Lessons Making Threads and Screws


I watched the Square one about Countersinks and decided to practice. Here is an exploded 3/4" screw (1000X). After making the countersinks in the origin area in the screen shot, I decided to use the hole to model a screw. I made the spiral lines and that took me some time. Then, I decided to take the threading pattern that Dave, R. showed me, scale it to fit this screw, and finish it. I’m in the process now. It took me a long time to figure out how to use the rotate tool to align the profile, but once I got the hang of it, the process started going faster. After I completed a spiral all the way around, all I have to do is move/copy faces. I found out that I need to have the hidden geometry showing to highlight the correct faces. Now it is going faster. I’m sure there are other tips and quicker ways to do this. Once it is done, then I can always copy it into other files where I need screws and countersinks of this size. But the process of practicing this much on my own has taught me things I can use in the future. At my age, I just hope all the repetitive work helps me to remember how I did it. :crazy_face:

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Good start. If it’s any help, you might consider increasing the pitch of the screw threads by quite a lot. If that’s supposed to be a 3/4 in. dia. screw, it must be no more than 1-1/2 in. long. A wood screw that short would only have a few turns. Maybe 6 or 8. A 3/4 in. dia. wood screw would be quite large. It would require a large screwdriver.

I didn’t explain too well. It is a 3/4" long, metal, wood screw. I can’t remember without pulling up the model again but the diameter is real small. It took me quite some time to figure out how to scale the threading to fit from the vise screw size to this much smaller size. Then, it took me a long time to place and align the profile.

This is an unsolicited preachy lesson that completely misses the point. The OP is using this exercise to practice their modeling skills, as they state in the first sentience of this thread. Picking a real world object and attempting to model it accurately is a great way to improve CAD skills on any platform, and screw threads are an excellent exercise. Dave R has some good tutorials on modeling accurate thread profiles in SketchUp.

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This is how it ended up. It is not a solid. The only errors with Inspector are lots of short edges. I don’t think that it would be worth fixing. It was practice anyway. Where it tapers to a point, it didn’t come together right. I winged it on the slope of the taper.
Countersink and Screw.skp (850.7 KB)

As we’ve mentioned several times, “Short Edges” is not an error. It’s simply a warning that you might have issues particularly if you do any Intersect Faces operations that further split those edges.

Those are some unusual threads on that screw. Looks like it would take a long time to drive it home, too.

If I ever decide to model another one, I’ll research or ask first for an appropriate profile for the threads. It was a lesson in aligning, navigating, and fixing very small line placing errors.