This is a derivative of "Knob for a 1/4in. Hex Screw by noobcake": http://www.thingiverse.com/thing:3596 I had a problem tightening a couple of metric M8 threaded clamps on my old drill press using the stock "7 bump knob" (2nd photo shows original and improved version). They never worked right and after looking at Noobcake's design, thought his would work way better. It did. There are 2 changes to the original design. The knob's hex opening now fits an M8 threaded hex nut and there is a hole through the knob to accommodate the 3" bolt shaft on the clamp. Print using your favorite SkeinForge settings. I set INFILL SOLIDITY RATIO to 0.3 in the FILL menu which provided a lot of strength to the star fingers. You might do some sanding on the back and front with 220A as needed. The M8 (8mm or 5/16" thread) hex nut should press fit into the opening after you clean out the leftover plastic cobweb. If you really want a sturdy nut installation, thead the nut on a mating screw held by a pair of pliers over a flame for 10-20 seconds and then press it into the nut recess. Hold in place until it cools down about 1 minute.