Making a negative

[GMDCNC]

Is there a (relatively) easy way of making a negative (essentially using a body or component to cut) of an object? Not trying to make a mold; trying to make a knob that can press fit on a McMaster-Carr wingnut.

I know I can just make a knob that will fit on a regular nut, and make a polygon to cut it out. I'm doing this because I want to, not because I need to.

[GMDCNC · Accepted solution]

Disregard. I figured out why combine wasn't working for me.

[TrippyLighting]

If you've figured out the problem please mark this therad as "solution provided" or whatever it was called. That way we can move on to other users in need of help 😉

Thanks in advance!