Starrett 54128 O1 Tool Steel Flat Stock 3/8x4.5x18 in

Product Description

The STARRETT 54128 is an O1 oil-hardening tool steel flat stock bar intended for toolmakers, machinists, and die makers who need a precision-ground blank ready for layout, machining, and heat treatment. Manufactured to AISI Type O1 specification, this flat stock measures 3/8 inch thick, 4-1/2 inches wide, and 18 inches long, with a weight of 8.6 pounds. Thickness and squareness tolerances are held to plus or minus 0.001 inch, making this stock suitable for applications where dimensional accuracy before hardening is critical. It ships as a single piece with a minimum order quantity of one.

O1 tool steel flat stock is used in toolrooms and machine shops for fabricating punches, dies, gauges, cutting tools, and fixtures. The oil-hardening grade responds predictably to standard shop heat-treatment procedures, producing a hard, wear-resistant surface while keeping distortion low compared to water-hardening grades. This piece is appropriate for both small-batch prototype work and production tooling applications where a pre-cut, precision-tolerance blank is needed to minimize material removal prior to hardening.

Key Features

• AISI Type O1 oil-hardening tool steel — predictable hardening response with low distortion
• Thickness tolerance of plus or minus 0.001 inch for precision pre-hardening layout
• Width tolerance of 0.0000 to minus 0.005 inch; length tolerance of plus 0.250 inch
• Squareness held to 0.003 inch per inch on all edges
• Single-piece packaging with no minimum order quantity beyond one unit
• Weighs 8.6 pounds — manageable for bench vise and surface plate work

Compatibility

Designed as a standard O1 oil-hardening tool steel flat blank suitable for general toolroom fabrication where AISI Type O1 material specification is required.

Installation Notes

Cutting, grinding, and machining of tool steel flat stock should be performed by a qualified machinist or toolmaker using appropriate carbide or high-speed steel tooling. Follow established shop safety practices when sawing or grinding, including eye and respiratory protection to control metal dust and swarf. Heat treatment of O1 tool steel requires controlled furnace equipment and quenching in oil; consult the material specification and applicable shop procedures before hardening. Allow the workpiece to fully cool before final grinding or surface finishing.