
| The numbers
calculate out very close for stub gear teeth...but if you run the
formulae in machinery's handbook for full-depth teeth it's pretty
conclusive they're 18dp. there was a major thread on this a couple
months ago that went up and down and all around. since it was my
original miscalculations that led to the misconclusion they're
16DP...:-) hell, if they WERE 16DP they're about a $6 item from any
of a number of sources. (3644) |
| I've measured
several on my 1939 Workshop C, they all work out to 18DP. Stan (3656) |
| How to run my
SB without the change gears |
| I have a 13"
Southbend that was shipped out of Southbend's factory on December
18th 1918. There are two gears that engage the spindle to drive the
back gears when wanted. However the gear on the spindle closest to
the chuck has a square nut on it and it is in a slotted hole so it
can be tightened up or down closer to the spindle. The pulley
closest to the chuck has a small slotted screw in it. Do these
relate? Is this square nut the key to running the lathe without the
back gears or is there something I'm missing. I have tried to loosen
the square nut and move in up as high as I could get it. It acted
like it wanted to engage the spindle but kept slipping. JKM
(4429) |
| There should be a
pin you pull to allow you to slide the metal block up into a mating
notch inside the cone pulley. You may be able to slowly turn the
cone pulley while pressing upwards (outwards might be a better
term). When the slot comes around, the block should slide into the
slot/notch, locking the cone pulley to the large gear, hence to the
spindle. Stan (4431) |
| I also have a
13" SB, with a quick-change gearbox, made c.1922, serial # 27052,
with the same method of engaging or disengaging the backgears (and
it can be a proper pain to get it to work !!) There is a slot in the
bullgear (the gear around the chuck, in which the square-headed bolt
can be extended outwards and then locked to engage backgear drive.
By placing the lathe in neutral and rotating the chuck by hand, you
can find this correct alignment position. (I marked on the face of
the bullgear with a spot of layout blue and then scribed a line to
make it easier to find this alignment position, but it still is a
bit of a chore. I believe in later models that SB went to a type of
spring-loading for the back end of the square-headed bolt ? Can
anyone confirm this and/or comment about this evolution in SB lathe
design ?) When I want to engage backgear, I place the lathe in
neutral, rotate the bullgear by hand, by pulling the leather belt,
until it is lined up in about the 9:00 position (closest towards you
when looking towards the headstock, and continue to rotate slowly
until the two shafts come into alignment; the shafts move at
different rpm's when operating so will come into alignment within
about 3 or 4 rotations of the shaft. When this slot is lined up, the
square-headed bolt can be moved outwards, towards you and bolted
tight. To disengage the backgear, I loosen the bolt and rotate by
pulling the leather belt until the bolt is in the 12:00 position and
the bolt should drop down due to gravity, placing the lathe back in
direct-drive. Lock the bolt and you should be back into direct-drive
mode. The book 'How to Run a Lathe' originally published by South
Bend and available as a reprint from Lindsay Publishing
http://www.lindsaybks.com/
is a very helpful book on SB lathes but of equal value for other
makes of lathes as well. Barry(4434) |
| 16 pitch gears
on SB 9 |
| Tom suggests 16
pitch gears in place of the 18 pitch standard gears. Since I had the
gear cutters for 16 PD 14-1/2 PA I thought I would make a set of
metric change gears to add to my QC box. I laid them out on paper to
fit the the gear end and found them to be very large and difficult to
fit. About that time I came onto a good supply of 20 PD 14-1/2 PA
Boston Gear mfg in sizes 20 to 120 teeth. They are smaller and fit
easily but I was concerned about the strength and found them to be
about 75% of the 18 PDs. Since I don't stress my machine I decided
to go ahead and make the only gear I did not have, the 127 T, I got
a blank and a cutter to make it. An interesting thing I found about
the same time in looking at a design of an alternate reverse gears
that used 3 gears instead of the usual 2, but reduced the gear load
by a factor of 6. In pursuing this design I measured my SB 9 reverse
gears and wonder of wonders they are 20 PD. So if the old saying of
a chain is only as strong as its weakest link 20 PDs should be fine.
Walt
(5055) |
| If you want to save
space you could make or buy 37 and 47 tooth gears (instead of 100
and 127 )as they will be within 2 tenths per thread For metric gears
probably close enough for all but the most exacting applications.
Tom (5056) |
| Reverse gear |
| I found about the
same time in looking at a design of an alternate reverse gears that
used 3 gears instead of the usual 2, but reduced the gear load by a
factor of 6. Details?? Is this a design with a 2-gear train for
forward and a separate 3-gear train for reverse, selecting between
the two trains with dogs, or is this something else. Anthony
(5068) |
| This is
a 3 gear forward and reverse. I have on my computer the article that
explains it but don't know how to copy it here. Send me an e-mail
and I will send it as an attachment in the return part. Walt (5121) |
| Pitch and
pressure angle of gears |
| I took the cover
off the gears on my SB 11" lathe last night to give them a cleaning.
I discovered that the 66 tooth gear on the slide-in-out shifting
shaft is missing a tooth, or actually 2/3 of a tooth. I called
LeBlond and they were pretty useless. They said that they don't
have anything for the 11", I asked if the 13" takes a 66 tooth gear
that she could give me the specs on (she couldn't). So now I'm going
to try to find a new gear from Boston or McMaster. Does anyone know
the pitch and pressure angle for the SB gears so I can try to find a
replacement? c (6495) |
| The
later, heavy 10" use 16 DP, 14 1/2 degree PA gears. It is my
understanding that the early lathes (before the 9" workshop series)
used the same DP and PA. The 9" workshop lathes used 18 DP, which
are harder to get these days, at least new. BTW, Boston Gear does
not list a 66 tooth, 16 DP, 14.5 degree PA gear in the spur gear
category, but they do have it as a change gear. This means you will
need to adapt the 3/4" ID, double-keyed center arrangement to
whatever your lathe requires, but this is a reasonable project to do
on your lathe. You can double check the DP by measuring the OD of
the gear. A 66 tooth, 16 DP gear should be 4.25" in diameter, or
very close. I am not aware that SB used anything but 14.5 PA on any
of the lathes at least through the '50s and '60s, so if the DP
checks I think you are relatively safe with buying the gear. Frank
(6499) |
| Frank, This
afternoon I started searching the archive since I hadn't gotten any
responses. I saw your posts about the metric conversion gears and
was going to drop you an email since you seem to know SB gears.
Looks like I was right, and you beat me to it ;) Thanks for the
info. As an aside, I saw in one of your posts that you're in Redbank,
NJ. That's where I was born. If you've ever noticed Ben's car wash
on Hwy 35 in Middletown, Ben was my grandfather. I used to live in
the house to the left of the building 1970-1975. Assuming, of
course, that it's still there. c (6500) |
| Corey I hope
the information helps. Actually I live in Middletown, with a Red
Bank mailing address. We are off Nutswamp road near where it crosses
the Navy road (near Middletown South High School, it that was there
when you were living here). I think the school was built right
around 1975 (which is when we bought the house). There is a car wash
just south of Oak Hill/Chapel Hill Road, but I don't remember if
that is (or was) Ben's. I think there is also another car wash on Rt
35, North of King's Highway/Harmony Road. I also don't remember the
name of that one. Frank
(6501) |
| I don't know
the roads around there, but the house address was 410 Hwy 35 and the
carwash was next-door, there was a Krauser's on the corner, moved
out when I was 5... Anyway, back to business. I'm trying to get the
sliding-gear stud off. I removed the nut on the back of the stud,
but I can't get the stud out. I built a tool which is a steel plate
with a .875 hole in it to capture the end of the stud. It has a hole
drilled at a 65 deg angle so that a dowel can pass through it and
engage the diagonal hole in the end of the stud. So far no joy. I'm
attaching pics of the gear stud, and my home-made tool. In the pic
of the gear you can see the broken 66 tooth gear. Suggestions for
getting the stud out are appreciated. C (6503) |
| Cory: Have
you thought about repairing the gear rather than replacing it. I
would think that some gear bronze would hold forever no more load
than is required. I could probably even be repaired with some SS
wire and JB Weld. Randy (6504) |
| Corey,
Other folks have been able to give you the specifics of the gears,
not having an 11 inch I didn't want to post on a guess. Do you have
a mill or drill press and access to an welding torch? I've fixed
gears by milling a slot at the root of the broken tooth and silver
soldering in a new tooth made from a bit of scrap cast iron. In some
cases I've pressed pins into holes drilled in the broken root, built
up the area with brazing, and flycut the tooth profile using a form
tool ground as needed. It sounds tricky, but is actually quite
simple to do. I procrastinated a long time before doing it the first
time, then wondered why I'd been so nervous once it was done. Stan (6505) |
| Frank Are you
sure about the DP for the 9" workshop lathes? I measured my spindle
gear as 1.3" and 24 teeth. This works out to a DP fo 20. This
is a commonly available type of gear. My lathe is missing all the
other gears so I couldn't check other size gears. I can't comment on
the PA but the teeth look almost square. Does this correlate to a
lower PA? I'll soon be collecting gears so I too would like to know
the correct specs. John
(6511) |
| You guys are
both right about 20 PD and 18 PD gears on the SB 9". Just recently
much to my surprize I found the spindle and reverse gears are 20 DP
, but the change gears are all 18DP 14-1/2 PA'. Walt (6516) |
| By the way,
the same story is true on the Heavy 10. The actual gear chain from
the stud gear down is 16 DP, but the gear on the spindle and the
reversing gears (as well as the gear they drive on the same shaft as
the stud gear) are 18 DP. Frank (6608) |
| Gears |
| I got a bunch
of gears with a lathe I bought. I am trying to piece together a full
set of change gears. At the moment I have doubles of 32T (I know it
needs two gears, I have 4). I have two gears of 52T, 56T, 60T and
80T. The numbers on the 80T match the Change gear numbers. I am
short 44T, 48T and 54T. I might also need 24T. The one I have is a
bit thick. Anybody have duplicates and wants to trade? I also have a
couple of gears not listed. I think they are the metric change
gears. NO they are not for sale. I have 116T, 64T and 72T. I also
have a couple of gears with the marks L42 and L19. I haven't found a
listing for them, but really haven't looked through all the SB
literature. Tom (7138) |
| I'm betting the 116
is half a 6:1 compound set maybe? (7142) |
| Tom I do not
remember who the seller was, but on ebay right now, there is a guy
selling a bunch of change gears. Clint (7148) |
| Clint, I saw
them. They are a bit pricey. I am trying to get a whole set to sell.
Tom (7150) |
| PKE Inc [eBay
ID pswelzen (at) aol.com] has a warehouse full of SBL stuff he's
trying to move. His initial asking prices on the Bay are a bit
steep, but in dealing with him face-to-face I have found him to be
quite reasonable. I was over there today and saw banks of shelves
full of 9 and 10K parts.
(7152) |
| Lathe gear |
| I realize this is the Southbend group and
this pertains to a Sheldon but there s a lots of expertise here and
I feel that the info would be brand generic. I have damaged fiber
straight cut gear on my 13 Sheldon lathe. It is between the spindle
the quick-change gearbox; near as I can measure is 3.137 outside
diameter, and 2.825 diameter between the valleys 180ø across the
gear. Sheldon says they do not stock gears for the old lathes like
this one ( 60 s vintage) but have them custom made; a lead time of 4
weeks and something over $200! MSC lists 2 gears with very close to
the same dimensions; one is metal and one is nylon. The diameter
across the valleys on the MSC gears is 3 ; looks real close to me.
