4-jaw chuck screw removal

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SteveM
Posts: 7763
Joined: Mon Jun 27, 2005 6:18 pm
Location: Wisconsin

4-jaw chuck screw removal

Post by SteveM »

Picked up a nice 8" 4-jaw chuck, which, while large for a 12" lathe, will do a particular job I have (just need to watch the stick-out on the jaws).

I want to pull it apart and clean it. I got the jaws out, but the forks that capture the screws don't have screws to hold them in. They may just be pressed in, but tapping on them with a punch (as hard as I dared, which is to say, not very) did not budge them.

Any suggestions?

Steve
Attachments
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20180424_211320.jpg
John Hasler
Posts: 1852
Joined: Tue Dec 06, 2016 4:05 pm
Location: Elmwood, Wisconsin

Re: 4-jaw chuck screw removal

Post by John Hasler »

I have a similar chuck. I had to whack some of the forks pretty hard to get them out.
SteveM
Posts: 7763
Joined: Mon Jun 27, 2005 6:18 pm
Location: Wisconsin

Re: 4-jaw chuck screw removal

Post by SteveM »

John Hasler wrote: Wed Apr 25, 2018 10:45 am I have a similar chuck. I had to whack some of the forks pretty hard to get them out.
OK, I left it soaking in penetrant.

Steve
jcfx
Posts: 713
Joined: Sun Aug 09, 2009 1:24 pm
Location: NY

Re: 4-jaw chuck screw removal

Post by jcfx »

John Hasler wrote: Wed Apr 25, 2018 10:45 am I have a similar chuck. I had to whack some of the forks pretty hard to get them out.
That's good to know, I stopped when those forks on my 4 jaw independent wouldn't budge with light tapping,
John Hasler
Posts: 1852
Joined: Tue Dec 06, 2016 4:05 pm
Location: Elmwood, Wisconsin

Re: 4-jaw chuck screw removal

Post by John Hasler »

Well, I was lucky. The first one started moving with light tapping, so I knew there were no concealed taper pins or similar. When the others were reluctant I felt safe in whacking them.
SteveM
Posts: 7763
Joined: Mon Jun 27, 2005 6:18 pm
Location: Wisconsin

Re: 4-jaw chuck screw removal

Post by SteveM »

Sitting overnight with penetrant (50/50 acetone / ATF) appears to have done the trick.

Once they started moving, they slid out fairly easily.

Not sure how important to get them back in the same hole, but I number stamped each of the forks.

Now I just need to clean it and put it back together.

Steve
pete
Posts: 2518
Joined: Tue Feb 10, 2009 6:04 am

Re: 4-jaw chuck screw removal

Post by pete »

Better to play it safe with chuck disassembly and reassembly imo. With 3 jaw well made chucks it's important to even get the pinions into the same holes during reassembly to duplicate how the chuck was finish ground. An independant may not really matter but I'm no chuck expert.With an independant the main accuracy consideration is having the jaw tips ground exactly square to the chuck face and parallel to the lathes ways. Might be worth a light regrind on the jaws just to be sure of that? Don Baily at Suburban Tools did a great video about preloading the jaws on a 3 jaw before grinding and I think the same idea is needed even on an independant for truing the jaw tips. If the jaws aren't true the work can have zero runout at the chuck face and be wobbeling more than you'd like an inch away from that.
SteveM
Posts: 7763
Joined: Mon Jun 27, 2005 6:18 pm
Location: Wisconsin

Re: 4-jaw chuck screw removal

Post by SteveM »

Here's the chuck all cleaned up and installed on the lathe.
20180428_212732.jpg
Here it is holding the piece of steel I plan to be machining with it:
20180428_212620.jpg
It's a bit big (8") for a 12" lathe, but it will be nice for large jobs such as this.

I'll be making clamps that have circular features by machining the face of the disk and then bandsawing it into segments.

Steve
pete
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Joined: Tue Feb 10, 2009 6:04 am

Re: 4-jaw chuck screw removal

Post by pete »

Now that cleaned up very well. Nice job.
earlgo
Posts: 1794
Joined: Sat Jan 29, 2011 11:38 am
Location: NE Ohio

Re: 4-jaw chuck screw removal

Post by earlgo »

Agreed, nicely done. Can I send my ATLAS 6" 4 jaw for a similar cleaning? :)
--earlgo
Before you do anything, you must do something else first. - Washington's principle.
SteveM
Posts: 7763
Joined: Mon Jun 27, 2005 6:18 pm
Location: Wisconsin

Re: 4-jaw chuck screw removal

Post by SteveM »

earlgo wrote: Sun Apr 29, 2018 4:04 pm Can I send my ATLAS 6" 4 jaw for a similar cleaning? :)
No big secret to my method and not a lot of work.

Disassemble
De-grease with Simple Green
Re-rust with Evap-o-rust
Clean up with steel wool and Boeshield
Lube and re-assemble.

Steve
earlgo
Posts: 1794
Joined: Sat Jan 29, 2011 11:38 am
Location: NE Ohio

Re: 4-jaw chuck screw removal

Post by earlgo »

That sure sounds easy enough. Thanks for the instructions.
--earlgo
Before you do anything, you must do something else first. - Washington's principle.
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