Value Collection 640-0422 Granite Surface Plate a Grade

Product Description

The VALUE COLLECTION 640-0422 is an A-grade granite inspection surface plate designed to provide a precise, stable reference surface for dimensional measurement and layout work. Machined from solid black granite, it measures 18 inches long, 12 inches wide, and 3 inches thick, weighing 80 pounds. The plate holds a unilateral flatness tolerance of 0.000050 inches, meeting A-grade requirements for close-tolerance inspection tasks. A Certificate of Conformance is included to support quality documentation requirements. Machinists, tool-and-die makers, quality technicians, and metrology personnel use this type of plate as the foundation for height gauging, part layout, and CMM reference work.

This surface plate is suited for use in machine shops, manufacturing facilities, inspection rooms, and toolrooms where repeatable, accurate surface reference is required. The 2-ledge base design allows for stable bench mounting and makes it easier to clamp or fixture work to the plate surface. At 80 pounds, the plate provides inherent rigidity and vibration dampening during measurement setups. It is appropriate for both production inspection environments and quality lab settings handling small to medium workpieces that fit within its 18 inch by 12 inch work surface.

Key Features

• A-grade flatness tolerance of 0.000050 inches for precision inspection work
• Solid black granite construction for natural rigidity and thermal stability
• 2-ledge base provides stable bench support and clamping access
• 18 inches x 12 inches work surface accommodates a wide range of small to medium parts
• 3 inches thick for added mass and vibration resistance
• Certificate of Conformance included for quality documentation

Compatibility

Designed as a standard A-grade granite reference surface plate for use with conventional height gauges, dial indicators, V-blocks, angle plates, and surface plate accessories used in dimensional inspection and layout applications.

Installation Notes

Surface plates should be installed by qualified metrology or toolroom personnel on a flat, level, and stable bench capable of supporting the full 80-pound plate weight without deflection. Clean the granite surface with an appropriate stone cleaner before first use and avoid placing the plate where it will be exposed to direct sunlight or HVAC airflow, as temperature gradients affect flatness accuracy. Never use the plate as a hammering surface or allow hard impacts, as granite is brittle and chips will compromise flatness. Periodically re-certify the plate per your shop calibration schedule to confirm it continues to meet A-grade tolerance requirements.