There are 3 gears mounted in a sort of triangle so the center one
can be adjusted for accommodating different diameter gears so the
increased diameter is no problem. What I need to know is if yall
think these will mesh correctly and whether I should get the metal
or nylon one. Price difference between the 2 is insignificant (both
at around 30 bucks). The MSC part numbers are 00230706 and 01786797
if you need any further details. Lew (7303) |
| I think
that as long as the amount of teeth is the same and the mounting
hole is correct, I would say go for it. Clint (7304) |
| Let me
add to my last post, if you are a little unsure, then get the nylon
gear, if they do not mess good, the nylon gear should be the one
with any damage done. If it works out well then later you could
order the metal one if you choose to do so. Clint (7305) |
| It don't any
make any difference if the number of teeth is the same or not if it
is an idler gear, as long as the pitch and pressure angle are the
same. One tooth movement on the spindle produces one tooth movement
on the gear box no matter what the idler is. This works only for the
idler or intermediate not the spindle or gear box. tom (7306) |
| The important
thing is whether or not the replacement is the same pitch and
pressure angle. Given the age of the lathe I would guess it unlikely
they would be 20-degree pressure angle. One formula for pitch is
P=[n + 2]/OD where n is the number of teeth and OD is outside
diameter for full-depth teeth. For stub teeth replace the 2 with a
1.6. All these formulas are in Machinery's Handbook [p.1922 n the
25th Edition, p.2204 in the 26th Edition]. When I went through all
this algebra with calculating the pitch on the change gears for a
9-inch South Bend, I found without knowing the number of teeth it
left me with equations with 2 variables. (7312) |
| Lew You
didn't mention the number of teeth. While as Tom says, the number of
teeth on an idler gear (a common term for the center gear in the
triangular configuration you mentioned) doesn't matter directly, the
ratio of the OD of the idler gear and the number of teeth tells you
about the size of the gear teeth, which does matter a lot. If the
gear in the catalog has the same number of teeth but a different OD
it won't work. The tooth size is different. If you can tell us the
number of teeth, and you already gave us the OD over the teeth, we
can find the diametrical pitch (DP), which is how gear tooth sizes
are stated. If you want to do it yourself, divide the number of
teeth + 2 by the OD in inches. The quotient should be very near 16,
18 or possibly 20, and that is the DP. If you get 17.9, you have an
18 DP gear, and likewise for other close values. Gear DPs don't come
in odd values. The other issue you need to work is the pressure
angle (PA), and unfortunately there is not an easy home method to
measure this. The only easy way I know of is to mesh the gear in
question with a gear of known PA, and see if it fits nicely (i.e. if
the teeth intermesh completely). There are two common PAs, 14 1/2
Deg. and 20 Deg. If the lathe is old it is quite likely that the PA
is 14.5 Deg. All of the "traditional" SB lathes use 14 1/2 Deg. PA
gears (of various DPs). If your Sheldon lathe is old I expect that
buying a 14 1/2 Deg. PA gear is a reasonable bet. The MSC catalog
should specify the DP and PA of the gears you are considering. I
expect either the nylon or the metal gear to be adequate. I expect
Sheldon used fiber as both a cost saving and to make things quieter.
SBs use all metal gears, so that should also work for you, and
perhaps last longer than nylon. However, you are likely not to use
the lathe enough in a hobby application to wear out a nylon one. On
the hub details (like the bore size at the center), I would buy
whatever you can find with the right DP and PA and close to the
right number of teeth, and adapt the center to fit. That is why you
have a lathe... If it turns out that what you have is something odd
which MSC doesn't sell, (like 18 DP), also tell us the thickness of
the gear. We may be able to point you to a SB gear which would fit,
perhaps with some hub machining. If all else fails there are used
lathe parts suppliers around like Sobel's who might well have the
right Sheldon gear, are generally knowledgeable, and honest. Frank
(7313) |
| Sorry I didn't mention the number of teeth; it s a 36 tooth gear. I
started reading the stuff in machinery s handbook and the math and
terminology lost me PRONTO! Just looked to me like there was a good
possibility that with the diameters being so close that my old one
might have that much wear and comparing the teeth to wagon spokes
with only .175 inch difference in the valley diameter this would
make a VERY miniscule difference in the distance between teeth. My
math is terrible; more see how it looks . Figured if you guys think
it would work I d try it; turn it by hand; and if it didn't mesh
properly all I d be out would be the time making a bushing (I think
the new gear only comes with a 1 bore; haven t removed the old one
measured the shaft yet but it looks like about 3/8 or «) and postage
as I think I could return it if it didn't work. Lew (7314) |
| 36 tooth,
3.137 OD, the DP = [38/3.137] = 12.11DP. 36 tooth, 12DP, 14.5 degree
PA, 5/8" bore--McMaster-Carr p/n 6325K1 price $26.04.
www.mcmaster.com It's an idler gear, it don't need a keyway, a plain
bushing will work. (7316) |
| Lew Those are
really big gears! The smaller SB lathes use either 16 or 18 DP
gears, and yours are 12 DP (i.e. much bigger teeth). Of course you
didn't tell us how big the lathe is, and 12 DP may be more common on
a large lathe. The 3" diameter mentioned in the MSC catalog is the
pitch diameter, which is between the OD and the diameter at the
bottom of the teeth. For a 12 DP gear the "peak" OD should be 3" +
2*(1/12) =3.167" and the "valley" OD should be 3"-2*(1/12), or
2.833", both of which are reasonably close to what you measured, so
that looks like 12 DP is what you have. Both of the gears in the MSC
catalog are 14 1/2 DP, so either one has a good chance of working
(with a suitable hub adapter). If you try either of the MSC gears, I
expect you won't need to make the hub adapter to see if the gear you
get is right. Just hold it in mesh with either the stud gear at the
top or the gear going to the lead screw. If the teeth mesh
completely and smoothly it should work. Frank (7317) |
| For stub
teeth: 36 tooth, 3.137 OD, DP= [37.6/3.137] = 11.99. The
calculations below are for full-depth teeth. I don't know if stub-
and full-depth teeth can mesh or not. (7318) |
| Lew, First
question, is a 36 tooth 12 DP 14.5 deg. PA gear what you're looking
for? I see that the two gears you've cited are both 3/4" width but
the nylon one has a 1/2" bore and no keyway while the steel one has
a 1" bore and two 1/4" keyways. Clearly the steel one is intended to
be a change gear, the other one might do but it's much less clear.
So you have to consider, is the tooth count (36), tooth size (12
DP), pressure angle (14.5), face width (3/4"), bore and hub
characteristics, and material correct for your application? Hope the
above questions are helpful to your decision. Anthony (7335) |
| kerfoot@c... writes: Gear DPs
don't come in odd values. That's not quite true. While it won't apply
in this case gears can be specified in diametral pitch, inch module,
inch circular pitch, metric module, metric circular pitch, and
probably a few others I'm not thinking of at the moment. A given
tooth size can be specified in any of these standards and will give
a different numerical value depending on which system you're using.
For instance, an 18 DP gear, which most of the people on this list
will be familiar with, could also be specified as having a circular
pitch of .1745" or as .0555" module, or as 1.4111 metric module or
as 4.4331 metric circular pitch. It will usually be fairly self
evident which value is appropriate but it's wise not to make snap
judgments. Anthony
(7336) |
| Anthony This is
where I m in the dark. The DP PA mean nothing to me. Like I said, I
looked the stuff up in machinery s handbook about gears and they
were throwing the math terms that totally confused me. I d guess
that the shaft is probably « but haven t removed the gear to see. I
m relatively sure it s mounted on a shoulder bolt; know it s an
idler so has no reason for a key. Figured as long as it s big enough
turning (or finding) a bushing is no problem. Probably the best
thing for me to do is to try to remove the gear tomorrow (Mondays
are usually killer days at our Laundromats) and post some pix of the
gear. There s plenty of room to post them on the Sheldonlathe group.
I'll let you know when they re posted. Lew (7355) |
| Simply put,
DP [diametral pitch] is big-teeth-or-little-teeth [tall or short],
the bigger the number the finer the teeth, the smaller the number
the coarser the teeth. PA is narrow pointy teeth or chunky blocky
teeth. (7357) |
| The
teeth are definitely flattened on the ends; not pointed. The ones on
the gear (at least one gear; didn't look closely at both) look much
more pointed, but the lathe is roughly 40 years old so this could be
wear? Lew (7359) |
| Yep. (7360) |
| I finally got the pix posted of the damaged
gear. Had to deliver a machine I sold (2k miles round trip) since I
started messing with this! The pix are on the Sheldonlathe list in
the photo section in folder lathe gear-lew as it has lots of space
available for pix. I was wrong about it being an idler; it s a drive
gear. Guess I was just trying to remember too much instead of making
notes. Dimensions are on the pix but may not be easily readable.
They are as follows: 3.153 outside diameter; 2.823 diameter at
valleys between the teeth; .255 between 2 teeth (measured at tooth
crowns); .75 bore; .125 keyway. The gear is .5 thick but there s
plenty of room for a thicker gear without any interference with
anything. Sorry the pix aren't better but my digital camera doesn't
like to do close-ups! Any help in determining what stock gear to
order DEEPLY appreciated! Lew (7578) |
| Lew, I'll get to
this tomorrow. I have to go to the MSC site again and I'm getting
tired. Anthony
(7594) |
LEW writes: I was wrong
about it being an idler; its a drive gear. Guess I
was just trying to remember too much instead of making notes.
Dimensions are on the pix but may not be easily readable. They are
as follows: 3.153 outside diameter; 2.823 diameter at
valleys between the teeth;
.255 between 2 teeth (measured at tooth crowns);
.75 bore; .125 keyway. The gear is
.5 thick but there's plenty of room for
a thicker gear without any interference with anything. Okay Lew,
before I give you the run down on your proposed gears let me suggest
that you check out Boston Gear and Browning for change gears. In a
*quick* web search I didn't find anything useful but if you go to a
local bearing supply house they should be able to give you
reasonable information regarding availability, price, and delivery
times. As you've realized that the gear is actually a change gear
you *should* replace it with a part that matches as closely as
possible. In your case this means: DP (Diametral Pitch) = 12 PA
(Pressure Angle) Probably 14.5 degrees, barely possible 20 degrees.
This is an important spec, you can't mesh one angle with a different
angle. As I presume the Sheldon is fairly old the 14.5 is very
likely. Teeth = 36 Face Width = 1/2" You say that there is plenty of
room for a wider gear but if you might ever want to compound gears
at the idler position it really needs to match the other gears in
the system. (You can always machine a wider gear down to the same
width.) Bore = 3/4" and Keyway = 1/4" Same considerations here
regarding interchangeability with the other change gears. The bore
and keyways need to match a bushing that serves as a bearing on the
stud that it turns on and also to couple two parallel gears on the
same stud for compound gear trains, that's what the keyways are for.
Regarding the MSC gears you were considering: MSC #00230706 Nylon
Probably OK 12 DP Correct 14.5 PA Probably correct 36 Teeth Correct
3/4" Face Width Possibly usable as is, possible to reduce width to
1/2" (nylon is reputed to be difficult to machine). 1/2" Bore
Possible to rebore (same warning about machining nylon). No Keyways
Possible to cut (same warning). MSC #01786797 Steel Probably ideal.
12 DP Correct 14.5 PA Probably correct (see above). 36 Teeth Correct
3/4" Face Width Possibly usable as is, possible to reduce width to
1/2". 1" Bore Over size. Possible to sleeve but would probably
require overbore and insert to accomplish the job (not
unreasonable). 1/4" Keyway Oversize. If overbored and provided with
an insert the bore and keyways would have to be remachined anyway
(not unreasonable). So your choices are based on how much adapting
you think you can do and are prepared to try. I suggest looking
first at Browning and Boston Gear as possible sources for a direct
replacement that doesn't need remachining. It also occurs to me, I
seem to recall that somebody who frequents the Atlas_Craftsman list
claimed to be able to cut any gear you wanted. You might post a
request there for leads. Or is there anybody on this list that might
be able to help, either with a direct replacement for the gear Lew
is looking for, or able to cut one for him, or know of anybody to
refer him to? Anthony
(7620) |
| Anthony
Thank you VERY MUCH for your research! I believe the metal gear will
be the way to go unless I can find the correct gear. It s kind of
crazy the way this lathe is set up; I'll take some pix of the setup
tomorrow as I sprung for a new digital camera (couldn't resist the
after thanksgiving sale) that will take close-ups. As to age this
lathe is mid 60 s vintage; a 13 gearhead; also pictured in my folder
on the Sheldon list. The way this lathe is set up there is a gear on
the spindle that drives a double gear meshing with the larger gear
(more teeth than this one) and this is the smaller one of that
cluster of two gears. This smaller gear meshes with a large gear
that would be the idler gear that s on the adjustable mount for a
gear trio if you had to change the individual gears instead of
having a quick-change. The bottom gear of this trio drives the
quick-change or would drive the leadscrew if the quick-change were
not present. The ? width would not cause a problem; worst case
scenario would be if I had to machine down the hub thickness because
the nut wouldn't go on. If it is too hard I have a surface/T C
grinder and also a toolpost grinder that should accomplish that.
Figured I could press fit a bushing into the gear and cut the
keyways with my shaper. I'll check with Boston and Browning to see
what they have. Lew (7622) |
| Lew. Hope
you can get the lathe fixed and going again. Bill
(7624) |
| UPDATE
Emailed Boston Gear; their ND36A would need (seemingly) only minor
modifications that look simple if done before the gear was hardened.
