Collet Run Out

[Stan]

Lots of questions:
1. Is the test repeatable? Can you remove the collet and replace it and get the runout in the same place? If so
2. Does the collet chuck or spindle have zero runout?
3. If you are measuring a test piece held in the collet, is the runout the same close to the collet as farther away?
4. Is everything free of dirt, burrs, bad drawbar thread etc?

 

[ozzie46]

Thanks for the reply Stan;

1.) Test piece was a mirror finished piece of .500 in. steel from a printer. The one the carriage that does the actual printing slides on. Don"t know what its called. Also a piece of .250 drill rod/silver steel. Both had identical run out.

2.) Havent checked spindle morse taper yet. Thats next.

3.) Measured close to collet. Thought that was best place to check.

4.) Everything is clean, no burrs, new .500 x 13 bolt for draw bar.


Ron

 

[ozzie46]

Did some more checking, Took the draw bar out re inserted the collet chuck and run out is just slightly less than .001 Looks like I need to make my own draw bar. to make sure it is concentric.

Ron

 

[New_Guy]

ok i just thought i would jump in here but why do you think that the drawbar would pull the chuck eccentric? is this a collet chuck with a MT on a lathe mill or are you using them in the machines tapper like MT and R8 collets?

 

[ozzie46]

#3 MT on a 7 X lathe spindle.

After I took out the rear bushing for draw bar screwed in the bolt run lathe very slowly and the bolt head made a rather large circle. Must have been at least an inch dia circle.

Ron

 

[Stan]

Ron: You may have solved your problem when you make a proper drawbar. That is the reason I asked about bad threads on the drawbar.

The reason for checking at two points is the same as when you center stock in a four jaw chuck. You can have it zero runout at the chuck but if the stock is not in line with the spindle you will have runout farther from the chuck.

 

[ozzie46]

The reason for checking at two points is the same as when you center stock in a four jaw chuck. You can have it zero runout at the chuck but if the stock is not in line with the spindle you will have runout farther from the chuck.
[/quote]


Was not aware of this. Thanks Stan.


Ron