These descend directly from the LMS Mini-Lathe cover knobs:
The top pair of screw heads aren’t quite flush with the cover, so the knobs have 1 mm extensions:
The bottom pair sit inside 4 mm recesses, so those knobs get matching extensions:
Attacking an anonymous 5 mm hex wrench with a Dremel cutoff wheel produced a quartet of 12 mm shafts and reduced drawer clutter by one unit.
In retrospect, I should have dismantled the cover, grabbed the screws in a vise with their shafts vertical, and epoxied all the knobs with perfect alignment. Next time, maybe.