| Backing plates (Sep 19,
2001) |
Setting up chuck backing plate
(Feb 4, 2004) |
| Machining a Mounting Plate for
Chuck (Feb 20, 2003) |
Need 4" backing plate for
Hercus/SB 9" (Mar 23, 2004) |
| 15" chuck mounting plate
(May 31, 2003) |
Question about lathe chuck
backplates (Mar 28, 2004) |
| Stuck backplate (Jul 22,
2003) |
Preparing A Backplate for a
3-Jaw Chuck (Aug 12, 2004) |
| Chuck backplate
(Aug 28,
2003) |
Backing plates (Dec 29,
2004) |
| 3 jaw chuck backing plate
(Feb 2, 2004) |
Backing plates (Dec 30,
2004) |
| Chuck backing plate question
(Feb 4, 2004) |
|
| |
| Backing plates |
| Anyone know of an
inexpensive source of threaded 1 1/2"-8tpi chuck backing
plates? Mike (1553) |
| MSC has what you
want. Their plates go for $60 plus S H P/N# 08565707 page 2423 in
their current catalog. They also have rough cast iron blanks ready
to be finished on your lathe. This poses an interesting question
here. How do I fit a face or backing-plate to my lathe when I have
no means of checking the fit when threading? The short answer would
be to make a plug gage that closely matches the spindle. Just like
any other threading job. I usually leave a tiny bit of stock for
lapping afterwards.( ,001-.002) Use the plug as a lapping tool. You
can omit this step if you think the fit feels good enough. I would
be sure the bottom of the threaded hole is the same depth as the
end- to- shoulder length of the spindle. And it must be flat. If
there is enough interest, we can do a shop lesson on threading
inside. Ron (1555) |
| Great idea! Could you include
scanned or CAD sketches rather than ASCII? By the way, how many
times can you use the gauge as a Lap tool before has to be replaced? GBA Chris (1556) |
There was an
article on this in either HSM or PIM. Let me look at my index and
see what the issue was and post that info. JWE
(1557) |
| I got a sales flyer from Grand Tool
Supply Company a year ago that had very good prices on cast iron
backplates, threaded and unthreaded. I recall prices $25 for a
threaded backplate, and bought two at the time. They were very
substantial castings from Poland, I think. I don't know if they
still offer these products and don't know if the prices have
changed. I didn't see backplates on their website, but they don't
show everything that they carry. http://www.grandtool.com Teterboro,
NJ 1-800-922-0512 Check their terms and conditions
carefully. I believe that they had a policy of charging extra for
small orders, so if you order $50 worth of merchandise, you may have
to pay a 10% premium, or something like that. If you're really
looking for a bargain, some people have used the weight from an
exercise set as a backplate. It is a rough casting with
approximately the right size and shape. But this takes LOTS of work
to finish and may have an inclusion or void in an inappropriate
place. I've seen these weights for sale for $2 each at discount
stores. In my opinion, this is not a good value. I've also heard of
people trying to use old automobile disk rotors as backplates, but
this hasn't been successful. It is hard to find a rotor that has the
right shape and enough metal where you need it. Bob
(1558) |
| A lesson on
internal threading would be great! Let's not forget the tips on
boring tool use to get the hole to the right ID. The number of
external threads I've cut can be counted on one hand. Internal
threading opens up a new territory. Mike
(1562) |
| I've got an old
dividing head I've restored on which I'd like to use the 1-1/2" 8TPI
chucks off my SB lathe. The nose on the dividing head is 1.75" 8TPI
with some sort of inside taper with about a 1.060" entry diameter.
