Starrett 56980 O1 Tool Steel Flat Stock 1/4x3x18 in

Product Description

The STARRETT 56980 is a precision-ground O1 oil-hardening tool steel flat stock bar intended for toolmakers, machinists, and die makers who need a reliable blank for custom tooling, fixtures, gauges, and cutting tools. Measuring 0.25 inches thick, 3 inches wide, and 18 inches long, this bar conforms to AISI Type O1 material specification. Thickness and width tolerances are held to +0.0100 to +0.0150 inches, and edge squareness is maintained at 0.003 inches per inch. O1 tool steel offers good machinability in the annealed state and responds predictably to oil-quench hardening, making it a standard choice for shop-made tooling blanks.

O1 flat stock in this size is commonly used in toolroom and job-shop environments for fabricating punches, dies, form tools, drill bushings, and precision fixtures. The 18-inch length provides enough stock to yield multiple smaller blanks or one longer tool component without additional splicing. This bar ships in the soft-annealed condition, ready to machine, then heat treat to the required hardness. Typical users include tool and die shops, maintenance machinists, and prototype fabricators who need over-the-counter tool steel without custom mill lead times.

Key Features

• AISI Type O1 oil-hardening tool steel — predictable hardening response with minimal distortion during oil quench
• Thickness and width tolerances of +0.0100 to +0.0150 inches for close-tolerance machining starts
• Edge squareness held to 0.003 inches per inch on all edges
• Length tolerance of +0.2500 inches — full positive allowance, no undersize cuts
• Annealed condition allows conventional milling, drilling, and grinding before hardening
• Single-piece packaging (Pkg Qty 1) with no minimum order beyond one bar

Compatibility

Designed as a general-purpose O1 tool steel flat stock blank suitable for toolroom, die shop, and maintenance machining applications requiring AISI Type O1 oil-hardening material in a 0.25 x 3 x 18 inch form factor.

Installation Notes

Machining and heat treatment of tool steel should be performed by a qualified machinist or toolmaker familiar with AISI O1 oil-hardening procedures. Secure the bar firmly in a milling vise or on a surface grinder magnetic chuck before stock removal. Heat treatment — including austenitizing temperature, soak time, and oil-quench procedure — should follow the material manufacturer's published guidelines; improper quenching can cause cracking or warping. Allow the bar to reach ambient temperature before layout work to ensure accurate measurement.