Asked the possibility of getting one with them doing the
modifications. Lew (7625) |
| Bill
The lathe still works but the partially broken tooth worries me
since it s a fiber gear! Lew (7626) |
| Anthony A couple of more pix are in the Sheldonlathe group pix
section now; close-up is a bit blurred but if you look carefully the
damaged tooth shows. The overall shows the position of the damaged
gear; it s the clean one. Lew (7644) |
| LEW writes: A couple of
more pix are in the Sheldonlathe group pix section now; close-up is
a bit blurred but if you look carefully the damaged tooth shows. The
overall shows the position of the damaged gear; it's the "clean"
one. I down loaded your pictures, I'm attaching the overall view
here. Counting from the top I see: Spindle gear Stud Gear + First
Gear (I don't know what else to call it). Idler Gear Screw Gear (I
presume this one is the input to the gearbox). Estimating from the
photo I would say: Spindle Gear = about 40 to 44 teeth. First Gear =
same as spindle gear Stud Gear = 36 (we know this) Idler Gear =
about 60 Screw Gear = about 36 (appears to be same as the stud
gear.) Does the lathe have a reversing mechanism for the power
drive? Is it in the gearbox or somewhere else? Any chance you can
post photos of any reversing mechanism? Aside from the reverse gear,
everything looks about as I would expect. Looking at the close up
photo on the Sheldon site, it appears that with your new digital
camera you fell into the trap for new users. Many digital cameras
have optical zoom and digital zoom. Optical zoom is perfectly
logical, it's like looking at the subject with a magnifying glass, I
recommend it for close ups. Digital zoom is an entirely different
story, all it does is crop the original picture, then apparently it
expands it to occupy the picture size that would have resulted if
you hadn't zoomed in. In the process the picture becomes pixelized,
that is to say you see the individual dots instead of the smooth
flow of information of a conventional picture. In this example
you're not seeing the pixels, I presume the electronics do some
dithering to "smooth out" the picture, but in fact there is no more
graphic information than in the pre-digital-zoomed picture, it's
just spread over a larger area. And it offends the eye and confuses
the brain. Play with it a bit but I think you'll find that for
technical matters a small picture is better than a larger one
resulting from digital zoom. By the way, for the person who was
talking about internal threading tools and said: "I'd attach
pictures to show you if it was permitted." You can see here that
they are permitted on this list. Not on all lists so you have to
read the rules for each list, but they are allowed here. Anthony
Attachment: (image/jpeg) GEAR02~2.JPG [not stored]
(7668) |
| Anthony
The reverse for the entire lathe is electrical (3PH motor). The
leadscrew reversal is inside the quick-change gearbox. Would have to
remove the gearbox again to get a pic of it (it s heavy and really
miserable to align for reattaching it). That s where my problem
started; the collar had slipped that holds one of the gears in place
causing it to try to go into forward reverse at the same time and I
think this is possibly what caused this gear to break the tooth. May
not be the cause but when I was looking for the lock-up problem is when
I discovered the bad tooth on this gear. May have been that way for a
long time since as I said it still works but makes me nervous. Kinda
like riding on a tire with cord showing! As to the camera I think it
focuses mechanically (Canon Powershot A200) but that I was either too
close or the autofocus is a bit off. You hold the shutter button half
way down until it finishes focusing and then press it all the way down
to take the pic. It s supposed to focus down to 2 . Plan to play with
it a little more on close-ups before taking it back to the dealer
(fortunately a camera store owned by a family friend v an electronic
discount place) or it could be that there was a very slow shutter speed
and the blur is due to camera movement; had to shoot available light as
the flash at that close distance washed out the pix. Anyway, from what
you can see from the pix do you think our assumption was correct for
the DP PA? If so I think I'll order the metal gear from MSC as soon as
I hear from Boston Gear unless Boston has a better deal on one that s
closer to the exact gear. Lew (7673) |
| LEW writes: Anyway, from
what you can see from the pix do you think our assumption was
correct for the DP PA? If so I think I'll order the metal gear from
MSC as soon as I hear from Boston Gear unless Boston has a better
deal on one that's closer to the exact gear. DP is a mathematical
function to describe the tooth size. Teeth divide by DP = Pitch
Diameter. 36/12 = 3", this matches the values in the MSC catalog.
Teeth + 2 divided by DP = OD. 38/12 = 3.1667" which is a close match
to the value you gave (not easy to retrieve it right now). Another
way of looking at it is N + 2 divided by OD = DP so 38/ 3.15 (lets
say) = 12.063---. You'll never see a real value like that, just
round it off to 12. As far as PA is concerned, I wouldn't be able to
tell unless I had another similar gear to compare it to. 14.5 is an
educated guess based on my knowledge of machine construction
practice. If it were me I would accept the steel gear from MSC if
Boston or Browning can't supply a more exact match. Anthony
(7706) |
| Change gear
question |
| Are change gears
for the 9" and 10" lathes interchangeable? Johnny (7333) |
| Light Ten [10K]
yes. Heavy Ten [10L] I think not, I believe the heavy 10 gears are
16DP and not 18DP as with the 9 and 10K, but someone check me on
this. Lurch (7334) |
| The gear chain from
the stud gear down to the input of the QC gearbox in a SB heavy 10
uses 16 DP gears (the gear on the spindle itself and the ones it
meshes with are 18 DP, but that is likely not relevant here).
However, except for odd cases like metric conversion gears you
shouldn't need to be playing with the gear chain on a heavy 10,
since they all came with QC gear boxes, and those QC boxes had a
wide enough range of threads to cover about everything you could
want to do. To my knowledge the change gears on the 10K (aka light
10) are the same 18 DP gears as on the 9" workshop series and later
(but not the earlier 9" Junior). Frank (7340) |
| The situation
is that I have a 9" C-model with a partial set of change gears. A
friend about 350 miles from me has come across a set that are
claimed to be from a 9 or 10 inch. the owner isn't sure which. The
price is extremely attractive. I have to travel that way in a few
days anyway, so that's not an issue. Is it safe to take a few of
mine [AND a caliper] with me and assume that if they *seem* the same
they *are* the same? Johnny (7341) |
| The
difference in tooth size between 16, 18 and 20 DP gears should be
visible to the naked eye if you put them next to each other. All the
change gears for my 9-inch have "NK" in the middle of the part
number so if any of them are stamped with a p/n that will tell you
something. (7344) |
| Curiouser
curiouser.... All of mine are labeled 32K**N1, with ** being the
tooth-count. Johnny (7346) |
| The
idler gear for mine is 33NK1, the 20-, 40-, and 56-tooth "A" change
gears and the loose "C" change gears I have are 32K**NK1. All for a
9-inch Wrkshop ca. 1937, all 18DP. I wonder what the difference between
a 32K**N1 and a 32K**NK1 is? perhaps the last "K" means it was issued
for a 10K? (7350) |
| As lurchix
says, the difference will be relatively obvious. However, an even
better test is just to mesh one of your gears with one of his. Two
gears with different DP won't come close to meshing nicely. While
you are at it, double check that the thickness and bore diameter are
the same. They should be, but who knows what gears get mixed up with
what lathes. Frank (7352) |
| JC writes: The
situation is that I have a 9" C-model with a partial set of change
gears. A friend about 350 miles from me has come across a set that
are claimed to be from a 9 or 10 inch. the owner isn't sure which.
The price is extremely attractive. I have to travel that way in a
few days anyway, so that's not an issue. Is it safe to take a few of
mine [AND a caliper] with me and assume that if they *seem* the same
they *are* the same? It's almost certain that if the gears are as
represented they will fit your lathe. To be certain, take the idler
stud and idler gear off your lathe and take them with you. If the
gears that you are considering will mesh correctly with your idler
gear and if they will fit properly on the bushing that is part of
your idler stud they will fit your lathe. By doing this you will
have checked the DP, the PA, the face width, and the hub details.
Anthony (7384) |
| Thomas writes:
There is a set of change gears on E-bay: item # 1789719558. It is
not a complete set. I think it is missing the 16T gears and maybe
some others. 11 gears is what I count. Its at $12 or so right now.
Before anybody goes for these you definitely need to ask the seller
some questions. They do *not* appear to be a standard set of South
Bend change gears. The seller says "Change Gears South Bend Logan,
11 gears, 100 to 30". No info on DP, bore and keyway, specific tooth
counts. They may be by 5s instead of the usual by 4s used by US
makers. Also I'm not certain that SB and Logan use the same size
gears. A lot of questions and no answers. Anthony (7407) |
| Nope, not for a Logan.
These are marked as 3/8" face width; Logan Lathe change gears were
7/16" or 5/8" Logan change gears were 16 DP, either 5/8" or 15/16"
bore, width as above. Scott Logan (7409) |
|
Change Gears |
| Could someone tell
me exactly what comprises a "complete" set of change gears for the
9"C Southbend? I have 1 each: 60-56-54-52-48-46-44-40-36-24 tooth in
loose gears but find that to thread a back-plate for this lathe
(8TPI) I need a 32 tooth gear. Johnny (7461) |
| Actually you need 2
32 tooth gears to make that thread. If my memory serves me my machine
has two with it. The leadscrew is 8 pitch so the gear ratio is
1-1.Check the ratio of your compound gear, maybe you can use two
different gears and cancel it out with the compound gear. RC
(7462) |
| Johnny, Look
at *pictures no longer available* It has files
with picture for parts of these lathes. It looks like you are
missing : the 16T, the two 32T and the 80T gears. Are you counting
the gears that are on your lathe? There are two 80T gears. One has a
Short 'pipe' section on it. I don't know the application of it
verses the other. Tom (7463) |
| Johnny, There
is also the two compound gears: 18/54T and 18/72T. Do you have the
threading plate or index plate that shows the combination of gear
changes? Let me know, I might be able to help out. Tom (7464) |
| Johnny; On
my 1939 9C, the standard gears are: 16, 32 (two provided), 40, 44,
46, 48, 52, 54, 56, 60, 64, 72, and 80 There are two 32T gears in
the set, you use BOTH of them for 8TPI. Stan (7465) |
| JC writes: Could
someone tell me exactly what comprises a "complete" set of change
gears for the 9"C Southbend? I have 1 each:
60-56-54-52-48-46-44-40-36-24 tooth in loose gears but find that to
thread a back-plate for this lathe (8TPI) I need a 32 tooth gear.
There are two questions here. Let's first take care of the 8 TPI
question. If you set up 24 stud driving a 40 idler with a 60 also on
the idler bushing driving a 36 screw gear you'll get 8 TPI.
Regarding the "complete set" of change gears, I looked at the chart
in "How to Run a Lathe" and counted up the gears required for all
the listed pitches. What I came up with is: 16, 18, 18, 24, 32, 32,
36, 40, 44, 46, 48, 52, 54, 56, 60, 72, 80. I think one of the 18s
and the 72 may be a special double gear. Does this help? Anthony
(7474) |
| I should have
two of the 32T gears and an 80T (change gear, not idler) available.
I should have a lantern tool post available, without the rocker or
tool holders. You should be able to get the whole sha-bang new from
KBC tools though. They have an import and ones made by Armstrong.
I'll figure what I have available over the weekend. I'll be back
Tuesday. By the way, what's the use for the 70T and 64T gears?
Tom (7476) |
| Here is
what I have, including those mounted on the machine: 24 32 [in stud
position] 36 40 44 46 48 52 54 56 60 72/18 Double [lower gear on
upper banjo arm] 56/18 Double [upper gear on upper banjo arm] 80 [on
lead-screw] The lathe is a 1952 (year) 9"C My situation is that I
have an opportunity shortly to buy a "set" of gears for a very nice
price, and I am trying to be certain that along with the inevitable
duplicates I also get as many as possible of the real *necessities*.