The question is, can I get away with turning the nose down to fit my
lathe chucks and still have enough strength to support milling? From
my 1946 Machinery's Handbook, I see that the thread depth for sharp
V-threads is .866/TPI or about .11" for my 8TPI nose thread. This
means that I can turn down the existing nose to 1-1/2" easily
enough, but here's the rub. 1.500 - 2 x .11 = 1.280, and the taper
hole is 1.060 at the end. Is a minimum wall thickness of (1.280 -
1.060)/2= 0.110" thick enough to use? Note: the inside tapers to
about 1.040 at 0.75" depth, yielding about 0.210 minimum wall
thickness 3/4" back from the nose. Paul R. (1563) |
| Machining a
Mounting Plate for Chuck |
| I've never seen one
before machining, so I'm wondering what is involved in machining a
"semi-machined" mounting plate for a 3-jaw chuck. I ordered the
plain back (Bison) and a mounting plate from Wholesale Tool. I could
have paid another $105 for one already done, but what kind of
amateur machinist would I be if I did that? Wallace (9432) |
| Thread the
backplate onto the headstock and face it off until square then turn
it to the diameter of the chuck. There is usually a lip on the back
of the chuck that it will fit into. Then layout the hole pattern for
the attaching bolts, drill and counter sink. Measure twice and cut
once. Mike (9434) |
| Wallace, I am
assuming you have a threaded lathe spindle and in that case you
should make an exact copy of your threaded spindle nose first to use
as a gage. This will be used to check the fit of your threads as you
are cutting the internal threads in the new backer plate. Check
often with your gage as you come closer to the finished size of the
internal thread. Your gage should thread in smoothly, by hand, into
your new backer plate with out any shake. I like to face off the end
of the 'spigot' now and then cut the relief or sometimes called a
'register' into the end of the 'spigot'. Now you are done with the
gage and you can put that away. I like to then thread the new backer
plate onto the lathe spindle with Prussian blue on the shoulder of
the lathe spindle and I take note of where the new backer plate
contacts the spindle nose shoulder. I then like to scrape the new
backer plate until I obtain 70 to 80 per cent contact between the
spindle shoulder and the end of the face plate spigot. Usually very
little scraping is needed. Then I face off the front of the new face
plate and cut the recess for the chuck and mark the mounting holes.
The mounting holes should have enough clearance that the mounting
bolts do not bind on the face plate when they join the face plate
and chuck. All in all not a hard job but be fussy with your
threading. Clean the chips out of the threads when you are using the
gage. bobL (9435) |
| 15" chuck
mounting plate |
| I am looking for a
chuck mounting plate for a very old 15". I'm not sure if I am
measuring the spindle right. Od of the threads measure 2 1/4" and
from top of thread to top of thread there is 7 threads per inch. I am
guessing this is a 2 1/4 - 6 thread but I cant seem to find a
mounting plate with that combination. Am I doing something wrong or
is this a rare size. stan (11628) |
| I looked in my
MACHINERY'S HANDBOOK 12 EDITION and could not find a 2 1/4" 7 or 6
tpi. It is not a American Standard Thread Series or a Acme Screw
Thread. What brand Lathe is it? What do the threads look like?
(11629) |
| Its a south bend
the old silent chain type with the motor and pulleys mounted above
the headstock. I'm wondering if it is a 2 1/4-8.maybe I'm not measuring
right.
