In that case, if you make your mounting part a square or rectangular block instead of a cylinder, this way you can avoid the use of a lathe. Or if you spec the

In that case, if you make your mounting part a square or rectangular block instead of a cylinder, this way you can avoid the use of a lathe. Or if you spec the outside diameter of your cylinder to be some common size (+/- some loose tolerance), then that would avoid machining the outside (as there's cylindrical metal slock). I also realized that my original suggestion of "set screw on the bottom part" is also probably hard to manufacture.