Starrett 54081 O1 Tool Steel Flat Stock 0.25x4.5x18 in

Product Description

The STARRETT 54081 is an O1 oil-hardening tool steel flat stock bar used in toolmaking, die making, and precision machining applications. Manufactured to AISI Type O1 specifications, this flat stock measures 0.25 inches thick, 4.5 inches wide, and 18 inches long. Thickness tolerance is held to plus or minus 0.001 inches, providing the dimensional consistency required for jigs, fixtures, punches, and gauges. At 5.75 pounds, this is a solid, full-size bar intended for shop floor use by machinists and tool and die makers who need reliable, heat-treatable tool steel ready for stock removal and hardening.

O1 tool steel flat stock is well suited to general-purpose toolmaking in both job shops and production environments. It is commonly used to produce blanks for cutting tools, gauges, dies, and forming tools where oil-quench hardening is part of the processing workflow. The 18-inch length provides adequate material for most standard tooling blanks without requiring additional joinery. This bar ships as a single piece and is ready for layout, machining, and subsequent heat treatment by a qualified tool room or heat treating operation.

Key Features

• AISI Type O1 oil-hardening tool steel — consistent chemistry for predictable hardening response
• Thickness tolerance of plus or minus 0.001 inches for precision fitment in close-tolerance applications
• Width tolerance of 0.0000 to 0.0050 inches (minus 0, minus 0.005 inches) for controlled stock sizing
• Length tolerance of plus 0.250 inches, minus 0 inches — never short of nominal 18 inches
• Edge squareness held to 0.003 inches per inch on all edges
• Weighs 5.75 pounds — full-density tool steel bar suitable for heavy stock removal

Compatibility

Designed as a standard O1 oil-hardening tool steel flat bar for use in general toolmaking, die making, and precision machining applications requiring AISI Type O1 material specification.

Installation Notes

Machining and heat treatment of O1 tool steel should be performed by qualified machinists or tool room personnel familiar with oil-quench hardening procedures. Always allow the bar to reach ambient temperature before layout and machining if stored in cold conditions. Oil hardening requires a controlled quench process — follow your heat treater's recommended austenitizing temperature and quench media specifications for O1 steel. Use appropriate cutting fluid during machining to extend tool life and maintain surface integrity.