A Combination Square with Square & Center Head from Starrett is a precision measuring and layout tool. It has several functions in one:
The square head is used for checking 90° and 45° angles, marking, and squaring edges.
The center head (sometimes called a “center-finding head” or “center head”) lets you locate the center of round work (like pipes, rods, dowels) by placing the center head’s arms against the round surface, marking lines, and finding intersections.
These tools include a rule (blade) that slides through the head(s), which is locked by a bolt. The blade is hardened steel and has graduated markings. Depending on model, it may include a spirit level vial and a scriber (a small metal scribe for marking) stored in the head.
