HAAS SL20 Problem

[BobAllen]

What am I doing wrong??
I am trying to turn a simple profile on the end of a 1.125 inch diameter shaft. Upon completion of the cycle, the profile in not concentric to the shaft (.004-.006 off). I have bored the jaws (several times now) and it doesn't seem to make much of a distance. Any ideas??

[Geof]

Originally Posted by BobAllen What am I doing wrong?? I am trying to turn a simple profile on the end of a 1.125 inch diameter shaft. Upon completion of the cycle, the profile in not concentric to the shaft (.004-.006 off). I have bored the jaws (several times now) and it doesn't seem to make much of a distance. Any ideas??

When you bore the jaws are you closing them on a ring so that they are loaded in the same manner as they are when they clamp on the shaft. Three pins in the jaw bolt holes and a ring with three holes at the correct diameter to go over the pins on a bolt circle that allows the jaws to close .01" smaller than your shaft size will do it.

[gar]

061023-1830 EST USA

BobAllen:

Put a piece of Thomson rod or other known round and straight stock in your chuck. Mount a dial indicator on the turret and check parallism, and TIR? From this try to determine the problem. Could be turret or spindle is out of alignment.

You can also use the dial indicator to scan across the chuck face.

.

[BobAllen]

I used a Huron chuck ring loaded at 200 hydrualic pressure when I bored the jaws.

[BobAllen]

How difficult is it to align the spindle or the turret??

[gar]

061023-2047 EST USA

BobAllen:

Not a job you want to do.

You want the best serviceman from your HAAS dealer, or some other expert familar with HAAS to do a lathe alignment. A person with the correct experience and tools is important.

But you can make your own measurements to get a good idea if you may need alignment.

.

[GOLETABRIAN]

Have you checked to see if your material is round to begin with? A lot of extruded material is not round. You didn't say but is it any kind of tubing? A 3 jaw chuck can distort tubing like crazy if you don't use pie jaws.

[daking]

Spindle or Turret alignment should not affect concentricity. It is a result of the relationship between the spindle bearings,the chuck jaws and the part. Assuming the jaws are bored correctly the next place to look would be the material. Are you chucking on a good round machined surface or a stock finish? You won't get a result any better than the surface you're chucking on.

Dave

[htishop]

This is just ashot in the dark but, if your turning a shaft and it is not properly supported in the draw tube, as it speeds upit will viberate until the slack is thrown to one side and this will throw your center off slightly depending on the size of material and length.