Starrett 54079 O1 Tool Steel Flat Stock 0.25x3.5x18 in

Product Description

The STARRETT 54079 is an O1 oil-hardening tool steel flat stock bar used in toolmaking, die work, jig fabrication, and precision machining applications. Manufactured to AISI Type O1 specifications, this flat stock measures 0.25 inches thick, 3.5 inches wide, and 18 inches long. Thickness tolerance is held to +/- 0.001 inches, making it suitable for applications where dimensional accuracy is critical before hardening. At 4.48 pounds per piece, this is a solid, single-length bar intended for cutting to final dimensions by machinists, tool and die makers, and metalworking professionals.

O1 tool steel is widely used in cold-work tooling, blanking dies, punches, gauges, and cutting tools. This flat stock is appropriate for both job shop and production toolmaking environments. It ships in the annealed condition, ready for rough machining prior to oil-quench hardening and tempering. The 18-inch length accommodates a range of part layouts without excessive waste. Edge squareness is held to 0.003 inches per inch across all edges, supporting accurate layout and setup directly from stock.

Key Features

• AISI Type O1 oil-hardening tool steel — consistent composition for predictable heat treat response
• Thickness tolerance of +/- 0.001 inches for precise pre-grind stock allowance planning
• Width tolerance of 0.000 to -0.005 inches — stock runs at or slightly under nominal width
• Length tolerance of +0.250 inches — full usable length guaranteed with positive overrun
• Edge squareness held to 0.003 inches per inch on all edges
• Supplied in annealed condition for machinability prior to hardening

Compatibility

Designed as a general-purpose O1 tool steel flat stock suitable for toolmaking, die making, and precision machining applications requiring oil-hardening material in 0.25 inch by 3.5 inch cross-section.

Installation Notes

Cutting, grinding, and machining of tool steel should be performed by qualified machinists or tool and die makers using appropriate coolant to prevent work hardening at cut edges. Heat treatment — including oil quenching and tempering — should follow AISI O1 specifications and be performed by personnel familiar with tool steel heat treat procedures. Always use proper personal protective equipment when handling and cutting metal stock. Secure workpieces firmly before any machining operation.