Starrett 53978 O1 Tool Steel Flat Stock 3/32x1/2x18 in

Product Description

The STARRETT 53978 is an O1 oil-hardening tool steel flat stock bar used in toolmaking, die making, jig fabrication, and precision machining applications. Manufactured to AISI Type O1 material specification, this flat stock measures 3/32 inches thick, 1/2 inch wide, and 18 inches long, with a weight of 0.24 pounds. Thickness and squareness tolerances are held to plus or minus 0.001 inches, making it suitable for applications requiring close dimensional control before and after heat treat. Machinists, tool and die makers, and maintenance professionals stock O1 flat bar for fabricating punches, blades, gauges, and custom tooling.

O1 tool steel flat stock is a standard material in job shops, maintenance departments, and toolrooms handling moderate-volume tooling work. The 18-inch length provides enough stock for most single-piece tool blanks or can be cut down for multiple smaller parts. Its oil-hardening grade means it responds predictably to conventional heat treatment without the distortion risks associated with water-hardening grades, making it a common first choice for general tooling stock where tight post-hardening dimensions matter.

Key Features

• AISI Type O1 oil-hardening tool steel material specification
• Thickness and squareness tolerance of plus or minus 0.001 inches for precise blank preparation
• Width tolerance of 0.000 to 0.005 inches under nominal
• Length tolerance of plus 0.250 inches, minus 0 inches
• Edge squareness held to 0.003 inches per inch on all edges
• Ready-to-machine flat stock form — no additional surface prep required before layout

Compatibility

Designed as a standard O1 oil-hardening tool steel flat bar suitable for general toolmaking, die making, and precision fabrication applications requiring a pre-toleranced blank in this thickness and width range.

Installation Notes

Cutting, grinding, and heat treatment of tool steel should be performed by qualified machinists or tool and die makers familiar with O1 oil-hardening procedures. Use appropriate personal protective equipment when cutting or grinding. Heat treatment should follow recognized guidelines for AISI O1 tool steel including proper quench oil temperature and tempering cycles. Always allow stock to reach room temperature before taking final dimensional measurements.