The DP, bore and thickness are correct. Johnny (7483) |
| On my 9C you
would use a 24 tooth gear on the lead screw to cut an 8 tpi. I see
no use of a 32 toother. That is assuming a 24 tooth spindle
gear. (7486) |
| Thomas writes: By
the way, what's the use for the 70T and 64T gears? What 70 and 64? A
64 could be combined with a 32 for 2-to-1 step up or step down, I
suppose with a 48 for a 4/3 or 3/4 ratio. There are other less
useful combinations. Anthony
(7489) |
| JC writes: 56/18
Double [upper gear on upper banjo arm] Was this supposed to be
54/18, which would give a 3/1 ratio? From the list you just provided
it appears you're only missing one 16 tooth gear. No harm in buying
the set of gears but you only need the one to complete your standard
set. Anthony
(7491) |
| JC writes: 32 [in
stud position] Amendment to my last message, you're missing one 16
and *one 32*. Sorry for the confusion. Anthony
(7492) |
| qbox09 writes: On my 9C you
would use a 24 tooth gear on the lead screw to cut an 8 tpi. I see
no use of a 32 toother. That is assuming a 24 tooth spindle gear. It
sounds as if you don't have a reversing tumbler. Any possibility you
could provide a photo of the left end of your lathe showing the
gears? Anthony
(7493) |
| Anthony, that should have read 54/18. Missing the 16 a 32 tooth
change gear and the 80 tooth idler gear. Maybe I'll get luck on
these coming up. Johnny (7494) |
| Change Gears
9" |
| Can someone
tell me what the DP and pressure angle is for the change gears on a
9". Mike (8248) |
| 16dp/14.5
pressure angle if you own a junior 9" or 18dp/14.5pressure angle if
you have a workshop 9",correct me on the latter if I'm wrong. Scott. (8254) |
| Just a
friendly note to share a recent experience: I have found that there
are two different size mounting holes for change gears on 9" SB
lathes. In addition, the older (I think pre- 1930?) have a different
pressure angle that will not mesh on the post- 1934 9" stud and
reverse gears. Randy Phillipe and I discovered this when we were
changing out my headstock. Consequently, I had to have the gear end
of my leadscrew machined, and a "stepkey" made to fit the gears. If
you buy any change gears, make sure they are the right size, or ask
for return privileges. Bob (8257) |
| In my
experience all the many SB 9s znd one 10K I have had in the last 50
years had change gears with 18 DP 14-1/2 PA. But the reversing gears
including the spindle gear were 20 DP 14-1/2 PA. The same idea goes
for the Heavy Ten ( 16 DP change gears 18 DP reversing both 14-1/2
PA.) I believe the 13 does the same thing, 14 16 DPs. Walt (8272) |
| The oddball gears that I had that were different came with my lathe,
but I should mention that the headstock was different than
"standard". Neither Randy Phillippe or Clint had seen one of these
before. The oil cups were on top of the spindle bearings, which
makes it older, and there was no fitting for a forward/reverse gear
set. There was a hole milled behind the spindle (at about 8 o'clock)
for a single reverse gear with a stud, which was held in place by a
spring-loaded plunger which located in a dimple on the shaft.
Everything else was consistent with "modern" 9" SB lathes. Can
anybody identify this model? Incidentally, Randy has the headstock
and change gears now, if anyone is looking for this type of
equipment. Bob (8277) |
| Bob, you
probably have a model 405-Y,same as me. It is a 9 workshop, and was
probably built, as mine was, in 1934; its not in the Feb.1934 repro
catalogue I have and I believe now-conjecture only-that it was
dropped in 1935 when the regular C model was introduced. I'm asking
Randy at SB via email and will ask Rose at LeBlond if that is the
case based on their records. Those gears, including the odd 39, 69,
42 etc tooth ones, should stay with it, but I'll be happy to buy
them if you don't want them. The only gear I have is the compounding
gear, 27/54 teeth, which is 20dp. I'm guessing the others are same.
I think this model, which is dimensionally the same as a model C,
and is not, repeat not, a 9 Junior or Toolroom, is sort of the
hidden 9 from the dawn of time. I'd be curious how many more are out
there and how easy it would be to convert to a later and more
familiar C. If anyone has an original catalogue from late 1934 or
early 1935 I wonder if it is listed. Qbox in the group has a
complete one and helped me figure out the gearing layout (thanks
again Bob D.) Bill (8279) |
| After reading
the previous email more closely, I see that Randy Philippe has the
gears-Randy, if you want to sell them let me know. Bill (8280) |
| Bill. I
first will say, I truly don't everything about these lathes but Bob
and I scratched our heads for a while on this one. I'm glad I
brought the extra gears along with the model C that I had, or we
would have been sol right off the bat. I would have to go look to be
sure but one set was 18 dp and the others were 20 dp. Not sure which
on which, I think the older ones are the 20 and the newer ones are
18, but to make this swap work, Bob used the later model gears from
mine and the drive gear off of the lead screw had a smaller bore and
key, so he turned down his lead screw to get his machine up and
running for now. His plans are to put a A model gear box and lead
screw on his lathe and the head that we put on his is an A. Once he
gets the box and screw from the A and drills the third hole in the
bed he'll be good to go, short of changing out the carriage and the
saddle. Does the carriage lock bolt on yours mount off of the rear
gib? His does. We had shown the picture of the head to several
people that had never seen one before with the detent pin for the
reverse gear. Sound like this is what you have. I believe all of the
gears are here. Do you have a chart to know how many there are
supposed to be? Maybe Bob does. I can't keep track of it all. Too
many variances on the different machines. You can call me at
319-378-9889. This will be easier than writing, and I'll go get a
list of the ones I have from Bob's and have it ready. I also have a
complete 1925 junior and the gears are different on it too. Along
with allot of other things. Where does it end? Randy (8286) |
| Here's one to add to the record. Bob Shankhill's 9" lathe,
which we think is from around 1934, had 20 dp, 14-1/2degree pressure
angle gears, all the way. The spindle is 20 dp and the 32 tooth
reverse gear which was held by a detent rod which allows it to be
removed is also 20 dp. The turning gear which is 105 teeth has a
bore of .625 and the key way is 3/16 wide. The bore on the later
model,56 and 40 tooth gears are .562 with a 1/8 wide key. This is
why he chose to turn the lead screw shaft down. Following is a list
of the gears that was with this machine: 32 reverse gear on shaft
that is removable,
105,100/20,54/27,69,64,60,54,48,45,42,39,36,33,30,24. Where the
problem was on his machine was the fact that none of his gears would
mesh to the later 18dp gears. If we would have had a 20 tooth, 20 dp,
stud gear for the reverse lever it would have worked, but then the
problem would reverse again when he was to go to the A model gearbox
which has the 18 dp gears on the banjo. I hope this helps. I swear,
every time I turn around I find something new and different. I wonder
if anyone knows why they made so many different machines with so
many different combinations. Now, Walt is probably correct, that in
the last 50 years, this is all he has seen, and is fact. I did not
bring this information to the group for an argument, or disagreement,
but just for more info to add, to what is just some of the things
that they possibly did over there at the south bend factory.
Randy (8287) |
| Randy, I
definitely want the gears, and I might be interested in the
headstock as well. I thought that all the gears would be 20 dp like
my compounding gear, but a recent post( I can't remember who from)
says that on most models the DP is different between screw gears and
compound gears or reverse/stud gears, I can't remember the post
exactly. My carriage lock is indeed off the rear gib, and the most
noticeable feature of this model is the open webbed tailstock, which
I don't think was on any other machine of this size and is as
distinctive as the reverse gear on the headstock. The full set of
gears are 30,33,36,39,42,45,48,54,60,and 69,as you can tell some
very funky ones there compared to the typical later SB Nine. I
believe this model was catalogued after the 1934 catalog was issued
and dropped/evolved into the regular 9 Workshop by the time the 35
catalogues came out. Most people look at Tony G's awesome lathe
website from the UK which says the Nine was introduced in 1935, but
this model may have slipped under the radar screen in historical
terms. Bill (8297) |
| Bill, I'm the
one that's been talking to Randy about the chucks. I have two chucks
that will fit your lathe, but I would like to replace them so I've
got something that will fit my new headstock (1 1/2 x 8). If you
have this size chuck, are you interested in swapping? Are you
interested in buying mine. Give me a number to call and a good time,
and I'll be glad to give you a call and discuss this. Bob
(8301) |
| Bob. Could
you tell me how many change gears are there in a set for the SB9C?I
think I have a complete set but just want to be sure. Bill C.
(8302) |
| Bill,
According to Randy, there are 12. If you want to sell them, I would
be interested. If the set is complete, please shoot me a price.
Bob
(8303) |
| Bob. I'm
sorry but they are not for sale. I was just wanting to make sure I
had a full set. These are the only ones I have for my lathe. But If I
hear of any for sale I will let you know. Bill C.
(8304) |
| I forgot to
mention that of the 12 gears, there should be two 32-tooth gears as
part of the set. Bob
(8305) |
| Bob B., sorry, I
don't know what I was thinking-I realize now that you want the 1 1/2
x 8, not the 1 3/8 x 10, which I have. My chucks are serviceable and
I've already ordered new ones which will be here after the first of
the year . I would like to wait until they come, but may be
interested if that doesn't work out. Bill (8306) |
| Bob. I just went to the shop and I do have both 32 tooth
gears. Sure glad the SB came with a full set. Bill C.
(8310) |
| I believe the Model
C change gear set includes the following *13* gears: 16, 24, 32, 32,
36, 40, 44, 46, 48, 52, 54, 56, 60. (Notice the second 32.)
Additionally there is an 80 idler (no keyways) and 18/54 and 18/72
compound gears to complete the set. If somebody can verify or
correct this information it would be appreciated. Anthony
(8316) |
| My SB9
Precision Workshop of unknown vintage (6"in. between saddle bolts
instead of 7") has the following: TG=116, Change gears = 16,
20,24,32,32,40,44,46,48,52,54,56,60,64,72,80, compound 108. Not
exactly the same as yours, but PDC. John T.(8317) |
| Anthony. Just came from the shop. Checked all the gears on my SB"C", My
gears are the exact as you listed. At least I don't have to worry
about finding any replacements. Bill C.
(8320) |
| I checked my
set and it includes an 80 tooth gear as well as an 80 tooth idler.
As the gears will let me make any combination as listed on the data
plate on the end cover, it appears that I have a full set. That
would make the full set 14 keyed gears 1 idler and 2 compound gears.
I believe the Model C change gear set includes the following *13*
gears:16, 24, 32, 32, 36, 40, 44, 46, 48, 52, 54, 56, 60. (Notice
the second 32.)Additionally there is an 80 idler (no keyways) and
18/54 and 18/72 compound gears to complete the set.
(8321) |
| Steve Obert writes: I checked
my set and it includes an 80 tooth gear as well as an 80 tooth
idler. As the gears will let me make any combination as listed on
the data plate on the end cover, it appears that I have a full set.
That would make the full set 14 keyed gears 1 idler and 2 compound
gears. Do you have a Model C or B? In "How to Run a Lathe" there are
separate change gear charts for the B and C. I originally figured
out the set of gears for each model by tallying which gears were
required from the two charts but originally I didn't know about the
compound 18/54 and 18/72 gears, I counted these as four separate
gears, 18, 18, 54, 72. I also didn't understand originally that the
80 in the idler position was a special gear without keyways so I
counted it as an 80 change gear. So it is now my understanding that
the Model C change gear set includes the following *13* gears: 16,
24, 32, 32, 36, 40, 44, 46, 48, 52, 54, 56, 60. (Notice the second
32.) Additionally there is an 80 idler (no keyways) and 18/54 and
18/72 compound gears to complete the set. And it is now my
understanding that the Model B change gear set includes the
following *14* gears: 16, 24, 32, 32, 36, 40, 44, 46, 48, 52, 54,
56, 60, 80. (Notice the second 32.) Additionally there is an 80
idler (no keyways) and an 18/72 compound gear to complete the set.
Notice that the Model B has added an 80 but dropped the 18/54
compound gear. This is not from direct experience of the two lathes,
only from reading the charts in the SB book. The differences are
based on the fact that the B has longitudinal and cross power feeds
through gearing in the apron, unlike the C which uses the split nuts
for longitudinal power feed (in effect a very fine pitch screw
thread) and no power cross feed. Can somebody with a Model B verify
the above list of gears? Anthony
(8326) |
| Anthony, I
have a model C with 14 gears. That is what I posted the list from.
There are settings on my chart that use the 80 as the screw gear (
on the leadscrew ). I think that looking at the chart on the lathe
and making sure that you have enough gears to make all settings on
the chart would insure that you have a full set. I don't see any
reason that a B would be different than a C, the only difference is
the power crossfeed and clutch on the apron. You would need the same
gears to get the same feeds. Unless they came up with different
combinations to give the same result. So it is now my understanding
that the Model C change gear set includes the following *13*
gears:16, 24, 32, 32, 36, 40, 44, 46, 48, 52, 54, 56, 60. (Notice
the second 32.)Additionally there is an 80 idler (no keyways) and
18/54 and 18/72 compound gears to complete the set. And it is now my
understanding that the Model B change gear set includes the
following *14* gears:16, 24, 32, 32, 36, 40, 44, 46, 48, 52, 54, 56,
60, 80. (Notice the second 32.) Additionally there is an 80 idler (no
keyways) and an 18/72 compound gear to complete the set.
(8327) |
| Steve Obert writes: I have a
model C with 14 gears. That is what I posted the list from. Alright,
I don't have direct experience of the "B" or the "C". It appears you
do have direct experience of the "C" but not the "B". There are
settings on my chart that use the 80 as the screw gear ( on the
leadscrew ). I looked this up again. You're correct, the "C" chart
shows an 80 as screw gear for very fine feeds but in no cases does
it use two 80s. I think that looking at the chart on the lathe and
making sure that you have enough gears to make all settings on the
chart would insure that you have a full set. This is what I did
originally as I didn't have access to either a "B" or "C" lathe.