(11630) |
| I just found a
reference to a 2 1/4-6 triple thread in a 1909 AMERICAN MACHINIST'S
HANDBOOK than belonged to my Grandfather. Could your thread be a
triple thread? (11631) |
| I'm not sure what
you mean about a triple thread, also I may have told you the wrong
thread. Its 2 1/4-7 threads per inch. It looks like the same style
thread as my 9" has, only bigger 15" chuck mounting plate. (11632) |
| A single threat has
one groove and a triple thread has three grooves. However, I may
have lead you down the wrong road. I have found to possible threads,
2 1/4-6 UN and 2 1/4-8 UN (Standard Series Unified Screw Threads) I
am now sure that you have one of these, most likely the 2 1/4-8. My
SB 9" has 1 1/2-8 UN threads. Gary
(11636) |
| Might I suggest
that you e-mail Rose with the appropriate SN information, and maybe
she can pull it out of her bag of information? If she can tell us
when and to whom sold, maybe the thread info will be in there also
if the machine has not been hacked by a PO (11637) |
| No, sounds like you
have a 14 1/2" lathe with the small holed spindle w/ 2 1/4"-6
threads. Why don't you check the FAQ for specs. dennis
(11639) |
| A quick look in the
Lindsay reprint of the 1934 SB catalog shows the 15" lathe of that
vintage had a 2 1/4 x 6 nosepiece thread. As someone else noted, the
later vintage (i.e. later than 1934) with the small spindle bore
also had a 2 1/2 x 6 spindle thread. Frank
(11644) |
| Stan, your thread is 2-1/4 x 6 TPI. This an old
standard size, not as common as 8 TPI but still standard. It dates
back to when industrial lathes still used threaded spindles instead
of Cam Lock or long taper. The reason your having difficulty
determining the TPI is you're counting the starting point as well as
the ending point. As a demonstration, lay down a ruler and count the
inch marks starting at zero and going up to and including 6. You'll
find you've counted 7, as in 0 1 2 3 4 5 6, but you know there's
only 6 inches. The same thing applies to your thread, don't count
the starting point but count every peak from there to your 1 inch
measurement. Anthony (11649) |
| Set your scale inch
mark on a thread peak and count the valleys between it and the next
inch mark. Jim not sure if and from top guessing this is that as
common lathes still counting the down a including 6. there's only 6
starting point (11652) |
| You guys are great,
I would like to thank all of you who who replied to my
problem. I am 100% sure now its a 2 1/4-6 spindle. I was counting the
thread at zero and as it happens there is a mounting plate selling
on ebay this morning. stan (11659) |
| Stan- What is the
serial number of the lathe? Rose (11691) |
| Rose ,thank you
for replying I wanted to contact you anyway the # on the bed is
47893 and on the guard it says catalog #3688c .15"x 6' bed. I assume
you replied about my question on the spindle thread. I think I have a
2 1/4-6 which I need an adapter for. Also I am missing some of the
gears from the headstock to the crossfeed gearbox. Is there a parts
list available so I can figure out what I have and what I'm
missing. stan (11694) |
| Stuck backplate
|
| Where I can get a new or s/h back plate for my 13"SB it is frozen on
the spindle. I've tried all methods suggested and Semtex won't get it
off. So I'm going to have to machine it off. (12878) |
| Thanks for the
advice Dennis. I've tried similar methods to this on many
occasions.. the last time I tried, I locked the spindle cone pulley
with a home made clamp (that held the spindle rigid). Then I bolted a
3" X 3/4" X 5 ft steel lever to the backplate...applied heat and put
on the pressure to the lever while my son hit the lever with the
hammer...I felt something go...? I thought I'd succeeded but no I'd
sheared the woodruff key in the spindle and I had to strip the whole
thing down to repair it and fit a new Key. I like to see the pic's,
but I'm not sure if it will fit co's I've got to check the thread
size. Ken (12892) |
| Ken, have you tried
going the other way might be a left hand thread. Duane (12898) |
| If it was A left
hand Thread I would have felt a bit silly. So I went off to my
workshop to check...but no it is a right hand thread... I am
thinking of splitting the back plate from the O/D down to near the
spindle. and then opening the gap "carefully" with a Fox wedge.
