[Newbie] Help needed - chuck jaws locked

[dan97526]

Working with my first lathe, an old Seneca Falls 12x36. It has a Skinner 3-jaw chuck.

I noted while I was familiarizing myself with the lathe that two screws that hold together the chuck halves were missing. I was making some test cuts and getting some wobble in the chuck. I put new screws in it and as I was tightening the last one I heard some odd creaking from the chuck. After that I attempted to open the jaws with the chuck key and they were locked tight. They are open a half-inch or so.

I removed the chuck from the faceplate and separated the two halves. Nothing was broken. I restated the pinion gears and reassembled the chuck. The interior of the chuck appears undamaged. The two halves mate up properly with a little rotation of the pinion gears but the jaws are still stuck. Please help!

Thanks in advance.

 

[darkzero]

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

 

[Tozguy]

Then reassemble the chuck without the jaws to see if scroll or pinions are binding?

 

[dan97526]

The scroll is stuck hard and fast.

 

[4ssss]

Next thing is to put it together without the pinions and see if the scroll will turn. If it does then take out the scroll and put it together and try turning each pinion. I think you may have squashed the radius where the pinions are. How that happened is beyond me.

 

[projectnut]

With a chuck this old I would assume you have single piece jaws as opposed to the 2 piece American Standard design. I would inspect the jaws to be sure they are installed in the correct orientation. Each jaw should be numbered and the body should also have a number by each of the jaw slots. It's possible one or more of the jaws are in the wrong location causing the scroll to bind.

If the jaws are in the proper location I would suspect you have a chip jammed between the scroll and one or more of the jaws. I would mark the scroll with a magic marker as to the location of each of the jaws. Then with the chuck disassembled I would tap on the face with a dead blow hammer to try and dislodge the scroll. Once the scroll is separated from the body I would inspect the mating surface between each of the jaws and the corresponding part of the scroll.

 

[darkzero]

The scroll is stuck hard and fast.

Uh oh, hammer time!





I wonder if that screw you mentioned that creaked when putting it in had something to do with it. Did the jaws move fine before putting that screw in?

 

[stupoty]

Uh oh, hammer time!

View attachment 291935



I wonder if that screw you mentioned that creaked when putting it in had something to do with it. Did the jaws move fine before putting that screw in?

As that cananian guy says "tappy tap tap" brass hammer time or soft bras/aluminium drift perhapsStu

I seem to remember m8ne needed a little encouragement last time i opened it.

Stu

 

[darkzero]

As that cananian guy says "tappy tap tap" brass hammer time or soft bras/aluminium drift perhapsStu

I seem to remember m8ne needed a little encouragement last time i opened it.

Stu

Haha, I love watching the 200 lb Canadian gorilla!

 

[dan97526]

Did the jaws move fine before putting that screw in?

Yes. It makes me think that the screws may have been left out for a reason. I'll know more when (if?) I can get the scroll gear out.