Emco v-10 Chuck HELP!! :)

Some of the new asian lathes have the backplate as an integral part of the spindle - are you sure that this is no the case on the Emco? You mention that the 'locking bolt' has been undone which imples the backplate really is separate - but exactly what does the end of the spindle look like, do you think, is it threaded, tapered, etc?

Jim

================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ==================================================

My V-10p had a flanged spindle with three bolts holding the backing plate to it. IIRC there was a short tapered extension on the flange that centered the backing plate. To change the chuck, you removed the three bolts (there was just clearance between the headstock and the flange for an open-end wrench). The chuck and backing plate then just dropped off as a unit. I haven't had that machine for over 20 years (wish I did, it was a nice machine) so I'm writing this from memory and CRS set in years ago. On my machine both the 3-jaw and 4-jaw had their own backing plates.

-- Bob (Chief Pilot, White Knuckle Airways)

I d> >

Your memory is probably in OK condition! Mine has the flange with the three bolt holes as an integral part of the spindle like yours was. However both the instruction book and the parts manual show the spindle as having a threaded nose. I presume mine is from a later production? The instruction book refers to machining the backplate in situ on the machine to fit a particular chuck, which also attaches to it with three bolts. It then states "A backplate which has been fitted to a particular chuck should be left fitted to it and not used for any other chuck, or on any other machine". On these machines the chuck and backing plate must have to be unscrewed to remove it. The OP's machine may be one of these.

-- Regards Malcolm. Remove sharp objects to get a valid e-mail address

I believe it has a tapered spindle (havent been able to remove the backplate to see) the three bolts on mine are allen bolts, I've tried with both the chuck still attached and removed, and soaked the spindle in wd-40 / RP7 to try and loosen the connection.. the 4 jaw chuck does have its own backing plate, and if real worst comes to worst, i can probably re- machine the backing plate to accept a new chuck, but i do like using the original parts and this wouldnt really help in the long run, as i'd eventually run out of backing plate :)

The "Locking bolt" is on a collar that fits around either the threaded section or tapered section of the spindle (again not sure) , I believe this had been added after market to stop the chuck spinning off when cutting in reverse :)

Thanks

Tom the Tinkerer Horologist in training NSW Australia

Tapered and threaded don't normally appear on the same lathe -- with one exception which I will mention below. If it is threaded, there should be a register following the threaded section. (That is -- either the same diameter as the threads, or larger, but cylindrical, with a step increase in diameter afterwards, which serves to locate the chuck.

If you have a locking bolt, it is most likely to be decreasing the diameter of the register part of the backing plate (via a split) to clamp onto the register of the spindle -- for the very purpose which you suggested. You may simply have a case of some rust having formed where the two meet, from water wicking down in the slot which the locking bolt clamps. You might try loosening the clamping bolt, and then driving a thin screwdriver blade into the slot to expand it a bit, and see whether that allows things to unscrew. Add some penetrating oil and perhaps some controlled heat to encourage the penetration. (More on this subject after the exception paragraph below.)

* The one exception to the "threads don't mix with tapers" rule which I suggested above is the L-00 (and other sizes, all starting with 'L'). This has a long taper, with a key mounted to the spindle nose, and a keyway in the female taper in the chuck backplate or the chuck if it comes without a backplate. The female taper on the chuck has an external threaded section, which is engaged by a loose threaded ring on the spindle which draws the chuck firmly onto the taper. To the best of my knowledge, Emco did not use the L-00 on any of their machines, though it is possible that E*n*co did -- totally different machines.

Threaded spindles have problems which require proper care to avoid.

1) The threads on both the spindle and the chuck *must* be clean or you risk getting the chuck stuck in place. You should make a spring loaded tool to clean chips out of the threads, and use it before mounting the chuck each time. (The register should also be clean.) 2) Another problem can come from either putting the chuck on loosely and starting a cut, or from noticing that the chuck is starting to unscrew from the spindle and switching it into forward to catch up with the threads. Either case causes the chuck to seat rather too vigorously, and risks having it on tight enough so removing it will be difficult at best.

It was a combination of the two above which led me to replacing my spindle (2-1/4x8 threaded) with an L-00 spindle when the opportunity arose. I have not regretted this conversion. (And I *did* have to fight a too-tight chuck a few times.

Note that there is one sure-fire way to deal with the problem, especially since your chuck can be removed from the backing plate. Remove it, procure a replacement backing plate, and machine the old one off of the spindle. Eventually, you will get down to the spiral of metal which made the threads of the chuck backing plate, which should be easy to unwind or unscrew from the spindle. Be careful with the register area. This is less likely to damage the lathe itself than some of the more vigorous means of freeing a stuck chuck.

Since you have another chuck which fits the machine, examine it closely, to see just how it works.

Once everyone knows what kind of spindle you have, you should get lots of suggestions on how to remove the stuck backplate. Since Emco has used several styles of chuck attachment over the years (mine, for my Compact-5, bolts the chuck to the spindle nose by Allen-head bolts passing through the chuck body between the jaws), and since some at last seem to be confusing Emco with Enco (the latter, in recent years, selling imported Asian lathes -- mostly Chinese and Taiwanese).

Good Luck, DoN.

You would be right :) at the headstock end of the nose there is an unthreaded portion, which is where the clamp fits, i will attempt the levering of the collar this weekend, although finding internal jaws would solve my problem for a while too.. I'll have to try and source a new backplate as well. although i feel a little anxious at cutting the existing backplate off :) Thanks so far

Tom the Tinkerer Horologist in training NSW Australia

[ ... ]

Note that *some* Emco chucks have reversible jaws. Remove them, and look at the teeth on the back which engage the scroll plate. If they look sort of like this:

[ (( (( (( (( (( (( (( ]

They are the normal non-reversible ones. However, if they look more like this:

[ () () () () () () () ]

(curved both ways on the two sides) they can be installed into the chuck body backwards. Note that this is more often found on smaller chucks than what you have, (e.g. one of the styles for the Compact-5, and the one which came with the Unimat SL-1000) but it just may be that you have them in your chuck. Note that these are not as strong as the non-reversible ones, so if you have them, be more careful about cranking down on the wrench.

Also -- just in case -- are your chuck jaws two-piece? The top jaws held onto the bottom with Allen head cap screws? If so, you should be able to unbolt them and reverse them.

I understand. It is a last-ditch solution -- and you will lose the special slit and clampable register collar, so other attempts to free and preserve the existing one should be tried first.

Best of luck, DoN.