Starrett 51548 Combination Square Set 12 Inch 4 Piece

Product Description

The STARRETT 51548 is a 4-piece combination square set built for layout, measurement, and inspection work across HVAC, plumbing, electrical, and general trade applications. The set includes a 12-inch steel blade graduated in 4R style, covering increments of 0.02, 0.03, 0.06, and 0.13 inches, giving technicians precise reference at multiple resolutions. Three head types are included: a square head, a center head, and a protractor head, all manufactured from forged steel for rigidity and durability. This set is designed for professionals who need a reliable, multi-function layout tool on the job site or in the shop.

The 51548 combination square set suits residential and commercial trade work where accurate scribing, angle transfer, depth measurement, and center-finding are routine tasks. HVAC installers use combination squares when fitting ductwork, fabricating sheet metal, and laying out equipment pads. Plumbers and electricians reach for them during rough-in layout and fixture alignment. The three interchangeable heads extend the utility of a single 12-inch blade across square, bisect, and angular measurement tasks without switching tools.

Key Features

• 12-inch steel blade with 4R graduation in four increments: 0.02, 0.03, 0.06, and 0.13 inches
• Three forged steel heads included: square head, center head, and protractor head
• Forged steel head construction for dimensional stability under repeated use
• 4-piece set covers square layout, center-finding, and angle transfer in a single kit
• Compact set weight of 2.375 pounds makes it practical for field carry

Compatibility

Designed as a general-purpose combination square set for trade and industrial layout applications where a 12-inch, 4R-graduated blade with interchangeable square, center, and protractor heads is required.

Installation Notes

Combination square sets require no installation but should be inspected for blade lock tightness and head alignment before use on critical layout work. Handle the graduated steel blade carefully to avoid nicks or burrs that can affect reading accuracy. Store the set with heads secured and the blade retracted or capped to protect graduation markings. Calibration verification against a known flat reference surface is recommended before precision layout tasks.