Another stuck chuck question

jrd-sb · May 29, 2020

Hi all. My SB 9 has a 3-jaw chuck which is stuck on there real good. I know it hasn't been off in at least 25 years, probably considerably longer.

I found a thread with a lot of useful tips for unsticking one, including make a wrench to grab the back end of the spindle.

Before I set about making one, possibly dumb question: My spindle has a hole, about 1/4", bored through the smooth end of the spindle, just outside the gear. Is there any reason I couldn't use a spanner-type wrench in there?

I'm trying to avoid doing something stupid and then having to post about it

Thanks in advance . . .

carlherrnstein · May 29, 2020

I would think it would hurt anything. I get my Chuck loose with a block of wood put the lathe and back gear an pull the bottom side of the belt usually pops right off pretty easy.

SBLatheman · May 29, 2020

jrd-sb said:
Hi all. My SB 9 has a 3-jaw chuck which is stuck on there real good. I know it hasn't been off in at least 25 years, probably considerably longer.

I found a thread with a lot of useful tips for unsticking one, including make a wrench to grab the back end of the spindle.

Before I set about making one, possibly dumb question: My spindle has a hole, about 1/4", bored through the smooth end of the spindle, just outside the gear. Is there any reason I couldn't use a spanner-type wrench in there?

I'm trying to avoid doing something stupid and then having to post about it

Thanks in advance . . .

Chances are that you will crack/break the end of the spindle.

iwananew10K · May 29, 2020

yep^^^
seen quite a few 9s and 10ks with a busted up spindle end.

MetalCarnage · May 29, 2020

Just in case you haven't found this thread - How to Remove a Stuck Chuck -- Tutorial It's the best one I've seen for safely removing a "stuck" chuck.

-Ron

Rudd · May 29, 2020

I'll say it again. I got a wartime 13, unknown provenance. Chuck was stuck but good. Penetrating oil, wrench on the end of the spindle, wood wedges under the pulleys, stuck.
I machined off the backplate, made a new backplate, and was back in business in a fraction of the time I'd spent risking damage and screwing around with a 40 dollar backplate.

jrd-sb · May 29, 2020

MetalCarnage said:
Just in case you haven't found this thread - How to Remove a Stuck Chuck -- Tutorial It's the best one I've seen for safely removing a "stuck" chuck.

-Ron

Yeah

I read that one, and a couple other references.

I made myself up a wood block arrangement, to get under one of the jaws of my chuck. Disengaged all the back gears, belt etc, so nothing was driving or impeding the spindle. I got a spanner of the right size, and gingerly tried pulling on the spindle from the gear end.

It was a non-event. I pulled a bit on the end of the spanner, and the spindle unwound from the chuck! I was amazed! I'd tried holding the belts, sticking a bar in the adjustment hole of the chuck and whacking on it, etc, all to no avail. A bit of concerted pressure did the trick.

Thanks for the input. One day I'll know these machines as the rest of the group, and won't have to ask these newbie questions.

SLK001 · May 29, 2020

Cut yourself a washer made out of wax paper or parchment paper that has an ID that is is OD of your spindle and an OD slightly bigger than the spindle shoulder and put it between any chuck and the spindle shoulder. This washer will go a long way in preventing a seriously stuck chuck in the future.

jrd-sb · May 30, 2020

Ah, I like that idea. I should keep a bunch of them in my box of lathe supplies.

DMF_TomB · May 30, 2020

many use crescent or adjustable wrench on vise jaw and whack wrench with dead blow or a lead hammer. obviously pin to lock or prevent spindle rotation aint heavy duty. having in back gear some use but gears can get damaged too..
.
my experience most damage is done locking spindle and using 18" crescent wrench to turn a tap. just saying if 12" wrench dont give enough leverage bigger wrench can overload and damage pin or gears. pin what about 0.2" or 0.25" dia, and gear teeth how big and thick ?
.
just saying avoid too big wrench sizes and too big a hammer

Dobermann · May 30, 2020

Just somethhing to think about: While taking off the chuck and cutting away the mount plate would certainly work as the "final solution," you might consider taking off the chuck (you were gonna take it off anyway) and then applying some gentle heat to the back plate near the center to see if that might loosen the thing enough to get it off. You could re-install a couple of the chuck mount bolts to give you something to use a lever against.

