Starrett 54120 O1 Tool Steel Flat Stock 3/8x1-1/4x18 in

Product Description

The STARRETT 54120 is an O1 oil-hardening tool steel flat stock bar used in toolmaking, die work, punches, gauges, and precision machining applications. Manufactured to AISI Type O1 specifications, this flat bar measures 3/8 inches thick, 1-1/4 inches wide, and 18 inches long, with a weight of 2.39 pounds. Thickness tolerance is held to +/- 0.001 inches, delivering the dimensional consistency required for accurate tool and die fabrication. The O1 grade offers good machinability in the annealed state and responds well to oil-quench hardening, making it a reliable choice for short-run tooling and precision components.

This flat stock is suited for machine shops, tool rooms, and maintenance departments working on tooling and fixture fabrication. Typical applications include cutting tools, blanking dies, drill bushings, and gauge blanks where close tolerances and hardenability are required. The 18-inch length provides a practical working blank that can be cut to size before or after hardening operations. Both manual and CNC machining operations are commonly performed on this material prior to heat treatment.

Key Features

• AISI Type O1 oil-hardening tool steel for reliable heat treatment response
• Thickness: 3/8 inches with +/- 0.001 inch tolerance
• Width: 1-1/4 inches with tolerance of 0.0000 to -0.005 inches
• Length: 18 inches with +0.250 inch length tolerance
• Edge squareness held to 0.003 inches per inch on all edges
• Good machinability in annealed condition prior to hardening

Compatibility

Designed as a standard AISI O1 oil-hardening tool steel flat stock suitable for general toolmaking, die making, and precision machining applications requiring close dimensional tolerances.

Installation Notes

Machining and heat treatment of tool steel should be performed by qualified machinists or tool and die makers familiar with O1 steel handling procedures. Always anneal or stress-relieve the stock if straightness is critical before finish machining. Oil quench hardening requires proper furnace and quench tank equipment — follow established shop procedures and applicable safety codes for heat treating operations. Use appropriate cutting fluids and tooling rated for tool steel during machining.