Heads up: many models on this page are AI-generated or uploaded untested. They may be misconfigured for the intended application — check the dimensions and tolerances, and verify or edit the model before printing or relying on it.*
4x4 Post Mailbox Arm Knee Brace
A 125 x 125 x 28 mm triangulated knee brace that screws to the 89 mm (3.5 in) face of a 4x4 wood post and props up the underside of a 2x4 mailbox cross-arm. It replaces the rusted stamped-steel brace, so a sagging or snapped arm doesn't mean buying a whole new post kit. Each leg has two 5.5 mm holes for #10 wood screws or M5 lag screws. The holes sit outboard of the diagonal strut, so a driver can reach them straight on. The brace prints on its side, which puts the arm's load in the plane of the layers.
Bolt-On Mailbox Door Snap Catch
A replacement snap catch for a mailbox whose original door tab has broken off. It bolts to a flat side wall with two M4 bolts (Ø4.5 × 10 mm slots, so you can set it up to 5 mm back from the front edge). A 2.2 mm × 41 mm spring arm holds a 4 mm hook finger in front of the closed door, and a 45° ramp lets the door push it aside as it shuts. The catch is 90 × 20 × 16 mm and prints on its side, so the arm flexes along the layers instead of across them.
Mailbox Signal Flag Replacement
Replacement red signal flag for a rural mailbox whose original blade snapped off — a 55 x 75 mm ribbed blade on a tapered arm with a 22 mm pivot hub, 124 mm tall overall and 6 mm thick at the hub. Pivots on the mailbox's existing M4 / #8 screw through a 4.5 mm bore with a 10 mm counterbore so the head and washer sit flush, and a 3.4 mm hole at the tip takes a zip tie for reflective tape. Two cut-out panels cut wind load and material; the 5 mm centre spine keeps the blade from flapping.