| SB 11" Gearbox question?
(Oct 1, 2001) |
Quick change gearbox problem?
(Jan 27, 2003) |
| QC Gearbox (Jul 10, 2001) |
How much for a gearbox
(Feb 7, 2003) |
| Gear box (Dec 7, 2001) |
Tumbler shifter? (Feb 23, 2003) |
| Heavy 10 Gearbox Question
(Jun 26, 2002) |
Calculating Gearbox Pitches (Mar 26, 2003) |
| Heavy 10" QCGB
Question (Jul 31, 2002) |
10"
QC Gearbox thread ranges (Jul 3, 2003) |
| QC Box Problem (Newbie)
(Aug 23, 2002) |
Gearbox thread charts (Nov 16, 2003) |
| 9" gears or gearbox? (Nov
6, 2002) |
9"
gearbox DP (Nov 25, 2003) |
| Quick change box ?s (Nov
16, 2002) |
QC
gearbox questions (Dec 24, 2003) |
| Gearbox "backlash" (Dec
5, 2002) |
Gear box ID (Mar 7,
2004) |
| Broken lever on QC gearbox
(Dec 12, 2002) |
Gearbox ratios and input gear
for metric lathe (Nov 20, 2004) |
| Rebuild QC box? (Dec 18,
2002) |
Any source for a 10K QC gear box
shift lever? (Dec 3, 2004) |
| Two levers or one? (Jan
23, 2003) |
Double tumbler vs single tumbler
(Mar 10, 2005) |
| |
| SB 11" Gearbox question? |
| I have recently
acquired a GB from a 11" SB. It is of the single tumbler version.
Planned use: I have a Burke No 4 Horizontal mill that I hope to
attach/adapt it to; like the little Atlas horizontal mills that have
the QG box for feed control on the table. Question: What's the
number of teeth on the gear (stud gear) on the GB (left side), and
what's the number of teeth on the gear (idler gear that mounts on
the fork) that drives the gearbox gear. This info will help me set
up the GB, and try to maintain the same feed ratios. Carl
(1668) |
| Coming off the Fwd/rev lever there is
either a 20 or 40 tooth gear - you switch these back and forth to
add a few more feeds. Any large idler gear on the fork (80 teeth
say). A 56 tooth gear on the input shaft to the gearbox. Note that
the threaded part of the GB input shaft is twice the width of a
single gear. Put the 40 (or 20) tooth gear on top of the 56 tooth
gear to fill the space and store the extra gear. Bill (1674) |
| QC Gearbox |
| I managed
to fabricate a replacement gear for my gear box. I reassembled the
lathe and tried it out and the gear works fine. The only problem I
have now is that the cone gear lever doesn't want to engage when I
have the notched bar that locates the levers installed on the
gearbox. The alignment of the cone gears with the notches is off.
There also seems to be quite a little end play (0.075" to 0.100") on
the shaft that the gears run on. I suppose that I need to put some
shims between the gears to take up the play and line up the gears
with the notch locations. Any advice? Glen (1061) |
| I just had some problems with the
QC on my old Sheldon Sebastian and ran into a similar situation upon
reassembly. Turned out I had a spacer in the wrong place. You might
want to double check for that. (1067) |
| Gear box |
| Could someone tell me if it is possible to mount a gear box
from a SB 10" lathe on a 9" lathe. What would be involved in a swap
such as this if it is possible. Gerald (2353) |
| It depends on a few things. Is it a Heavy 10" or Light
10", is it a top lever box (not sure they used them on tens), and
how keen are you on drilling holes in your bed? If the box is the
later 2 front lever, off a light ten, and you are willing to drill
and countersink a hole in your bed, it's fairly easy. A quick rundown: *
You need a leadscrew off a model A OR you can shorten your current
leadscrew (complete with taper pinned collar, keyway for drive gear,
and thread for end nut) * You need a leadscrew drive gear from an A.
(i.e. if your box is off a lathe with the same bed length as your 9"
try to get the leadscrew) * You will need to drill a mounting hole
in the bed for the right end of the box. * You will need a sector
arm (gear carrier) off an A model. The B and C model arms won't
clear the gearbox. That's about it. The model A leadscrew will also
give you the keyway to drive the power apron (unless you have a
model B, in which case you already have it). Frank (2354) |
| Heavy 10 Gearbox Question |
| I want to restore my heavy 10, it
is of WWII vintage. I believe it is a tool room version, quick
change gearbox, and taper attachment. This has the earlier QC box
with one tumbler. How does this compare with the two tumbler
version, just a strong ?, just as useable?? I know to make a setting
can involve three setting one the lathe, and that is OK. but in
working this lathe over, would it be of nay advantage to switch to
the new QC box? Stan (4765) |
| Haven't been in Huntington
Beach for at least 5 years, lovely place! I don't know if the two
tumbler style offers any functional advantages over the single lever
version, other than not having a sliding gear cluster on the banjo
as you noted. My '29 13 incher has the single tumbler gearbox, quite
worn, which still does the job, my 9 is a change gear model, so I
have no frame of comparison. Do keep after the lube on the banjo
gear shafts though! My lathe was a real rusted hunk, now mostly
restored/refurbed. The folks who ragged it out apparently never
lubed these shafts, and I ended up boring out the gears by around 15
thou and making new shafts. Those shafts with the multiple oil
grooves, ball stop detents, and angled oil feed holes intersecting
the oil grooves aren't as easy to make as you might think. If yours
are in decent shape keep them that way and save yourself a headache
:-) If cutting metric threads is an important issue for you, you
might have to change gearboxes and banjos, as the banjo for the
Feller (top lever) gear box doesn't have any means for mounting
transposing gears - at least on one as old as a '29. The newer
models may have accommodated this requirement. Stan (4771) |
| It sounds like we have the same lathe. Mine
says catalog number 187Y and the serial number is 98348 - is that
close to yours? I am not sure my gearbox is any good (the rest of
the lathe looks okay and it only cost $20). (4788) |
| Heavy 10" QCGB Question |
| The instruction plate on my WWII vintage heavy 10
lists 3 controls: the lever with 8 different settings, a sliding
gear that can be "in" or "out", and a top lever with 3 settings -
left, center, and right. There is a small lever sticking out of the
top of the gearbox that has 2 positions that work, and possibly a
third one that does not. Is this the sliding gear? If so, what is
the top lever? If the lever on the top of the gearbox is the top
lever, what is the sliding gear? (5505) |
| The lever has 3
positions: Left, Right, and Center. It may be stuck, partly from
years of accumulated gunk. Try fiddling with the lead screw (roll it
back and forth) as you try to shift the lever. It should lock into
place. The sliding gear is directly under the spindle, by about 8
inches, and has a little knurled portion on the knob. As you slide
it in or out, different gears mesh together from that axle and the
one driving it. One pair is big-to-small, and the other pair is
small-to-big. This changes the drive ratio greatly, by a factor of
8, if you check on the chart. Try taking off the back cover and
you'll see how it works. Jon p.s. my Heavy 10
has a serial number that is above 148,000, and was made in
1944 (5509) |
| QC Box Problem
(Newbie) |
| I have just got
myself an early SB 10L Heavy Toolroom Lathe (Heavy is right - my
back can attest to that!). I'm embarking on giving this nice bit of
machinery a birthday and then intend have many happy years of using
it. Would someone please steer me in the right direction re removing
the two gear clusters from the single-bottom-lever type QC Box. The
QC box has accumulated an impressive amount of swarf and gunge which
I would dearly like to be rid of! (gears look ok though). Dave (5955) |
| I took my 9"
gearbox apart and there was a taper pin or two that needed to be
pounded out (more like a good tapping) first. Then the rod that the
