Starrett 54181 O1 Tool Steel Flat Stock 5/8x4x18 in

Product Description

The STARRETT 54181 is an O1 oil-hardening tool steel flat stock bar used in precision toolmaking, die making, and machine shop fabrication. Manufactured to AISI Type O1 specification, this flat stock measures 5/8 inch thick, 4 inches wide, and 18 inches long, with a weight of 12.82 pounds. Thickness tolerance is held to plus or minus 0.001 inches, and squareness is maintained at 0.003 inches per inch on all edges. These tight tolerances make it well-suited for applications where dimensional accuracy in the pre-hardened or soft-annealed state is critical before heat treatment.

O1 tool steel flat stock is used in job shops, tool and die operations, and maintenance departments for fabricating punches, dies, gauges, fixtures, and cutting tools. It arrives in the annealed condition, ready for machining and then oil-quench hardening. The 4-inch width and 18-inch length provide enough material for medium-sized tooling blanks without requiring initial rough cutting on most standard applications. Machinists and toolmakers working in both production and prototype environments will find this size practical for a broad range of workholding and cutting tool projects.

Key Features

• AISI Type O1 oil-hardening tool steel for reliable heat treatment response
• Thickness held to plus or minus 0.001 inches for precision fit-up
• Width tolerance of 0.000 to minus 0.005 inches for consistent stock removal planning
• Length tolerance of plus 0.250 inches, minus 0 for full usable length
• Squareness: 0.003 inches per inch on all edges for accurate layout work
• Supplied in annealed condition, ready for machining prior to hardening

Compatibility

Designed as a standard AISI Type O1 oil-hardening tool steel flat stock suitable for general toolmaking, die making, and fixture fabrication applications requiring a 5/8 inch by 4 inch by 18 inch blank.

Installation Notes

Machining and heat treatment of tool steel should be performed by qualified toolmakers or machinists following standard shop practices. Proper personal protective equipment must be worn during cutting, grinding, and heat treatment operations. Oil-quench hardening requires controlled furnace temperatures and a suitable quench tank with appropriate quenching oil — follow the material specification guidelines for AISI O1 when establishing soak times and quench procedures. Ensure all machining is completed before hardening, as post-hardening work typically requires grinding.