Starrett 51549 Combination Square Set 12 Inch 4 Piece

Product Description

The STARRETT 51549 is a 4-piece combination square set built for layout, inspection, and measurement work in trade and industrial settings. The set includes a 12-inch steel blade graduated in 16R style, covering 1/32, 1/64, 1/100, and 1/50-inch increments for versatile readability. It ships with three head types: a standard square head, a center head, and a protractor head, all made from forged steel for durability under regular shop use. This set is used by machinists, pipefitters, ironworkers, and general contractors who need reliable angular and linear reference across multiple layout tasks. The complete set weighs 2.375 pounds.

The 51549 is suited for both shop and field use where multiple measurement references are needed without switching between separate tools. The square head allows 90-degree and 45-degree reference, the center head locates center points on round stock, and the protractor head transfers and measures angles directly from the blade. This set fits standard layout and marking workflows in mechanical, structural, and fabrication trades. It is appropriate for both residential and light commercial construction contexts where precision layout is required.

Key Features

• 4-piece set includes square head, center head, and protractor head plus one 12-inch blade
• Steel blade with 16R graduation covering 1/32, 1/64, 1/100, and 1/50-inch increments
• Forged steel heads for resistance to wear and deformation under shop conditions
• Protractor head enables direct angle transfer and measurement from the blade
• Center head locates center on cylindrical or round workpieces
• Single blade accepts all three heads for compact, interchangeable use

Compatibility

Designed as a standard 12-inch combination square set compatible with typical layout and inspection applications requiring interchangeable square, center, and protractor heads on a common blade.

Installation Notes

Combination square sets require no installation but should be inspected for blade-to-head squareness before use on critical layout work. Store the set in a dry environment to prevent blade corrosion and protect graduation markings. When using the protractor head for angle transfer, verify the locking mechanism is fully engaged before scribing. Handle forged steel heads with care to avoid impact damage that could affect head-to-blade seating accuracy.