(Updated 30 May 2023 with more thread clearance and separated STL files for Cura users.)
Ever since I became a father, I wanted to make this nut and bolt toy for my child that encourages hand-eye coordination. I didn't have a 3D printer at the time. Before I knew it, my kid was old enough to build our Prusa MK3S printer himself with a bit of supervision and help from me. So now I finally got this toy printed. Too late for my kid... although it turns out that he thinks it's a pretty nice fidget toy. There's something satisfying about spinning the nuts on the bolt.
My objectives for this were:
I couldn't figure out how to eliminate all sharp edges in OpenSCAD. When you cut a thread into something, it's going to leave an edge somewhere. So I put a little recessed eyelet on the bolt head with the intent to print it with ABS and hang it in an acetone vapor bath to dull any edges. However, we no longer have any babies in the house, so there's no need, and the edges turned out not-sharp anyway. Also, the edges are primarily on the nuts, so the edges aren't exposed when the nuts are on the bolt.
Not that it matters, but the hex bolt head and hex nut and dimensions comply with ISO sizes for the thread diameter. It just "looked" right, even with that non-ISO sinusoidal thread.
This project represented some milestones for me:
Printer: Prusa I3 MK3S
Supports: No
Resolution: 0.15 mm layers, 0.4 mm nozzle
Infill: 15% gyroid
Filament: Generic ABS (any material will do, probably even flex)
Notes:
I suggest a wall thickness of 3 or more perimeters. I also used a 5mm brim to be sure the parts didn't separate from the bed.
Designed in OpenSCAD after figuring out a new way to generate threads from a stack of thread cross-sections, described in my article https://www.nablu.com/2020/01/new-approach-to-screw-threads-in.html - ISO threads can be generated this way, and the script includes functions for hex bolt head and nut sizes.
Category: Mechanical Toys
The author marked this model as their own original creation. Imported from Thingiverse.