This knob is designed to work with either a 1/4-20 bolt or 1/4-20 nut depending on whether you need a male or female knob. The nut or bolt is inserted into the hex hole and is glued with a thin CA such as Loctite 420. When making a male knob, it works well to fill the hole with epoxy, such as 3M DP110, and then add the cap.

Bambulabs

Bambu X1C

Yes

.2mm

35%

It works best printing the knob with the recess on the build plate. That way the outside of the knob takes the build plate texture and the supported surfaces are hidden once the fastener is installed