Surface Plate Calibration

Written by Rahul Verma | Updated: September 18, 2025

Granite Surface Plates Maintenance

For plates up to 14 feet diagonal, Infinita Lab offers complete granite surface plate calibration in our lab or on location within a 100-mile radius. Using differential levelling feet and a computerized calibration system, highly qualified professionals measure the wear on surface plates. This technology carries out a trustworthy surface evaluation and generates thorough diagrams of measurement readings that explain wear and deviation from the grade accuracy criterion in great detail.

Cleaning before measurement and a little polishing following surface plate calibration are among the quick and dependable services offered by Infinita. Granite plates can be lapped or resurfaced as necessary to bring measures into compliance with grade standards. During this process, the surface is polished using an abrasive paste to get rid of all debris. Our field service specialists can resurface plates to any grade required by your quality management system.

Infinita Lab offers A2LA-accredited surface plate calibration services, and the tools our specialists use have NIST-traceable calibrations. Following the service, a calibration certificate is created that includes grade requirements, “as found” and “as left” conditions, and a thorough explanation of the work done to restore flatness. Depending on the frequency you select, we will email you a reminder notification when it is time for calibration.

Checking for wear and grade requirement deviations is part of the measurement during surface plate calibration. In many instances, appropriate resurfacing can return the plate’s surface to within the acceptable range of flatness. Federal specification GGG-P-463c specifies the flatness limits for standard-grade surface plates AA, A, and B.

Taking good care of your surface plate

Your surface plate will be better protected if it is cleaned frequently and covered when not in use. To maintain the right flatness and assure measurement accuracy over time, calibration should be done regularly. The frequency of use and the state of the environment where the surface plate is positioned should be taken into consideration when determining the interval between each surface plate calibration when it is not mandated by a company’s quality requirements. Longer intervals between calibrations are often permitted with minimal usage and a clean environment.

Infinita Lab Capabilities

Granite surface plates up to 14 feet diagonally can be calibrated
Resurfacing, cleaning, light polishing, and repair are all included in the service.
There are provided elaborate graphics with measurements to illustrate deviation from grade criteria.

The Process Of Surface Plate Calibration

Infinita Lab’s field crew offers granite surface plate calibration and resurfacing on-site. During calibration, our professionals will take measurements all over the surface to determine the surface’s flatness and repeatability.

The base plane and roof plane are two parallel planes that contain points on the surface that are used to determine how flat something is. The overall flatness of the surface is determined by the distance between the planes. A grade name and a tolerance are frequently included with the flatness measurement. The divergence from the standards established for the grade of the surface plate will be assessed using these readings.

A measurement taken anywhere on the surface of a plate will repeat within the stated tolerance if repeatability is verified by measuring various local flatness zones across the surface.

To provide a precise surface that delivers precise measurement, granite surface plate calibration must include both flatness and repeatability readings. We will resurface the plate to bring it back to flatness once we have located any low areas.

Video 01: Surface Plate Calibration