I've already mentioned that I didn't know about the two double-gears,
I counted them as four individual gears. I also didn't know about
the idler-only 80 tooth gear so when I saw an 80 sometimes used as
an idler and sometimes used as a screw gear I presumed they were the
same gear. Based on what you've said I'll adjust my count to include
an 80 change gear and an 80 idler gear. I don't see any reason that
a B would be different than a C, the only difference is the power
crossfeed and clutch on the apron. You would need the same gears to
get the same feeds. Unless they came up with different combinations
to give the same result. I too don't see why there would be a
difference but if you look st the change gear charts for the "B" and
"C" lathes you will see that they are *not* the same. One difference
between them is that the "B" chart has notations regarding the feed
rates being different from the screw cutting rates but,
additionally, the setups for fine feeds are actually different from
the "C" model due to getting part of their reduction through the
internal gearing in the apron. The "B" chart does *not* ever include
the 18/54 compound gear. Evidently this is the *only* difference
between the "B" and "C" change gear sets. I hope I'm capable of
learning. Anthony
(8381) |
| 9 Inch Change
Gears |
| Does someone have
the list of the standard Model B and C change gears? I have pictures
but not the #'s of teeth and I believe there is a set on Ebay
(finally !!). (9020) |
| From South
Bend Lathe publication 903E, the 9/10K parts list dated 11-15-64,
the complete set is: 16-24-32-36-40-44-46-48-52-54-56-60-80 plus an
80 idler--and the 42 for cutting 27tpi was an extra-cost accessory..
Oh darn, I left one value out of my chart. (9026) |
| A complete
set of change gears for the SB 9" 10K, model B C consists of the
following: 16,24, (2)32,36,40,44, 46, 48, 52, 54, 56, 60, 80.
Fourteen (14) gears in all. In addition a 18/72 combination gear, a
18/54 combination gear (C only) and 80T idler gear are needed. My
Revised Edition, "How to Run a Lathe" shows pictures of the index
plates showing all the above on page 73. If South Bend (LeBlond)
still has them, the index plate part number's are, model B,
AS1525NK3, model C. AS1527JNR2 . Neil (9028) |
| Robert, I
have the operation, parts, and maintenance manual for the 9 inch
southbend on CD rom as a pdf file. It shows 16T, 24T, 32T, 36T, 40T,
44T, 46T, 48T, 52T, 54T, 56T, 60T, 80T change gears. Also an 80T
idler gear and 18/54T 18/72T compound gears. This book has part
numbers listed and all. Rush (9037) |
| Gear pitch |
| Seems as though I
read somewhere that the headstock gears in a 9" "A" model were 18DP.
Can someone verify this? If so, what pressure angle are they? 14 1/2
degree or 20 degree? Jim
(9094) |
| Yes, 18DP, 14.5 PA. I've cut some of my own and used them
on my 9" SB.. Fred
(9098) |
| Fred, Did you
mill the gears or use a hobber? (9114) |
| See the "Transposing Gear" folder in the Phoros
section. Fred (9162) |
| More pix:
http://groups.yahoo.com/group/SouthBendLathePix
(9165) |
| Fred, how did you generate the 127 tooth gear? My dividing
head will not do 127-- either 124, or 128. An acquaintance of mine
that is a gear cutter told me that he uses a 127 gear [ any DP? ] to
index the new gear. Have you heard of doing it this way? Jim
(9167) |
| Jim The two
files stored here show how to generate any custom index count that
is not achievable by normal means.
http://groups.yahoo.com/group/mwmills2/files/IndexingConcepts/
JWE (9170) |
| Gear |
| Does anyone have
the dimensions for the gear on the bottom of the thread dial to
follow the leadscrew on a 10" machine? leadscrew is 750X8. stirboy (9573) |
| The treading dial I
have is off an atlas lathe, but works fine on my sb. The dimensions
for the gear are .700 dia,.375 thick with 16t,hope this might help.
Scott
(9589) |
| Scott. The thread
dial on my SB is from a Logan lathe and works fine on the SB. I did
have to modify the body length to fit my lathe but that wasn't a
problem. Bill C.
(9591) |
| I have
a 10K with what appears to be the original thread dial. The casting
has 886NK2 on it and the thread gear is steel and has the following
number stamped on it. "THD-101NK", The gear measures: Diameter=
1.310 OD , gear face width=0.507, and it has 32 teeth. Put about + -
0.005 on the measurements as I did my best to measure the gear that
is recessed in the casting and covered with grease. Should be easy
to buy a gear and make one. You will need the O.D. of the dial which
I didn't measure. When I start to thread I engage the thread dial ,
move carriage until the number one comes up on the mark , then I
engage the split nut which requires slight movement of the carriage
to drop in, now move the thread dial casting in-out on the mounting
to get the number 1 right on the mark again then tighten the set
screw to lock the thread dial in position, lastly open the split nut. DVC (9603) |
| 9" SB Gears
questions |
| My preliminary
inspection indicates that 9" SB's use 18 pitch gears with a .450
bored and broached center and that these may be SB specific as I
have (so far) been unable to locate matching 18 pitch gears. Does
anyone have a source for 18 pitch gears in 20, 40 and 56 teeth. The
bore is not that critical. (9853) |
| You might
check with Dick Triemstra at Bridgeman Machine in Detroit; I think
he has some southbend parts. There are other used parts dealers but
Dick is the only one I've dealt with personally. He s a great guy
and will go out of his way to help you. Phone number is
313-366-1060. Lew (9855) |
| Valley chain
and gear in San Marcos CA the number is at work but 411 will have it,
they ship too. I bought my gears from them for about what the used
ones were going for on Ebay. My new 80 tooth cost $40.00. My machine
uses 16 DP with a .750 bore. but I have heard of south bend machines
using anything under the sun. Valley chain will have or can get 16
DP. Kerry (9858) |
| We went all
up and down the 20t gear question about a year ago here on the list.
I've run all my sources for used and new-old-stock dry. 40's and
56's are readily available. My next project is putting together
packages of all the odd small gears needed for metric threading on
non-QC lathes. I can provide info on several people willing to hob
the 20, including Scott Logan right here on this list, but the
bottom line is it's not worth anybody's time for a quantity of less
than 10. A typical quote from the several dozen I got is "$250 each
in lots of 1 and $30 each in lots of 10". Lurch (9860) |
| Brian,
Thanks for mentioning my name, and yes, we have the capability to
cut these gears. Unfortunately, every time I have offered services
or products (gears and belts, specifically) to this group, I have
only received complaints about how expensive my prices were. For
that reason, I'm not going to pursue this any further than this
email. You should be able to get these parts from LeBlond Ltd.
LeBlond Ltd Ed Morris emorris@l... 3976 Bach Buxton Rd Amelia OH
45102-1014 Tel (888) 532-5663 x206 Fax (513) 943-0101 I will say
that my price for a 20T gear would be somewhere around $30-$40 each,
in any quantity, but without a commitment of at least a couple of
orders (let's say 3 or 4 gears), we are not going to make these. For
reference, Logan Change Gears are 16DP, 0.44" wide, and 0.625" Bore
w/0.156" keyway. All gears are steel or Class 40 Cast Iron, and are
fully machined with cut teeth (no die-castings were ever used) Some
sample prices: LP-1036 16T 28.51 LP-1037 18T 30.84 LP-1038 24T 38.36
LP-1041 40T 61.55 LP-1044 48T 74.54 LP-1047 56T 88.32 LP-1050 72T
117.93 LP-1051 20T 36.59 LP-1056 100T 192.93 LP-1057 127T 236.45 All
prices in US Dollars and valid for 30 days, FOB Ex Works. We accept
Visa, MasterCard, Discover/Novus or American Express. Minimum Order
- $25.00. Scott S. Logan (9861) |
| I've no idea
what shipping from UK would be, but I'd guess these prices compare
quite well in dollars. Boxford gears that fit South Bend
lathes. Boxford lathes are SB clones. Len (9863) |
| The 9"
Workshop and Precision Series lathes use 18dp gears. 18dp is not a
standard gear pitch - I don't know if it ever was. The older 9"
lathes (Series R, etc.) use 16dp, which is a standard pitch. A wide
variety of 16dp gears are readily available from industrial
suppliers and gear manufacturers. (9866) |
| It may be cheaper to switch to 16 or 20 DP. And for all those that
choked on
$250 per gear in a single piece price has never cut gears or know
anything that is involved. I'd say that's a damn fair price
considering the setup time involved, all be it pricy for just one
gear for a hobby lathe you need to remember the cost involved with
time and it's time you are paying for. Kerry(9869) |
| That is my current
thinking: change the 20 (40) from the tumbler, the 80 idler and the
56 gearbox drive to corresponding 16 or 20 pitch gears. The 20 (40)
"stands proud" of the tumbler so if this was changed its "a clear
shot" to the qc box. As the 80 and 56 are never changed on a qc
equipped 9" there is no reason why this would not work if the
correct ratio of spindle to qc box could be replicated with the
replacement gears. Has anyone actually done this ? what gears are
used to preserve the correct spindle to qc gearbox ratio ? And for
all those that choked on $250 per gear in a single piece price has
never cut gears or know anything that is involved. I'd say that's a
damn fair price considering the setup time involved, all be it pricy
for just one gear for a hobby lathe you need to remember the cost
involved with time and it's time you are paying for. Kerry (9870) |
| Kerry, You
are right about setup. It can be a major cost in any manufacturing
system. The way I read Scotts note, you might as well order ten
gears for $50 more. Then sell the rest off and hopefully recoup
your investment. Tom (9872) |
| If I had the
money I think that's what I'd do or try to get a bunch of guy's
together that need the same stuff and place a bulk order but that
would be even harder. buying ten and selling nine would be the way
to go. Kerry
(9873) |
| To change the
18dp gear train to 16dp (or 20dp), replace the stud(20T/40T),
idler(80T) and screw(56T) gears with 16dp gears having the same
numbers of teeth. Hopefully you can find (or modify...) gears with
the correct bore and keyway. Each of the 16dp gears will be a
slightly larger diameter (18/16 + a bit) but the geartrain does not
have fixed center distances. The idler gear slides along the bracket
to adjust the tooth mesh/clearance. For the standard QC setup there
should be lots of extra adjustment room. I can't speak for all of
the ratios on the Model B or C change gear lathes. Some of those
ratios may be tight with the larger 16dp gears (or wouldn't mesh
with 20dp). You could always make a longer or wider bracket if the
16dp was cramped. The more teeth on the gear, the larger the
difference in diameter between the various pitch series. Could those
of you who use the big 100/127 or 127/135 metric transposing gears
let the group know whether another pitch series would work in those
setups. Thanks. *Don't forget that although small standard gears
like 20T may cost only a few $, gears with lots of teeth, like 80T
or 100T can cost a lot more. (9875) |
| Typical
shipping cost quotes UK-US for a 100/127 were around œ25 to 30 which
rather took all the fun out. This is a big and relatively heavy gear
and had to be sent as a parcel which basically start at œ20. Smaller
ones will be much cheaper if they are light enough to be treated as
a letter package. I'd guess anything under 1/2 lb would be OK. Best
way is to get someone flying over to carry it out use UPS for the
stateside leg. Clive (9876) |
| From Boston
Gear via my local dealer (Valley Chain And Gear 760 744 4200) they
have 20 to 128 change gears not spur gears. These are already set up
to use a double keyed bushing to create compound gearing or fit
right on to my idler bolts. They are a direct fit and replacement on
my mid 30's 9" C model. The gears that I was looking at were the 54
tooth 72 tooth and an 80 tooth and they were priced $32, $39, and
$42 respectively. Not bad for brand new considering that some of the
harder to find gears go for 20 to 50% more then new on Ebay. Kerry
(9877) |
| Agreed. When
converting from C to A and you have a gearbox but not gears and
unless you are lucky enough to find the correct SB gears it makes
sense to just buy the four gears new and convert the gear train from
the spindle to the gearbox to 16 or 20 pitch. The next shortcut is
the leadscrew conversion. You can convert a C to an A but I had a 4
foot C and a 3 1/2 foot A leadscrew and gearbox. I made a 6 inch
extension for the right side leadscrew bearing to accept the shorter
A leadscrew--under the theory that you never or rarely rarely work
at that extreme end of the machine. Doc (9879) |
| FYI: Yes, the
9" Precision series lathes (the little 9") use non-standard 18dp
change gears. To make things more interesting, the spindle and
reverse tumbler are 20dp and the gears inside the QC gearbox are
16dp. I believe that the older 9" lathes used 16dp throughout.
