Wobbly chuck, how to diagnose?

[AlexPeel159]

Recently purchased a Logan 1922, with a threaded 2 1/4 - 8 spindle. Came with a 3 jaw chuck, Logan 430 6". The chuck has a serious visible wobble to it. Not a "I am not sure I think it might have a wobble" wobble, but a "oh yeah that is wobbling" wobble. I have tested the registration face of the spindle and the spindle interior. It was about 0.00075 - 0.001 runout for both. When I tested the chuck with a 0.5 inch gauge pin I got up to 0.018 runout at 1" away from the jaws. I have cleaned and deburred the spindle (nothing large just some small nicks). I also cleaned out the chuck threads, checked for any damage in the thread area, which there doesn't seem to be any, and ran a precision stone across the back face. Again nothing obviously bad, and while nicked up quite a bit nothing seemed raised. The chuck has a lot of visible external wear so it seems like its been well used but notthing major outside of something looks like it hit the top face of the jaws. Not experienced enough to be able to identify the damage but its not smooth like a facing operation. Probably crashed something into it. I have tried seating it several times and it contacts the registration face of the spindle smoothly, nothing binding on the threads, BUT I noticed that it only fully contacts on one side. On the other I was able to fit a 0.003 feeler gauge into the gap.

I have purchased a 6" 4 jaw, also an old Logan, and it threads on fine and does not have the same apparent wobble and seems to seat fully on the spindle all the way around. Seems pretty smooth on rotation like one would expect.

Question is how do I proceed from here? I was planning on taking it apart and cleaning it, which I am sure it needs, but I am thinking that wont help the fact it does not even seat flat on the spindle. Are there more tests I should be doing? Should I attempt to resurface the back registration where it meets the spindle? If so how would I go about doing this? The only other thing I have is the 4 jaw.

 

[Jimsehr]

Recently purchased a Logan 1922, with a threaded 2 1/4 - 8 spindle. Came with a 3 jaw chuck, Logan 430 6". The chuck has a serious visible wobble to it. Not a "I am not sure I think it might have a wobble" wobble, but a "oh yeah that is wobbling" wobble. I have tested the registration face of the spindle and the spindle interior. It was about 0.00075 - 0.001 runout for both. When I tested the chuck with a 0.5 inch gauge pin I got up to 0.018 runout at 1" away from the jaws. I have cleaned and deburred the spindle (nothing large just some small nicks). I also cleaned out the chuck threads, checked for any damage in the thread area, which there doesn't seem to be any, and ran a precision stone across the back face. Again nothing obviously bad, and while nicked up quite a bit nothing seemed raised. The chuck has a lot of visible external wear so it seems like its been well used but notthing major outside of something looks like it hit the top face of the jaws. Not experienced enough to be able to identify the damage but its not smooth like a facing operation. Probably crashed something into it. I have tried seating it several times and it contacts the registration face of the spindle smoothly, nothing binding on the threads, BUT I noticed that it only fully contacts on one side. On the other I was able to fit a 0.003 feeler gauge into the gap.

I have purchased a 6" 4 jaw, also an old Logan, and it threads on fine and does not have the same apparent wobble and seems to seat fully on the spindle all the way around. Seems pretty smooth on rotation like one would expect.

Question is how do I proceed from here? I was planning on taking it apart and cleaning it, which I am sure it needs, but I am thinking that wont help the fact it does not even seat flat on the spindle. Are there more tests I should be doing? Should I attempt to resurface the back registration where it meets the spindle? If so how would I go about doing this? The only other thing I have is the 4 jaw.

I would take the back plate off the chuck and make sure it is true.
Then worry about the chuck.

 

[Makintrax73]

Does the chuck have a back plate adapter? My Logan chuck (5") does not. If your Logan chuck is like mine where the threads are integral to the chuck itself I'm not sure you're going to find a solution.

 

[tq60]

Take it apart and clean it.

A small wire wheel in a die grinder works well.

Sent from my SM-G781V using Tapatalk

 

[matthewsx]

Make a welding positioner.

If I get to be 102 years old I’ll probably have a little wobble too.

John

 

[Jimsehr]

Make a welding positioner.

If I get to be 102 years old I’ll probably have a little wobble too.

John

1922 is the model #. Not the age.

 

[markba633csi]

Whether the chuck has a backplate or not, the gap at the shoulder means something is really tweaked- probably need to replace

 

[woodchucker]

I have a binder clip (black with two wires to open the jaws) , I took the wire off, sharpened the part farthest from the U with flats. It allows me to put it in my 1.5 -8 chuck backs to clean the threads on the chuck. Get a big one, makes a great cleaner, especially if you get a chip stuck hard in there.

Like @Jimsehr said, take the backplate off the chuck if it has it and check for true. If it's integral, try cleaning alone.

 

[Asm109]

That is no longer a chuck. It is a door stop or boat anchor.

 

[woodchucker]

That is no longer a chuck. It is a door stop or boat anchor.

you don't know that. too early to tell.