Starrett 54178 O1 Tool Steel Flat Stock 5/8x2-1/2x18 in

Product Description

The STARRETT 54178 is an O1 oil-hardening tool steel flat stock bar used in toolmaking, die work, jig fabrication, and precision machining applications. This bar measures 5/8 inch thick, 2-1/2 inches wide, and 18 inches long, with a thickness tolerance of plus or minus 0.001 inches and a length tolerance of plus 0.250 inches. Manufactured to AISI Type O1 material specification, it is designed to be machined in the annealed condition and then oil-quenched to achieve final hardness. Machinists, tool and die makers, and metalworking shops are the primary users of this stock.

O1 tool steel flat stock is suited for applications requiring good wear resistance, dimensional stability during heat treatment, and machinability before hardening. Typical uses include punches, dies, gauges, woodworking tools, knives, and small precision fixtures. This flat bar configuration allows stock to be cut to length, machined to a profile, and heat-treated to service hardness in a typical tool room workflow. The 18-inch length and near-net dimensions reduce material removal and setup time.

Key Features

• AISI Type O1 oil-hardening tool steel for predictable heat treatment response
• Tight thickness tolerance of plus or minus 0.001 inches for close-tolerance tooling work
• Width tolerance of 0.000 to minus 0.005 inches holds near-net width for minimal stock removal
• Length tolerance of plus 0.250 inches provides usable stock beyond nominal dimension
• Squareness: edge squareness held to 0.003 inches per inch on all edges
• Supplied in annealed condition for machining prior to oil-quench hardening

Compatibility

Designed as a standard O1 oil-hardening tool steel flat stock bar suitable for general tool room, die shop, and precision metalworking applications requiring AISI Type O1 material specification.

Installation Notes

Cutting, grinding, and machining operations should be performed in the annealed state before heat treatment. Standard shop safety practices apply when cutting tool steel, including use of appropriate personal protective equipment and secure workholding. Heat treatment to final hardness must be performed by qualified personnel following established procedures for O1 oil-hardening steel, including proper soak temperature and oil quench sequence. Allow the part to fully cool to room temperature before any finish grinding to final dimensions.