How do you model threads? Add matl or subtract matl?

Just curious, how to you guys model external threads, like on a bolt. Do you create a triangle to add material to a shaft that is at the root diameter? Or do you create a triangle to subtract material from a shaft that is at the major diameter?

For example here is a screenshot of where the matl (fundamental triangle) is added to the root diameter shaft…
image

Most of us do not model the threads. I import bolts, nuts, pipe, etc., from McMaster-Carr using STEP file format. Then add or subtract as necessary.

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I often make nuts and bolts in Shapr just for the fun. There are a couple of videos on YouTube showing how to make them.

https://youtu.be/G6Roo0ztiuM

https://youtu.be/TS0OmrwH1XI

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Hi
I always subtract. It is the way bolts and screws are actually manufactured and it is, in my opinion, the best way to get a clean start for the filet when you model chamfer before doing the subtraction.

Best regards
PEC

This is s great video! This answered what I have been looking for.

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Just for giggles I added a thread to a shaft. Oh yeah, now I have to clean up the thread where it goes past the end of the bolt. Oh and then I’ll have to add a chamfer. Aw, no fun. I think I’ll go back to subtracting my triangles from the bolt! :sweat_smile:

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That’s a good effort.

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I always subtract - just like a lathe tool. It is time consuming tough - but the result is awesome. I did a lot of drawing for (small, desktop-size) CNC’s. Here - drawing the spindle is mandatory (some of them have multiple thread pitches).


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haha, I thought I was the only one! Mcmaster’s catalog is My Go-to for threads. Embed the bolt, subtract, voila! Threads!

Same, so easy to do !