Starrett 54173 O1 Tool Steel Flat Stock 5/8x3/4x18 in

Product Description

The STARRETT 54173 is an O1 oil-hardening tool steel flat stock bar sized at 5/8 inches thick, 3/4 inches wide, and 18 inches long. Manufactured to AISI Type O1 specification, this flat stock is a general-purpose tool steel used for dies, punches, gauges, and cutting tools where moderate wear resistance and good machinability are required. Thickness tolerance is held to plus or minus 0.001 inches, and squareness along all edges is controlled to 0.003 inches per inch. At 2.39 pounds, it ships as a single piece ready for bench work or heat-treat processing. Machinists, toolmakers, and die makers are the primary users of this material.

O1 tool steel flat stock in this size range is suited for light to medium tooling applications in job shops, maintenance departments, and prototype fabrication environments. The 18-inch length provides workable stock for most standard punch and die sets, fixtures, and gauge blanks. Because O1 is oil-quenching steel, it offers lower distortion during heat treatment compared to water-hardening grades, making it a practical choice when dimensional stability after hardening matters.

Key Features

• AISI Type O1 oil-hardening tool steel for lower distortion during quench
• Thickness held to plus or minus 0.001 inches for consistent material removal
• Edge squareness controlled to 0.003 inches per inch on all edges
• Width tolerance of 0.000 to minus 0.005 inches for close-fit applications
• Length tolerance of plus 0.250 inches ensures full usable length
• Single-piece quantity suitable for one-off tooling and repair work

Compatibility

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

Installation Notes

Tool steel flat stock is worked by machinists and toolmakers using standard milling, grinding, and sawing equipment. When heat treating, follow the quenching procedure appropriate for O1 oil-hardening steel and use proper personal protective equipment during the quench process. Inspect dimensional tolerances before and after heat treatment, as hardening may introduce minor distortion. Secure workpieces firmly before machining to maintain the tight tolerances specified for this stock.