Simple Knobs for clamping and jigs

Wood of your choice, Bamboo laminated to pine shown. Extra-Wide 1/4" hex nuts or standard 5/16" hex nuts, or standard 5/16" hex screws. McMaster-Carr part number 92680A029

Shaper Origin, your prefered bit for cutting the outside, and perhaps the .260" bore. A 1/8" cutter for the hex recess works well for harder materials. In softer materials a 1/4" cutter can be used and the hex corners will sometimes displace the extra material. A 1/8" radius round-over bit in a router table will make a nice soft top and bottom edge. Whiteside 2000c ($22) (or as part of the #404 4 piece set, ~$80) is a good option.

The advantage to using the extra-wide hex nut is that it is the same dimension (~.490) as a regular 5/16” hex nut or bolt, allowing you to convert the knob from 1/4” to 5/16” by just boring out the center hole and swapping in the 5/16” nut or bolt. The ribbed design was inspired by the @Waddos Candy Machine knob: https://www.shapertools.com/hub/creators/5bf168a6c608b60017bc80c0/shares/5bf175d7c608b60017bc8102 The examples were cut from a small piece of scrap which required the use of the adjustable height tape board shown in the second image. Immediately after they were cut they replaced the 1/4-20 nuts that had been used to lock the tapeboard in place.