Starrett 56993 O1 Tool Steel Flat Stock 5/16x2x18 in

Product Description

The STARRETT 56993 is an O1 oil-hardening tool steel flat stock bar measuring 5/16 inches thick, 2 inches wide, and 18 inches long. Manufactured to AISI Type O1 specifications, this flat stock is used as raw material for toolmakers, machinists, and die makers who need a machinable blank that can be hardened through an oil-quench heat treatment process. The piece ships in an annealed, soft condition ready for machining. Thickness and width tolerances are held to +0.0100 to 0.0150 inches, and edge squareness is controlled to 0.003 inches per inch, making it suitable for precision tooling applications where close dimensional control matters before hardening.

O1 tool steel flat stock is a standard material in job shops, tool-and-die operations, and maintenance departments. It is commonly used to fabricate punches, dies, gauges, fixtures, blades, and other tooling components that require a good balance of toughness and wear resistance after hardening. The 18-inch length makes this piece practical for a range of small to medium tooling blanks without significant material waste. Machinists working on manual mills, surface grinders, or CNC equipment will find this size well-suited to single-piece or small-batch tooling projects.

Key Features

• AISI Type O1 oil-hardening tool steel — machines in annealed state, hardens via oil quench
• Thickness: 5/16 inches with tolerance of +0.0100 to 0.0150 inches
• Width: 2 inches with tolerance of +0.0100 to 0.0150 inches
• Length: 18 inches with tolerance of +0.2500 inches
• Edge squareness held to 0.003 inches per inch on all edges
• Weight: 3.19 pounds per piece

Compatibility

Designed as a general-purpose O1 oil-hardening tool steel flat stock blank suitable for machining into punches, dies, gauges, fixtures, and similar tooling components in job shop and industrial maintenance applications.

Installation Notes

This material is supplied in the annealed condition and should be machined prior to heat treatment. Oil-hardening tool steel requires controlled heat treatment including proper austenitizing temperature and an oil-quench cycle followed by tempering — this work should be performed by qualified tool room personnel or a commercial heat treater familiar with O1 steel. Allow all machining, grinding, and finishing operations to reach final dimensions before the hardening cycle. Use appropriate personal protective equipment when handling cutting fluids and heat treatment oils.