I did
successful job like this some years ago on some cast iron bearings
that had frozen to a 3" dia steel shaft in Fawley Power
station...I'll let you know if it works or not. Ken (12928) |
| Ken, Did you try
warming it up? If not try this, Lock spindle with back gear, set up
your pulling system you had before, warm hub with heat lamp or torch
don't get it super hot just good and warm, put some tenchen on it,
not so much that you break something like before. Take hammer and
bump over the threads. Don't get ruff with it. Thought being, pipe
threads get stuck at couplings, if you slap the coupling a few times
with hammer they will unscrew real easy. Sounds like it got shoulder
up and locked. Duane (12929) |
| Chuck backplate
|
| Anybody got a six
inch 1 1/2 X 8 backplate they would like to part with? If not maybe
you can steer me to an inexpensive supplier. Sorry about the blank
post. My typing finger (one of two) just got stung by a bee and
isn't quite right, hit the wrong key. Larry (13647) |
| Larry, six inch back
plates can easily be made out of 2X150# blind flanges.. for the 1
1/2 dia. u will need a blind but say for the 2 1/4X8 thread a socket
weld or weld neck works fine for a blank. Stirboy (13671) |
| Interesting idea,
Bill. I hadn't heard of such things. A quick look shows a 2" x6"
150# type 304 blind flange selling for $24.00. A cast iron
unfinished back plate from Enco lists for about $42.00 (nearly twice
as expensive!). That said, I think I would avoid steel and stick
with C.I. for my primary back plates as C. I. is supposed to reduce
vibration and will not gall the spindle threads. Still a cool idea!
It would be interesting to hear from members with experience with
non-C.I. tooling for threaded spindles. Paul R.
(13676) |
| There is a seller
on E-Bay who sells back plates that are threaded, but need turned to
fit the chucks. I bought one. Its of decent quality. The threads are
OK. I haven't machined it yet. So many projects. You also might look
at the Bison back plates. I think they are reasonable. Although
listed for Bison chucks only, I would think you could turn the to
fit. Tom (13679) |
| When I had to
replace chucks stolen from my garage shop, I purchased one threaded
and one unthreaded backplate thinking that I would need to first use
the threaded one to get a chuck going in order to machine the
unthreaded one. I ended up using only a face plate for both since
the shoulder was not quite right for the spindle. It was too long
and too loose. If you've got the time and patience (and guts), I'd
recommend that you do your own threading so you can get the best fit
on the thread and shoulder. After machining, I did some fine-tuning
by using some Prussian blue and hand scrapers to get uniform contact
on the spindle shoulder. After machining the spindle interface,
screw it onto the spindle and machine the face of the backplate to
mate with your chuck. Makes a big difference in repeatability and
chuck removal. Paul R. (13680) |
| When I needed a
backplate for my new TOS chuck (excellent chucks BTW) I bought a
cast iron blank from Chronos in the UK, and followed the simple
instructions on Tony Griffith's site for fitting.
http://www.lathes.co.uk/latheparts/page7.html
The blank was riddled with a lot of very hard spots that had to be
ground out with a dremel during machining. However, Chronos do sell
a Boxford backplate, part machined and threaded for around œ19,
roughly $30. Len (13681) |
| Paul, one of my
points being these can be found many places if one has a few
contacts for little or nothing and affords a novice some boring /
threading experience without the fear of ruining a higher dollar part. stirboy (13687) |
| Point even more
well taken. Paul R. (13688) |
| As I'm in no hurry and this is not a primary chuck I'm
going to sit and wait for an 'opportunity' to arrive. I really like
the blind flange idea and some other suggestions. They're a lot
better than my idea of a CI 5 pound barbell weight. Larry (13694) |
| Tom, the reason
bison backplates are for bison chucks is because they are also
drilled and threaded to fit the holes in bison chucks you can use
them for other chucks but some of the holes might interfere and you
could end up with partial holes fred(13697) |
| 3 jaw chuck
backing plate |
| One of my 3 jaw
chucks that I have doesn't have the 1-1/2 8tpi backing plate. It's a
union chuck made in new britian CT 6". I would be very happy if I
could use this on my SB. Is it better just to ebay it or look for a
source for a backing plate? currently it looks like a 1-5/8 12 tpi
plate. Who is best to look for pricing on a plate? I currently have
2 other chucks that fit my 2 SB lathes. I don't have a 4 jaw.
(17018) |
| You can get a
Buffalo backing plate from Enco, Wholesale Tool etc for around $50.
