Collett adapter for 3in1 machine

[user 1493]

Attached are photos of an adapter that I made so that I could utilize a collett set on my Smithy three in one machine. The spindle is a MT4 and the collett set is MT3.

I cut a piece of 12-1.25 all-thread 0.625 inches long and then bored and threaded a hole 0.375 inches deep for a 6-32 thread. This was installed in the end of the collett holder.

I ground off approximately 3/16 inch off the end of the tang on a MT3-MT4 adapter to remove most of the hardened section. I then bored a 0.375 inch hole through the tang.

I bored and threaded a hole 0.375 inch deep for a 6-32 thread in the end of a piece of 3/8 inch all-thread that would act as the drawbar.

I cut the head off of a 6-32 socket head screw and glued it into the end of the drawbar with Locktite.

I made a stepped washer from a piece of 1 !/2 inch aluminum round stock to support the drawbar at the outside end of the spindle.



I installed this on my machine and tested it for concentricity by putting a 1/2 inch mill in a collett and checking it with a DTI. The runout was 0.0002.



I made the drawbar removable so that I could use a wedge to remove the collett holder from the adapter.

 

[Noitoen]

You could "sacrifice" the adaptor and cut the back portion. That way you could use the full diameter draw bar.

 

[user 1493]

I considered that but I was concerned that it could be difficult to remove the sleeve if it got stuck.