As suggested in other replies, be very cautious about using levers and levers with pipes to loosen the plate against the back gears and locking pin because you could break the gears and/or shear off the lock pin.

I'd certainly entertain thoughts of machining off the back plate before using brute force methods.

GenePoole · May 30, 2020

Dobermann said:
Just somethhing to think about: While taking off the chuck and cutting away the mount plate would certainly work as the "final solution," you might consider taking off the chuck (you were gonna take it off anyway) and then applying some gentle heat to the back plate near the center to see if that might loosen the thing enough to get it off. You could re-install a couple of the chuck mount bolts to give you something to use a lever against.

As suggested in other replies, be very cautious about using levers and levers with pipes to loosen the plate against the back gears and locking pin because you could break the gears and/or shear off the lock pin.

I'd certainly entertain thoughts of machining off the back plate before using brute force methods.

I did this on an SB 13. Stripped it down to just the backplate, then with a oxy-acetylene torch with a lazy flame (propane torch or heat-gun would probably work too), just heat it in the area around the spindle enough for some smoke to start coming off. Popped loose by hand (with a glove).

SLK001 · May 30, 2020

I just read the other thread on removing stuck chucks. I've used something like that in the past to remove threaded lenses from microscopes, but using wood instead of aluminum. The method that I use now to remove chucks that are resistant to being removed is this:

It slips into the rear of the spindle and with a few turns of the locking screw grips the spindle like it is welded on. I have got into the habit of putting the wax paper washers between my chucks and my spindle, so any resistant chuck easily spins off with this contraption. I have building instructions for this spindle crank in the "What have you built FOR your SB lathe" thread here.

jrd-sb · May 30, 2020

Wow, that's great!

Another one for my project list . . .

Mark Rand · May 30, 2020

On my Myford, I put the lathe in lowest speed on the belts, but not back gear. Then use a light adjustable wrench/crescent wrench on a jaw and give it a sharp rap with a light (1 lb) ball peen hammer. You don't need to lock the spindle, the inertia in the motor and pulleys will provide the resistance. The lighter hammer is so that you provide a sharp shock to the chuck, rather than the more steady force you get with a heavier, slower moving hammer.

jrd-sb · May 30, 2020

Mark Rand said:
Then use a light adjustable wrench/crescent wrench on a jaw and give it a sharp rap with a light (1 lb) ball peen hammer.

That's kind of one of the things I tried first (I used a bar between jaws, laid flat on the side of one of them), but no good. On my SB 9, the drivetrain isn't all that beefy; maybe it just wasn't massive enough to make that method work. Or maybe I loosened it just a bit, so that later it came off easily.

packrat2 · May 31, 2020

Mark Rand said:
On my Myford, I put the lathe in lowest speed on the belts, but not back gear. Then use a light adjustable wrench/crescent wrench on a jaw and give it a sharp rap with a light (1 lb) ball peen hammer. You don't need to lock the spindle, the inertia in the motor and pulleys will provide the resistance. The lighter hammer is so that you provide a sharp shock to the chuck, rather than the more steady force you get with a heavier, slower moving hammer.

Yes some heavy handed non lathe person did a number on my used Myford small lathe back gear {broke several teeth off}...

sealark37 · May 31, 2020

The first rule is, "Don't try to lock the spindle with the back gears". Make a wooden clamp to hold the step pulley. Heat is your friend. Even a small chuck is a wonderful heat sink. Use a torch rosebud or other high output heat source to warm the chuck. Heat until it is too warm to hold your hand against it. Lock a 9 or 10 inch bar crosswise in the jaws of the chuck, and deliver a sharp blow to the bar. Don't over-do it. If it doesn't come free, use the PB Blaster liberally, and try again tomorrow.

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