You will have to fit the chuck and probably bore the shoulder out
some but they are tapped for 1 1/2"-8. I have an 8" one but the
surface is discolored from the monkey snot they put on them. If you
are interested you can have it for what I paid for it, I was going
to bore it out to 2 1/4" but I can just as easily get another one
already 2 1/4". One of these projects I will get to someday. JP
(17019) |
| Chuck backing
plate question |
| I have looked for a
good description of how to "fit" a backing plate to a chuck but
can't find one. I have a Cushman 3 jaw with a backing plate
currently fitted. The problem is the chuck and the face of the
backing plate don't run true. If I put a dial indicator on the face
of the bare plate I get .005 + - out of true Now if I flatten or
true the plate and reinstall the chuck is this chuck only good for
this lathe? Is this a normal thing to have to do? (17036) |
| Go to this link for
instructions on how to fit a chuck
http://www.lathes.co.uk/latheparts/page7.html
Yes The chuck may only work on the machine it is fitted to. Jim
B. (17039) |
| Setting up
chuck backing plate |
| I have a Cushman
3 jaw chuck that has a backing plate. Is there a good source to
explain the process for fitting the plate to the chuck. The face
plate is on the chuck but it doesn't run true. Also after doing so
is that chuck to be used only on the lathe it was set up for? The
reason I ask is because the chuck/backplate don't run true. If I put
a dial indicator on the face of the base plate it doesn't run true.
If I face it to run true will that make that chuck fit that lathe?
(17041) |
| Greetings, Not sure
why Yahoo decided this was spam, apparently their latest efforts at
filtering are still in the training stage. In any event, the first
two entries at MetalWebNews in the metal removal file section likely
tell you more than you want to know, but everything you need to know
(at least for now.) The link is:
http://www.metalwebnews.com/mr.html
Stan (17047) |
| But, before you
start cutting metal off your backplate make sure there are no burrs,
pieces of swarf stuck in a thread etc If you have the 1-1/2 threaded
spindle realize that the "register" portion between an SB and Atlas
are not the same. (17059) |
| Need 4" backing
plate for Hercus/SB 9" |
| I have obtained a
Burnerd 4" 3 Jaw chuck without backing plate. I seek assistance in
obtaining a new backing plate for machining to suit existing spindle
arrangement, hopefully in Australia but otherwise in USA. (17902) |
| A good option is to
make a wood or mdf pattern and get a local foundry to cast you one.
The pattern is just two circles of suitable thickness and dia cut
out and screwed together. Then you machine it. (17911) |
| Question about
lathe chuck backplates |
| What is the function of a back plate? Philip (18051) |
| Many chucks do not
have threads specific to a lathe. The spindles of various lathes
have different threads. The backing plate adapts the more or less
"universal" chuck to the specific lathe that it is being used on. It
is usually of cast iron with a threaded bore to fit the lathe in
particular and a flange to fit the chuck. The chuck in turn may have
a bore somewhat smaller that the OD of the chuck into which the
backing plate is fitted. It is usually necessary to turn the backing
plate on the lathe that it is to be used on in order to insure the
best concentricity and trueness. Chucks can be purchased with
threads machined to fit various lathes but the backing plate/chuck
combination tends to result in a truer system. Jim B. (18053) |
| Preparing A
Backplate for a 3-Jaw Chuck |
| I just got an adjust-tru 3-jaw chuck
from Plaza. It came with a backplate but it isn't from this chuck. I
think I need to cut a better surface on the back of the backplate.
