Starrett 57050 O1 Tool Steel Flat Stock 3/4x4x18 in

Product Description

The STARRETT 57050 is an O1 oil-hardening tool steel flat stock bar measuring 0.75 inches thick, 4 inches wide, and 18 inches long. O1 is a general-purpose cold-work tool steel known for its consistent response to oil-quench hardening, good dimensional stability during heat treatment, and moderate wear resistance. This bar is cut to length from stock conforming to AISI Type O1 material specification and is intended for use by machinists, toolmakers, and die shops that need a reliable, pre-sized blank ready for layout, machining, and hardening. Thickness and width tolerances are held to +0.010 to +0.015 inches, with edge squareness held to 0.003 per inch across all edges.

This flat stock is suited for fabricating punches, dies, gauges, bushings, and small tooling components in job shop and production toolroom environments. The 0.75 by 4 by 18 inch size provides a workable blank for medium-scale tooling applications where stock removal prior to hardening is required. It ships as a single piece per package, making it practical for one-off tool builds or low-volume production runs. Machinists working to tight finished dimensions should account for the stated oversize tolerances when planning rough stock allowances before heat treat.

Key Features

• AISI Type O1 oil-hardening tool steel for predictable heat-treat response
• Thickness and width held to +0.010 to +0.015 inches over nominal
• Length tolerance of +0.25 inches over nominal 18 inches
• Edge squareness: 0.003 per inch on all edges
• Ready-to-machine flat bar format — no saw cutting required to reach nominal size
• Single-piece packaging with MOQ of 1

Compatibility

Designed as an OEM-style replacement or standard toolroom blank for applications requiring AISI O1 oil-hardening tool steel flat stock in 0.75 by 4 by 18 inch nominal dimensions.

Installation Notes

Machining and heat treatment of O1 tool steel should be performed by qualified toolmakers or machinists familiar with cold-work tool steel handling procedures. Always rough machine close to finished dimensions before hardening and tempering to minimize distortion. Use appropriate cutting fluids during milling and grinding operations. Hardening and quenching operations must follow the steel manufacturer's recommended thermal cycle for AISI O1 to achieve target hardness without cracking.