knob for 1/4" bolt
Knobs for 1/4" bolts! Diameter of pictured knob is about 40mm (~1.5 inches).
Once printed you will need to drill out the small hole the bolt goes through with a 1/4" drill bit as it's modeled a bit undersized. I do this on purpose and then always drill the hole out so it's super clean/round.
You can put either a 1/4" bolt or a 1/4" nut into the knob depending on your project design.
Tip: Epoxy the bolt (or nut) in place if the knob will be regularly completely unscrewed so you don't loose your bolt (or nut).