2x4 Lumber Rack Arm Socket
A wall bracket that turns a scrap 2x4 into a cantilever lumber-rack arm: the socket takes a nominal 2x4 end (38.1 x 88.9 mm actual) in a 39.2 mm channel, 71 mm deep, with 4.5 mm cheeks that pin the wood with two 5.5 mm cross screws per side. The 8 mm back plate takes four #10 or M5 screws into a stud on a 30 x 48 mm pattern, counterbored 3 mm so the heads clear the lumber. Overall 78 x 48 x 88 mm — print a pair per arm for conduit, moulding, pipe and offcut storage.
garage 2x4 lumber-rack wall-bracket