This is a universal knob to be used with an M5 machine screw. The screw may travel some 12mm though the shaft. Hence, this knob may be of use for tightening elements together.
Dimensions: total height 18mm, diameter 26mm
The shaft is kept at tight tolerance and the head of the machine screw may just so run into the knob.
If the screw is too long for your use case, some nuts may be added to the screw. The nuts and screw head have room to be hidden in the shaft of the knob.
Monoprice Maker Pro Mini 10
DAS FILAMENT PLA
The knob was designed with FreeCAD 0.18
- create, in the yz/ xz-plane, a sketch for half the cross-section of the knob; align it left/ right hand side of the center z-axis while the middle is on the z-axis
- create a rotated object; the rotation axis is the z-axis
- create a sketch on the top surface of the knob having the shape of a hex nut
- create a pocket leaving 2mm at the bottom
- create one little, rectangularly shaped embossment on the perimeter of the knob where it needs grip; place the sketch symmetrically to a vertical radial axis and make it partially stay inside the body of the knob
- create a pad
- do a rotationally symmetric pattern generation of the pad from step 6
Two knobs printed, the left still having the inner support.
Example use case with an M5 x 30 inserted - the fit is tight and screw pulls in as soon as attached to mating object.