This is a pressure release knob for the 20 ton jack on the Harbor Freight 20 ton shop press item 32879.

Saw some other knobs but either they didn't fit or they were scaled wrong or whatever so I decided to create my own.

The shaft size is 9.2mm in size and the knob itself is 50mm in diameter.

Printed in PLA with no supports. Used a base infill of 40% for the knob part and a 80% for the shaft because nothing too strong ever broke. Probably doesn't need to be that high, but it feels nice.

I have included the Fusion 360 .f3d file if you need to modify it for your jack.