Here’s another experiment with printing a 1/4-20 thread in a part. When I printed the square horizontally the screw wouldn’t go all the way through, I assume the layers near the bed printed a little differently. So I rotated the object on end, this time allowing support to be generated for the hole. The result is that the bolt can be threaded all the way through, but it’s a little tighter than fingers can manage so I used a small wrench. I printed this on my Makergear M2 in ABS with 0.1mm layers with 80% fill, so I’m sure you can break it, but you’re not going to do it barehanded.
I also do woodworking so it would have been very convenient for me to learn Sketchup and use it for both, but it really isn’t the right tool for solid modeling and lots of the bad models out there which are non-manifold seem to have been created with Sketchup.
I would also have preferred to go with an open source solution and there are some things I certainly don’t like about Autodesk Fusion 360’s cloud based approach, but it’s free for enthusiast (non-commercial) use and sheesh is it powerful. You can start out with the kind of 3D modeling you’re used to in Sketchup and then switch into a mode where you’re pushing and pulling on things to sculpt them in an organic way, all the time keeping parametric constraints on the whole thing.
For completeness I tried printing one with the cube tilted 30 degrees to see if the threads would still work when the “grain” is printed at an odd angle. Like the 90 degree one above I had to use a wrench the first time, but after that it works fine. The last piece to this learning experience is going to be to figure out how to convince Autodesk Fusion 360 to drill and thread a SAE hole in an otherwise metric design.
The 90 degree threaded hole should work better if you put a chamfer on the bottom of the hole. The first layer would then not smoosh over into the hole.
I agree, I’ll try that next time. This was mostly me goofing around with Fusion 360.