Relay Board Slotted Nut-Track Rail
This is a 110 x 12 x 8 mm standoff rail for mounting bare AliExpress relay and SSR boards, which ship without any mounting hardware. It has an M3 slot along its full length, and hex nuts slide along a 5.8 mm channel inside it. Print two rails and set them apart to match the board's hole spacing in one direction, then slide the nuts to match the other. That way any 1/2/4/8-channel board fits without a hole pattern being guessed. Use M3x6 or M3x8 screws. Two outrigger ears with 5.5 mm holes, 76 mm apart, fit M5 T-nuts on 2020 extrusion or #8 wood screws into a panel, and the 8 mm height gives the solder joints under the board room to clear.
electronics relay-board ssr standoff
⚠ Flagged: automotive electrical. Not for safety-critical use without independent engineering review.