Starrett 56972 O1 Tool Steel Flat Stock 1/4x1/2x18 in

Product Description

The STARRETT 56972 is an O1 oil-hardening tool steel flat stock bar used in toolmaking, die making, punch fabrication, and precision machining applications. Manufactured to AISI Type O1 specifications, this flat stock measures 0.25 inches thick, 0.5 inches wide, and 18 inches long. Thickness and width tolerances run from +0.010 to +0.015 inches, while length tolerance is +0.25 inches. Squareness is held to 0.003 inches per inch on all edges, making it suitable for applications where consistent geometry is critical before heat treatment. Machinists, tool and die makers, and maintenance professionals typically stock O1 flat bar for fabricating custom tooling components.

O1 tool steel flat stock is a standard material in job shops, toolrooms, and maintenance departments. This bar is used in the annealed condition and is intended to be machined to final dimensions before oil-hardening heat treatment. Common applications include blanks for flat punches, gauges, blades, arbors, and small fixture components. The 18-inch length makes it practical for benchtop work and standard milling setups without further sawing in most toolroom applications.

Key Features

• AISI Type O1 oil-hardening tool steel — machines well in the annealed state and responds uniformly to oil-quench heat treatment
• 0.25 inches thick by 0.5 inches wide by 18 inches long — ready-to-use flat bar format
• Thickness and width tolerance: +0.010 to +0.015 inches for consistent stock removal planning
• Length tolerance: +0.25 inches
• Squareness held to 0.003 inches per inch on all edges for accurate layout and setup
• Ships as a single bar (Package Quantity: 1)

Compatibility

Designed as a general-purpose O1 oil-hardening tool steel flat bar suitable for use in any toolroom, job shop, or maintenance application requiring annealed AISI O1 material in 0.25 inches by 0.5 inches cross section.

Installation Notes

O1 tool steel flat stock is worked in the annealed (soft) condition using standard milling, grinding, sawing, and drilling operations before heat treatment. Oil-hardening heat treatment should be performed by a qualified heat treater or experienced toolmaker following established procedures for AISI O1 steel. Secure the workpiece properly in vises or fixtures during machining to maintain dimensional accuracy given the close tolerances. Do not attempt to cold-bend or straighten this material without proper equipment, as tool steel is prone to cracking under improper mechanical stress.