gears ride on can be tapped out. Mine had 60 years of gunk and came
apart fairly easy. Just remember how you took it apart as the
diagram is not helpful enough to put it back together from a box of
gears. Alex (5957) |
| Just in case you wanted to avoid the work and risks of
disassembly! unless there is a lot of known abrasive grinding swarf
in the gearbox, it's probably unnecessary to dismantle it. a good
way to get the grunge out is to take it to an old-fashioned service
station that has a parts washer and have them put it in there
overnight, or put in in a 5-gal bucket and cover it entirely with a
good solvent. I use paint thinner for a slow breakdown to save the
outer paint and labels but there are better ones, I have heard
kerosene and diesel work well but have a lot more odor and leave it
on the parts longer, and take many paints off with them. this
solvent action will break up most of the hardened oils and then you
can wash out the chips and residues. using gasoline may make you
wish you didn't because it has additives that bond to metals and the
smell stays on there for a really long time. Both Coleman fuel and
naphtha seem to evaporate off OK though. the same batch you use for
the gearbox will work fine for the apron and spindle if you are
going to do them too, just let it sit for a few days and decant off
the light colored part for re-use, most of the greases and gunk will
settle to the lower layers. Removing the main shaft that the
selector handles ride on may be a good thing because these often
work up burrs and scratches from operation. the gears on the other
shaft are not often too dirty ( grease yes, but swarf etc -no.) and
can be cleaned with solvent bath and brushes, doesn't need removal
from the shaft. my first one was used in a metal and then a woodshop
and had 50 years or more of grease, metal, and wood packed in there
like glue - it all came out really nice with some diligent scrubbing
and the shaft operation is wonderful. I used brake and carburetor
cleaner and some small scrapers and brushes to hit the really
hardened spots at the gear roots and a few other nooks, and was very
glad I didn't have to tear it down. Putting a witness mark on each
one of those hardened parts is very difficult if you think you can
mark it all then tear it down and re-assemble. I wouldn't even think
of starting disassembly without a digital camera to give you pix to
work from and back to. the cleaning is NOT that much easier and no
faster on the separated parts. I elected to hand lap/polish the
selector handle shaft, touched up any scratches in the bores of the
handles and their gears with extrafine cratex, and the mating side
surfaces just to be sure there were no burrs from way-back that
would work up more scratches, now it's working like a newly
broken-in unit. these gears are really hard metal, don't expect
anything softer than carbide or diamond to touch them for polishing
or deburring. btw - there are a lot of ways to make an OOPS in
breaking down the apron and the gearboxes, that can cost you a lot
of heartbreak with parts and re-assembly and then fixing up the
damage if something isn't quite right. Parts can get lost, screws
stripped or slots and heads damaged, springs and their mating little
parts can just fly away, pieces get broken, cracked, dropped and
dinged, pins get bent or peened, shafts scored, numerous ways to get
ugly scratches just from trying to hold the thing in a clamp or vice
- unless you really have the urge, tools, and skills to take it ALL
apart or it is really broke and has to be fixed, there's a lot to be
said for getting it clean without disturbing the alignment of the
parts and the good status of all the pins etc. most machine
mechanics subscribe to the principle that you don't have to tear it
all the way down to its bearing balls to clean it up and make it
work like almost new - clean it in place first and then check for
actual wear on parts and replace or restore what needs it. You can
feel how much play and if there is appreciable grit in there after
you clean it if you put a little very light machine oil on it -
3-in-one or wd-40 is a good start. This technique works on the apron
but I would not suggest it on the cross-slide, way too much dirt and
grit gets in there - needs torn down to get at some of it.
(5982) |
| Dave, I'm also the
new owner of a very old heavy 10. I sent away for the parts manual
and the machines "birth certificate" which is really useful and
knowing something about the machines history is pretty cool too.
Mine was sold to the Wright Aeronautical company in Cincinnati in
1941 and subsequently found it's way to the Air Force, probably
Wright-Patterson AFB, which is where I work. so it is well used, but
I love it anyway. It has a couple of problems that I want to take
care of, and like you I want to give it a good cleaning. One of my
problems is in the gearbox, so I do need to disassemble. The parts
manual is a big help as it shows the pins and screws involved, if not
the exact location. Go slowly and use a brass punch to coax the bits
apart. Make sure you have all the pins and screws accounted for and
if the assembly doesn't move under gentle tapping, stop and find out
why. Mine has come apart without much trouble until I got to the CL
shaft (find number 35 on form 915-B). It appears that the key must
be removed before the shaft will slide out, and I'm struggling with
that. Does anyone have any suggestions? The shafts have worn the
case at the non-bushinged end. I'm thinking of adding bushings to
this location. Does anyone have any thoughts on this? I'm also
having some trouble removing the clutch shaft from the apron. Is the
clutch shaft nut right hand thread, and what is the best way to hold
the shaft from turning while trying to remove the nut? (5988) |
| The machine screw
retaining the clutch knob is LH, but both the knob itself (which
threads onto a pull rod that goes back to the clutch plates at the
back of the assembly) and the large nut which retains the shaft that
passes through the front wall of the apron are RH. Can you tighten
the clutch enough to use that to hold the shaft while loosening the
nut? Otherwise, the only thing to hold is the gear on the shaft
(which turns an idler gear that in turn drives the longitudinal and
cross feeds). Perhaps you can remove the idler shaft, and then use
some kind of pliers (with suitable protection) on the gear that is
part of the shaft. Frank (5991) |
| One
trick you can try for getting tight keys out is the application of
some CRC or similar - leave for a while - thump with a drift hammer
to shock it loose (not too hard or you could spread the key making
things worse) . This often loosens the key enough to to pull it out
(sounds brutal but it often works). More brutality is to 'ding' the
key on its end just above the shaft (if you can get at it) with a
chisel and lever the mother out. The history of my Heavy 10 is that
it's been in the Broadcasting Industry most, if not all of its life
and ended up in a television studio complex which is where I work -
this is in New Zealand. Would you mind telling me where you got your
parts manual from - assume it was LeBlond. Dave (6000) |
| Frank, I wedged a corner of a shop towel
between the gears and the nut came lose. It took enough force that I
would have been concerned that it was left handed. I now have the
apron disassembled and all looks good. (6021) |
| 9" gears or
gearbox? |
| I recently
picked up a 9" Workshop C and it didn't come with any change gears.
Anyone know where I could find a set of change wheels? Or would I be
be better off putting a model A gearbox on it? There's a gearbox on
Ebay right now, but I don't know what else I'd have to change to
mount it. Mark (7008) |
| Mark, Check out
the files section:
http://groups.yahoo.com/group/southbendlathe/
There has been a lot of discussion of the subject on the list, too.
