New top jaws for my 10" Bison chuck

L

Long Tom

Stainless

Joined

Aug 21, 2011

Location

Fiddlefart, Oregon

• Oct 22, 2014

• #1

I spun a hardened part in my 3-jaw Bison chuck and messed up my jaws. It appears these are a standardized part, yes? What would you advise for replacements?

It's a Set-Tru style. Hoping that means I don't have to grind or hard-turn them in situ?

 

L

Limy Sami

Diamond

Joined

Jan 7, 2007

Location

Norfolk, UK

• Oct 22, 2014

• #2

Hard or soft?

 

L

L Vanice

Diamond

Joined

Feb 8, 2006

Location

Fort Wayne, IN

• Oct 22, 2014

• #3

The standard bit is the precisely made face that mates with the master jaw and the approximately shaped upper part. The workholding surfaces need to be ground in place on the chuck.

Larry

 

L

Long Tom

Stainless

Joined

Aug 21, 2011

Location

Fiddlefart, Oregon

• Oct 22, 2014

• #4

Limy, hard. Soft is what I SHOULD have been using. Actually, a 17mm collet is what I should have been using and is what I'm using now.

L. Vanice, lacking a toolpost grinder, could a patient guy turn the jaws into... true... right on the lathe? Carbide has got to be harder than the jaws.

I called one place. ~$300 for Bison brand jaws. Yowsa.

 

A

Achilles Bill

Aluminum

Joined

Jan 31, 2014

Location

Berlin,CT.

• Oct 22, 2014

• #5

Quite a few years ago I needed to replace the hard jaws on an 8" Bison chuck. Bought the jaws from MSC and tried them on the chuck. As I suspected they needed to be ground . I brought the chuck with jaws installed to someone that used to do ID/OD grinding for me and had him grind the ID for me.

 

EPAIII

Diamond

Joined

Nov 23, 2003

Location

Beaumont, TX, USA

• Oct 22, 2014

• #6

If you are going to have to grind the new jaws, why not just grind the damaged ones.

 

I

Ironwoodsmith

Aluminum

Joined

May 23, 2009

Location

Friday Harbor, WA

• Oct 22, 2014

• #7

How deep did the damage go? I made a grinder out of a good die grinder mounted on the tool post. You have to compress the jaws to grind them. Spin up the chuck and take light cuts. The worst part about it is the grit in the chuck. Cover the carriage and ways with something. I masked off with paper.

 

rklopp

Diamond

Joined

Feb 27, 2001

Location

Redwood City, CA USA

• Oct 22, 2014

• #8

Why grind if it's a Set-Tru chuck? Just buy some new top jaws an re-adjust the trueing screws if necessary. If standard tongue & groove top jaws, you can buy from Abbott or Dillon instead of Bison, I think.

 

L

Long Tom

Stainless

Joined

Aug 21, 2011

Location

Fiddlefart, Oregon

• Oct 23, 2014

• #9

rklopp said:

Why grind if it's a Set-Tru chuck? Just buy some new top jaws an re-adjust the trueing screws if necessary. If standard tongue & groove top jaws, you can buy from Abbott or Dillon instead of Bison, I think.

Click to expand...

Well, that was my thinking: why do I need to grind 'em if it's a Set-Tru? So maybe that is true.

As to how much damage. The part had a rounded shoulder I was using as a stop against the jaws. Part is on a live center as well. Crashed the cutter into the helical gear on the end (part of what I was machining off the shaft) and the part spun.

All of which would've been ok, just stupid, except there was a milled keyway extending onto the shoulder I was using as a stop. It ate up the last (outermost) tooth on the jaws pretty good.

I'll check those other sources for them. Thanks!

 

M

metlmunchr

Diamond

Joined

Jul 25, 2004

Location

Asheville NC USA

• Oct 23, 2014

• #10

I doubt you'll find them anywhere for less than $300 for a 10" chuck. US Shop Tools has about the cheapest prices around on a wide range of chuck jaws, and their 10" hard tops are $300 - $350 depending on the gripping configuration.

USST says the American standard tongue and groove hard tops will typically produce .010-.012 runout unless ground in place. If they've gotta be ground, it'd be a lot cheaper to grind the ones you have.

 

L

Long Tom

Stainless

Joined

Aug 21, 2011

Location

Fiddlefart, Oregon

• Oct 23, 2014

• #11

Can't really though. It's just the last tooth of the jaw face that got wrecked, and it's wrecked bad. You'd have to grind off... gosh.... probably .080" to get to clean metal.

 

Putch

Hot Rolled

Joined

Nov 15, 2011

Location

Butler, PA

• Oct 23, 2014

• #12

you could make a grinding fixture that locates off the tongue-in-groove on the back of the jaw, and grind each jaw till cleanup and the same height, then lay them on their side to grind the angles that meet up with the gripping surface if you wanted. Maybe have em rehardened? I don't know about that part though