In my collection of 'it will come in useful one day' I have a plain bearing spindle that accepts this collet. Unusually the front of the collet has three flats that allow it to be tightened from the front (there is no drawbar hole).

Parallel part of body is 6mm diameter and the thread is M5 fine, overall its about 40mm long. It has the mirrored 'C' logo which I think is Crawford and also has 1801 stamped on it.

I'm curious what this type of collet was used for

Ian P

Definitely a similar method of tightening but its less than ideal from an engineering point of view as the spanner is twisting the tines of the collet. Even odder in my case is that this particular collet was holding a LH 3mm drill.

The spindle is solid and has the female thread at the bottom of the tapered bore but I can only presume whatever was being drilled did not put too much load on the spindle.

In the next day or so I will post pictures of the spindle unit and some other parts that I have, I have a feeling its Swiss (possibly Schaublin) and probably from a 'auto' lathe.

Ian P