(9902) |
| I believe my
lathe is mid 30's and yes it it 16DP from the spindle to the screw
gear. Kerry (9907) |
| This is
starting to get involved and I would like to have an idiot- proof
way to check - like with a quick micrometer check of the diameter??
the shop person at my house ( aka this author) is not always in
possession of his full faculties and does not trust himself to make
the correct calculations at all times. Cliff Clavin's beer-
buffalo-and-brain-cells theory of why natural selection enhances
brain function seems to have brought along a few other.... shall we
say side-effects?? (the remaining math brain cell lags behind some
days when the shop area is a refuge from work.) Could some of you
astute fellows give us a quick-check measurement to determine
whether the gears are 16, 18, 20 DP? f'rinstance on a 20 tooth
standard stud gear, is the diameter of a 16 DP substantially
different than an 18 and what would they be? same-o for maybe one or
two other common sizes like the 40, 16? (9910) |
| How can I tell if my lathe is a 'precision' or just a regular?
Paul N (9911) |
| The
formulas for calculating gear dimensions are pretty straightforward,
and the basics are dead easy. OD=Outside Diameter PD=Pitch Diameter
T=Number of teeth DP=Diametral Pitch PD=T/DP OD=(T+2)/DP DP=(T+2)/OD
Example: DP OD 30T 14 2.286" 16 2.000" 18 1.778" 20 1.600" Yes, I
know there are other types of gears, such as circular pitch, module
etc., but those do not apply (AFAIK) to South Bend Lathes. Scott
S. Logan (9912) |
| Paul, I'd
look at Tony's UK Lathe page for some info. SB made two types of
9inch lathes. The 9 Junior was basically a Heavy 10 or 10L. These
are not as common as the lighter built 9 "Workshop"
precision. The
precision is basically a selling name. Although some of the 10K's
and 9 Workshops did use this or toolroom to denote the use of a more
accurate lead screw. I think most of these type also came with a
taper attachment. Probably the easiest way to tell the difference is
the through bore in the spindle. The 9 "workshop" had about a .875
through bore. The Junior should have about 1-3/8 through bore.
Tom (9913) |
| Change gears
|
| I just recently
purchased a 9" South Bend off of E-bay, the lathe was in good shape
but was missing all the change gears but the 80, 56 and 24 tooth
gears would any of you have spare change gears that you would be
willing to sell for a decent price or know of a place that might
have used gears for sale, I am really looking for the following
gears (16,32,40,44,48,52,54)
(10295) |
| I just recently
purchased a group of gears from a UK firm G M
http://www.gandmtools.co.uk/
These were new and the prices were less than or competitive to those
on E-Bay. They ranged from L11 to L16 )with approximately 1.5$ to
the L (pound)). I got t20 24T, 30T, 36T. 48T, 54T and 60t gears for
L90 with an L16 shipping charge. Total was about $150. They arrived
in a few days.
(10304) |
| Leadscrew gear |
| Len, Later today
I'll check the gearing I used on my "C" before I added the QC
gearbox. Doesn't your gear cover have a chart on it? If not, the
"How To Run A Lathe" booklet specifies the gearing. Anyway, I'll
check and let you know the gear I used for slow feed. (I believe it
was 32T). John (12480) |
| JT, Take your
80 tooth gear to a machine shop and have a key way broached in it.
Then it will work. Duane
(12482) |
| John
I have the booklet, and the cover does have the chart, but there is
just something about these gears that puts me in a coma I ain't a
dimwit normally, but I have an IQ of about 15 in this area.. ;O))
Len (12486) |
| John, presumably you mean the banjo
gear? Putting a 32 where the 52 is at present would make it faster
I thought. I can't simply broach a keyway into the 80, even though I
have some broaches, because that itself looks as if it has been adapted.
It has a free running bush in a larger hole than
usual. Looks like I'll have to buy a couple in opposite sizes. They
are very reasonably priced on
http://www.gandmtools.com
if any one else needs gears. This is a UK site, but I believe US
members have already used these people, with reasonable freight
rates and fast service. Len
(12490) |
| Len, You're
right, the 32T would make it move like a bat outta hell! I just
checked my machine and for the slowest feed it calls for 16T stud
gear, a 116T gear on the lead screw, and the compound gear that goes
between them is 18Tx108T. Let me know if this helps and whether you
need any of those gears as I might have some. I don't want to sell
them, but you could borrow them for testing or until you locate any
you need. John
(12494) |
| Len writes: I have the
booklet, and the cover does have the chart, but there is just
something about these gears that puts me in a coma. I ain't a dimwit
normally, but I have an IQ of about 15 in this area. And in a
message dated Fri, 4 Jul 2003 20:07:54 +0100, Len Smith writes:
presumably you mean the banjo gear?. putting a 32 where the 52 is at
present would make it faster I thought. Len, First order of
business, the finest feed listed for the Model C in HTRAL uses a 16
and an 80, plus 18/54 and 18/72 compound gears. The 16 and 80 need
keyways, the two compound gear do not, they should have bushings in
the bore like the 80 idler gear you described. You will also need
one extra idler stud. To describe the setup, let's call the stud
gear ST, the first idler A, the second idler B, and the screw gear
SC. ST = 16, A = 18/54, B = 18/72, and SC = 80. The easiest way to
"build" the setup is to start at the screw and work back to the
stud. Mount the 80 on the SCrew. The idlers both mount on the long
slot of the banjo. Mount the 18/72 as B with the 18 engaged with the
80 at SC. Mount the 18/54 as A with the with the 18 engaged with the
72 at B. Mount the 16 on the STud. Swing the banjo up so that the 54
on A engages with the 16 at ST. Setup Complete. To understand what
you've accomplished, create a formula with the driver values
multiplied together, then divided by the driven multiplied
together, then multiplied by the *pitch* (.125") of the leadscrew.
So the formula becomes: (16 x 18 x 18) / (54 x 72 x 80) = (1 / 60) x
.125" = .00208333" feed per rev. (HTRAL gives this as
.0021") The gearing has reduced the leadscrew rotation to 1/60 of
that of the spindle. That means that in order to turn the leadscrew
one revolution the spindle must turn 60 revolutions. At the end of
these 60 revolutions the leadscrew will have moved the carriage
1/8". In order to move the carriage 1" the leadscrew will have to
rotate 8 times, therefore the spindle will have to rotate 8 x 60
revolutions, or 480 revolutions. With the described setup the
spindle turns 480 times to move the carriage 1" therefore in 1
spindle revolution the carriage will move 1/480" = .0021". Presuming
you know simple math, you know you can make reductions in the values
in the formula. For instance 18/54 = 1/3, 18/72 = 1/4, and 16/80 =
1/5, therefore the formula becomes: (1 x 1 x 1) / (3 x 4 x 5) = (1 /
60) x .125" = .0021" You can make similar calculations for any of
the other setups provided in the chart. You can also calculate the
result of any other gear train you setup using the same sort of
calculations. Anthony
(12509) |
| South Bend also made some gears they called turning
gears. The one I have is a 116 tooth. It fills the gear guard. With
this gear on the screw and the compound gear on the banjo I get an
excellent finish on my B model workshop lathe. Something like that
might show up on ebay, I would think. RC
(12548) |
| Gear alignment |
| I have a 9-C
and the gear on the tumbler bracket does not line up laterally with
the gear on the banjo. Am I missing something or is there a drawing
that shows all of the parts and there location? Bob (12562) |
| The tumbler
gear is on the headstock and the banjo is on the bed. You need to
loosen the bolts that hold the headstock to the bed, and align the
two gears. RC
(12565) |
| RC It's the
lateral alignment. not the mesh. Bob (12566) |
| Bob, That's
what he's saying. Move the headstock towards the tailstock or away
from it to line up the gears. You may be able to just loosen the
banjo and slide it further onto the leadscrew support or the other
way. It's a lot easier to do than loosening the headstock nuts which
are under the bed and hidden by the foot. Glen (12567) |
| Bob, You are
not trying to drive a compound gear from the stud gear with the
smaller gear of the compound towards the banjo, are you? Glen (12568) |
| RC, Thank you
for the solution. I did just what you said and my problem went away.
Thanks again, Bob Murray (12575) |
| Glen, Some
people have to be hit in the head before anything sinks in. Thanks
for your input. It works fine. Bob
(12576) |
| 9-C Change
gears pressure angle |
| What is the
pressure angle of the 9-C change gears? Bob (12583) |
| Bob, The pressure
angle is 14 and 1/2 degrees. The DP is either 16 or 18. It seems
earlier models had the bigger gears. Be careful in purchasing change
gears on eBay. I bought a stack of change gears for my 9" C before I
converted it to an "A". The guy swore they came off a 9" C but they
were 16 DP. Glen (12597) |
| 40 Tooth stud
gear |
| When I bought my
lathe it was missing the 40 tooth stud gear. I never had one until
Paul kindly sold me an extra he had. Up until last night I thought
that it replaced the 20 tooth stud gear if you wanted to cut any of
the eight tpi the 40t is required for. Know I am not so sure! Can
anyone tell me for sure where it goes? Gary (12797) |
| That's where it
goes! When you cut coarse threads, it makes the lead-screw turn
twice as fast. Included is a rough picture showing the proper gears
for a model A. Swap the 20T and 40T when you are cutting coarse
threads. Paul R. (12799) |
| Yes, if I
understand you correctly. Here's the deal. Normally, you have the
20T gear stacked on top of the tumbler reverse gear, and you store
the 40T on top of the 56T gear on the input to the QC gearbox. When
you are threading something that calls for the 40T gear, you swap
the 20 and the 40. The train would be as follows: Spindle drives one
or the other of the tumbler gears which drives the inside (bottom)
stud gear. The inside stud gear drives the 40T stud gear stacked on
top of it (until you swap it back to the 20T) because they are keyed
on the same shaft. The 40T stud gear drives the 80T idler gear which
drives the 56T gear on the input to the QC gearbox. The other stud
gear, the 20T in this case, is just stored nicely on top of the 56T
gear allowing you to tighten down the nut holding the 56T 20T gears
on the QC input shaft. Paul R. (12822) |
| Change gear
diameter |
| I am missing my 16t
change gear, I have bought most of my gears off of eBay or through
individuals but have been unable to get a 16t even from Mr. Griffith
in the UK, he is out of them and I have sent 3 e-mails to no avail
and he couldn't tell me when he was going to get new ones for sure.
I found the right cutter at a local tool shop but I need the outside
diameter of this gear before I start, would anybody be willing to
measure one of there's and let me know what the outside diameter is?
(13367) |
| If your gears are
18 DP the diameter is the number of teeth plus 2 divided by 18.
16+2=18 18/18=1 inch. Glen Reeser(13370) |
| Old 13" gears |
| I just acquired an
OLD 13" x 32" Model 32 (I think) s/n 15139. This makes it circa 1918
I believe and it sure looks like the picture of a 1918 model. It
appears to be in great shape, however, my treasure did not come with
any extra gearing so I am stuck with one feed rate right? That seems
about like buying a car with only one transmission speed. Short of
swallowing a cyanide tablet can someone give me some advice as to
what to do now? Also, the headstock spindle is treaded for 1 3/4" x
8. This isn't standard is it? (14274) |
| In regards to Old
13" gears, the gear that is on the machine is probably the gutting
feed gear. So unless you are going to cut threads on this machine
you will not kneed any other gears. I have a 1920 SB 21" and I only
use one feed gear for turning, and I have all the gears that go with
my lathe. The only time I change out is when I cut threads. (14275) |
| Measure the OD of
one or both of the two gears you do have which form the gear train
down to the leadscrew, and count the number of teeth. From this you
can find the diametrical pitch (DP) of the gears you need by
dividing the diameter by the number of teeth +2. You should get a
number like 14, 16 or 18 (or possibly 12 or 20). Also measure the
thickness of the gears, and the ID of the hole in the center. There
is another parameter called pressure angle, but from what I can tell
all of the old SBs used 14.5 degree PA, and that is also what most
of the used gears for sale are. Now you know the type of gears you
need. Also determine the TPI of the leadscrew (either look it up or
count the number of threads over a measured distance). Once you know
the leadscrew TPI you can determine with some simple math what gear
choices cut various threads or provide various feed rates. An easy
to do this is find a gear chart for another SB lathe with the same
leadscrew TPI. Now you can make a list of tooth-counts you would
like to have. Now you have some choices. Watch Ebay. Call some of
the used lathe parts suppliers like Dave Sobel. If the DP is 16 (or
12 or 20) you can buy new gears for ~$35 each in small tooth-count
sizes from Boston Gear (or others). If you find used gears with the
right tooth-count and DP you can use your lathe to make them
thinner, bore out the center hole, or make a bushing to shrink the
center hole. I don't know that there were any standards for lathe
spindle threads, but ! think 1 3/4" x 8 was not one of the more
common sizes. Having said that, guys like Dave Sobel have some of
everything, or you can buy blank backing plates and thread them
(once you get some gears...) Frank (14276) |
| Others have already
addressed the gear issue, I can't offer more on that. I would
suggest you double check the spindle nose, 1 7/8 - 8 was standard on
early 13 inchers, have it on my '31 13 incher. No, it's not standard
either, but it does show up now and then. Stan (14277) |
| Today's common gear
pitches are 10, 12, 16, 24 and 32 etc. If you find you have 14DP or
18DP or some other not so common pitch, you can get the gear cutters
from MSC. JP (14279) |
| I'll probably try
and buy the gears new and adapt them. I remember reading somewhere
about "non-standard" P.A. for Southbend gears, but that could be
remedied by using a complete set from the stud gear on. Also I
imagine the spindle was repaired sometime during it's long life thus
resulting in the 1 3/4" x 8 threads. (14290) |
| Your Spindle thread
may very well be 1 3/4"x 8 TPI, they increased the spindle bore in
1926 on the 13" lathes from 3/4" through hole to a 1" through hole
so it is reasonable to believe that they also increased the size and
thread of the spindle as well. Measure it with a good caliper or
better yet, call LeBlond and get the spec sheets for your lathe you
will be glad you did. A big help to me was finding a copy of How to
Run a Lathe printed the same year my lathe was made. I was lucky
enough to find a copy with the covers torn but otherwise perfect
making the collectors value very low. It took some time but I found
a 20th edition at about 1/4 the price I paid for a 26th edition, the
early version is about half as many pages as the later version but
both worth far more because of the information each has. Terrance
(14297) |
| Diametrical
pitch |
| I have a 1930s sb
workshop (9c),is the dp for the gears 18 0r 16, I keep getting 18
with the calculation N+2/OD. I thought it should be 16 ? Rick
(14408) |
| Rick, Mine's 18.
