Re: [CAD_CAM_EDM_DRO] Gorton mill

> I have here before me the (5/32") collet that was in it.
> It's about 2-1/2" long, 1" across the face, the taper is
> about 1" long, the shank is 1-1/2" long and about 5/8" OD,
> with three flats. The threads for the drawbar look like
> about 7/16". (I'm using a plastic ruler, my mike is at
> home.) I would guess the OD of the spindle to be about
> 1-1/8".
>
> Anyone have any ideas for a magic R8 conversion for it?
>

the Hardinge collet catalog lists the folowing collets as having
been used on Gorton mills

collet ; back bering dia ; OAL ; thread ; Hardinge part#

4NS ; .826 ; 3.5 ; .800x20RH ;1625

9B ; #9B&S ; 4.125 ; 1/2-13RH; 1707

GTM ; .625 ; 2.437 ; 7/16-20RH ; 1789

R8 ; 950 ; 4.0 ; 7/16-20RH ; 1757

looks like a match on the GTM Gorton taper with a max collet size of 1/2"
it would take a lot of the material out to bring the spindle up to an R8
but there is alot of tooling available with a 1/2" or smaller shank

couldnt hurt to ask Hardinge about pricing and availability on the
GTM collets
http://www.hardingeworkholding.com/