Starrett 58898 O1 Tool Steel Flat Stock 3/8x5/8x36 in

Product Description

The STARRETT 58898 is an O1 oil-hardening tool steel flat stock bar intended for toolmakers, machinists, and die makers who need a precision-ground blank for fabricating punches, dies, gauges, cutting tools, and similar toolroom components. Manufactured to AISI Type O1 specification, this bar measures 3/8 inches thick by 5/8 inches wide by 36 inches long and weighs 2.39 pounds. Thickness and squareness tolerances are held to plus or minus 0.001 inches, making it suitable for applications where dimensional accuracy before heat treatment is critical. O1 tool steel offers good machinability in the annealed state and responds well to oil-quench hardening.

This flat stock is used in toolroom and machine shop environments for producing short-run tooling, jigs, fixtures, and wear components. Its pre-ground surfaces reduce setup time when milling or grinding to final dimensions. Typical users include toolroom machinists, die makers, and maintenance technicians working in manufacturing facilities, metalworking shops, and industrial maintenance departments. The 36-inch length allows blanks to be cut to multiple shorter pieces as needed for individual tooling projects.

Key Features

• AISI Type O1 oil-hardening tool steel for predictable heat-treat response
• Thickness tolerance of plus or minus 0.001 inches for precision fitment before hardening
• Width tolerance of 0.000 to minus 0.005 inches for consistent stock sizing
• Length tolerance of plus 0.015 inches
• Squareness held to 0.003 inches per inch on all edges
• Single 36-inch bar per package — ready to cut to length

Compatibility

Designed as a standard AISI O1 oil-hardening tool steel flat bar suitable for general toolroom fabrication wherever O1 grade flat stock at 3/8 x 5/8 x 36 inches is specified.

Installation Notes

Cutting and machining of this bar should be performed in the annealed state using appropriate metalworking equipment; wear proper PPE including eye protection and cut-resistant gloves when sawing or grinding. Heat treating to final hardness requires controlled furnace equipment and an oil quench — this work is typically performed by a qualified toolroom machinist or heat-treat specialist following the material supplier guidelines for O1 steel. Finished tooling should be inspected for dimensional compliance after hardening and tempering before placing in service.