Search the archive for "conversion". If this generates more specific
questions, feel free to ask 'em. I did an A to C conversion as did
Clint and several others on the list. Glen (7009) |
| Mark, I would say a
set of change gears would cost around $80. They do come up on E-Bay
from time to time. I am in the process my self of a 'C' to 'A'
conversion. You would need to get an 'A' lead screw, or a 'B' lead
screw and shorten and thread the one end, or cut a keyway down your
'C' leadscrew and shorten and thread it. You will need to drill one
more hole in you lathe bed to hold the change gear box. You will
also need the gear that goes on the end of the lead screw. I think
Lurch is still checking a price on that gear and fit. QC boxes have
been going a bit cheap on E-Bay of late, around $100. That is with
out a leadscrew. I think the dealers get $300 with a leadscrew. Let
the board know how you want to proceed. I think another member has a
few sets of change gears. I'm not quite ready to sell mine, but if
no other offers let me know. Tom (7013) |
| Thanks for the info. I'm
not too pumped on drilling another hole in the lathe (I'm supposed
to be working on my race car, not my tools! :-). For the occasional
times I'm going to need to thread stuff, a set of change wheels
would do me fine. So, if anyone has a set of good working condition
change wheels they'd be willing sell, I'd love to have them!
Mark (7014) |
| Mark I would like
to add, if doing a full conversion to an A, you will need to obtain
the Saddle and apron/carriage for the power cross feed. This is not
completely necessary to do, but only if you want a full conversion.
While shopping for the leadscrews, you can buy a longer screw if you
find a good deal and cut it down very easily. If you find a mod A
screw, make sure they include the gear that goes on the end where
the QC box dives it. Clint (7021) |
| It is not big
deal to drill the mounting hole in the bed if you ever do decide to
convert. I think that the C will suit you fine also, just a little
effort to change gears for different thread cutting. You can find
the change gears on ebay from time to time. Clint (7022) |
| Quick change
box ?s |
| I have the box off
of my 9" A and did some heavy cleaning. Got enough metal out of it
to build a tailstock. It was packed. I'm wondering how much play
should be in the drive train?? or perhaps put differently, how much
rotation should occur of input shaft before motion is detected in
the output shaft? What is the impact of excessive play? There is
noticeable wear on some of the gearing and some play in the shaft
end bearings. (7325) |
| I
wouldn't worry about play in the gearing as long as the gear box is
smooth running and there is still plenty of tooth engagement. All
cutting is done under load so the "back lash" is taken up when the
tool hits the work. Just make sure that you start the tool a bit in
front of the work when threading. End play in the leadscrew itself
can be shimmed out or machined out by removing a bit from the
shoulder where the drive gear seats. Glen (7459) |
| Gearbox
"backlash" |
| Somebody asked a
question about how much slop one could expect in a gearbox. I
checked my 9" A and in the A range (fastest feed coarsest thread) is
see only a little, maybe 5 degrees or less. On the "E" range
(slowest feed finest thread) I see about a half turn on the input
shaft between feeding forward and feeding reverse. Glen
(7795) |
| Glen, In
comparison to your findings, my gear box seems to be the direct
opposite. Unfortunately, when I first received the lathe I did not
note any of these instances. I immediately stripped down the machine
and began the cleaning and repairing process; so I was not sure if
this was normal or not. Jeff (7800) |
| This makes sense.
Every time you double the TPI you throw in an extra pair of gears.
Each pair of gears has some clearance between the teeth. Anthony (7811) |
| Broken lever
on QC gearbox |
| I just bought a gearbox off of ebay for my 9" south bend
lathe. The post office dropped it it wasn't insured. It is the
double lever type the left lever broke. The box has a catalog number
544 R. (all the inside gears are good) Also I need the gear that
goes on the left side or can I use the one on the lath now (It is
the standard gear change type) On the lead screw, do I use mine just
modify it or do I need a different leadscrew. Mike
(7942) |
| Mike, Are the
pieces of the lever all there? Perhaps you can braze the bits back
together. The leadscrew you have would have to be cut down and
rethreaded and a keyway cut for the gear that you mention. If you
are also adding power cross feed, you need to cut a keyway down the
entire length for the key in the apron worm gear. Most of the time
the gear is sold either with the gearbox or with the leadscrew. I
just bought a worn out leadscrew from Pete Swelzen in Libertyville,
Illinois to get the gear for our Dutch friend Bert. I recently
bought a SB handwheel from an eBay seller Hutchwood. He said he had
been to an auction at the South Bend factory and bought literally
tons of stuff. He said he had two pallets of lead screws. I haven't
seen any of them on eBay yet, but you could email him and ask. He
might need some help in identifying exactly what he has got. This
may be the reason they aren't up on eBay, yet. Glen (7945) |
| Mike, I forgot
to mention the input gear train set-up. You need to get a 20 tooth
gear for the stud gear. Talk to Lurch about this. You need a large
idler gear, typically 80 tooth. you need a 40 tooth gear for the
stud gear end to get the coarsest threads listed on the gearbox
nameplate and you need a 56 tooth gear for the gearbox input. The 40
tooth normally is used as a spacer sitting on the end of the gearbox
input when you aren't using it. Most of these gears should be in
your change gear stack already with the exception of the 20. Glen (7946) |
| Mike You might
contact Dick at Bridgeman Machine in Detroit; real nice guy to deal
with has parts. Matter of fact I just bought 2 handles from him for
a 13 Southbend; different casting number. Though. Phone number is
313-366-1060. Lew (7948) |
| It is the double
lever type the left lever broke. Mike Hi Mike, If the lever isn't
too fractured, maybe you could braze it back, or arc weld it with a
nickel rod (or have it done). There are some notes on welding cast
iron in this months online newsletter from Lincoln. The lever appears
most likely to break across the bend between the gears the pin. That
looks like it could be jigged up to fit well, since you have the
other one for a model. Best of luck to you. It's a real
disappointment to buy an important part and have it damaged in
shipping. Mike (7956) |
| Mike, I have
repaired a couple of handles that have broken including the gearbox
tumbler lever. If the fit-up of the pieces is good, you can braze it
back together. This is what I did and the repair was undetectable
after the lever was repainted. If you are familiar with
Oxy-Acetylene brazing, you could repair it yourself. The important
thing is to fixture the lever while brazing so that the spring
loaded detent knob will index properly with the holes in the gearbox
housing. In my case, I removed the knurled knob and spring loaded
detent from the "nose" of the lever. I temporarily glued the pieces
together and used high temp. foundry/casting plaster to make an
impression of the lever. I made and mounted an alignment rod to keep
the "nose" aligned correctly. After the plaster had cured, I removed
the lever and undercut the plaster in the area of the break so that
the heat could get all the way around the break. Then, I separated
the pieces and dressed the butting surfaces before brazing. Then I
place the pieces back in the plaster impression and brazed them
together. After cooling, all that was necessary was to clean off the
excess flux and braze (a little milling was required around the key)
and repaint the lever. If the parts don't fit well, then the repair
becomes more difficult to do. Webb
(7962) |
| Glen, my lathe
already has power feed. The lever broke just under the spring loaded
part is all there. I thought about brazing or trying to JB weld it.
