Finger Screw with knurled surface

I had some cariage bolts with a square-neck, that I thought would give a nice finish, when pressed into the recess in the finger screw. I made this for a M6x1mm bolt that has a head diameter of approx. 15 mm.

The bolt head is pressed into the recess the first time you tighten the finger screw.
It was a tight fit on the screw I used, but I had no problem drawing the head into the knob, thanks to the good finger grip.