Keyhole mount clip for rectangular tubing

thingiverse

I designed an adapter to hang my mailbox from clips attached to my porch railing. The railing is a rectangular tube measuring 38.5mm in width and 19.6mm in thickness. My mailbox features a keyhole-style hanger with diameters of over 8mm and 4mm respectively. The back panel of the mailbox is recessed about 13mm from its frame's rear edges. I printed two adapters, which I then attached to my porch railing, before hanging the mailbox from them. It might have been wiser to model this as two separate parts, with pegs that screw into the clip or serve as standoffs accepting a real screw. However, this approach worked satisfactorily for me. This solution is tailored to my specific situation, but if it proves helpful to someone else, I'm glad to share it.