Home > News > Content

Granite Surface Plate Specifications

- Jan 10, 2018 -


Granite Surface plate calibration is the only sure way to know that you are working with a level surface and can expect accurate workmanship when the surface plate is in use. Surface plates wear over time and must be properly maintained to ensure flatness and continued precision measurement.


Jinan Fortune Precision Machinery co.,ltd provides complete granite surface plate calibration for plates up to 14 ft. diagonal in our lab or on site throughout PA, NJ, DE and some surrounding areas.

The highly skilled technicians measure surface plate wear with a computerized calibration system using differential leveling feet. This system provides reliable surface evaluation with detailed diagrams showing measurement readings that clearly explain wear and deviation from the grade accuracy specification.

Our qualified team has a lot more to offer:

  • When needed, lapping or resurfacing is provided to bring measurements within grade guidelines. This procedure involves polishing the surface with an abrasive paste to remove all unwanted material. Our field service technicians have the ability to resurface to any grade needed by your quality system.

  • Granite surface plate calibration also includes cleaning and a light polishing.

Calibration services performed by LTI Metrology are A2LA accredited and the equipment used by our technicians has a NIST-traceable calibration. You’ll receive a Calibration Certificate showing:

  • Detailed results

  • Grade requirements

  • Any work completed to restore flatness

  • “As found” and “as left” conditions

Measurement during granite surface plate calibration includes checking for wear and deviation from the grade requirements. In many cases, proper resurfacing can bring the surface of the plate back within flatness tolerances. Flatness tolerances for standard grade surface plates AA, A and B are defined in federal specification GGG-P-463c.


Regular cleaning and covering when not in use will help protect your surface plate. Granite surface plate calibration should be performed routinely to maintain the proper flatness and ensure measurement accuracy over time. The intervals between each surface plate calibration should be based on the following:

  • Frequency of use (light usage will generally allow for longer intervals between each calibration)

  • Condition of the environment where the surface plate is located

  • Your company’s quality requirements.


  • On-site calibration in PA, NJ, DE and beyond

  • Calibration includes resurfacing, cleaning, light polishing and repair, when needed

  • Surface plates up to 14 ft. diagonal

  • Detailed diagrams with measurements explaining deviation from grade specifications are provided


The field team at Jinan Fortune Precision Machinery co.,ltd provides on-site granite surface plate calibration and resurfacing. During surface plate calibration, our technicians will measure both surface flatness and repeatability by taking measurements in locations across the surface. These reading will be used to determine deviation from the guidelines set for the grade of surface plate. Once low areas are identified, we will resurface the plate to restore flatness.

Both flatness and repeatability readings are critical steps in granite surface plate calibration to insure a precision surface that provides accurate measurement.

  • Flatness is measured using points on the surface contained within two parallel planes, the base plane and the roof plane. The measurement of distance between the planes is the overall flatness of the surface.

  • Repeatability is verified by measuring various local flatness areas across the surface to help guarantee that a measurement taken anywhere on the surface of a plate will repeat within the stated tolerance.

granite air bearing-00036.jpg

Related News

Related Products

  • Special Granite Surface Plate
  • Granite Surface Plate for CMM
  • Measuring Equipment
  • Granite Inspections
  • Granite Base for Laser Cutting Machine
  • Precision Black Granite Measuring Instruments with Grade00 of DIN, JIS or GB