{"product_id":"spi-12x18x3-a2-granite-surface-plate-grade-a-2-ledge","title":"Spi 12X18X3-A2 Granite Surface Plate Grade a 2-ledge","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\u003cp\u003eThe SPI 12X18X3-A2 is a Grade A black granite inspection surface plate used as a precision reference datum in dimensional measurement and quality control applications. Measuring 18 inches long by 12 inches wide by 3 inches thick and weighing 75 pounds, this plate provides a stable, flat reference surface for layout, inspection, and gauging work. The unit holds a unilateral flatness tolerance of 0.000050 inches, meeting the exacting requirements of precision metrology environments. Two accuracy certificates are included with each plate, and NIST traceability is provided. It is typically set up and used by machinists, quality technicians, and metrology professionals.\u003c\/p\u003e\u003cp\u003eThis surface plate is suited for use in machine shops, quality labs, and manufacturing inspection stations where a reliable flat reference is required. The 2-ledge configuration provides convenient support and positioning on a stand or bench surface. The black granite construction resists corrosion, does not burr, and maintains dimensional stability across normal shop temperature ranges. The included accuracy certificates support documented inspection processes and audit requirements.\u003c\/p\u003e\u003ch4\u003eKey Features\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003eGrade A flatness with 0.000050 inch unilateral tolerance\u003c\/li\u003e\n\u003cli\u003eBlack granite construction for corrosion resistance and dimensional stability\u003c\/li\u003e\n\u003cli\u003e2-ledge design for stand or bench mounting support\u003c\/li\u003e\n\u003cli\u003eNIST traceability certification included\u003c\/li\u003e\n\u003cli\u003eCompliant with ASME B89.3.7-2013, GGG-P-463c, ISO 17025, and ISO 9001\u003c\/li\u003e\n\u003cli\u003eTwo accuracy certificates included with each unit\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eCompatibility\u003c\/h4\u003e\u003cp\u003eDesigned as an OEM-style precision reference surface for use with standard surface plate stands and inspection bench setups sized for 12 inch by 18 inch granite plates.\u003c\/p\u003e\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\u003cp\u003eSurface plates should be installed and leveled by a qualified metrology technician or machinist. The plate should be positioned on a rigid, vibration-free stand or bench capable of supporting 75 pounds, with all three ledge points making consistent contact. Avoid dragging abrasive objects across the surface and protect the plate from thermal shock and impact. Periodic recertification of flatness is recommended to maintain measurement integrity.\u003c\/p\u003e\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOverall Length\u003c\/strong\u003e: 18 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWidth\u003c\/strong\u003e: 12 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThickness\u003c\/strong\u003e: 3 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 75 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial\u003c\/strong\u003e: Granite\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eColor\u003c\/strong\u003e: Black\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePlate Type\u003c\/strong\u003e: 2-Ledge\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGrade\u003c\/strong\u003e: A\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUnilateral Flatness Tolerance\u003c\/strong\u003e: 0.000050 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTraceability\u003c\/strong\u003e: NIST\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandards\u003c\/strong\u003e: ASME B89.3.7-2013, GGG-P-463c, ISO 17025, ISO 9001\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIncludes\u003c\/strong\u003e: Two Accuracy Certificates\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eStandard Information\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: SPI\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: 12X18X3-A2\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SPIROTHERM","offers":[{"title":"Default Title","offer_id":51716192174386,"sku":"12X18X3-A2","price":496.63,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/32c3f4b0e28a3db22f0d4b24b1c9a227.jpg?v=1788522930","url":"https:\/\/voomisupply.com\/products\/spi-12x18x3-a2-granite-surface-plate-grade-a-2-ledge","provider":"Voomi Supply","version":"1.0","type":"link"}