Starrett 58899 O1 Tool Steel Flat Stock 3/32x1/4x36 in

Product Description

The STARRETT 58899 is an O1 oil-hardening tool steel flat stock bar intended for toolmakers, machinists, and die makers who require precise, machinable stock in the annealed state prior to hardening. Manufactured to AISI Type O1 specifications, this flat bar measures 3/32 inches thick, 1/4 inches wide, and 36 inches long. Thickness and squareness tolerances are held to plus or minus 0.001 inches, ensuring consistent stock removal and accurate finished dimensions when machined before heat treatment. At 0.24 pounds per piece, this is a single-bar unit quantity suited for prototype work, tooling repairs, and small-run die components.

O1 tool steel flat stock in this size range is commonly used in machine shops, toolrooms, and maintenance departments for fabricating punches, dies, cutting tools, jigs, fixtures, and general tooling components. The 36-inch length allows multiple parts to be cut from a single bar, reducing waste. This stock ships in the soft, annealed condition and must be hardened and tempered by oil quenching after machining to achieve working hardness. Licensed machinists and tool and die makers are the primary users of this material.

Key Features

• AISI Type O1 oil-hardening tool steel — machines cleanly in the annealed state and responds well to standard oil-quench heat treatment
• Thickness of 3/32 inches held to plus or minus 0.001 inches tolerance for consistent stock removal
• Width of 1/4 inches with a tolerance of 0.000 to minus 0.005 inches
• Length of 36 inches with a plus 0.015 inches length tolerance
• Edge squareness held to 0.003 inches per inch on all edges
• Sold as a single bar with a minimum order quantity of one piece

Compatibility

Designed as a general-purpose O1 oil-hardening tool steel flat bar suitable for toolroom and machine shop applications where AISI Type O1 material specification is required.

Installation Notes

Machining of O1 tool steel flat stock should be performed in the annealed condition using standard HSS or carbide tooling. Heat treatment — including austenitizing, oil quenching, and double tempering — should be performed by a qualified heat treater or experienced toolroom machinist following established metallurgical procedures for AISI O1. Always allow the bar to reach ambient temperature before taking final dimensional measurements. Appropriate personal protective equipment, including eye and hand protection, is required during cutting and grinding operations.