Starrett 54478 O1 Tool Steel Flat Stock 3/4x1-1/4x36in

Product Description

The STARRETT 54478 is an O1 oil-hardening tool steel flat stock bar supplied in a 0.75 inch thick, 1.25 inch wide, 36 inch long profile. O1 is a general-purpose cold-work tool steel known for good dimensional stability during heat treatment, moderate toughness, and ease of machining in the annealed state. This flat stock is used by toolmakers, machinists, and die makers as raw material for punches, dies, gauges, jigs, fixtures, and cutting tools. The AISI Type O1 material specification means the steel is designed to harden by quenching in oil, making it suitable for applications requiring a hard, wear-resistant working surface with controlled distortion.

This flat stock is a standard choice for tool and die shops, maintenance and repair operations, and prototype fabrication environments. It ships in the annealed condition, ready for machining before heat treatment. The 36 inch length accommodates multiple blanks from a single bar, reducing scrap. Typical applications include custom punches, form dies, drill jigs, and small fixture components where tight dimensional tolerances are required before and after hardening.

Key Features

• AISI Type O1 oil-hardening tool steel for controlled, low-distortion heat treatment
• Thickness tolerance of plus or minus 0.001 inches for precise blank sizing
• Width tolerance of 0.000 to minus 0.005 inches for consistent fit in fixture applications
• Length tolerance of plus 0.015 inches with zero minus allowance
• 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 standard AISI O1 oil-hardening tool steel flat bar suitable for general toolmaking, die making, and fixture fabrication applications requiring oil-quench heat treatment.

Installation Notes

Machining and heat treatment of O1 tool steel should be performed by qualified toolmakers or machinists familiar with cold-work tool steel processing. Rough-machine parts to near-net shape before hardening to minimize post-heat-treat grinding. Oil quench per material specification requirements; follow established shop procedures and applicable safety protocols when handling heated steel and quench oils. Grinding after hardening should be performed with appropriate wheel selection to avoid thermal damage to the hardened surface.