Binding balls - Hoglet/HPD_F1 GitHub Wiki
The HPD F1 is extensively using 5.8 mm balls in printed joints. Printing circles on a 3D printer is known to be tricky as the material wanders inwards. This means that for some people it might be a small play and for others the ball binds inside the socket.
On the EVO 3 we use a variant on the "hexagonal hole trick" inserting a wavy line that seems to equalize the result between printer/slicer setups.
If you still have problems check:
- Is your printer and filament correctly calibrated? Over extrusion will make a smaller hole.
- Are the balls correct diameter?
There also seem to be a problem with Cura ~5.4 that removes the thin gaps that are in the model and make a single circle. Workaround is to enable "Detect thin walls".