Thumbscrew for hex bolt
Initially I wanted a thumbscrew to fit onto the adjustment screw when synchronizing the carbs on my bike. This escalated a bit, so here's an assortment of thumbscrews for 7-8-10-13mm screw heads.
The outside diameter of the wheel is 20mm.
The hex size is modelled at +0,2mm oversize, which at least on my printer gave a snug fit over the screw head.
No supports, print with your preferred filament.