ER 20 Collet Blocks

[olderdan]

I have not been able to find collet blocks in this size as they seem to start at ER32.
In my AJS restoration I have had to make many new bolts and it is cheaper to use round stock than buy correct size of hex bar. I also use them for slotting screw heads.
I have made two collet blocks for hex and square bolt heads, these are not precision but within a .002 thou T.I.R. which is fine for bolt heads etc and used in my vertical slide on the lathe.


A typical use is a Triumph repair chain case adjuster bolt which has a stripped thread, the large one gets bonded in and both have O rings.
I recently past over a nice milling machine locally but a 82 years young I decided not to bother.