[Newbie] Operating Screw Retainer Pin Disaster - SB 4-Jaw Chuck

[woodchucker]

There is no visible physical damage to the pins such as would be caused by hammering but I'll throw them in a collet and have at them with a dial test indicator and make sure there are no bumps.

I'm off to see my cardiologist this afternoon but tonight after dinner I'll slit up a 3/8" wooden dowel and use that with a strip of emery cloth in a hand drill to clean the body. I'll then set the pins in a collet and take care of them with a strip of emery cloth and some WD40.

Hopefully I'll have some good news before the end of the day.

I think the peening would be on the chuck. It might be a few punch marks, or peening of the hole itself. They would not peen the pins... I think they are hardened.

 

[woodchucker]

This can happen easier than one might think, I learned that the hard way quite recently. One a close fit such as a precision bearing and shaft or a light press fit it really doesn’t take more than a few tentative tap-tap-taps with a light hammer to swell the very end just a hair. Not enough to see dings or visibly deform anything but still enough to make removal decidedly miserable. The old adage “bigger hammer, bigger damage” does not necessarily bear true in all cases.

-frank

yea, I guess that's true.
I always use a brass punch that I made immediately after getting my lathe restored. Not pretty, but I wanted it stout for just what you are saying.

 

[SLK001]

I wouldn't touch the pins. Where you want a looser fit is in the hole - anyway, cast iron is easier to reduce (enlarge) than hardened steel. Perhaps a film has built up over the years. The pins should easily drop into the hole, because the back plate retains them.

 

[tq60]

Stop...

It went together many years ago so it should now.

Get a mic and measure the pins, check for roundness or hammered mushroom.

Your pressing may have damaged.

Also look for damage in the holes.

You may consider tossing the pins in a zip lock with some oil and freezing them, oil fights condensation when pulled out and makes slippery.

Get a hot plate to heat chuck to toasty then pins may slip in or tap in with brass hammer.

Sent from my SM-G781V using Tapatalk

 

[markba633csi]

That's entirely possible- the factory may have frozen the pins and warmed the chuck to install. I would probably polish the pins too rather than messing with the holes. Pins can be replaced easier than chuck bodies. If you polish too much just use a touch of loctite.
-Mark

 

[karlsangree]

The chuck is back together a working better than I could have expected. I can now spin the chuck key with one finger where before it took two hands. After a careful inspection it appears that a lot of the stiffness was caused due to damage caused by misuse. It looks like a previous owner(s) had crashed the carriage into the chuck hard enough to put some pretty serious divots in the face.

Anyway, it's all sorted out now and working great. Thanks to all who contributed a part of the solution. Cheers!