Starrett 53999 O1 Oil-hardening Flat Stock Tool Steel

Product Description

The STARRETT 53999 is an O1 oil-hardening flat stock bar made from AISI Type O1 tool steel, supplied in an annealed condition ready for machining, grinding, and hardening in the shop. It measures 0.125 inches thick, 0.5 inches wide, and 18 inches long, with a thickness tolerance of plus or minus 0.001 inches and a length tolerance of plus 0.25 inches. O1 tool steel is a general-purpose oil-hardening grade valued for its dimensional stability during heat treatment, good wear resistance, and ease of machining. Machinists, toolmakers, and die makers use this stock to fabricate punches, dies, gauges, cutting tools, and other precision tooling components.

This flat stock is suited for job shops, tool rooms, and maintenance departments that require small-quantity tool steel in a ready-to-machine form. The 18-inch length makes it practical for bench work and small tooling projects without requiring saw cutting from full-length bar stock. It is commonly used in applications where tight dimensional control and predictable hardening response are required, including jig components, forming dies, and wear plates.

Key Features

• AISI Type O1 oil-hardening tool steel for predictable heat treatment response
• Thickness tolerance of plus or minus 0.001 inches for close-tolerance tooling work
• Width tolerance of 0.000 to minus 0.005 inches
• Length tolerance of plus 0.25 inches
• Edge squareness: all edges held to 0.003 inches per inch
• Supplied in single-piece quantity, no minimum bundle required

Compatibility

Designed as a general-purpose O1 oil-hardening flat tool steel stock suitable for fabrication of punches, dies, gauges, and precision tooling components in standard tool room and machining applications.

Installation Notes

Cutting, grinding, and heat treating of tool steel should be performed by qualified machinists or toolmakers following established shop safety procedures. Eye protection and appropriate PPE are required when machining or grinding. Heat treatment to final hardness should follow the material manufacturer's recommended O1 hardening and tempering cycle. Allow the part to reach ambient temperature before final grinding to finished dimensions.