GMT Precision Surface Plates

GMT Metrology Precision Surface Plates are made to DIN and IS Standards. They can also be made to conform to Standards as requested by the customer.


A rigorous quality control inspection is carried out at all stages. Similarly, a final inspection is carried out at a High Precision Computerized Electronic Level calibrated by a NABL accredited lab at regular intervals.

Accuracy Under Load

Granite Surface Plates can support a total normal load of 25 kgs. per 0.1 sq. m.


Each plate comes with a certificate of accuracy as per standards in the specification. GMT’s inspection equipment to certify its plates is NABL certified.

* NABL – National Accreditation Board for Testing and Calibration Laboratories.

Technical Data – Precision Surface Plates

GMT Granite Surface Plates are available in five grades. The typical application of these five grades of plates is as under:

GRADE 00 as per DIN : 876 : 84 is of laboratory grade. Hence, it is specified for precision measurement in gauge rooms and metrology laboratories.

GRADE 0 is of inspection grade. It is specified for general work in quality control.

GRADE 1 is of tool room grade. It is specified for production checking work through the shop.

GRADE 2 & 3 are intended for use in shops for general inspection.


GMT uses select granite with uniform distribution of light and dark constituents to manufacture precision surface plates. Hence, in such granite, the distribution of minerals is even, resulting in a homogenous appearance. The following are the representative properties of our granites:

Texture : Fine

Specific Gravity : 3.08 g/cm3

Hardness : Scleroscope over 90

Modulus of Elasticity : 9.0 to 12.0 x 105kg/cm2

Moisture of absorption : Nil

Flatness Tolerance: The flatness deviation of a local area of 250 mm x 250 mm of the working surface shall not exceed :

3.0 µm for plates of Grade 00

3.5 µm for plates of Grade 0

7.0 µm for plates of Grade 1

15.0 µm for plates of Grade 2

30.0 µm for plates of Grade 3


Above all, the co-efficient of expansion of Granite is among the lowest for natural materials.

Granite does not rust nor corrode or react chemically with other substances.

It may chip but will not develop a burr.

Also, it is easy to keep clean.

Granite Surface Plates Stands.

These are fabricated of heavy angle iron and reinforced to ensure rigidity. Also, the design of the stand withstands the weight of the granite surface plates and comes with three levelling screws for levelling the granite surface plates.

Optional Accessories

Suitable Rexine Cover to protect both the plate’s working surface and side faces at extra cost.

To meet special requirements, we offer:

Bigger size Granite Surface Plates with extra thickness.

Surface Plates with inserts with drilled and tapped holes.

Straight Edges.

Master Squares.

Granite Cubes.

Master Cylinder made of hardened and ground steel.


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