It will compatible with 

• M4 25 or 30mm bolt or screw
•  8/32 1-1.25 inch bolt or screw in freedom unit

Print Setting:

• Layer height 0.20 or smaller depending how smooth you want.
• Print on the given orientation
• no supports needed

Here is other version of knobs

Noted 

• if you want to make your own size feel free to download the freecad file or just let me know. 
• If you enjoy this model please consider to buy me some filament ( Paypal )