I suppose I can't Mig it due to it being cast. I guess that I would
need two gears One for the left side of the gear box the one that
would go one the leadscrew inside the box. By the way, I do have a
full set of change gears to try to get the correct combination. Mike
(7964) |
| Mike, The one gear
you need that is not commonly part of a change gear stack is the 20
tooth gear. This is the first gear in the train on the reverse
tumbler assembly for all but the coarsest thread settings marked on
the QC gearbox. These are scarce because many people upgrade their
C's or B's to A's. I was lucky in that I got the 20 tooth gear with
the gearbox I bought for my conversion. Lurch has done a nice thing
for the whole list by finding a source for the 20 tooth gear and
buying the entire inventory. I am helping Bert our Dutch list member
collect the parts he needs to fix his lathe and I have bought this
gear from Lurch. The output gear is not so hard to find, but you
will probably not be able to get it by itself. Most sellers will
keep it together with either the gearbox or the leadscrew. If you
didn't get it with the gearbox, you will probably have to buy a
leadscrew with the gear on it. This is what I had to do for Bert.
Your model B leadscrew will have to be cut down, rethreaded for the
nut, keyway cut for the gear and the collar moved. This sounds like
a lot, but it is really pretty straight forward if you have a lathe.
Glen (7966) |
| Glen, there would
be no problem on cutting a keyway if needed, as I bought a
Bridgeport J-head mill from my place of employment in sealed bidding
about 5 years ago. If I can get the gears replace my lever that
would be a very good start. Mike (7967) |
| Another way to fit
an existing Model C leadscrew to a new QC gear box using your
existing lathe is to cut to length, keyway cut for the gear, move
the collar and then, rather than rethreading for the nut to hold the
20T gear on, drill and hand tap the end of the leadscrews for a screw
and washer to hold the gear on. This way you can do the whole job on
your lathe that your adding the QC gear box to because you do not
have to do any threading just straight turning. I did mine that way.
It works beautiful and the whole process was much easier and done on
my lathe that I was adding the QC box to. Neil (7971) |
| Rebuild QC
box? |
| Is it
feasible to rebuild a 9A quick change box? The toggle gears are
badly worn and the cluster shaft case hole is egg shaped. the rest
of the gears have wear but not too bad. It all works but it is
sloppy. Set at 224 TPI, I get 270 degrees of input rotation before
the output shaft moves. A little out of spec I would think. Are
parts available without having to get a loan? (8096) |
| I
would think you could re-bush and bore-bush the offending holes
pretty easily. I still have an extra QC casting and some parts for a
second QCGB from my 9" model A if you are real desperate. All that
said, as long as the QCGB does not bind or jam, the amount of slop
from input shaft to output shaft makes no difference. You just need
to make sure you start each threading pass far enough away from the
actual thread start to wind up all the backlash (or wind-up the
backlash by hand each pass). You will always have a bunch of
backlash between the spindle and the carriage. Lead-screws are
notorious for backlash -- both in the half-nuts and thrust bearings.
Paul R. (8111) |
| Paul, Our
friend Bert in the Netherlands is looking for a replacement gear for
his QC box. He needs one of the larger ones that goes on one of the
the levers. Can you help him? Glen (8116) |
| The gear he
needs is the one mentioned here:
http://groups.yahoo.com/group/southbendlathe/message/8039
Glen (8117) |
| Randy was
offering me a gear to this evening Great work guys!! I make my self
the gear I have sent the pictures to Anthony. I have not so much
faith in the gear where I created a new tooth its a gear 2 gears
together 1 16 and 0ne off 32 teeth 16 DP the 16 teeth gear I
repaired but I am not really happy with it also asked Randy Phillippe
for that gear to I forgotten to inform you about this (8118) |
| Two levers or
one? |
| I noticed the
pics of the nicely restored 10" Heavy. Beautiful job. The gear box
has (or at least all I could see) just one lever. My 10" Heavy has 2
levers on the gear box. Are there different models of the 10" Heavy?
Eric
(8852) |
| That's
the older gearbox. Known as a single tumbler gearbox. Some call it a
Flather gearbox. I'm not sure about that connection, but Flather made
lathes and gearboxes in the early 1900s. I think I read that in www.lathes.co.uk RC
(8858) |
| Quick change
gearbox problem? |
| I
just purchased a South Bend lathe on eBay. This is my first lathe. I
purchased the South Bend "How to Run a Lathe" book to try to understand
what was going on with the lathe (I thought it was pretty poor for a
newbie). At the ripe old age of 59 I may have gotten scammed but not
sure. My problem is with the gearbox: is it broken or am I doing
something wrong. I have the following machine; 10"(L) toolroom
(8187RN), underneath belt motor drive with a 4.5' bed. Serial Number =
134118 (has a metal plate that said it complied with War Production
requirements!). It is mounted on a sheet metal bench with curved
tubular legs (see page 102 in the SB book for a shorter version of the
bench/lathe). At this point I have not turned it on because I want to
first understand what all those levers and wheels do (the fact that the
power cord had been removed by the seller reinforced that decision). So
I started doing a little cleaning and oiling. I explored the carriage
and how it worked. I took off the cover for the gears and turned the
spindle by hand to learn about the mechanism (shift lever, etc.) Then I
got to looking at the lead screw and noticed that no matter how I
engaged the "Top Lever" and the bottom lever on the gearbox, the lead
screw never moved. I would think that it would turn as I rotate the
spindle by hand since the feed reverse level is engaged (and with the
gear cover off I do see that the gear delivering power to the gear box
input shaft is turning). The gearbox's top lever moves just a few
degrees in either direction. I can hardly tell the difference between
left, center, and right. I also used a mirror and flashlight to try
look from the bottom to tell what was happening but couldn't tell much.
Peering in from left end of the gearbox I can see the input shaft
turning inside the box and if I turn the lead screw by hand I can see a
gear on the end of it turning (just slightly above the input shaft's
"gear teeth"). The bottom gear change lever moves very stiffly. I
wanted to look inside the gearbox but removing the gearbox looks like a
major task (I don't have a lot of specialized tools or skills but if
you know how to do it and it doesn't take exotic (for the household
handy man) tools please tell me) Basically the lead screw is getting no
power. What could I be doing wrong? If it is broken, is there a
reasonable fix? I would appreciate your input (soon if possible since I
may need to have a heart to heart conversation with the seller ). Hugh
(8942) |
| Hugh If all
the parts appear to be there, then there may just be a sheared key?
If all the drive gears from the spindle to gear box are there, I am
not sure what the gearing is on the 10L. The gear box should come
off easily enough if need be. There may be others to chime in on
other methods than what I mention for the 10L You will need to
remove the leadscrew bearing on your right and there should be three
screws coming from the top way down through the gear box. This is
done after removing the saddle and carriage. Keep in mind before
doing all this, check out all your options first. Depending what
gear it is in, the leadscrew is not going to turn as fast as the
input gear, so doing it by hand, you may not be seeing the little
amount it is turning. I would try this, go ahead and wire the motor
in and start it up. Then see what is happening with the motor and
headstock, and then engage the forward/reversing lever and see what
is happening from the gear box. If you cab not get power out then a
keyway may be sheared or even missing. Lets just hope that the teeth
on a gear is not sheared. I do not think there is a lot of harm
could happen by starting up the machine Let us know what happens.
Clint (8946) |
| Clint
I am going to make comments below
within the body of your response to bring you up to date. I'll mark
those with "@@@@" and insert " my text inserts bump a line of your
text to a new line. GOTO Clint's response RETURN TO THIS POINT when
finished reading through my comments embedded within your text.
