Starrett 54138 O1 Tool Steel Flat Stock 7/16x3/4x18 in

Product Description

The STARRETT 54138 is an O1 oil-hardening tool steel flat stock bar used in toolmaking, die making, and precision machining applications. Manufactured to AISI Type O1 specification, this flat stock measures 7/16 inches thick, 3/4 inches wide, and 18 inches long. It holds a thickness tolerance of plus or minus 0.001 inches and a squareness tolerance of 0.003 inches per inch on all edges. At 1.67 pounds, it is sized for benchtop work and short-run tooling projects. Licensed machinists, tool and die makers, and skilled fabricators typically work with this material when building punches, dies, gauges, and similar precision components.

O1 tool steel flat stock is used wherever a machinable blank is needed that will subsequently be oil-quenched and tempered to a working hardness. Common applications include die components, cutting tools, jigs, fixtures, and wear parts in light-duty tooling setups. This bar is supplied in the annealed condition, making it readily machinable before hardening. It is suited to job shop, maintenance, and prototype tooling environments where close dimensional tolerances are required from the start of the machining process.

Key Features

• AISI Type O1 oil-hardening tool steel — machines in the annealed state, then oil-quenches to working hardness
• Thickness tolerance of plus or minus 0.001 inches for consistent stock removal planning
• Width tolerance of 0.0000 to 0.0050 inches (negative direction only)
• Length tolerance of plus 0.250 inches, minus 0 inches
• Edge squareness held to 0.003 inches per inch on all edges
• Single-piece quantity — no minimum order beyond one piece

Compatibility

Designed as a standard AISI O1 oil-hardening flat stock bar suitable for general toolmaking, die making, and precision fabrication applications requiring a pre-machined blank in annealed tool steel.

Installation Notes

Tool steel flat stock is machined and fitted by tool and die makers or machinists using conventional milling, grinding, and drilling equipment. Always follow established heat-treating procedures for O1 tool steel, including controlled pre-heat, austenitizing, and oil-quench sequences, before finish grinding to final dimension. Ensure appropriate personal protective equipment is used during machining and heat treatment. Consult applicable shop safety standards when handling hot workpieces during the quenching process.