Starrett 50056 Combination Square Set 12 Inch 3 Piece

Product Description

The STARRETT 50056 is a 3-piece combination square set built for layout, inspection, and measurement work in mechanical, plumbing, HVAC, and electrical trades. The set includes a 12-inch steel blade and both a square head and a center square head, giving technicians two head types from a single blade. Graduation follows the 4R pattern, providing four scales: 1/16, 1/32, 1/64, and 1/8 inch. The blade is machined steel and the heads are cast iron, offering the rigidity needed for accurate scribing, squaring, and center-finding on metal, wood, or PVC surfaces. The set weighs 1.5 pounds, making it practical for field and shop use.

This combination square set is used in commercial and residential trade applications where accurate layout and transfer of measurements is required. HVAC technicians use it for ductwork layout and equipment alignment. Plumbers and pipefitters rely on it for pipe layout and fitting alignment. Electricians use it to mark enclosures and panels. The dual-head configuration makes it especially useful when center-finding on round stock or marking 90-degree reference lines on flat stock.

Key Features

• 3-piece set includes 12-inch blade, square head, and center square head
• 4R graduation provides four scales: 1/16, 1/32, 1/64, and 1/8 inch
• Steel blade construction for durability and dimensional stability
• Cast iron heads resist wear and maintain accurate seating against the blade
• Center square head enables fast centerline location on cylindrical or round workpieces
• Compact 1.5-pound total weight suits both bench and field use

Compatibility

Designed as a standard 12-inch combination square set suitable for general trade layout and inspection tasks across HVAC, plumbing, electrical, and mechanical service work.

Installation Notes

This tool requires no installation but should be inspected before use to confirm the blade locks securely in each head and that the head faces are clean and free of debris. Loosen the blade clamp only enough to reposition, then retighten firmly before scribing or squaring. Store the set protected from impact to prevent casting damage to the heads, which can affect measurement accuracy.