An old pre war British or European thread was 1/2-12. Some machines carried this over for some time such as my new to me 50's steinel sv4 mill. I thought that I could find some 3mt collets with this thread on the British ebbay, no luck so far. I am beginning to think that my best bet is to re thread the draw bar to the standard 3/8-16 thread. ANY input would be most appreciated. My initial feeling was not to modify the mill and modify a set of collets as the taps for 1/2-12 are readily available. All of the collets I have seen for sale are listed as hardened. With out a specific hardness listed I question whether I can re thread them in a simple manner with out anealing and rehardening. By using Tony Foale's mt adapter adaptation for reworking mt's i think that i can work the back side of the collets. Will just need a positive way to keep the collets enguaged in the adapter. Thinking a pointed set screw that just catches the edge of the collet will work. Thanks for reading.