Customizable Thumbscrew

thingiverse

This is a highly customizable thumbscrew design for various sizes of hex bolts. You can adjust the width and height of the hex shape, the diameter of the bolt, and even the amount of slack in the print (I default to 5%, or 1.05, but you can experiment with different values). You can also customize the number of bumps on the thumbscrew and their size, as well as the height of the shaft itself. This is particularly important if you need to keep the thumbscrew at a certain distance from the surface it's pressing against. For reference, here are some standard hex bolt sizes: US: http://academics.triton.edu/faculty/fheitzman/hexheadbolts.html Metric: http://www.fairburyfastener.com/xdims_metric_hhcs_coarse.htm Some earlier designs I've seen didn't work out well because they required bridging to transition from the hex shape to the bolt. This often resulted in a weak bond between the thumbscrew and the bolt. To address these issues, I added an internal and external taper to the design so that no bridging is needed, and the thumbscrew gains extra strength. When printing this part, you have two options: If it's printed tightly, you can press fit the parts together after removing any excess material inside the cavities. On the other hand, if your print comes out loose, a small amount of glue around the bolt head will keep everything secure. Keep in mind that the real utility of this part lies in its ability to turn the hex head, so while the fit between the thumbscrew and the bolt is important, it's not crucial.