[Newbie] Help needed - chuck jaws locked

[mikey]

Have you tried removing the scroll & check if the jaws move freely in the slots? I would start from there.

Listen to Will. Take a hardwood dowel that fits in the jaw slot and tap in each of the slots until the scroll breaks loose. The jaws should slide freely after that. If not, then you have some chips/debris in there. Clean everything, lube it properly and reassemble. The chuck should work fine.

 

[dan97526]

I spent most of the evening banging on it. I couldn't say if the scroll gear moved or not. I tried hitting the face with a dead blow mallet. I tried tapping the scroll get with a brass punch to turn it. No luck.

Unfortunately the way the jaws are positioned currently, I can't get anything on the scroll gear; it is entirely covered by the jaws.

I do have a theory on what is binding it. I noticed tonight that one of the screw holes was half full of chips and general grime. I dug around in it with a wire and the plug actually pushed through into the chuck body. So I must have pushed a wad of it into the void between the chuck body and scroll gear.

Anyway, I put it to soak in naphtha. Hopefully I'm right about the plug and it will break it up. Beating on the chuck will resume tomorrow. Thanks everyone.

 

[darkzero]

I've got my bag of popcorn waiting to see the outcome. Hope you get it firgured out!

 

[mikey]

Unfortunately the way the jaws are positioned currently, I can't get anything on the scroll gear; it is entirely covered by the jaws.

After soaking it but before you whack it any further, put a piece of plywood down on a solid surface. Turn the front half over with the scroll facing down and try to bang it solidly but evenly on the plywood. Quite often, this will dislodge the scroll so it falls out. You might need to gently tap on each jaw to knock it loose from the scroll before doing this. I have yet to see a scroll that I can't knock loose with either a hardwood dowel or that piece of plywood.

 

[MarkM]

Try using a magnet to clean out the scroll but I think it needs to be taken apart cleaned and probably need some filing and such. Being this old the grime and swarf has probably been compacted somewhere in the mechanisms that need the proper service. Those holes may have a purpuse beyond what we would think about nowadays. They were some crafty folk back then. Id be interested to know more about those holes and there function.

 

[stupoty]

I spent most of the evening banging on it. I couldn't say if the scroll gear moved or not. I tried hitting the face with a dead blow mallet. I tried tapping the scroll get with a brass punch to turn it. No luck.

Unfortunately the way the jaws are positioned currently, I can't get anything on the scroll gear; it is entirely covered by the jaws.

I do have a theory on what is binding it. I noticed tonight that one of the screw holes was half full of chips and general grime. I dug around in it with a wire and the plug actually pushed through into the chuck body. So I must have pushed a wad of it into the void between the chuck body and scroll gear.

Anyway, I put it to soak in naphtha. Hopefully I'm right about the plug and it will break it up. Beating on the chuck will resume tomorrow. Thanks everyone.

Mr Pete has a video disassembling a 3 jaw.

His scroll drops out with a bit of a tap on a surface, I remember mine being quite close fitting and required some gentle taps.

Stu

 

[Cadillac]

The scroll is gonna be a snug slip fit on the ID.

 

[dan97526]

After a couple hundred drops onto plywood on a concrete floor the scroll gear has moved a little. Two jaws are out. Tapping on the interior face of the scroll gear with a brass punch isn't doing much but wrecking punches. I decided not to get impatient and get out the bfh. I still have an eighth or so to go before I can slip over the cast-in arbor. Worn out from bending over and picking it up, and frustrated, I've put the chuck back in the solvent and I'll repeat the process tomorrow.

I'm really baffled by this. Something that is supposed to turn freely and come out without this kind of trouble shouldn't get stuck this hard.

 

[stupoty]

might be worth giving little taps through each slot as it's probably cocking a little as it comes out.

Might be some swarf caught in between the scroll and the chuck body perhaps, or a small area of light rust.

The scroll has to be quite snug to give good repeatability I'm thinking.

Small progress at least

Stu

 

[dan97526]

Well, i finally got the chuck disassembled. My theory on the plug of swarf was half right - it did cause the problem but not how it I was guessing. The plug broke out/deformed the thin wall of the screw hole, which pushed enough material into the way of the scroll gear to lock it in tight. The scroll gear will not seat currently and I'm not going to force it.

The picture makes it look worse due to reflected light, but it's enough to interfere. So next question, how do i fix it? I'm thinking I could get a machinist to turn it down or hone it, or I could just go at it with a die grinder. It doesn't look fatal to me, but I'm inexperienced.