Starrett 54209 O1 Tool Steel Flat Stock 7/8x4x18 in

Product Description

The STARRETT 54209 is an O1 oil-hardening tool steel flat stock bar used in tool and die making, jig and fixture fabrication, and precision machining applications. Manufactured to AISI Type O1 specifications, this flat stock measures 7/8 inch thick, 4 inches wide, and 18 inches long, with a weight of 17.85 pounds. The O1 grade offers good machinability in the annealed state and responds well to oil-quench hardening, making it a common choice for punches, dies, gauges, and cutting tools. Tight dimensional tolerances are held throughout, supporting precision layout and stock removal work.

This flat stock is suited for tool rooms, maintenance shops, and production environments where O1 tool steel is specified. Typical applications include blanks for custom cutting tools, die sections, forming blocks, and wear plates. The 7/8 inch thickness provides substantial cross-section for heavy stock removal or for parts that require through-hardening with minimal distortion. Machinists, tool and die makers, and metalworking tradespeople working to close tolerances will find the controlled dimensions on this bar ready for layout and machining directly from the shelf.

Key Features

• AISI Type O1 oil-hardening tool steel for good machinability and predictable heat treat response
• Thickness held to plus or minus 0.001 inches for precise stock allowances
• Width tolerance of minus 0 to minus 0.005 inches ensures the bar fits within nominal width
• Length tolerance of plus 0.250 inches provides extra material for squaring ends
• Edge squareness held to 0.003 inches per inch across all edges
• 17.85-pound bar weight suitable for substantial tooling blanks

Compatibility

Designed as a standard AISI O1 oil-hardening tool steel flat stock suitable for general tool room and precision machining applications requiring this alloy grade.

Installation Notes

Cutting, grinding, and machining of tool steel flat stock should be performed by qualified machinists or tool and die makers using appropriate cutting tools rated for tool steel. Always follow proper heat treatment procedures per the applicable material specification when hardening O1 steel, including correct quench media and temperature controls. Use personal protective equipment including eye protection and gloves when sawing or grinding. Ensure workholding is secure and stable before beginning any machining operation.