Jaws too tight on a 4 Jaw chuck

PurpLev

PurpLev

Active User
Registered
Joined
Feb 22, 2012
Messages
924
So a while back I got a 4 jaw chuck from someone on the net that had it laying around unused. I got it, cleaned it up and put it together and noticed that the jaws are REAL tight - but seeing that it was supposedly never used took it for just that, and assumed it would loosen over time.


I tried using this chuck a few weeks ago - this time with the jaws reversed, and as before all the jaws were real tight to close with 1 jaw on the extreme to the point I could not close it past a certain point no matter how hard I tried. I decided not to break it and ended up using a different chuck for that project, but it got me thinking - maybe it's not that it's NEW - maybe its just defective?

I tried filing the edges of the jaw(s) to make it(them) fit smoothly to no avail.

Is there anything I can look for or do to regain use of this chuck+jaws or am I better of chucking it (pun intended) and getting a different chuck all together?
 
Sharon,

Have you tried systematically checking each jaw in a different slot to see if there's a good fit for each one? If it were mine, I'd try that first followed by complete disassembly and careful measuring (with telescoping gages etc) each slot and jaw. Determine which ones are the closest match and make whatever adjustments are necessary.

My 3 and 4 jaw chucks are about one year old now. They were tight when I got them and still are -and I'm darn happy about it. A chuck with wiggly/sloppy fitting jaws can be a nightmare in some circumstances.


Ray


PurpLev said:
So a while back I got a 4 jaw chuck from someone on the net that had it laying around unused. I got it, cleaned it up and put it together and noticed that the jaws are REAL tight - but seeing that it was supposedly never used took it for just that, and assumed it would loosen over time.


I tried using this chuck a few weeks ago - this time with the jaws reversed, and as before all the jaws were real tight to close with 1 jaw on the extreme to the point I could not close it past a certain point no matter how hard I tried. I decided not to break it and ended up using a different chuck for that project, but it got me thinking - maybe it's not that it's NEW - maybe its just defective?

I tried filing the edges of the jaw(s) to make it(them) fit smoothly to no avail.

Is there anything I can look for or do to regain use of this chuck+jaws or am I better of chucking it (pun intended) and getting a different chuck all together?
Click to expand...
 
As previously posted, I would check that the jaws are fitted to the correct slots first. Failing that, I would check the actual surface finish. It may be the case that a little lapping compound might solve the issue and free up the jaws a little. The only issue with the lapping compound is the clean-up necessary to avoid premature wear.

Paul.
 
both really good suggestions,
my old really used and abused 4 jaw has numbers on the face and each jaw, just like a 3 jaw, might check the jaws, face, back for some markings
 
Thanks for the replies.

the jaws and chuck are marked 1-4, and I have been matching the jaws to their respectable slots. I've also lapped the jaws to try and smooth it out. I will go over these again though to see what else it could be.
 
how much movement do the screws have in the chuck body? one might have something that has moved it out of ilignment, or allowing it to move and bind
 
Is it the screws, or the slots? Could be burrs on the threads on either the jaw or the screw if it is the threads. If it is the slots, you'll just have to lap them in.
 
Some clean lube can do wonders also.
 
I had a similar problem and after I verified the jaws were parallel, I noticed the chuck slots were not. It took a fair bit of filing with some small files but I eventually got it to work fairly well, not perfect but way better than it originally was. If I remember correctly, the chuck was made in India.

Good Luck with yours!
 
Thanks for ideas. I'll check screw movements and slot parallelism - those makes sense to me as the culprit based on what I've tried so far.
 
You must log in or register to reply here.
Back
Top