Problem: stuck chuck

[morrisman]

Hi all.. the chuck on this machine hasn't been removed for many years . Not many places to hold the spindle in order to remove the chuck ..Pics explain it . At the LH end of the spindle is a round lock nut , this appears to lock the gear onto the spindle and apply pre load to the bearings ..I may be able to remove the round lock nut and gear and fit a normal nut , I will then have something to grab onto with a spanner ..Any ideas appreciated ... I dont want to damage anything obviously ...MIKE

[nadroj]

For my 9 inch Hercus, I was able to loosen a stuck chuck by gripping the gear.
See: Aluminium split block gripping on spindle gear teeth. | Flickr - Photo Sharing! (http://www.flickr.com/photos/28257637@N08/5145477564/in/set-72157625309682242/)

Jordan

[pipeclay]

When and if you manage to remove the Chuck backing plate with out having to dismantle the spindle,put a piece of paper or fibre cut to the register size of your spindle.

At times the Hercus 260 can be very hard to remove the Chuck and Backing plate from the spindle.
By putting the paper or thin fibre washer between the two surfaces it creates an air gap if you have to apply heat.

Generally it will burn away creating a gap and allowing removal of Chuck and Back plate..

If you can make a jig to hold your spindle from turning either put bolts into the backplate that is on your spindle or put the chuck back on so as to give you some purchase,after doing this and locking thespindle in position with something more than the back gear preferably wedge a bit of steel or hardwood timber between the bolts or jaws of the chuck and give it a good hit.

If you dont hit it hard you will be chasing you ar-e for ages trying to get it off.

If after attempting to get it off and you have no luck you will need to machine the backplate off,not a great drama a new piece of cast will be under $20.

[Anorak Bob]

For my 9 inch Hercus, I was able to loosen a stuck chuck by gripping the gear.
See: Aluminium split block gripping on spindle gear teeth. | Flickr - Photo Sharing! (http://www.flickr.com/photos/28257637@N08/5145477564/in/set-72157625309682242/)

Jordan

Neat Jordan:2tsup:

BT

[Ironwood]

I had a bit of trouble getting the chuck off my Forbes lathe.
I was given plenty of advice in this thread, and eventually got it off ---- http://www.woodworkforums.com/f65/having-trouble-unscrewing-chuck-lathe-135107/

[morrisman]

Good ideas there ..I will also apply some gentle heat around the hub of the back plate ... these problems need patience . Mike

[Bryan]

I reckon this problem is exactly why a lot of older lathes come with busted back gears. Just a theory, but i would say whatever you do, don't engage the back gear.

[Stustoys]

What about spraying the spindle with a can of the freezing spray I can never find when I need it?
Last I saw it was about $20 a can so I'd try the cheaper ideas first.

Stuart

[morrisman]

Yes Stuart ..I have used that freeze stuff . I had some old stuck car brake cylinders ... pistons jammed . It didn't work in that case , dont know why .

[Stustoys]

Yes Stuart ..I have used that freeze stuff . I had some old stuck car brake cylinders ... pistons jammed . It didn't work in that case , dont know why .
Brakes pistons don't(or shouldn't) have any metal to metal parts(that I can think of) so shrinking one wont help much. You're normally trying to push a rusted piston past the seal.
Are you talking about caliper pistons? If compressed air wont shift them pump them out with a master cylinder(assuming you haven't tried that already)

I've only used the freeze spray once on a pillar drills MT3 chuck, a mate beat it to death while I held my hand to catch the chuck, nothing. "why don't we try the freeze spray lol", one little tap and the chuck fell on the bench. oops

Stuart

[Anorak Bob]

I reckon this problem is exactly why a lot of older lathes come with busted back gears. Just a theory, but i would say whatever you do, don't engage the back gear.

More than a theory Bryan,

My brother in law bought a Hercus Craftsman ( in my mind the most attractive lathe Hercus made) and it had a total of 12 teeth missing from the back gear assembly. To facilitate chuck removal, the seller supplied him with a mandrel like device made from a 3/4 inch Dynabolt welded to a 3 foot long piece of pipe. Installed inside the spindle bore and tightened up, all you had to do was imobilize the chuck with a block of wood between the jaws and bed and lean on the pipe. Obviously after snapping off that many teeth, there had to be another way.:doh:

I use the back gear to remove my chuck but then, I did the chuck up.

Bob.

[4-6-4]

Greetings chaps, The broken teeth on the back rear indicates the back gear was engaged while trying to undo the chuck. This can be repaired. I had a Shenhai lathe that the chuck was sometimes vet difficult to get off. I used a flat steel bar 1 3/4" x 1/2 "on edge between the jaws and a judicious strike with a hammer. I said a judicious sharp strike with a hammer did the job. Does the face plate have any holes in it where you could fasten a piece of steel to it to use a hammer on. I would do this with out the back gear engaged. You do not want any more teeth broken on the back gear. A sharp wack might do the job. 4-6-4

[Abratool]

Here are a couple of ideas I use to avoid the problem of stuck chucks.
Always clean the internal threads of the chuck back plate, with an old dry toothbrush then wipe the threads clean with a piece of cloth.
Likewise for the threaded spindle nose.
Apply clean oil to both the internal threads & the threaded spindle, & the shoulder of the spindle nose
Carefully screw on chuck, & gently apply pressure as it approaches the shoulder on the spindle. Best not to lock the chuck on too tightly by spinning it up to the shoulder.
With heavy chucks & in any case to avoid thread damage & lathe bed dings a piece of wood made to fit across the lathe bed at the correct height, makes things easy. :2tsup:
Thats been my experience, & 2 cents worth for today.:)
regards
Bruce

[morrisman]

Managed to get it off ..huge relief :D As the lathe came with a spare 32 tooth gear . I risked damaging the 32 gear already on the spindle end.. I grabbed it with Stilson wrench :o . installed two bolts in the backing plate holes , tightened them down ...used a crow bar across the bolts ....heated up the backing plate, Theh with a sledge hammer ,gave it a big hit ..it came off first hit :2tsup: MIKE