Taking Chinese 3 Jaw Metal Lathe chuck apart for cleaning

[goldstar31]

Al,
Coffee not working yet, mind in slow motion....can you elaborate on your system for a newbie? I've just used my tailstock to pinpoint..
Jim

In GadgetBuilder.com's site it is called a Bump Center

Norm

 

[Jim Woodworth]

In GadgetBuilder.com's site it is called a Bump Center

Norm

This is going to require some "fun" in the shop to test. I'm very intrigued. Thanks for enlightening me.

 

[JimDobson]

I made one a few years ago -

 

[KarlH]

The square stock is mounted in the tool holder with the bearing vertical. The square stock is either perpendicular to or inline with the axis of the spindle, depending on which face you want to align.
With your work piece snug in the chuck, you slowly advance the bearing in toward the workpiece. Contact will be made at the "high" spot on the work piece, and the bearing will push the work piece a bit "lower." Eventually the bearing will be making light contact with the entire piece, and the piece is aligned. You can then finish tightening the chuck.

 

[Tim1974]

Or it flys out and hits you in the head ! Bit dodgy in my opinion

 

[Jim Woodworth]

The square stock is mounted in the tool holder with the bearing vertical. The square stock is either perpendicular to or inline with the axis of the spindle, depending on which face you want to align.
With your work piece snug in the chuck, you slowly advance the bearing in toward the workpiece. Contact will be made at the "high" spot on the work piece, and the bearing will push the work piece a bit "lower." Eventually the bearing will be making light contact with the entire piece, and the piece is aligned. You can then finish tightening the chuck.

I made one a few years ago -

Thanks for the visual.

 

[Jim Woodworth]

The square stock is mounted in the tool holder with the bearing vertical. The square stock is either perpendicular to or inline with the axis of the spindle, depending on which face you want to align.
With your work piece snug in the chuck, you slowly advance the bearing in toward the workpiece. Contact will be made at the "high" spot on the work piece, and the bearing will push the work piece a bit "lower." Eventually the bearing will be making light contact with the entire piece, and the piece is aligned. You can then finish tightening the chuck.

Worded very well, added to the visual above I think I'm buying in to the process. Thanks, Jim

 

[Jim Woodworth]

Tim1974 notes my one concern, Would spinning the chuck by hand suffice?
I can remember way back in school the instructors being very strict with students about not tightening work in the chucks thoroughly before powering up.

 

[Jim Woodworth]

Thanks Jim Dobson for the original chuck cleaning post,
Because of your post I got brave enough to take down and clean up at least enough to function a 3-jaw that I had never used. it was stuck solid.

 

[mcostello]

Hand speed will work also.

 

[goldstar31]

Of course. it is a wonderful way to 'bell mouth' a chuck.

A piece of exact diameter metal to the work to be machined and placed inside the chuck would avoid this.
Ah well?

Norm

 

[NickP]

The Chinese chucks are well worth the money but its worth the effort to strip down and clean
I also take off the sharp edges even the gear teeth.As has been said a light coat of grease
once tried oil and learned by my mistake it tends to get thrown everywhere

If you wanted to use oil you could try steam oil - it’s much thicker and more ‘gloopy’ so doesn’t tend to get thrown off things so quickly. Personally, although I’m no where near an expert I use grease in mine as it tends to stay put for the most part.

Nick

 

[harborfreight8x12]

Hello all. In answer to Tim1974, safety is my primary concern and I always wear a full face shield that meets Z87.1+ standard. That said, first I try re-chucking the piece to see if it centers on its own, if not, then I use the 'bump' center but only turning the chuck by hand. At this point, the chuck is only lightly snugged so as not to damage or 'bell mouth' the jaws. Others have said that they use a bar of nylon pressed against the piece, but I love to make gadgets and skateboard bearings are reliable and inexpensive.
Kind regards, Al