Which levers can be moved while the motor is under power? I adjusted
everything and then turned on the motor which I am sure is a strain
on the motor, the gearing, and it dims the lights! I purchased this
lathe to pursue my hobby interest in robotics (which will be of a
large, autonomous, not r/c type) and I will also need (well maybe I
should say "want") to purchase a mill (perhaps a drill/mill? ENCO?).
I jumped on the South Bend because I had heard they were so much
better than the imports like say the Birmingham. On the other hand,
a live plow mule beats a dead racehorse every time. The fact that
getting power to my garage will cost several $1,000 (long story)
made the 110 volt motor on this eBay item appealing. Would
appreciate any thoughts on repair parts/ availability. Again, thanks
you very much for your help to this point! Hugh League City, Texas
(near Houston) No "white" or "black" wires and certainly no "green"
one. I did use a 3 wire cord and attached the green wire to a screw
in a terminal box that apparently had been added some time in recent
(the last 40 years!) history. As a precaution I didn't touch the
machine while plugged in and had all levers in position when I
started it up and stood on plastic!. I'll take a few voltage reading
between the machine and ground to ensure safety) missing. @@@@
That's
what was worrying me. As I peeped into the left side of the gearbox
the gear teeth machined into the shaft of the input shaft (I am sure
there is a descriptive name for a shaft constructed like this) were
very close but did not touch a gear wheel that would turn when I
manually turned the lead screw. Upon reflection and further
restricted "peeping" I am thinking those maybe were not meant to
mesh so I don't know at this time if teeth are sheared. @@@@ Are
there replacement parts available for the gearbox. assuming I get
that removed? @@@@no smoke or bolts of lighting..just dimmed the
lights briefly. @@@@Can ANY levers be shifted while under power?
Once powered up I didn't adjust levers such as the
"forward/neutral/reverse" lever, the "backgear" lever, the big lever
that puts tension on the flat driving belt, the top and bottom
gearbox levers, or anything on the carriage/apron. The carriage lock
down bolt is loose so I can manually feed the carriage and I can
manually turn the lead screw. (8952) |
| Hugh; I'll
try to explain the way these critters work so you can figure out if
it's an adjustment, missing part, misunderstanding of how it works,
or something bad (hopefully not the case!) I also have the top arm
style gearbox on my '29 13 incher. There may be some differences
between our gearboxes but they will be minor. Just to be sure, you
are sliding the 8 position swinging arm lever to some point where
the slot in the plate screwed to bottom edge of the gearbox lines up
with the boss on the gear change arm, and raising the lever up and
engaging the plunger pin in the hole? Please don't be insulted by
this, it's just that you mention this is your first lathe. On these
top lever gear boxes, you can see the ends of the shafts from the
carriage side. This lets you get some ideas without laying under
things playing with mirrors and flashlights. Check first: The shaft
directly below the leadscrew is the opposite end of the input shaft.
It should be turning whenever the reverse tumbler is engaged (either
direction, just not in the center. If it isn't, either the input
shaft is sheared or the input gear is loose/off the shaft/ the banjo
is swung out of mesh, the gear train for some reason (gear left off
is common, tumbler not engaged) isn't providing input to the
gearbox. The lower of the two shafts towards the front is driven by
the gear on the 8 speed selector lever, and has the 8 gear cluster.
The lever must be UP and the plunger in a hole for this shaft to
spin. If it doesn't turn, try another setting. It is possible for
one gear to be missing a few teeth. It this shaft doesn't spin in
any position, look for a missing gear on the swing arm itself. The
input shaft is splined its entire length, the swing arm has a gear
that spins whenever the input shaft turns. Swinging the arm up
meshes this gear with one of the eight gears on the speed selector
shaft. Assuming this shaft turns, the upper of the two shaft
towards the front is the 3 speed shaft. With the 9 position
selector lever in any of the holes, it should turn whenever the
input is turning. You can see the relative speed with respect to the
input shaft change easily as you move the top lever from right to
center to left. If this shaft is turning and the leadscrew doesn't
rotate, check the end of the leadscrew inside the gearbox. The
leadscrew is driven by a gear that mounts on the end of the
leadscrew and meshes with a gear on the end of the three speed
shaft. If the nut comes off the end of the leadscrew, this gear can
get loose. The leadscrew is still secured by the leadscrew support
at the tailstock end of the lathe, so all looks good. It is a fairly
large nut, with a collar. Was the lathe shipped with the leadscrew
removed? You may have missed mounting this part. Note that with the
8 position swing arm down, you can turn the leadscrew by hand and
all but the input shaft will rotate if all is well. Just make sure
the halfnuts are disengaged before doing this, it can be alarming
when things move when you aren't expecting them too. With the
reverse tumbler in the center position and the swing arm in the
leftmost hole (or any hole, this just is the one with the least
mechanical disadvantage) you can run the entire geartrain up to the
tumbler by turning the leadscrew. You can even turn the spindle this
way in you engage the tumbler, provided the drive belt is loose or
you have a really strong grip :-) Hopefully this will help you sort
it out, it's the sort of thing that a person familiar with the lathe
could tell what is wrong is just a minute or two if they were in
front of the lathe, but over email takes a bunch of words!
Stan (8960) |
| Hugh I could
not tell from your post whether or not the motor worked? If it does,
put the gearbox in any gear, then engage the belt tension lever,
then put in reverse or forward and get back with what Happened with
the lead screw. There was another response to your mail, once you
have all engaged then perform the visual inspection as suggested in
the email You can get parts for your lathe on ebay once you figure
out what you need, if any needed? Even if there is a little
something wrong with your lathe, you will find that you will not be
sorry for getting the South Bend, as long as it is not wore smooth
out. Even if you need to fix a few things, you will not be sorry,
and look at it on a positive note! fixing anything on it will just
make you more familiar with it's operation, etc. It will also allow
you to check out the other parts for wear and do any cleaning,
adjusting and lubricating Since you are going to be doing hobby
work, the Homier Mini Lathe has been a good machine for me
http://www.homier.com
also http://www.littlemachineshop.com has info for them and
comparisons for the other mini mills. Homier has the best pricing
between the sellers of the mini mills. They also give excellent
service I have a picture of my mini mill on my web site, do not
laugh at my web building, that is my weak link!!! I have been
spending several months building the site and will eventually get
around to finishing. Some of the pages are not completed, but enough
work to give you a look at some of the things I do here is the link http://www.clints101.com We wait for your getting back. Clint
(8965) |
| Hugh, Maybe I
can give you an idea of how your box works. The input gear on the
outside turns the mainshaft. Your bottom lever, or tumbler lever,
has a gear that is turned by the mainshaft. The tumbler lever gear
will engage a cone gear on the cone shaft, by sliding the tumbler
lever back and forth, and engaging a lock hole on the front of the
gear box. The cone shaft then turns the clutch shaft through a
sliding clutch and clutch gears. The top lever will move a sliding
clutch on the clutch shaft, right, center or left. The sliding
clutch has a gear and is keyed to the shaft, and will turn the
clutch shaft. The left or right position will lock the sliding
clutch to a gear that is engaged with the cone shaft, but is free
spining on the clutch shaft. That will turn the clutch shaft. In the
center position, the sliding clutch will engage a cone gear and then
turn the clutch shaft. The clutch shaft then has a gear that engages
the gear on the leadscrew. I have found that I have to turn the
leadscrew to get the top lever to engage the gears in the left or
right position. It has to be lined up just right to engage. There
are three keys that, one may be sheared. The input gear to the main
shaft, the output gear to the leadscrew on the clutch shaft, or the
leadscrew gear on the leadscrew. I think all the keys would be
standard key stock. Sorry its longwinded.
