Pictures?
It's not very interesting...

Tool end is standard M12x1.75 and the nut end is M14x1.25 (Spark plug thread!)
Made from some 12mm steel rod and a lump of 3/4 steel hex pinned together with an M5 roll pin.
Not my idea, of course! the difference in thread pitch forces out the collet as you undo the draw bar. All I had to do was cut the M14 thread in the top of the mills spindle.
To be honest though it's never been a chore giving the standard draw bar a swift tap with a copper and hide to eject collets. Unlike an R8 taper that needs a fair bit of torque to hold it in place, MT tapers are self locking and only need to be nipped up a little in most cases.
Just thought it was an interesting project and I already had the materials!
