Stuck Chuck

[sdgrand]

My Grizzly 4-jaw self-centering chuck for my wood lathe (stock number G8784, 1" 8tpi) is stuck in the fully-open position. Three of the four jaws can be "wiggled" slightly, but the fourth is completely immobile. Tapping each jaw lightly with a plastic faced mallet produced no results. Grizzly Tech Support suggested removing the circlip (retaining ring) at the back of the chuck to take it apart, but it would not come apart after doing so. The chuck is normally opened and closed using two "tommybars." I'd appreciate any suggestions anyone may have to try to get it unstuck. Thanks in advance, Shel

 

[n7bsn]

Shel

I'm guessing that the in-ability to dis-assemble the chuck and the jaws being stuck are related.

One thing you might try is soaking the chuck in a solvent, is the issue is "stuff" the solvent can remove that would do it.

But I'm with Griz Tech Support, the key is going to be taking it apart.

 

[Odie]

This is an "off the wall" comment.....

You might try forcing the jaws open a little and try wiggling that one jaw that has no play to it. If you can get it to move at all, you might be able to solve the issue.......

.....Worth a shot, but not very scientific!

ooc

 

[Bob Chapman]

Just a thought, but you might get somewhere by heating it. A hot oven rather than a blowtorch might be best.

Bob

 

[Jim Carroll]

Not fully familiar with the grizzly chuck but does it have a jaw limiting screw like the early nova chucks had.

This screw was located where the jaw slide runs in an out and some thought they had to use the jaws to the extremes, they woulod then run over the top of the screw, in most cases it just lopped the top of as they were fairly soft but sometimes they would bind up in the jaw thread.

The only way was to force the jaws back to the closed position and take out the broken screw, then dismantle the whole chuck to get rid of any loose parts and clean up the jaw slides.

 

[Bill Boehme]

Here is something almost guaranteed to work, but it requires the assistance of another person and is similr to using an impact driver. While once person applies a very strong force on the Tommy bars (in the direction that would make the jaws move in the direction that you want -- closed in this instance), the second person uses a hammer and applies several smart blows onto the face of the chuck so that it squarely hits the stuck jaw. Use a steel hammer as you want to generate a very high impulse force and other types of hammers would not be as effective. To be clear, no tapping or smashing, but something that would be appropriate for driving an 8d nail into pine. A one-pound carpenter's hammer would be about the right size.

 

[Richard Baker]

Shel,
The stuck jaw is probably stuck on a roll pin which I think is supposed to limit its travel. Suggest Bill's procedure, applying closing pressure with the tommy bars while tapping on the outside diameter of the stuck jaw. I do suggest light tapping at first and note if the jaw moves. If it moves, repeat with same level of force. If not more, hit it harder.

 

[Dale Miner]

Assuming that the chuck is stuck with the jaws still on, take the screws out that are holding the jaw to the stuck jaw slide. After the screw are removed, the jaw may need to be pried from the jaw slide to disengage the bayonet mounting engagement. If the pin that is in the jaw is causing the bind, the slide should be free once the jaw is removed.

Later,
Dale M

 

[Bill Boehme]

Shel,
The stuck jaw is probably stuck on a roll pin which I think is supposed to limit its travel. Suggest Bill's procedure, applying closing pressure with the tommy bars while tapping on the outside diameter of the stuck jaw. I do suggest light tapping at first and note if the jaw moves. If it moves, repeat with same level of force. If not more, hit it harder.

Good point about the roll pin being the possible cause.

Assuming that the chuck is stuck with the jaws still on, take the screws out that are holding the jaw to the stuck jaw slide. After the screw are removed, the jaw may need to be pried from the jaw slide to disengage the bayonet mounting engagement. If the pin that is in the jaw is causing the bind, the slide should be free once the jaw is removed.

Later,
Dale M

Good solution if the roll pin is the problem.

 

[sdgrand]

I located the slot under the immovable jaw and cut

away the pin jamming the jaw using a one-eighth inch

endmill (in the drill press using a vise affixed firmly to

the drill press table). At that point the chuck became

unstuck and I un-assembled it completely; after

cleaning off accumulated gunk (mainly oily sawdust),

I'm ready to re-assemble it. Before doing so should I

coat the moving parts with (a) oil, (b) grease, (c) paste

wax, (d) something else, or (e) none of the above? Also

thoughts on whether to start the spiral at jaw one or at

jaw four will be appreciated....

 

[n7bsn]

IMO, oil, grease etc would allow "junk" to quickly get stuck and once more foul the chuck

I would use a dry lub

TTFN
Ralph

 

[Steve Worcester]

I agree, a dry lube. T-9 (I think it's dry) or any of the many high quality dry bike chain lubes would work.

 

[Bill Boehme]

Nothing greasy or oily. Graphite is good. Also, my universal shop lubricant, Johnson's Paste Wax, works great. After the VOC's evaporate, the remaining wax is dry (a mixture of carnauba and other hard waxes). I use it on my Oneway Talons and it makes them operate very smoothly. I tried T-9 once, but it was a mess. T-9 contains some soft waxes and oils. Its original claim to fame was to displace moisture and lubricate pulleys and bellcranks in difficult to access areas of aircraft such as the tailcone and wings where small inspection holes are the only access and, even then, may require some real effort. One of my airplane partners had long skinny arms so he was the one who got elected to reach in with a can of T-9 to do that chore. My job was to torque off bolt heads.

 

[n7bsn]

I'm not sure I would use Boeshield T-9. I mean I use it on the ways, the TS and BS tops, etc. But i'm uncertain about using it in the chuck