{"product_id":"starrett-56981-o1-tool-steel-flat-stock-1-4x3-5x18-in","title":"Starrett 56981 O1 Tool Steel Flat Stock 1\/4x3.5x18 in","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe STARRETT 56981 is an O1 oil-hardening tool steel flat stock bar used in toolmaking, die work, jig fabrication, and precision machining applications. Cut to 0.25 inches thick, 3.5 inches wide, and 18 inches long, this flat stock is supplied in the annealed condition and ready for machining before oil-quench hardening. Thickness and width tolerances are held to +0.0100 to 0.0150 inches, and length tolerance is +0.25 inches. Edge squareness is maintained to 0.003 inches per inch across all edges. The piece weighs approximately 4.46 pounds. Tool and die makers, machinists, and metalworking tradespeople are the primary users of this material.\u003c\/p\u003e\n\u003cp\u003eO1 tool steel flat stock in this size range is well suited to fabricating punches, dies, gauges, fixtures, and cutting tools in both job shop and production tool room environments. The 0.25-inch thickness allows straightforward milling, grinding, and drilling operations prior to heat treatment. Once machined to near-net shape, the bar is oil-quenched to achieve the desired hardness. This size is appropriate for medium-scale tooling work where a wide, flat profile is needed without the cost of a full plate.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003eAISI Type O1 oil-hardening tool steel composition for predictable heat-treat response\u003c\/li\u003e\n  \u003cli\u003eTight dimensional tolerances: +0.0100 to +0.0150 inches on thickness and width\u003c\/li\u003e\n  \u003cli\u003eEdge squareness held to 0.003 inches per inch on all edges\u003c\/li\u003e\n  \u003cli\u003eLength tolerance of +0.25 inches allows trim-to-fit flexibility\u003c\/li\u003e\n  \u003cli\u003eSupplied annealed for full machinability before hardening\u003c\/li\u003e\n  \u003cli\u003eSingle-piece quantity available with no multi-piece minimum requirement\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eDesigned as a standard AISI O1 oil-hardening tool steel flat bar suitable for general toolroom and die-making applications requiring a 0.25-inch by 3.5-inch cross-section profile.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eMachining and heat treatment of O1 tool steel should be performed by qualified machinists and tool and die makers familiar with proper annealing, hardening, and tempering procedures. Secure the bar properly in a milling vise or on a surface grinder magnetic chuck before any material removal. Oil quenching should follow established shop procedures and applicable safety protocols for flammable quench media. Always relieve internal stress with a tempering cycle immediately after hardening to reduce the risk of cracking.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial\u003c\/strong\u003e: Tool Steel\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial Specification\u003c\/strong\u003e: AISI Type O1 Oil Hardening\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThickness\u003c\/strong\u003e: 0.25 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWidth\u003c\/strong\u003e: 3.5 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLength\u003c\/strong\u003e: 18 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThickness Tolerance\u003c\/strong\u003e: +0.0100 to +0.0150 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWidth Tolerance\u003c\/strong\u003e: +0.0100 to +0.0150 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLength Tolerance\u003c\/strong\u003e: +0.25 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eEdge Squareness\u003c\/strong\u003e: 0.003 inches per inch, all edges\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 4.46 pounds\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eUNSPSC Code\u003c\/strong\u003e: 31231200\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eStandard Information\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: STARRETT\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: 56981\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"STARRETT","offers":[{"title":"Default Title","offer_id":51539410387250,"sku":"56981","price":270.49,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/6555d28ffd7e02d6cc316d25961d7428_78009552-3dda-41b8-b918-f15d6a3b22fb.jpg?v=1785839567","url":"https:\/\/voomisupply.com\/products\/starrett-56981-o1-tool-steel-flat-stock-1-4x3-5x18-in","provider":"Voomi Supply","version":"1.0","type":"link"}