This knob is designed to have a 9/16" (3/8" Threads) nut or bolt head pressed into it. It is an intentionally tight fit but a standard nut can be pressed into this knob using a vise or strong clamp. I originally designed this knob to replace degraded knobs on a Rigid brand miter saw stand but its use is universal. Update: I have also included a scaled down knob that holds a 7/16" hex nut or bolt head.