(8970) |
| After a
careful engineering analysis combined with a review of a study of
dynamic motion I flooded the gearbox with WD-40 and it started
working! I sprayed it in every hole/opening in the gearbox that I
could find. I guess I did some good but hope I did no harm! The
carriage and cross feed both move when the shift lever on the
carriage is in the proper position for each. I hooked up the motor
which worked. Question: I guess this is basic but there were only 2
wire ends (no plug) from the motor (they were accessible at an
external wiring box from a conduit added sometime in the past. The
conduit leads into a box into which plugs a weird plug from the
motor.) I assume I have been safe in adding a 3 wire power cord with
the green wire attached to the wiring box (the round box is firmly
attached to the metal bench that supports the lathe. I don't know if
the bench qualifies as a place to attach the neutral green) I agree
with the benefit of trying to figure out what is going on with the
machine. I really got into it and think I figured out a lot of what
is going on...sort of. Your site is looking good. I am going to
build a small foundry (per Gingery. I may have the spelling wrong)
but need to use bottled gas due to being in one of those
neighborhoods with small yards. Is there a metal casting yahoo
group? Mini-mills: I may look at that. I have been looking at an
Enco Mill Drill which are on sale till end of this month. Do you
know anything about them? I was thinking it would also give me a
drill press. Lubrication: Message number 91 has a list of lubes
purchased. I was thinking about duplicating this since Home Depot
doesn't really have anything other than 3-in-1 and WD-40! Gear/lever
shifting: I never change anything on the "left end" when the motor
is running (back gear shift, slide gear, gearbox,
rev/neutral/forward, and flat drive belt). Does that sound right?
Half nut on carriage: that lever seems to only move a few degrees
(when carriage/cross-feed shift is in neutral). Is that correct? How
do I know if it works?
(8992) |
| I want to someday take the gearbox apart and
visually inspect it now that I have your description of how it
works. As a follow up. I flooded every opening with WD-40 and it
seemed to free things up because it is now getting power to the lead
screw. I think it may have loosened up something on that clutch in
the gearbox that you discussed. Hugh (8993) |
| Hugh For
metal casting try
http://groups.yahoo.com/group/gingery_machines/messages
http://groups.yahoo.com/group/hobbicast/messages John (9000) |
| One more http://groups.yahoo.com/group/metalcasting
lurch (9001) |
| It should move
about 10 or 15 degrees. You can tell if it works because it will
grab the leadscrew and you wont be able to move the saddle with the
handwheel anymore. You can also see the nuts engage with a
flashlight and maybe a mirror under the apron. You may need to
jiggle the saddle a little or have the leadscrew turning to engage
the nuts. There is an interlock between the crossfeed/longitudinal
feed shift lever to keep the halfnuts from engaging at the same
time. Check this too. Glen (9002) |
| How much for a
gearbox |
| I was wondering how much $ one would expect to pay for a
gear box to convert a model c 9" ? Dave (9120) |
| I paid about
$125 for mine. Try to get the leadscrew and 20 tooth gear with it.
Glen (9121) |
| I paid $310,
including the 20T. lead screw gear, 2 years ago. Purchased from a
dealer. (9124) |
| If Glen got
his including the leadscrew for $125 then he got a great deal. One
of the used suppliers http://www.mermac.com/ lists it
at $300. One complete assembly just sold on ebay yesterday for $165.
Typical ebay prices are $170 to $270. John (9125) |
| If Glenn got
the QC box, leadscrew and gear for $125, then he did real good. I
got one off of E-Bat around October for about $100 or $125 shipped I
think. I didn't get the leadscrew or gear with it. I think I picked
up a 'B' leadscrew for about $30 shipped and got the gear from
Lurch. I doubt he has any left. So I'd press hard to get the gear
included. I think SB parts and lathes have gone cheap since October.
I look though that prices are going back up. Tom (9127) |
| Tumbler
shifter? |
| I have a SBL
9A cab model UND built May 1946. This lathe has one thing I can't
stand. The tumbler reverse gear set is locked in position by
loosening a square head screw, shifting and retightening. When did
SB make the change to the pull out shift/lock knob setup? Was it an
option? Has anyone modified this lathe to the pull out style? I have
the casting assembly ready to try the change, but some metal has to
be added to the headstock. RichD
(9490) |
| You should check the archives. I have a 9A that was
supposed to have the spring detent. My headstock has a rectangular
boss on the front left hand side. There are three holes ~1/4" deep
that the detent engages in. I can take a picture of it for you if
you like. When I got the lathe it had been stripped of all the drive
train. I finally gave up on buying the proper tumbler and got a
pretty good deal on the older style tumbler. The old tumbler casting
is thicker than required for my lathe and as a result the tumbler
gears were too far to the left and barely engaging the spindle gear.
I faced off the casting enough to get it to fit. I cut off the
handle and now have to fasten on a bracket and make up the spring
detent assembly. From the parts drawing it isn't clear how the
tumbler assembly is constrained from moving endways. It looks like
there is a retaining clip of some sort. Can you provide me with the
details of that clip? John (9499) |
| I made an adapter
plate and was able to install and use the tumbler shift assembly.
The adapter was not that hard to make but the two holes for the
tumbler must be done very carefully as they determine the gear mesh
and clearance. Send me an email if you want a jpg drawing. Bill (9500) |
| John, I have
occasional access to a 10K with the spring detent selector and took
pics with the mod in mind for later. The casting is retained by a
circle clip in a groove on the end of the barrel of the casting.
This depresses when pulled out of the HStk. I have not checked to
see if my selector casting will be a viable change over. The gears
did not come with, so I hope it's just a matter of swapping them
over. Rich (9514) |
| Calculating
Gearbox Pitches |
| The following
should help with calculating pitches on an SB lathe with an inch QC
gearbox nad inch leadscrew. The important thing to know is the final
internal output from the gearbox is a 28 tooth gear driving a 20
tooth gear on the leadscrew. The formula for the pitch cut is: All
drivers multiplied together divide by all driven gears multiplied
together, this quantity multiplied by the TPI or pitch selected.
