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.
2020 Mid-Span Diagonal Knee Brace
A 45° diagonal brace that bolts onto the inner faces of two 2020 extrusions meeting at a right angle. Each foot sits 60–112 mm out from the corner, so the corner itself stays clear. Each foot takes two M5 bolts (5.5 mm clearance holes, 20 mm apart) into T-nuts, and a 5.6 mm key rib drops into the 6 mm slot to stop the foot twisting. Braced this way, a gantry or rover frame is triangulated and resists racking under motor torque much better than a plain corner gusset. The part is 112 x 112 x 20 mm, printed flat so the bracing load runs along the layers.