Núm Vặn Bu Lông M12 (Bolt Knob M12)

A knob handle design for M12 bolts with hex head of 19mm.

The bolt head has a snug fit at least with my printer settings.

Print Settings

Printer: Hellbot Magna 2 230

Material: PLA

Supports: Yes

Resolution (with 0.6 nozzle): 0.36 

Infill: 25%

Wall Thickness: 4 Layers

I think the overall stiffness of the part will depend primarily on the Wall Thickness.

Finally I simply tighten a nut with a washer so that the head fits inside the knob.