Starrett 56994 O1 Tool Steel Flat Stock 5/16x2.5x18 in

Product Description

The STARRETT 56994 is an O1 oil-hardening tool steel flat stock bar measuring 5/16 inches thick, 2.5 inches wide, and 18 inches long. It is manufactured from AISI Type O1 tool steel, a material widely used in toolmaking, die making, and precision machining applications where consistent hardening response and dimensional stability are required. The stock ships in an annealed condition, allowing machinists and toolmakers to cut, grind, and fit the material before heat treating to final hardness. Thickness and width tolerances are held to +0.010 to +0.015 inches, and length tolerance is +0.250 inches.

This flat stock is suited for job shops, tool and die operations, and maintenance facilities that fabricate custom tooling, punches, dies, gauges, fixtures, and wear plates. The 18-inch length provides enough material for small to medium tooling components without excessive waste. Its square-ground edges, held to a squareness of 0.003 inches per inch on all edges, reduce setup time and allow direct layout work off the stock surface. This material is typically processed by machinists, toolmakers, and skilled metalworking professionals.

Key Features

• AISI Type O1 oil-hardening tool steel for predictable heat-treat response
• Thickness and width tolerances of +0.010 to +0.015 inches for precise stock allowance
• Length tolerance of +0.250 inches — cuts clean to final length with minimal loss
• All-edge squareness held to 0.003 inches per inch for direct layout use
• Annealed condition allows full machining before hardening
• Single-piece packaging with no minimum order beyond one unit

Compatibility

Designed as a general-purpose O1 oil-hardening flat stock for toolmaking, die making, and precision machining applications requiring AISI Type O1 tool steel in flat bar form.

Installation Notes

O1 tool steel should be machined and ground to final dimensions before heat treatment. Oil-hardening heat treat operations should be performed by qualified personnel following accepted metallurgical procedures and applicable shop safety codes. Always wear appropriate PPE when cutting, grinding, or heat treating tool steel. Allow material to cool properly after heat treating before handling or finishing operations.