A set of 13 matte black machined parts, made up of stepped cylindrical pins and flat rectangular blocks that each carry a round-ended pin on top, machined to customer drawings. The four largest pieces are stepped cylinders, each a wide round body with a narrower spigot rising from it, in two body sizes and two spigot lengths. Smaller stepped cylinders follow the same form at reduced size. The rectangular blocks have squared sides with a short round-ended pin on the top face, and the smaller pieces have a shouldered, tapered top running into the pin. The set runs down to a single small round-ended pin. All parts share the same even matte black finish.