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.*
Twin-Pin Board Edge Center Marker
Two 6 mm steel dowel pins press into 6.05 mm bores 100 mm apart, with a pencil clamped exactly halfway between them. Set the pins on either face of a board up to 94 mm thick, twist until both pins touch, and slide it along to draw a true centre line. The 8.2 mm pencil bore has a 2.5 mm split and an M3 pinch screw with a captured nut, so it grips pencils from about 7.4 to 8.2 mm. The bar is 120 x 24 x 12 mm.
Round Stock Center Finder
A 90 mm V-jaw layout plate that drops over the end of any round bar, dowel or pipe from about 9 to 70 mm diameter; scribe through the long centre slot, rotate the stock 90° and scribe again — the crossing point is dead centre. The 8 mm deep V lips self-centre the tool so it can't rock off the end face.