Stan (14415) |
| Southbend did use
18 DP gears and 14 DP as well. Not common today but sized for the
location in the machine. You can get cutters from MSC but places
like Boston gear don't make the gears anymore. JP (14426) |
| I thought it was
suppose to be 18 dp for the workshop and 16dp for the Junior models.
That's the way mine and my buddies gears are on our 3 lathes. He has
a 9" Jr. and a Workshop 9" and I have a Workshop 9", the Workshops
have 18dp and the Jr has 16dp, his 9" Jr is much larger framed than
a 9" Workshop. (14430) |
| I also recently
bought a 9C. My gears are 18 dp, 14.5* pressure angle and I believe
that was just about standard for the SB9s. I haven't found any place
to buy new ones but many are sold on e- Bay. I believe I saw a
complete(?) set a few days ago. You can usually get them at very
favorable prices there, especially for sets. They almost never list
the dp but if it's listed as "south Bend 9" it will most likely be
the correct size. I haven't gotten a misfit yet. And if I do, I'll
just auction it - with a proper description of course. Of course you
can have them made ($$$) or make them yourself. I would love to
get a compound for cutting metric threads but am presently limited
on both time and money. Paul A. (14465) |
| Change gear
question |
| I was wanting to
setup for cutting threads on my Southbend 9C.I was going to setup
for 16 tpi, installed the 48 tooth on the leadscrew,24 tooth on the
stud but when I started to add the 80 tooth as an idler it wouldn't
fit on the bolt sleeve. The diameter of the holes in my change gears
are the same as the diameter on the leadscrew=.56"dia.The diameter
of the sleeves are .62.Is there a special size sleeve that fits the
bolts that also fit the hole in the gears. Bill C. (15151) |
| If your 80 tooth
gear has a keyway slot it is a turning gear. My 80 tooth idler gear
has no key way, a 0.625 diameter bore and an oil hole leading into
the bore. The1952 edition of HTRL shows an 80 tooth being used on a
C as a screw gear . not to cut threads but for feeds of .002 to .006
There must be two different 80 tooth gears. Jim B. (15153) |
| Jim. So I must need
to find another 80 tooth gear with the larger hole or make a new
adapter sleeve that will fit the hole on the gears. Doesn't look
like I'm going to learn to cut screw threads with this lathe then,
just use for turning I guess. Bill C. (15154) |
| I got mine on E-Bay
for about $20 There is one on there now, 2575042167. Its at $10 with
6 days left to go. In addition there is a $5 packing charge
+shipping. If that is too steep keep looking. They show up pretty
often. The alternate is to bore/drill and ream out the gear you have
to 0.625. Jim B.(15156) |
| Jim. I just made a
sleeve to use till I can get some money in about Feb. before I could
buy anything. Bill c. (15157) |
| Bill, I just bought
a set of gears from Plaza Machinery in VT. and I think they will
have the 80 you are looking for. I think a single gear is about $20.
If you have a question or need some additional info, give me an
email-Jerry (15158) |
| Be sure to keep the
gear well oiled and lots of luck. Jim B. (15162) |
| Jim. I'm going to
make a couple extra sleeves to have on hand in case it starts to
wear down. I made the sleeve from a piece of 4140.Took only a few
minutes to turn it down and used a tailstock drill to drill the
bore. This is about the most economical way I could get the piece.
Will buy a regular gear when I get the money. Bill C. (15164) |
| Make the
sleeve/spacer. Doing that will make you satisfied that owning the
lathe is Handy! Darrell (15168) |
| Darrell. I made a
couple more sleeves today to have for extras. I did some searching
and found there should be two 80 tooth gears in the set. The ones
with the key-way and the other that has the larger diameter opening
and built in bushing to be used as an idler. Guess I'll have to try
and locate one when I get some green-backs. Bill C. (15169) |
| 16 Tooth Stud
gear |
| I am hoping that
some one could point me in the right direction In locating one of
these Items. It as a 16 pitch and needs to be 16 teeth only. To
complete the set that I received with the machine this is a
southbend and appears to be in good shape. also am needing the
eighty tooth gear as I found this one to be cracked. the hole dia.
is 1/2 width" If any one can help with the date on this I would
appreciate this info. The tail stock reads 30178. Catalog 25-X Fred
(15568) |
| Fred I have a 16
tooth, 16 dp gear with a 5/8 bore and a .159 wide key and the gear
is .441 wide. I also have an 80 tooth gear that is 18 dp with a 9/16
bore and a 1/8 wide key and the gear width is 3/8". If these are the
gears you are looking for, you can reach me at peep38k (at) mchsi
(dot) com Randy (15572) |
| Yes I do think that
this might work however I well need to have the 80 tooth bored to
.625 and the keys in both gears broached to or filed to a .191, I
would prefer the key to be cut right ? Is this something that you
can do? If you don't mind could you quote me a price for these two
gears and get back with me. Fred (15573) |
| You do understand
that he has offered you two non-compatible gears? Read this: I have
a 16 tooth, 16 dp gear with a 5/8 bore and a .159 wide key and the
gear is .441 wide. I also have an 80 tooth gear that is 18 dp with a
9/16 bore and a 1/8 wide key and the gear width is 3/8". Since these
gears are in the same train they have to have the same DP. Randy has
offered you 16T-16DP and 80T-18DP gears, they won't mesh with each
other. Anthony (15604) |
| Anthony I know you
are wise and yes, it's pretty obvious that these two gears will not
mesh. That doesn't take rocket science to figure that out, but some
south bend lathes had two different dp gears on the side of them.
Was you aware of that? I'm not sure which lathes they are but I have
seen it. I ran into this once before on an early model 9" lathe for
a customer down in Kansas. All I could do was tell this person what
I have. It's his decision to figure out what he needs. I can't
possibly know exactly what he has since the request was not
descriptive enough. I left the guy my email address, he never
contacted me. I have the equipment, but I don't have the time to
modify these, if they are not the right bores and keys, I suggest to
keep looking. Thanks, Randy writes: however I well broached to this
something Read this: key and the a 9/16 bore DP. (15609) |
| Randy, I didn't
intend to claim you were misleading him. I just felt that is was
important for him to understand that these two gears could not be
installed in a continuous gear train due to the difference in DPs.
Often people who are new to such mechanisms don't understand the
terminology and might easily overlook the potential conflict. Better
he should ask you additional questions than unknowingly to acquire
non-compatible components from you or anyone else, then feel he has
been taken advantage of. I know that you have been a good friend of
this group and a good source of service parts. If I left the
impression that you were trying to cheat him that was most certainly
not my intention and I apologize for any uncomfortable feelings.
Anthony (15619) |
| Still sounds like
the16 tooth will work for me. this machine came without the 16 It
would be nice to slow the feed rate down. The 80 that I have is only
cracked and I thought that I would try to replace it, however I may
be able to fix this by machining two washers that would rivet
together? Let me know what you think. this is an older machine
catalog X-25. just not sure what year the switches and oiler caps
are pat date 1915 - 1921 on the switch. fred (15620) |
| Anthony It's good
that someone like you with your knowledge keeps an eye on what's
going on and I appreciate that. Rose caught me once on here too
regarding the 1/4" difference between a 5C collet closer for a
2-1/4-8 and a D4 spindle. I've picked up on several things from you
over the last couple of years, and that's good for me. When I get
stuck with a customer I tell them to write the group for the
answers. I am aware that you know quite a bit about these machines,
far more than me. I can't keep up with all the different
combinations, my memory isn't that good. The lathe I'm referring to
was about a 1932 if I remember right. The gear drive off the spindle
was one dp and the lower drive gears were another. I can't remember
what we were trying to do, it was Bob Barnetts 9" lathe from Kansas.
I thought that maybe he was needing one from both, who knows? I
understand where you are coming from, some folks don't even know
what dp stands for. When Eckeday sent me this post, this is what I
was thinking of, one of each, that's why I put in a detailed
description of both gears but you are right, he might have
overlooked the two dp's. My guess is, I've probably had close to 60
of these lathes in different stages in the last two years and have
close to 20 right now. Some are complete and some are missing
pieces, the worst is yet to come. I'll have my new shop finished in
about a month, then I'm going to lay them all out, get the parts
straight and sell everything I can and start over with a clean
slate. Next spring should be interesting when I get all these lathes
sorted and the cabinets full of parts on their way to ebay. Thanks
Anthony, and remember when you see my name keep a close eye out for
me. All I can do is put what I have out there and let someone help
me sort it out. There is such an assortment here, I'd guess I
probably have 2-300 gears here alone in all sizes of dp and teeth
ranges I wonder if I'll ever get done. The thing is, then what would
I do? Randy (15622) |
| Calculating DP
on Gears |
| Several posts have
included a formula for calculating Diametrical Pitch when I believe
you know # of teeth and Major Diameter of the gear. I have been to
message archives and have searched DP, Diametrical Pitch and Gear
Calculating with no luck. Can anyone share again that simple
formula. Ron (16822) |
| Number of teeth +2
/ diameter, take the closest whole number. JP (16823) |
| In reference to the
above question would the DP of the Spindle Reversing Gear on a Heavy
10" be 18 DP? Don't own a Heavy 10" but trying to make some
calculations for this item for the Heavy 10" Handlever Closer. Ron
(16828) |
| Mine are, Spindle
gear and reversing gears 18DP, Bull gear 14DP. 1957 Heavy 10. JP
(16831) |
| JP: What about
Pressure Angle for the reversing gear? Ron (16833) |
| I believe they are
14 1/2 degrees as are most SAE drive train gears. Its hard to
measure unless you have a gear gauge or matching pitch gear or rack
of known pressure angle. You can cut a piece of card stock to the
angle and approximate width to check it. Only verify the angle at
the center of the tooth. The involute profile rounds the top and
bottom plus there is extra clearance in the bottom and usually extra
meat at the top, called the addendum and dedendum. A 29 degree ACME
thread is the same angle, 14.5 each side. Metric gears and fine
pitch instrument gears are generally 20 degrees. JP (16835) |
| South Bend Lathe
used 14 1/2ø pressure angle. For most North American machinery, it
is the standard that was used. You will see 20ø on more modern
machinery, with metric gears With an experienced eye, you can see
the difference. 20ø pressure angle teeth have a much more narrow tip
on the teeth. Guy (16857) |
| There are two
formulae depending on whether the gear teeth are trimmed or not.
Both are simple and both will give you an answer that is
unmistakable. Diametrical Pitch, P, = (N+2)/ D or, P = (N + 1.6)/ D
N is the number of teeth. D is the OD of the gear. At 09:02 PM
1/25/2004 -0500, you wrote: Several posts have included a formula
for calculating Diametrical Pitch when I believe you know # of teeth
and Major Diameter of the gear. I have been to message archives and
have searched DP, Diametrical Pitch and Gear Calculating with no
luck. Can anyone share again that simple formula. Ron (16881) |
| Here is a link for
determining any gear formula you need. Excellent site for lots of
different engineering information.
http://www.engineersedge.com/gear_formula.htm Bill Collins
(16884) |
| 9" B or C
change gears |
| I have six gears
that I think should fit the 9B or C, could someone verify this for
me. The gears are 18dp 3/8 face width 9/16bore with a 1/8 keyway.
