Pin hinge (print-in-place)

Two interleaving leaves and a captive pin, printed pre-assembled.

A pin hinge is a knuckle (barrel) hinge whose two leaves interleave along a shared axis, with a captive pin running through every knuckle. The pin has an enlarged cap at each end that’s trapped in a pocket inside the outer knuckles, so it can’t slide out — yet the whole thing prints pre-assembled and articulates with no supports and nothing to snap together. The clearances that let it turn are plain geometric offsets; about 0.3 mm is a sound FDM default.

1. Set each leaf’s length, the hinge length, and the leaf thickness.
2. Set the knuckle count, pin and knuckle diameters, and the clearance gap.
3. Generate: the whole hinge drops in as one pre-assembled, editable part.