{"product_id":"starrett-56990-o1-tool-steel-flat-stock-5-16x1x18-in","title":"Starrett 56990 O1 Tool Steel Flat Stock 5\/16x1x18 in","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\u003cp\u003eThe STARRETT 56990 is an O1 oil-hardening tool steel flat stock bar used in toolmaking, die work, punches, and precision machining applications. It measures 5\/16 inches thick, 1 inch wide, and 18 inches long, and is manufactured to AISI Type O1 material specification. Thickness and width tolerances run from +0.010 to +0.015 inches, length tolerance is +0.250 inches, and squareness is held to 0.003 inches per inch on all edges. The stock ships in an annealed, machinable condition ready for machining, grinding, and subsequent oil-hardening heat treatment. Machinists, tool-and-die makers, and toolroom technicians are the primary users of this material.\u003c\/p\u003e\u003cp\u003eO1 tool steel flat stock is suited for low-to-medium production tooling where oil-quench hardening is the chosen heat treatment method. Typical applications include blanking punches, forming dies, drill jigs, gauges, and small machine parts requiring a hardened working surface. This bar stock is commonly used in job shops and toolrooms handling one-off and short-run tool fabrication where tight dimensional tolerances on raw stock reduce pre-machining setup time.\u003c\/p\u003e\u003ch4\u003eKey Features\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003eAISI Type O1 oil-hardening tool steel for predictable, controlled heat treatment response\u003c\/li\u003e\n\u003cli\u003eTight dimensional tolerances: +0.010 to +0.015 inches on thickness and width\u003c\/li\u003e\n\u003cli\u003eSquareness held to 0.003 inches per inch on all edges for accurate layout and setup\u003c\/li\u003e\n\u003cli\u003e18-inch length with +0.250-inch length tolerance provides usable stock with minimal waste\u003c\/li\u003e\n\u003cli\u003eAnnealed condition allows machining, drilling, and grinding before hardening\u003c\/li\u003e\n\u003cli\u003eSingle-piece minimum order quantity suits low-volume toolroom and prototype work\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eCompatibility\u003c\/h4\u003e\u003cp\u003eDesigned as a standard AISI O1 oil-hardening tool steel flat bar compatible with conventional toolroom heat treatment processes requiring oil-quench hardening.\u003c\/p\u003e\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\u003cp\u003eMachining and grinding operations should be completed before heat treatment. Oil-hardening heat treatment of O1 tool steel should be performed by a qualified heat treater or toolroom professional following established metallurgical procedures. Use appropriate personal protective equipment when handling during and after heat treatment. Post-hardening grinding operations should account for scale removal and final dimensional finishing.\u003c\/p\u003e\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\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: 5\/16 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWidth\u003c\/strong\u003e: 1 inch\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: +0.2500 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSquareness\u003c\/strong\u003e: 0.003 inches per inch, all edges\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 1.59 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUNSPSC Code\u003c\/strong\u003e: 31231200\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eStandard Information\u003c\/h4\u003e\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: 56990\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"STARRETT","offers":[{"title":"Default Title","offer_id":51540427702578,"sku":"56990","price":141.32,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/6555d28ffd7e02d6cc316d25961d7428_d33ac779-14f4-4743-a242-43bc3ffc8391.jpg?v=1785854857","url":"https:\/\/voomisupply.com\/products\/starrett-56990-o1-tool-steel-flat-stock-5-16x1x18-in","provider":"Voomi Supply","version":"1.0","type":"link"}