Thumbscrews, knurls and threads

This weekend I was designing some parts using Fusion360. I had a couple of challenges but learnt a lot along the way. The part I wanted to model was a  thumbscrew which I’m going to be using in a future project for HackSpace magazine. I wanted to model it so I could see the part in relation to the others and hence size them accordingly.


My first challenge was to complete the straight knurls. My first attempt failed. I had created a sketch with many small triangles which could the cut away from the body of the screw.  This caused Fusion360 to use loads of memory and my machine ground to a halt.

I followed Taylor Stein’s advice and used the pattern tool once I’d created my cutting triangle. In Taylor’s example, he adds the chamfer to the disk after applying the pattern. I did this the other way around and added my chamfer’s first as this seemed a more natural way of doing things. It did, however, cause me a little bit of fun when selecting the right faces to cut with the triangular cutter.


I had initially created some holes and then added threads. These seemed fine in the preview but when I’d rendered them they were coming out smooth. So I went back and discovered that there are a load more options on the hole making tool such as counterbore, countersink and tapping the holes. Switching to that did not help the renders.

I then spotted an option in the document settings “Threads: Cosmetic”. This is actually quite useful if you think about it. It allows you to get your CNC or 3D printer to print a regular hole and you can then tap it as a second step. It also simplifies the model to improve the speed of display and manipulation So I turned it on for the rendering and back off again afterwards. I also spotted there was a per hole option to create the threads as modelled that you can set when the hole is created.

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