4-40 screw for cutting a thread

I’ve provided the STL because I was forced to in order to publish this - but the intention behind this is to insert it into your 3D model and subtract it from the model, in order to cut a threaded screw shaft. You shouldn’t use the full length of it, it would have too much resistance against the screw. Generally what I do with this is put the end of it in the bottom part of small project box enclosures and subtract it. I don’t know why I made it so long, you can chop it up if you’d prefer.

For the top part of project boxes, don’t use a screw thread: cut a straight circular shaft through the model of 0.118” diameter. This accommodates the screw shaft. Use whatever larger hole that you prefer at the top to accommodate the screw head. I use flathead screws for a neater look. For this, I make a slightly indented circle above the shaft (0.005” or so) then chamfer it down to meet the unthreaded screw shaft. See second picture. This should accommodate most brands of flathead 4-40s.

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