Re: [CAD_CAM_EDM_DRO] 5C collet closer drawbar threading problem

On Tuesday 08 July 2003 02:39 pm, Kim Lux spake:

> The drawbar we are making is machined from a piece of seamless
> mechanical tubing. We've got it adjusted for zero runout.
>
> We are cutting a 1.044" OD x 24 TPI thread on the outside of a 1.250"
> piece of tubing turned down to 1.030" This will pull on the internal
> thread of the collet to close it in the chuck.
>
> We've threaded two of these drawbars now and both times the collet has
> significant runout when threaded to the drawbar. Why ? The thread
> seems to be high quality.

> What is the solution to this problem ?

I've seen this before with a thread that was not machined correctly, Kim.
I would scrutinize the thread first.
Have you actually measured it for size?
Also, are you sure that the material wasn't pushing away during cutting?

Just a few thoughts.

Weyland