The FAQ does not list all needed information. If these do indeed fit
I will offer them to the group first before E-bay. I also found some
gears that had Myford written on them, does anyone know if there is
a group for these lathes. Scott (18973) |
| Yes these gears,
9/16 ID, 18 DP, 1/8 keyway and 3/8 face fit the 9-C. The gears with
MYFORD may also fit. When I was collecting gears for my 9-C (which
is a Model 405 and originally had 20 DP gears) I bought a group of
brand new gears from the UK. I believe they fit either lathe. I
eventually used 20 DP gears all around. Jim B. (18975) |
| Jim, they Myford
gears are 20dp,I have not found out which lathe they fit, not even
sure they are Myford gears as I was just going by what was written
on them with permanent marker. Scott. C. (18976) |
| Myford is a popular
lathe for hobby use in the UK. Glen (18980) |
| Check out this
site:
http://www.lathes.co.uk the gears I 9/16bore (18981) |
| How much is a
set of Change gears? |
| All of the change
gears for my 9C lathe are missing? How much is a complete set of
gears? Or should I just purchase gears as needed? Torfinn (19603) |
| I have paid
anywhere from $10 to $30 per gear on e-bay. I have seen complete
sets go from $250 and up. Nearer to you I have purchased from G M
tools, The Mill, Mill Lane, Ashington, West Sussex, RH20 3BX TELL
01903 892510 (I mentioned them before)24T, 24T, 30T, 36T, 48T, 54T
and 60T gears at a cost of L90 on 27.3.03 These are Boxford Gears
But they fit the SB-9 (That is the SB-9's which uses 18DP gears, not
the early 20DP units) Shipping to the US was L16 Do you have a
"turning" gear and compound gears? Jim B. (19605) |
| Yes I do have the
turning gears, but I am missing one gear and a nut. Torfinn (19608) |
| You need at least a
24 tooth gear. The other gear that goes there is either 16 or 18 I
don't remember which. I have both gears home. The nut is a standard
Inch thread. G M can supply either. I have both and I will not use
them (My lathe uses 20 dpi) don't know how to ship to you however.
Jim B. (19609) |
| Torfinn I checked
to night. The second stud gear is a 16 tooth gear. The nut is a 7/16
- 14. The real nut is larger across the flats than what I can buy at
the Hardware store. Either size will work. There is also a 32 tooth
gear used on the stud. To start turning all you want is the 24 tooth
gear. The 16 is nosier and is used primarily for threading, although
it will give a finer feed. You will need the 16 tooth one for 5
through 7 threads per inch, 20 through 30 tpi and 64 through 120
tpi. The 32 is used for 8 through 16 tpi. the 24 is used for all the
others below 120. If you want to do metric threads you will need a
set of transposing gears. But to start turning all you need is the
24 tooth gear and a nut. Jim B. (19616) |
| Typically I sell
them for $20 a gear. Jeff (19617) |
| 9 Inch Model
"C" Gears |
| Would anyone know
what the two large gears, the "1 to 6 Compound Gear" and the "116
Tooth Turning Gear" were used for? These two gears came with a Model
C I purchased years ago. (21911) |
| I think the 116 is
a super fine finishing gear. I think the 9 'C' I purchased a few
years back has one too. Not sure on the '1 to 6' compound gear. Tom
(21916) |
| With my C, I use a
2:1 and a 5:1 and a 105 Turning gear. This give me a feed of
((105/24)/10)*0.125 = 0.003" per revolution of the spindle. Jim B.
(21931) |
| Mine came with
those as well. Figure a 20t stud gear, and 6:1 reduction, to a 116t
screw gear, with an 8tpi leadscrew, gives a slowest-possible-feed of
[(20/116)*(1/6)*(1/8)]= .0035919"/turn. With an additional 4:1
compound gear in the train, slowest possible feed is .00089"/turn.
Those are some DARN slow feeds. Tom (21938) |
| Gearing for
threading |
| I do not think you
can cut two threads per inch on a 9" South Bend. If you could
somehow figure out how to do it using change gears it would put too
much stress on the lead screw. Using the quick change gear box and
the 40 tooth drive gear, the fewest number of threads per inch you
can cut is 4. (I have never tried to cut 4 tpi but have heard that
even that is hard on the lathe!) Gary P. (24794) |
| In his articles on
building the Quorn tool and cutter grinder Prof Chaddock talks about
cutting such a thread. I won't go into the details of the gearing,
but he ended up driving the leadscrew through a worm drive with a
milling head mounted in the toolpost to do the actual cutting.
Bernard R (24796) |
| Henry writes: I have a
9"South Bend lathe with 4' bed. S/N 8653NR8 and quick change gear
box 644A. Is a one to one ratio between the spindle and the lead
screw available through the gear box set up and how to arrange the
gears to cut threads two to the inch? Others have pointed out to you
that the gear train from the spindle through the gearbox is not
designed to carry the extra torque requirement of the 4:1 stepup
ratio to make the 8 TPI leadscrew cut a 2 TPI thread. It has also
been suggested that if you're absolutely determined to try this that
it would be best to drive the leadscrew and let it drive the spindle
which becomes a 1:4 reduction drive, much easier on the machinery.
Having provided the above warning, any gearing between the spindle
and the gearbox providing a 10:7 ratio and selecting 4 TPI would do
the trick. Likely examples are: 80 stud - any idler - 56 gearbox
(you can't use the 80 idler for the stud gear because it doesn't
have a keyway). 40 stud - any idler - 28 gearbox (you'll have
difficulty finding a 28 tooth 18 DP gear). 50 stud - any idler - 35
gearbox (requires 2 nonstandard gears). 60 stud - any idler - 42
gearbox (42 will be hard to find). 40 stud - 2:1 stepup - 56 gearbox
(the 2:1 stepup gears replace the usual 80 idler). The change gears
don't fit on the standard idler stud, you have to get or make a
special stud and sleeve arrangement to replace the standard one. If
you decide on this option, likely gears are 48 and 24. The setup
would be: 40 stud driving 24 on intermediate stud, 48 also on
intermediate stud driving 56 on gearbox. To repeat, in each of the
above setups select 4 TPI on the gearbox. And another repeat, I DO
NOT RECOMMEND ANY OF THESE SETUPS, especially if the motor drive is
to the spindle and the spindle then drives the leadscrew. Anthony
(24885) |
| Henry writes: Anthony, I appreciate
your prompt and well written response to my question about
threading, but I find I erred and I need to know the gearing set up
for three threads per inch. Can you furnish that? The most obvious
solution is: 40 stud - any idler - 42 gearbox, select 4 TPI. Again,
42 is an odd gear. There are other solutions, such as: 40 stud
driving 36 on intermediate stud, 48 also on intermediate stud
driving 56 on gearbox, select 4 TPI. The 36 and 48 can be replaced
with any combination that will result in a 3/4 ratio. It depends on
what gears you have or are willing to acquire. Anthony (25191) |
| Henry, Another
obvious one slipped my mind because it was early in the morning when
I made my last response. 40 stud driving 24 on intermediate stud, 48
also on intermediate stud driving 56 on gearbox, select 6 TPI, will
result in 3 TPI. Again, any combination which will result in a 1/2
ratio at the intermediate stud will work for this. Anthony (25192) |
| What gears
come with SB Lathe |
| What gears were
ship on SB 10H,13,14 1/2, 16 and etc. that had QCGB by South Bend?
On a Model A 9 inch it came with 20T small stud, 80T Idler and a 56T
on the gear box plus a stored 40T which was to change with the 20T.
What was the set up on other SB lathes? My reason for asking is
this. If one is looking at a used SB lathe we would need to know if
it had the right gear combo with it . Dave (25373) |
| Keep in mind that
those sets of gears would also depend on whether the lathe had a
single-tumbler or double-tumbler QC gearbox. Arne (25383) |
| Dave, My 1952 13'SB
with two tumbler QCB comes with: 24 tooth stud gear (mounted), 48
tooth stud gear (Stowed) for cutting 4,4-1/2,5,5-1/2,5-3/4,6,6-1/2,7
tpi threads or high traversing rate feeds. 80 tooth idler gear. 54
tooth screw gear on QCB input shaft. The not in use stud gear is
stowed on the QCB input shaft next to the screw gear. Nick (25384) |
| I am really
interested in just double tumblers QCGB lathes. I should have put
that in our first post. Dave (25395) |
| 14-1/2" and 16"
2-Tumbler QCGB lathes: Stud gear: 24T Idler gear: 80T Screw gear:
64T Extra Stud gear: 48T (25396) |
| Nick writes: My 1952 13'SB
with two tumbler QCB comes with: 24 tooth stud gear (mounted), 48
tooth stud gear (Stowed) for cutting 4,4-1/2,5,5-1/2,5-3/4,6,6-1/2,7
tpi threads or high traversing rate feeds. 80 tooth idler gear. 54
tooth screw gear on QCB input shaft. The not in use stud gear is
stowed on the QCB input shaft next to the screw gear. This is a very
odd combination. I understand the 9", 10K, and 10L, which use 20 or
40 stud, 80 idler, and 56 screw gear. This is related to the fact
that the final drive from the gearbox is the 28 in the cone driving
a 20 on the leadscrew, leadscrew being 8 TPI. It's my understanding
that the leadscrew on the 13" and larger lathes is 6 TPI. Can
anybody verify the 6 TPI and tell me what the gear on the leadscrew
that meshes with the cone is and whether it meshes with the 28 on
the cone? I'm trying to get the same grasp of the larger lathe
gearboxes that I have of the smaller ones. Anthony (25400) |
| Dave and all others
taking interest in this matter, After seeing this Post, I must amend
my count, the screw gear on my 13" 2-tumbler QCGB lathe is also 64T.
I figured the larger lathes would use the same gear ratios, just
larger parts. Sorry about my inability to keep track of how many
times I counted to ten may have caused. Nick (25401) |
| The leadscrew on
our 16" is indeed 6-TPI. The leadscrew gear is 24T and the gearbox
cone gear that this meshes with (3rd cone gear from the right) is
also a 24T. The 28T cone gear is the first (and largest) cone gear
from the right. Arne (25404) |
| Nick writes: After seeing
this Post, I must amend my count, the screw gear on my 13" 2-tumbler
QCGB lathe is also 64T. I figured the larger lathes would use the
same gear ratios, just larger parts. Based on this information, it
appears to me that the 13" and larger lathes all have a 6 TPI
leadscrew and that the 28 in the gearbox cone drives a 28 on the
left end of the leadscrew. Can anybody verify these guesses? Also,
does anybody know which model of SB lathe was the first to use a
2-tumbler QCGB? Anthony (25413) |
| Anthony, If my
ability to count gear teeth has improved since yesterday, what I
found on my 13" SB with QCGB. a) The lead screw is 6 TPI B) The 3rd
largest gear of the cone drives the lead screw gear C) both of these
gears appear to have 24 teeth. The gear on the lead screw is hard to
count the teeth on as it is not very accessible. Does this make
sense, as I am not at the point were I am trying to make sense of
any of this. I am just trying to help when I think I can.
Nick (25425) |
| Arne writes: The leadscrew on our
16" is indeed 6-TPI. The leadscrew gear is 24T and the gearbox cone
gear that this meshes with (3rd cone gear from the right) is also a
24T. The 28T cone gear is the first (and largest) cone gear from the
right. Hope this helps! Arne, Absolutely! The reason I speculated
that there was a 28 meshing with the 28 was I was looking for a 1:1
output ratio. From my knowledge of the 2-tumbler gearbox for the 9",
10K, and 10L lathes I thought SB had an aversion to extending the
leadscrew out far enough to run a 24/24 ratio. If they'd done so on
the smaller gearboxes they could have avoided the silly 56 tooth
screw gear which creates a non 1:1 or 1:2 ratio in the primary gear
train, between the stud and the gearbox. In fact, 24/24 is much more
in line with common practice. Because of other gearing within the
box it's desirable to have all gears using the same DP and shaft
centers separated by a distance suitable to a total tooth count of
48 teeth for gears meshed together. 28/28 doesn't meet this
requirement but 24/24 does, as does 16/32 (that last combo is a
clue). In any case, thank you for the information. It all helps.
Anthony (25432) |
| Anthony, something
I forgot to mention in my post was that I noticed in the parts
manual that the 10L with the standard 2-tumbler gearbox and the 10L
with the wide-range gearbox have different part numbers for the stud
gear and the screw gear (The idler gear is the same on both). Don't
know if this would mean different number of teeth or some other
difference. Arne (25434) |
