Starrett 51542 Combination Square Set 12 in 4 Piece

Product Description

The STARRETT 51542 is a 4-piece combination square set built for layout, inspection, and measurement tasks in trade and shop environments. The set includes a 12-inch steel blade with 4R graduation markings at 1/16, 1/32, 1/64, and 1/8 inch intervals, along with three interchangeable heads: a standard square head, a center head, and a protractor head. The square head and center head are forged steel for durability under repeated use. At 2.375 pounds, the set is substantial without being cumbersome. HVAC techs, pipefitters, plumbers, electricians, and general contractors use this type of set for scribing lines, finding centers, measuring angles, and verifying square on sheet metal, pipe, conduit, and structural work.

This combination square set suits both residential and commercial installation work. The 12-inch blade length covers most standard layout tasks encountered in mechanical trades. The three included heads expand the tool's utility beyond simple square checks: the protractor head allows angle measurement, and the center head locates the center of round stock. Tradespeople who work with ductwork, panel enclosures, conduit runs, or pipe supports will find all three head types useful on a single job. The 4R blade graduation is the standard choice for general trade measurement work requiring fine resolution without optical magnification.

Key Features

• 4-piece set includes square head, center head, and protractor head with one 12-inch blade
• Steel blade with 4R graduation: 1/64, 1/32, 1/16, and 1/8 inch increments
• Forged steel construction on center head and square head for long-term durability
• Single blade accepts all three heads, reducing carry weight and tool count
• Protractor head enables direct angle layout without a separate bevel gauge
• Center head locates center on cylindrical stock without calculation

Compatibility

Designed as a standard 12-inch combination square set compatible with typical combination square blade accessories from the same product line where blade groove dimensions match.

Installation Notes

A licensed or journeyman tradesperson in any mechanical or construction trade can use this tool without special certification. Keep the blade locking mechanism snug before scribing or marking to prevent blade shift during use. Inspect the blade edge for burrs or nicks before use, as blade damage affects measurement accuracy. Store the set in its case or a protected location to prevent head damage and blade warping.