I’ve got an almost complete set of M673 Hexagonal collets smallest starting at 12MM all the way to largest going to 30MM, previously used on our Miyano CNC lathes. 

Manufactured by Crawford 

All Serrated apart from the smallest 12-14MM 

Sizes of all the Hexagonal collets are as follows:

12-14MM, 14-16MM, 16-18MM, 

18-20MM, 20-22MM, 24-26MM, 26-28MM, 28-30MM,

Any questions please don’t hesitate to ask.