Knob for 1/4" sized bolt/nut

I needed a knob for ¼"-20 (well threading doesn't matter but nut / bolt heads sized for ¼" english hardware. 

There is a slight amount of slop in the hex area to make sure the nut / bolt head slips in without too much force. All areas have a filet except for the bottom where the bolt passes through.

Printed mine with 3 perimeters 20% infill. I added a bolt and tweaked it down pretty good, more force than I think someone would with a fastener like this and it held-up without issue.