Starrett 54215 O1 Tool Steel Flat Stock 1x2.5x18 in

Product Description

The STARRETT 54215 is an O1 oil-hardening tool steel flat stock bar used in toolmaking, die making, jig fabrication, and precision machining applications. Manufactured to AISI Type O1 specification, this flat stock measures 1 inch thick, 2.5 inches wide, and 18 inches long, with close-tolerance grinding on all faces. Thickness tolerance is held to plus or minus 0.001 inches, making it suitable for applications where dimensional accuracy is critical before and after heat treatment. At 12.73 pounds, this is a solid, full-section bar intended for professional shop use by toolmakers, machinists, and die makers.

O1 tool steel flat stock is used in fabricating punches, dies, gauges, bushings, lathe centers, and other toolroom components that require oil-quench hardening. This bar is supplied in the annealed condition, ready for machining to final dimensions before hardening and tempering. It is appropriate for low- to medium-run tooling in job shops, maintenance and repair operations, and production tool rooms. The 18-inch length provides a practical starting blank for a wide range of toolroom projects.

Key Features

• AISI Type O1 oil-hardening tool steel — annealed condition, ready for machining
• Thickness tolerance of plus or minus 0.001 inches for precision fitment
• Width tolerance of 0.000 to minus 0.005 inches for consistent stock sizing
• Length tolerance of plus 0.250 inches, minus 0 inches
• Squareness held to 0.003 inches per inch on all edges
• Solid flat bar geometry suits punch, die, gauge, and jig applications

Compatibility

Designed as a standard AISI O1 oil-hardening tool steel flat stock suitable for general toolroom machining, die making, and gauge fabrication where oil-quench heat treatment will be applied after final machining.

Installation Notes

Machining of O1 tool steel flat stock should be performed by qualified machinists or toolmakers using appropriate cutting tools rated for tool steel. Heat treatment — including hardening and tempering — should follow established metallurgical procedures for AISI O1 and is typically performed by a qualified heat treater or in a controlled atmosphere furnace. Always allow the bar to reach thermal equilibrium before precision grinding operations. Handle with care after hardening, as O1 in the hardened condition is brittle until properly tempered.