This means (Stud x Conversion Driver x 28 (Gearbox Gear)) divided by
(Conversion Driven x Screw Gear (on Gearbox) x 20 (Leadscrew Gear)),
this quantity multiplied by the TPI or pitch selected. For the
standard setup this simplifies to (Stud x 28) divided by (Screw Gear
x 20), this quantity multiplied by TPI or pitch selected. If you use
the inch pitch in the above calculation you can convert to
millimeter pitch by multiplying the resultant figure by 25.4. If you
use TPI in the above calculation you first have to convert to inch
pitch by taking the reciprocal (1 divided by TPI), then multiply by
25.4. Anthony
(9888) |
| Does anyone
know if it is possible to change my model C's "Standard graduated
collars" on cross feed and top slide to the larger direct reading
type?. The graduations on the originals are somewhat worn and could
do with replacement, and I'd like to go for the direct reading
version if possible. Len (9889) |
| 10" QC Gearbox
thread ranges |
| Can someone tell me
what 'extra' threads you can cut with the 2-lever QC gearbox on a
10" SB compared to the earlier 1-lever models? Ideally a picture of
the plate off each type would let me compare. Andy (12448) |
| Attached is a picture with three types of different QC gear box
plates. The top one is a heavy 10 with a single lever, the middle is
a 9", and the bottom is a heavy 10 with two levers. I think it's
what you're looking for. Dave (12449) |
| Gearbox thread
charts |
| I have noticed
lately the need for South Bend thread charts, lubrication and other
charts by SB owners. I have an extremely inexpensive solution which
reproduces the original SB charts exactly. My cost was 28 cents for
a photo reproduction. But if you wanted an original SB chart from SB
it would cost probably up to $80, or for about $40 get a
frankenlathe reproduction that shows up on e-bay ever so often. I
can e-mail a gear change chart for a 9" C I made with a digital
camera, hand held in open shade. Good but could be better with
higher resolution and tripod support. To get the photo in a size I
wanted and without resolution loss I downloaded in the computer to a
floppy disc. Took it to Wal-Mart and shortly for 28 cents got the
good easily readable reproduction. This could be covered with the
tough clear plastic and put right on your lathe. I did not need the
chart I made and did it as a demonstration of the super low cot of a
copy. What I really wanted was a copy of a 9" A gearbox chart to
cover my dinged up one. And also a non readable chart for my 13"
gearbox. What I had in mind was to get SB owners with good charts to
make good digital copies, load them on floppies and send them to
people that might want to send a buck in the mail to cover the cost
of a floppy and mailing cost. It seems like SB made a gilizion
different charts so respondents would have too say what chart they
had. For instance my 9" A gearbox says cat no. 670Y Model A 3' bed
Chart no 1 and has threads from 4- 224. I have looked at charts in
the photo section and none look like they could make a large size
prints. Going the floppy route preserves the resolution and the
receiver can make copies for his own use. So e-mail if you want a
copy I have. Got my buck ready to get the floppy I want. Walt
(15021) |
| For your
Model A gear box, you should contact dt38k1954" peep38k@m... Randy
sold me in Feb or March a brand new brass reproduction tally plate
for my SB 10K gear box. You cannot get anything better. All you will
need to do is stamp the numbers with letter punch on the tally
plate. It worth the expense. Randy also has other tally plates. Guy (15022) |
| Walt
Thanks for your post. Now I can rest, and not spend anymore of my
time and money making frankenlathe reproduction plates, for guys
that want to restore their south bend lathes. All of you guys asking
me to make others, take note of this generous offer. My thanks go
out to all of my customers, satisfied with what I had to offer and
that sent me thank you letters for offering these. Randy (15031) |
| Randy Woe!!!!
No, he is talking about pix not plates, we want your plates if we
are restoring, I believe he is talking about pix for those that
cannot read their plates, something to go by, there is a big
difference On my restorations, I want the original looking repro
plates! like you have came up with. Clint (15032) |
| Randy,
Don't desert the ship. The plates man, the plates. I am in the
process of restoring a 9A HMD and will need all the plates. Haven't
seen or heard of anything that can compare with what you have so
diligently provided to the community. Fred (15033) |
| 9" gearbox DP
|
| Does anyone know
the DP and PA of the gears used in the QC box? I'm specifically
interested in the tumbler shift gears. John (15202) |
| John I
have an 9-10k A model gearbox with some gears available. I took this
down for a customer that needed a lever. You can reach me at
peep38k(at)mchsi(dot)com. Randy (15206) |
| Randy I'm a
diehard DIYer so I'm planning on cutting a couple of replacement
gears. There is a cutter on ebay that may be the right one and I was
wondering if I should get excited about it. John (15211) |
| QC gearbox
questions |
| First, it is always best
to get the nomenclature straight. Are there proper names for the
lettered and numbered levers? Second, I can see that the lettered
lever should only be changed with the lathe off but what about the
numbered one? I don't think it is possible to get the gears to mesh
without rotating. And finally, the lettered lever is binding on the
shaft. I have to feel under the box and push the body of the lever.
The gears are in excellent shape, the lever has no side play and I
doused everything with the "B" gear oil before installing but I
wonder if I should have used a little assembly lube on the shaft.
(15917) |
| The gears should
NOT be changes with the lathe running. You can rotate the head or
leadscrew by hand to help the gears to mesh. As far as I know the
levers are called tumbler levers. JP (15935) |
| Gear box ID |
| I was
wondering if anyone out there could tell me what gear box I have by
the part #? It reads model A CL6441. Dave (17627) |
| It would seem that
you have the same QC gear box as the toolroom version. 48 pitches
from 4 to 224. William (17631) |
| Gearbox ratios
and input gear for metric lathe |
| This enquiry
started with the assertion that threading dials can't be used when
metric threading, or they would only work with two or three useful
thread pitches. But at GEARS in Oregon last September, Brett
Flemming showed me page 85 in the 1958 HTRAL (the 55th edition) the
illustrated thread dial for metric threading (supplied with the all
metric lathe), the significant features of which are division of the
dial into prime factors (3,5, 7 (and 2)) and four pinions to engage
the leadscrew (i.e. adjustable range). I thought if I could find out
what leadscrew was used I would figure out how this all works, but
it isn't that simple. By joining your group and reviewing the F.A.Qs
section I found the metric lathes used a 3mm pitch leadscrew. In the
article "Changing to Model A.." I found that for inch lathes, the
input gear to the gearbox is 56 tooth (Why is this not listed
elsewhere ?). Of course the inch scale lathes use 8 thread per inch
leadscrews. The changeable stud gears of 24 and 48 teeth are used,
so the ratios from spindle to gearbox input are 3/7ths and 6/7ths.
In the metric SouthBend, stud gears of 20 50 teeth are used but I
don't know the input gear. I would like to know all the gears so I
could write out the equation of ratios; and I would like to know how
the mechanism works. But for now I have two questions, A and B. A).
Why is the longitudinal feed not equal to pitch ?. [Not about cross
feed, that is listed elsewhere; on the metric lathe as 1/10th of
Pitch; in the inch lathe as .375 of linear feed] In the gearing
chart for Model C lathes (no gearbox) the feed equals the pitch. In
the gear charts for inch lathes with gearbox--Model A--the ratio
between pitch and linear feed varies from 2.9619 to 2.9815 but
average 2.9726; in the metric gear change chart the ratio between
pitch and linear feed varies from 2.9197 to 2.9304 but averages
2.9278. Whether the fractions are the result of rounded calculations
or not, the set-up for ten threads per inch cannot move the carriage
0.0337, that would make 29.67 threads per inch. ? B) What is
the gear used in the metric lathe for gearbox input? Richard
(22155) |
| A few months ago, I
went back on the drawing board and made all mathematics calculations
for the gear box. It covers all combinations, feed rate and cross
feed rate. The difference that you noted on the charts are because
model A and B lathe have a different apron that doesn't use the split
nuts for normal threading operations. It uses a key way that drives
a worm gear. My spread sheet does all those calculations for SB9 and
10K lathe model A. If you want a copy of it, just go on the
following link. You need excel 97 or later to open it. You can
change the gear ratio at the gear box input and everything changes
instantly. You can calculate metric feeds On the tables, some values
were rounded off. The gear box chart says that power cross feed are
0.3 times longitudinal feed when it is a little bit less than that
actually when you make all calculations. A simple swap of the lead
screw is probably not a good solution as the metric gear box is
completely different. I have not made the exercise yet with the
exploded view. Guy (22158) |
| The presentation of
your questions is a little confusing but I'll try to help. A) On the
Model C the longitudinal feed is simply the screwcutting pitch as the
drive is the leadscrew driving the carriage through the split nuts.
