Starrett 57551 A2 Tool Steel Flat Stock 0.125x3.5x18 in

Product Description

The STARRETT 57551 is an A2 air-hardening tool steel flat stock bar intended for toolmakers, machinists, and die makers who need a reliable, consistent starting blank for custom tooling, jigs, fixtures, and punches. Measuring 0.125 inches thick, 3.5 inches wide, and 18 inches long, this flat stock ships in an annealed condition, ready for machining before hardening. The A2 tool steel alloy provides good dimensional stability during heat treatment and a balanced combination of hardness and toughness after air hardening. At 2.23 pounds per piece, it is a manageable stock size for bench or machine work.

This flat stock is suited for machine shops, tool and die operations, and industrial maintenance departments producing short-run tooling components. Typical applications include forming dies, cutting tools, wear plates, and gauges where A2 material is specified. It is equally useful in production tooling environments and prototype shops where controlled heat-treat distortion is a priority. The 18-inch length provides enough material for multiple blanks depending on the finished part size.

Key Features

• AISI A2 air-hardening tool steel — balanced hardness and toughness with minimal distortion during heat treatment
• Thickness tolerance of +0.010 to 0.015 inches for predictable stock removal during surface grinding
• Width tolerance of +0.010 to 0.015 inches for consistent fit in fixtures and vises
• Length tolerance of +0.25 inches allows for squaring and facing on both ends
• Square tolerance of +0.010 to 0.015 inches supports accurate layout and machining setups
• Single-piece minimum order quantity — no bulk commitment required

Compatibility

Designed as a standard AISI A2 tool steel flat stock blank suitable for machining into custom tooling components wherever A2 material is specified by design or print.

Installation Notes

Machining and heat treatment of tool steel flat stock is performed by qualified machinists and toolmakers. Material should be machined in the annealed condition prior to hardening and tempering. Air-hardening heat treatment should follow established AISI A2 procedures or the shop heat-treat specification; do not quench in oil or water. Always use appropriate guarding and personal protective equipment when grinding or cutting tool steel stock.