chuck sticking on headstock spindle face

[Shay Vings]

My Teknatool G3 chuck tends to stick to the drive spindle of my Record DML 305 lathe. Originally I tried a leather washer but later realised that leather absorbs moisture which created rust on the spindle face so I have given up that idea.

It seems wrong to put soft washers there when the lathe manufacturer has gone to such a lot of trouble (;-) to machine the spindle drive face flat and smooth.

I try not to overtighten but roughing down inevitably creates some tightening shock loads

The spindle thread seems fine: its the mating faces where the problem seems to occur

Ideas?

 

[cornucopia]

use a nylon washer- that sorts it.

 

[CHJ]

If you don't have easy access to propriety nylon washers then cut yourself one out of some thick plastic like an ice cream box, or turn one out of an old plastic chopping board.

 

[myturn]

What do you mean by "stick" ?

Locking the headstock, inserting the chuck key and giving a sharp jerk/tap on the key should loosen it.

I wouldn't put any soft washer between the chuck and spindle.

 

[CHJ]

Placing a rigid plastic (well rigid as far as the expected loads are concerned) between chuck and spindle face is regular practice, far less risk to machine than having to apply excessive shock loads to the spindle and bearings to release the 'wrung tight' friction fit of the chuck/spindle interface.

Even used on heavy machine tools where risk of damage to gear teeth etc. is to be avoided.

 

[paulm]

As Chas says, self made washer from thin chopping board used on mine after having major problems removing a chuck after using the Kel McNaughton coring system which created masses of torque and made removing the chuck afterwards almost impossible !

Cheers, Paul

 

[myturn]

Well I think something's not right if the chuck is on so tight it won't come off using normal methods.

I regularly use my lathe in reverse for sanding and some hollowing where it is convenient to get a scraper in the far side and the chuck has never come undone through reverse motion but always comes off with a tap on the key with the spindle lock engaged. I do have a locking collar but have never had the need to use it yet.

I've also used a bowl-saver where the loads have been so great as to break the foot off the wood, but still the chuck comes off when required.

Maybe it's down to how often you remove the chuck, I usually swap mine over several times for each item to save changing jaws and to go between prong-drive and chuck so perhaps leaving it on for long periods without removing it causes this.

 

[CHJ]

It's more down to the quality of fit, if the two surfaces happen to be machined such that they form a perfect, for want of a better word 'airtight' fit then the chances are it will grab with sufficient friction to be difficult to break.

I have one chuck that grabs well, some time ago when using engineers blue to check fits when I was cleaning up the spindle nose It showed a large area of contact, another chuck only had actual contact on about a third of the collar face. (rear chuck collar not perfectly square and coarser machining)

 

[wasbit]

Milk cartons are a good source of plastic for making washers.

Regards
wasbit

 

[Paul Hannaby]

What do you mean by "stick" ?

Locking the headstock, inserting the chuck key and giving a sharp jerk/tap on the key should loosen it.

I wouldn't put any soft washer between the chuck and spindle.

If you like your chuck in one piece, don't ever use the chuck key as a lever to loosen the chuck. You risk damaging the scroll mechanism. A much less risky way is to open the jaws wide enough to insert a long screwdriver or some other lever between the jaws, tighten the jaws on the screwdriver and use that to loosen the chuck while engaging the spindle lock.

Putting a washer on the spindle will loose a few fractions of a millimetre in accuracy but in most circumstances, that isn't significant to us woodturners anyway. I would challenge any woodturner to remount the same piece of wood twice with better accuracy than we're talking about here!
I use a nylon washer with my chuck because that also acts as a good seal for my vacuum chuck so I just leave it on the spindle almost all the time.

 

[dickm]

Not so long lasting, but possibly less likely to introduce any measureable inaccuracy, is to use a piece of heavy-ish quality printer paper, liberally soaked with oil, as a washer.

 

[chrisbaker42]

Looking through the forum for something else I cam across a 2002 post which was a review of the axminster m950 lathe and it suggested there that the use of ptfe tape at the end of the thread should solve the problem, I am certainly going to give it a go.

 

[Redkite]

How did the PTFE work out Chris?

Would a rubber strap wrench, as used for removing oil filters, be a safe and effective way of releasing a troublesome chuck?

 

[minilathe22]

I use a piece of gasket paper, maybe started off 2mm or so thick but has now squashed down very thin. I had not considered that it might absorb water, I may put a little oil on it to prevent this.

 

[hawkeyefxr]

I did just this, my chuck got well and truly stuck. some how the chuck loosened by about a quarter of a turn, when i stated the lathe it snapped back the the face of the chuck and spindle slammed together and it was 'stuck'.
I did free if off after a few hours and made a leather washer to go between the faces, this was ok but not good. So i cut one from an old plastic milk bottle using my dividers, i scored the out diameter round and round till i could just push the disc away from the main part of the milk bottle side. I then did the same on the inner circle and wound up with a perfect plastic wash. No more sticking chucks.

 

[Phil Pascoe]

I made a hot melt glue washer - I just went around the spindle with hot melt then did the chuck up to within a couple of mil.

 

[Lons]

I also have thin plastic washers on both my lathes cut from milk bottle carton and no sticking or problems. Metal to metal is never a good idea imo.

 

[NazNomad]

I use a leather one, but after reading this lot I'm going to switch to plastic tomorrow.

 

[graduate_owner]

I bought a metal lathe, Myford M series, on which the chuck was stuck tight. Really tight. The previous owner had engaged the back gear to lock the spindle, and hit it so much they broke about 5 teeth off the bull wheel. Talk about ham fisted. Anyway I tried running in reverse, using a lever etc but nothing worked. Finally I unscrewed the chuck from the backplate to reduce the amount of metal there, and heated the backplate with a propane torch. It just unscrewed by hand.

K

 

[Phil Pascoe]

:idea: I thought to make some metal washers of different thicknesses to increase the versatility of the indexing.