I need to buy a 3 jaw adjust true chuck

Hmm .... maybe it is Enco. Let's see. New England Brass and Tool has a new line called "Fuerda" (sounds Spanish) in which they offer the 6" 6-jaw for $450.00 in semi-steel, and 6-1/4" for $700.00 in Forged Steel. Both have two-piece jaws.

The same people have the Bison full *Set-Tru* in 6-jaw Forged Steel and two-piece jaws for $950.00 in 6-1/4". (Was your price for Set-Tru or normal fixed mounting?

Agreed!

Good Luck, DoN.

Don't forget to make a donation to your sheriff's re-election campaign and mention you appreciated this. This little offer may probably buy another favor down the road. The sheriff is a good person to be friends with.

Karl

It's a forged set-tru, p/n 7-868-0600 on that page. You got me second guessing my memory so I looked up the price. It was $368.95 in 2003; no back plate. It came from Enco, no doubt from a sale flyer, but that's still a big increase in 8 years.

I could maybe use a 3 jaw with a hardinge-pin-lock if the price was right...

at work but

Michigan may be

Greetings Jim, I do a lot of work that has to run true better than .0005". When I dial in a part in the 3 jaw adjustables it repeats better than .0005" at that diameter and chucking pressure. When I change diameters and need to re-adjust the chuck it almost never takes me more than 2 minutes. HOWEVER, if I had only one chuck it would be a 4 jaw. Lots of the time I bore jaws, and three jaw chucks with top jaws make that real easy. None of my 4 jaw chucks have top jaws, but I'm sure they can be had. BTW, I bought several years ago a 4 inch chuck on a 5C arbor. It is Chinese made. I was unable to find one that wasn't. I took it apart and made it adjustable. The jaws were all in the same plane and perpendicular to that plane but the back face of the chuck was not perpendicular to the jaws. I tightened the jaws onto a just turned spud and machined the back of the chuck true. Then I modified the chuck to be adjustable, with only 3 equally spaced screws instead of 4. It repeats better than .0008". And adjusts fast, but not as fast as 4 screws. Cheers, Eric

I do not have a 3 jaw chuck that is adjustable. But what I think is the advantage is in production. You can adjust a three jaw once and then machine a hundred parts without having to spend that 2-3 minutes per part.

Dan

" snipped-for-privacy@krl.org" fired this volley in news:65cf7d1e- snipped-for-privacy@a31g2000vbt.googlegroups.com:

You can do that with a 4-jaw, too. If you torque all 4 jaws to the same torque, only loosen two jaws, are using the same o.d. workpiece each time, and re-tighten those two jaws to the same torque as before, it's every bit as true as a scroll chuck would be.

It's in the maneuver, not the hardware.

Besides, only collets are accurate on every chuck-up.

LLoyd

at work but

Michigan may be

For a single workpiece -- none.

For multiple workpieces of the same diameter (e.g. production), it repeats quite well (though not for workpieces of differing diameters, where it is at the mercy of wear on the scroll and the "interrupted threads" of the jaws.)

And is about the same dialing in an Adjust-Tru style of chuck. But you only have to do it once for a run of however many parts you want to make in one setup.

Production work -- where time per part is more important than set-up time.

Of course -- for enough parts, soft jaws bored to size can be even better -- especially if you need a step against which to set the part for depth control as well.

Enjoy, DoN.

at work but

Michigan may be

Don't mean to be a smart-ass, but could someone tell me the advantage of a 3-jaw chuck that you can dial in verses a 4-jaw independent chuck.

It seldom takes longer than 2-3 minutes for me to dial in a 4-jaw chuck to .001". I have a dial indicator and base all set up and seldom use a 3- jaw chuck any more. Am I missing something?

Greetings LLoyd, With a 4 jaw you at least need to tighten two jaws. With a three jaw only 1. And accurate 3 jaw chucks will repeat better than .0005". If it was true that the time difference was practically nil then everybody would use 4 jaws almost as much as 3 jaws. But for even a few parts a good 3 jaw is significantly faster than a good 4 jaw. Eric

--Unless you spend a LOT of time on the lathe you prolly don't need one. I do a LOT of lathe work so I've got a 4-jaw and I also have a 6-jaw Buck Adjust-tru. Turns out I use the Buck most of the time. For irregular shaped work I can leave a jaw out and sometimes it'll work. For square stuff I use a split bushing to center it and the advantage of 6 jaws really shines. Also the jaws on a 6-jaw chuck are much pointier so I can hold stock as small as maybe 3/16" dia without resorting to collets.