The Granite Cube is essential in inspection, maintenance, calibration, and assembling areas to inspect and calibrate perpendicularity and parallelism. Also, you can use Granite Cubes to check machine alignment and for component inspection. Further, you can use them as a reference to accurately measure the straightness, squareness, and parallelism of multiple axes of any machine.


All six faces of the granite cube are accurately lapped using a GMT lapping machine. These are of very high quality. A wide range of customers use GMT Lapping Machines to lap an extraordinary variety of materials, from silicon wafers and granite to gold. For more information on these machines, please click here. As a result, you can be very confident in the cube’s quality and the flatness and squareness of the reference surfaces.

Also, we provide through holes to reduce the weight of the cube and for easy handling. Besides, we provide tapped inserts, on request.


  • Made from the highest quality Indian Black Granite used in metrology
  • All faces are accurate, opposite sides parallel and adjacent sides perpendicular to each other
  • All edges and corners are rounded
  • We provide finer accuracies on request
  • We provide storage case on request
  • Ideal for measuring the straightness, squareness, and parallelism of 3 axes of any machine

We make Granite Cubes in a wide range of sizes. The largest we have made are 1000 x 1000 x 1000(in mm) with the following Accuracy:

  • All faces Flatness, Squareness & Parallelism 5 micrometers.
  • Besides Granite Cubes, GMT manufactures Surface Plates, Angle Plates, Box Angle Plates, Straight Edges, Bench Centres, and other metrology products. Please refer to the photo on top.


We also check every cube we produce with digital inspection equipment. The calibration of this equipment is to NABL* Standards. This means the parameters are traceable.

*NABL – National Accreditation Board for Testing & Calibration Laboratories

Finally, please visit us at– a new blog dedicated to all GMT customers…interact with our technical experts.