Starrett 57021 O1 Tool Steel Flat Stock 1/2x3x18 in

Product Description

The STARRETT 57021 is a flat bar of AISI Type O1 oil-hardening tool steel sized at 0.5 inches thick, 3 inches wide, and 18 inches long. O1 is a general-purpose tool steel valued for its ease of machining in the annealed state and its ability to achieve high hardness after oil quenching. This stock is supplied in an annealed condition, ready for machining, grinding, and heat treatment by toolmakers, machinists, and die makers working in job shops or maintenance environments. At 7.65 pounds per piece, it offers substantial material volume for tooling blanks, dies, punches, gauges, and similar precision components.

This flat stock is suited for fabricating tools and dies in both small-batch job shop and production maintenance settings. The 18-inch length provides enough material for multiple tooling blanks from a single piece. The tight dimensional tolerances make it appropriate for applications where near-net stock reduces finish machining time. Professionals in tool and die, mold making, and precision machining trades commonly specify O1 flat stock for components that require consistent hardness response and dimensional control through the heat-treat cycle.

Key Features

• AISI Type O1 oil-hardening tool steel for predictable heat treat response
• Thickness tolerance: +0.010 to 0.015 inches for consistent stock removal planning
• Width tolerance: +0.010 to 0.015 inches
• Length tolerance: +0.250 inches
• Edge squareness: 0.003 inches per inch on all edges
• Supplied in annealed condition, ready for machining prior to heat treatment

Compatibility

Designed as a general-purpose O1 oil-hardening tool steel flat stock suitable for tooling, die, punch, and gauge fabrication applications where AISI O1 material specification is required.

Installation Notes

Machining and heat treatment of tool steel should be performed by qualified toolmakers or machinists familiar with O1 steel handling procedures. Oil quenching requires appropriate personal protective equipment and fire-safe equipment. Always verify final dimensions after heat treatment, as minor distortion may occur during the hardening and tempering process. Follow applicable shop safety codes and equipment manufacturer guidelines when operating grinding, milling, or heat-treat equipment.