Truing a 3 Jaw Chuck

[stang5197]

We have a adjustable 3 jaw chuck on our Haas HRT 210 Rotary table. I have two much run out on a part that we are working on about 0.0065".

I have never adjusted a 3 jaw chuck, any advice on how to do it? I can't find alot of info. about doing it on the web. Working with a 4jaw is not problem but a 3 jaw appears to be a whole different animal.

[Geof]

You say it is an adjustable 3 jaw, is this the adjustment you want to use? How is it attached to the HRT? We use a three jaw chuck on the same rotary and center it on a spigot fitted in the bore of the rotary. The final alignment we do will a piece of round stock in the chuck and a dial gauge. Have the mounting bolts just snug and then tap the chuck with a plastic hammer until the stock in the jaws is running true.

[stang5197]

Takes makes perfect sense. This part has me so frustrated I never even thought of centering it up that way.

Thanks again Geof, you just kept me from pulling the rest of my hair out.

[HuFlungDung]

Here was an idea for a fancy adjustable setup for a chuck. It is nice for moving a heavy chuck with heavy parts in:

http://www.cnczone.com/forums/showthread.php?t=13411

[Geof]

And if you check Hu's link you will find both he and I are consistent in the advise we give .

[stang5197]

Hu, that is an incrediable idea. Like they said you should be mass producing those. That will be something I will make in the near future when time allows.

You guys have me so motivated I am going to go in today (Sunday) and use the old hammer trick for now, to get these parts out the door.

Thanks for all of the help. For some reason I couldn't find Hu's thread before when I was searching.

[Geof]

Originally Posted by stang5197 .....You guys have me so motivated I am going to go in today (Sunday) and use the old hammer trick for now, to get these parts out the door.....

Is it good or bad to motivate someone to work weekends? I am going to have to ponder that one .

[th-ton]

normaly is can adjust the three jaw chuck in a few ten micron using dial indicator to get the aligment from the work pice and adjusted the jaw holding place at the machine.. if normaly we do the tooling precision machining we often used this way for the secondly process ( ex: turnning the sprue bushing for the plastic injection mould.