I had this U2 grinder, a Deckel clone.  Its no Deckel, but its a made in Tiawan version that is a lot better than the low end offshore clones.

It came to me in package and the intent was always to sell it, but the collet closing nut was missing.  I contacted Heinman who contact Pregraph.   The manufacturing would even quote the part.  Unbelievably (at least to my old fashioned notions of how to run a business and take care of the customer) the manufacturing told Heinman to come back when when they had larger parts quote, a small piece was a waste of their time.

Seriously?  And this is to your distributor?  If I were Heinman, or any distributor reading this, I’d look for a new product line to sell.  &$^@@)!

ok, after calming down I set about to make one.  Slightly complicated in that this clown (Freudian, meant clone) follows the Deckel collet (more or less) and has a metric buttress thread.

A drawing found on the web suggests the Deckel buttress thread has angles of 50 and 5, but these appeared to be 45 and 5 which is what I went with.  Odd as a standard metric buttress thread is 30 degrees.