The Model A and B lathes have a keyway cut along the length of the
leadscrew. Within the apron a worm is mounted concentric to the
leadscrew and is driven by a key within the worm which takes its
drive from the leadscrew keyway. The worm then drives a train of
gears which can be engaged to drive either the longitudinal feed
wheel or the crossfeed screw. So, while the Models A and B do take
their drive from the leadscrew it's not through the pitch of the
leadscrew but instead through a train of gears. To fully understand
the drive ratio you would then need to know the worm ratio plus the
ratios of the gear train providing the longitudinal feed. B) On the
metric Model A lathe, the stud gears are either 20 or 50 (as you
already know). The gearbox input is 45. The internal cone of gears
in the metric gearbox is 16,18,20,22,24,26,28, 30. Not asked in your
specific questions but mentioned in your message, on most of the
inch Model As the stud gears are a choice of either 20 or 40, not
the 24 and 48 you cite. What isn't obvious unless you've been inside
the gearbox or have read the parts manuals is that the final drive
from the gearbox is the 28 tooth gear of the cone driving a 20 on
the leadscrew, therefore the final drive ratio is 7/5. So,
expanding, the input ratio is either 5/14 (20 to 56) or 5/7 (40 to
56) and the output ratio is 7/5 (28 to 20). The cone is 16, 18, 20,
22, 23, 24, 26, 28. There may be an initial internal step up of 2/1
but I'm not quite certain. Regarding the metric gearbox, I'm not
quite certain what the final output ratio is. Anthony (22171) |
| Any source for
a 10K QC gear box shift lever? |
| I only can seam to
find them as a assembly with the box for Hundreds$$$$. Adam (22548) |
| Did you try Plaza
Machinery? I just purchased two for my 9" from Joe. (22550) |
| Try Fred aka imsteamer 914-720-5523 he is in this group. Bob (22551) |
| I'd suggest Dick
Treimstra at Bridgeman Machine in Detroit (313-366- 1060) or Rose
Marvin at Parts Works (rose@p...); Dick has lots of used parts I'm
told Rose used to work for the parts dept. at Southbend; might be
able to get you a better deal than ordering direct from Clausing. I
have had excellent dealings with both of them! Lew (22552) |
| Double tumbler
vs single tumbler |
| Does anyone know
the answers to any of the following questions? What are the
advantages of the double tumbler gear box over the single tumbler
gear box, if any? What year did South Bend start making the double
tumbler gear box? Is it possible that a lathe made in 1960 was made
with a single tumbler gear box? Gary
(25914) |
| My .02 is
that lathes made in the 60's had double tumbler gear boxes. My 1952
South Bend 13" has a double tumbler gear box (DTG-103T). Nick (25917) |
| My 1951 Heavy
10 has a single tumbler. I suspect the answer varies for different
size lathes but it is my impression that the single tumbler was
phased out in the 50's. (25918) |
| I would say early 50s, I have had some later/mid
50s machines with double.
(25920) |
| Answering only this one question, there
are actually three different gearbox options: Single tumbler Double
tumbler "standard" Double tumbler wide ratio Single tumbler has 48
ratios directly selectable without having to change out any gears.
Tumbler selector is directly in front of operator, high/low pitch
selector is at left end of lathe, a little inconvenient. Because of
the high/low selector it is more difficult to regear for odd threads.
Double tumbler "standard" has 40 ratios directly selectable plus 8
additional by changing the stud gear. Both tumblers are directly in
front of operator so as long as you don't need coarse pitches
between 4 and 7 TPI it's more convenient to operate. Much easier to
regear for odd threads. Double tumbler wide ratio has 70 ratios
directly selectable by operator. Includes additional pitches. Will
cut finer pitches and feeds without regearing. Easy to regear for
odd threads. IMHO, wide ratio would clearly be first preference.
"Standard" probably second preference due to greater ease of
regearing. Single tumbler preferred over change gears as long as you
don't need to do a lot of regearing for odd threads. Anthony
(25927) |
| Gary, I
Have a Heavy Ten with a double tumbler set up. The tumblers alone
give 70 different combinations of feeds or threads, just by moving
the two levers. I'm not sure about a single tumbler set up, but it's
probably around 10 different changes, and possibly many more by
changing some of the gear train gears. I don't know the answers to
your other questions. (25944) |
| Could email me a
photo? Or could you tell us what are the 22 additional threads over
the 48 TPI on the normal double lever? Gary (25946) |
| I got a photo here for you where you can see them
all. It is a large file so dialup people may not want to look.
http://tools4cheap.net/2005/chart.jpg Jeff (25949) |
| Jeff,
I was going nuts trying to get a good picture out of my camera
phone, and a small camera my daughter has. I'll have to break down
soon and get a good digital camera. This is exactly how mine looks
too. (25951) |
| Jeff, would
you be so kind as to tell us what lathe did this QCGB come on? Do
you know if it ever came on 13" SB lathes? I must admit that I want
one like you have. It looks like it cuts 27 TPI, without a special
gear, and must have something closer to some metric threads than the
48 choices that most of us have. I only heard of the 70 combination
gear box this morning in Anthony's very articulate answer, to I
think it was Gary's, question. I must admit that I did not know what
he was talking about when he mentioned this unit. I have never seen
one of these before, I am impressed. Please do not get the
impression that I have seen a lot, as I am rather new to this. I am
currently bogged down in overhauling my lathes head stock and back
gear assembly. I seem to learn something new every day from the
South Bend users group. The only down side that I can see is that I
bought a "junk" or "parts" 48 combination QCGB so that I could see
how it works (later, when I have the lathe working correctly). I bet
a 70 combination gear box would tax all but Anthony's mind figuring
out how all of the combinations are achieved. Nick (25954) |
| Jeff what is
the possibility of you having parts for a 16/24 southbend.
Leon (25955) |
| Nick- Yes the
13" had them too. This particular one in the photo is from a heavy
10 and is for sale. I have a 13" parts lathe coming in on
Monday and
several heavy 10s as well. I don't recall at the moment how many
threads are on the 13 I bought but it is a double tumbler box. Email
me offline if your interested in buying it or any parts for that
matter. Jeff
(25957) |
| Gary P. Hansen
writes: Or could you tell us what are the 22 additional threads over
the 48 TPI on the normal double lever? 6-3/4, 13-1/2, 27, 54, 108.
216, 7-1/2, 15, 30, 60, 120, 240, 256, 288, 320, 352, 368, 384, 416,
432, 448, 480. Besides 27 and 30 plus their multiples, and these are
useful to some people, the real advantage is that the power feeds
are extended down to half the pitch available on the standard box.
And of course, if you're willing to change out some gears in the
train from the stud to the gearbox you should be able to reduce
these finer feeds by a factor of at least 4, for a total reduction
factor of at least 8 or more beyond that available using the
standard box with standard gearing. Anthony
(25964) |