That would be the surface that will seat against the collar on my
spindle. I can thread the backplate on my spindle backwards but it
will run to the end of the spindle threads and doesn't get to seat
against the collar on the spindle. Can I make a light facing cut
without damaging the spindle threads? Once this is done I will turn
the backplate around and make a nice surfacing cut on the part that
mates with the chuck. Are my plans going in the right direction? I
sure don't want to ruin my spindle. Tom (20480) |
| You can make a
small spacer to make up for the groove to hold the plate out. Bob (20481) |
| Search the
archives for backing plate. I know it can be tedious, but good
instructions have been given. Sounds like either the register depth
is not deep enough for the backing plate to bear or that the
threading in backing plate is not long enough. Mount it like it
would be with a chick and look into the spindle nose end? what do
you see? dennis (20490) |
| Backing plates
|
| I've been
looking for a source for a backing plate for my 6" Buck adjust tru
to fit my SB 10L w/2 1/4 x 8. I found some new PBA's for $225 but I
was trying to find something a little cheaper. Enco has some
undrilled set tru import blanks tapped for the 2 1/4 x 8 spindle. I
not sure yet if they are thick enough for the adjust tru shoulder.
How is the spindle fit quality of the import plates? Gary
(23517) |
| You should
fit the backing plate to your spindle no matter were you get it
from. The Enco backing plates are made in Poland. JP (23524) |
| I bought
the exact same plate for my 6" adjust tru from:
http://www.plazamachinery.com/index.html
They are great and have a lot of goodies. He works with a lot of
folks in our group. Very good material. Tom
(23531) |
| I just bought an
unfinished cast-iron 6" backing plate from Wholesale Tool for $16
and machined it to fit my 2-1/4" x 8 spindle and 6" Bison 3-jaw. The
material machined very well and there's plenty of material to work
with. The hub is bigger than 3" diameter (I'm not at my shop right
now, so I can't measure it.) and the plate thickness is at least 1".
If you don't mind doing the boring and threading, that's a great
price and frankly, I like to custom-fit these to the intended
spindle register. Ed (23556) |
| Boy that's a good
price. Guess I will have to gobble up a few and buy some more chucks. (23558) |
| Maybe I am looking
at the wrong web site but I am not having any luck finding
unfinished backing plates. I am looking at
www.wttool.com.
(23561) |
| I finally found
them. I would have to say that their search engine could be more
comprehensive. This is for the 6 11/16"
http://www.wttool.com/p/1922-0005
and this is for 8 17/64"
http://www.wttool.com/p/1922-0010. (23565) |
| I hate to see what the old wttool looked like if this
is the new version. Bob (23566) |
| Tried that already
they are to thin sent both back, look in
www.mscdirect.com. (23578) |
| Yeah, their search
engine is pretty difficult - that's why I use the paper catalog,
then just put in the part number. Ed (23704) |
| Backing plates
|
| Hoping that a raw backplate would be the ticket, there are none that
will do. I was hoping to make one full diameter for a 9A (9"+), but
all I have found are bored or cast way too big for a 1.5-8 thread.
Anything above 8" jumps to bores to suit 2.1/4" threads. I checked MSC, J L and WT. Are there any other sources? RichD
(23569) |
| Rich,
www.mcmaster.com has 9"x1" for $48.00 pn 8926k33 9"x1 1/2" for
$67.00 pn 8926k14. Bob (23570) |
| Bob, Well, that may
do. 1"+ up to 1/4" is good. My SB 7.1/4 FP is about 1.1/16" thru the
hub. McM is in town, Atlanta. I may have to go for a visit.
RichD (23572) |
| Rich: Did you look
in the McMaster- Carr catalogue? Widths to 2". Diameters to 12"
Ron (23573) |
| Ron, I found no
"backplates" or lathe chucks there, but raw iron discs are sold. Bob
directed them to me. I wonder if this stuff is oversize on the
diameter as all the continuous cast bar is that I have. RichD (23576) |
| Rich: Yes it was
the discs I was looking at and not backing plates. Have you tried
KBC ? Tried to look at on-line catalogue for them but struck out.
Can't seem to get to a catalogue type site for them web site.
Ron (23577) |
| Victor
www.victornet.com
sells an 8 1/2" with a 1 1/4" hole for $37. (23579) |
