Price range: $49.65 through $80.96
O-1 Tool Steel 3/16″ × 3/16″ square bar is manufactured from oil-hardening tool steel (O-1 grade) and produced to ASTM A681 / SAE J437 specifications for tool, die, and precision machining applications. The 0.1875″ × 0.1875″ square bar features a uniform cross-section suitable for machining, grinding, and heat treatment, providing excellent dimensional stability, wear resistance, and edge retention after hardening. O-1 tool steel offers good machinability in the annealed condition and achieves high hardness when oil-quenched and tempered, making it ideal for precision tooling and custom fabrication. This material is commonly supplied in standard cut lengths for shop use.
Sold in 18″ or 36″ lengths.
Applications:
O-1 Tool Steel 3/16″ × 3/16″ square bar is commonly used in precision toolmaking, machining, and industrial fabrication, including:
• Punches, dies, and forming tools
• Gauges, fixtures, and jigs
• Knives, blades, and cutting tools
• Small shafts, pins, and wear components
• Prototype machining and custom tool fabrication
• General-purpose tool and die shop applications
Advantages:
• High hardness capability: Reaches ~60–65 HRC after heat treatment
• Excellent machinability: Easily machined in annealed condition before hardening
• Dimensional stability: Low distortion during oil quench compared to many tool steels
• Good wear resistance: Suitable for cutting, forming, and precision tooling
• Versatile supply lengths: Available in convenient 18″ or 36″ stock lengths for fabrication flexibility
Summary:
The 3/16″ × 3/16″ O-1 oil-hardening tool steel square bar is a precision-grade material designed for toolmaking, machining, and industrial applications. Its machinability, predictable heat-treatment response, and high hardness potential make it a reliable choice for punches, dies, and custom tooling. It is typically sold in 18″ or 36″ lengths for shop and manufacturing use.
* Prices are subject to change without notice due to fluctuations in the metals market. | All “Value Length” and “Value Pack” item measurements are subject to standard mill tolerances. | Products may be manufactured several thousandths of an inch over or under the stated dimensions and still be within acceptable mill tolerances. All bar, tube, structural, pipe, sheet, plate, and similar products sold on our website are custom cut to the lengths and sizes selected by the customer at the time of purchase. These are not stocked as pre-cut items. Because each order is cut specifically to customer specifications, all cut materials are considered custom products and are not eligible for cancellation, return, or exchange once production has begun. Our standard cutting tolerances are:
