3D-printable metric screws, nuts and washers. Pick a size, preview in 3D and download the STL.
Drag to rotate. Screw/nut pairs print reliably on FDM from M6 up.
Settings live in the URL, so bookmark or share the link to keep this configuration.
The test kit is a short screw plus three nuts at clearance −0.1, current and +0.1, in that order away from the screw. Print it, pick the nut that fits, and set that clearance.