I have always just crossed my fingers and "gently" hit the drawbar on my X1 mill to remove things from the MT2 socket. Sometimes while doing it, I have pondered the unused screw thread inside the top of the spindle...

Presumably, the unknown designer intended this M12 x 1 thread to help discourage people from hammering on the bearings; sadly the supplied drawbar makes no use of it. So today I made the simplest possible mod to bring it into use. Since the business end of the drawbar is M10 x 1.5, engaging the top with the M12 thread gives us a differential screw of effective pitch 0.5 mm, captive at the top.
The new part is a 20 mm sleeve, M12 x 1 outside, 10 mm clear inside, shown here with the drawbar...

Here it is stuck on the drawbar with high strength retainer.

In use, the drawbar protrudes a few mm from the top of the spindle. After screwing the collet loosely into position, a turn at the top pulls it in, or pushes it out.

The mill can now relax when I pick up the hammer.
Mark