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.
outdoor mailbox 4x4-post knee-brace