Starrett 54009 O1 Tool Steel Flat Stock 1/8x3.5x18 in

Product Description

The STARRETT 54009 is an O1 oil-hardening tool steel flat stock bar used in toolmaking, die work, and precision machining applications. Manufactured to AISI Type O1 material specification, it measures 0.125 inches thick, 3.5 inches wide, and 18 inches long. Thickness and squareness tolerances are held to plus or minus 0.001 inches, making this stock suitable for applications where dimensional accuracy is critical before heat treatment. Licensed machinists, toolmakers, and die makers work with this material to fabricate punches, dies, gauges, and similar components that require a hardened finish after rough machining.

This flat stock is suited for use in job shops, tool and die operations, and maintenance departments handling custom tooling. O1 tool steel machines cleanly in the annealed state and responds predictably to oil-quench hardening, making it a standard choice when close dimensional control is needed both before and after heat treat. Width tolerance is held at 0 to minus 0.005 inches and length tolerance allows up to plus 0.250 inches. Edge squareness is controlled to 0.003 inches per inch on all edges.

Key Features

• AISI Type O1 oil-hardening tool steel for predictable heat treat response
• Thickness tolerance of plus or minus 0.001 inches for precision pre-machined fitment
• Width tolerance of 0 to minus 0.005 inches maintains consistent stock sizing
• Edge squareness held to 0.003 inches per inch on all edges
• Length tolerance of plus 0.250 inches provides usable overage for cut-to-length work
• Supplied in annealed condition, ready for machining prior to hardening

Compatibility

Designed as a standard O1 oil-hardening flat tool steel bar suitable for toolmaking, die making, and precision fabrication applications requiring annealed stock that will be finish-machined and oil-quench hardened.

Installation Notes

Cutting, grinding, and machining of tool steel should be performed by qualified machinists using appropriate coolant to prevent localized heat buildup. Heat treatment including oil quenching should follow AISI O1 guidelines and is typically performed by a heat treat professional or in a controlled furnace environment. Always allow the bar to reach ambient temperature before final inspection for dimensional conformance. Proper personal protective equipment is required when cutting or grinding tool steel.