Starrett 56958 O1 Tool Steel Flat Stock 3/16x1/2x18 in

Product Description

The STARRETT 56958 is an O1 oil-hardening tool steel flat stock bar used in toolmaking, die-making, and precision machining applications. It conforms to AISI Type O1 specifications, delivering consistent hardness and dimensional accuracy in pre-hardened and annealed conditions. This bar measures 3/16 inches thick, 1/2 inch wide, and 18 inches long, with a thickness tolerance of +0.0100 to 0.0150 inches and a width tolerance of +0.0100 to 0.0150 inches. Edge squareness is held to 0.003 inches per inch across all edges. Machinists, tool and die makers, and general metalworking professionals stock this material for fabricating punches, dies, gauges, and cutting tools.

O1 tool steel flat stock is suited for job shops, tool rooms, and production environments requiring reliable pre-annealed bar stock ready for machining and subsequent oil hardening. The 18-inch length provides enough material for small-to-medium tooling blanks without the need to cut down longer stock. The 3/16 x 1/2 inch cross section is commonly used for thin blade-style tooling, flat punches, and template work. This piece ships as a single bar, making it practical for low-volume or prototype tooling needs.

Key Features

• AISI Type O1 oil-hardening tool steel for consistent hardenability and wear resistance after heat treatment
• Thickness and width tolerances of +0.0100 to +0.0150 inches for precise machining stock allowances
• Length tolerance of +0.25 inches to ensure minimum usable length is met
• Edge squareness held to 0.003 inches per inch on all edges for accurate layout and fixturing
• Annealed condition allows straightforward machining before oil-hardening heat treatment
• Single-bar quantity suits prototype, repair, and low-volume tooling work

Compatibility

Designed as a general-purpose O1 oil-hardening tool steel flat stock suitable for use in any tool room or machining application requiring AISI Type O1 material in a 3/16 x 1/2 inch cross section.

Installation Notes

This material is supplied in the annealed condition and is intended for machining to final shape before oil-hardening heat treatment by a qualified tool and die maker or heat-treat professional. Secure the workpiece properly in a vise or fixture during machining to maintain dimensional accuracy. Follow appropriate shop safety practices when cutting, grinding, or heat treating tool steel, including the use of PPE and adequate ventilation. Consult AISI O1 heat-treat guidelines for austenitizing and quench procedures specific to the finished tool design.