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Surface Plate Grades and it’s types

Surface Metrology specify the function of the surface. The important parameter is surface roughness.In manufacturing industries, a surface must be within certain limit of roughness.

Video of Surface Plate


Therefore, measuring surface roughness is vital to quality control of machining a work-piece.

granite surface plate

By Surface Measurement, we can predict the performance of the component and control the manufacturing process.  

Basic Terminology in Surface Measurement


Flatness is define by the distance between peak and depth point of surface plate.


It is the property of a solid body to resist deformation.


It is the process of Level the table by it’s support system.

pink granite surface plate
Grade-00 surface plate

Types of Surface Plate

According to Material used, There are three types of Surface Plate

  1. Granite Surface Plate(IS 7327,ISO 8512-2)
  2. Cast Iron Surface Plate(IS 2285,ISO 8512-1 )
  3. Glass Plate(IS 14900)

Granite Surface Plate

Granite surface plate have more rigidity for the same depth with the absence of corrosion. They provide a high modulus of rigidity and are moisture free.

Metallic objects like manufactured components/jobs can easily slide on their surface. The usual range available from 400*250*50 mm to 2000*1000*250 mm.

surface plate grade 0

Grading System

Grade-00 (Prefer for Metrology laboratories )
Grade-0 (Prefer for General work in Quality Control)
Grade-1 (Prefer for tool room)
Grade-2 (Used for Shop Flore)
Grade-3 (Also, used for shop Flore depend upon needs of customer )
grading system of granite surface plate

Cast Iron Surface Plate

Cast-Iron surface plates used after rough machining is done followed by seasoning for suitable period. Then, heat treatment for relive the internal stress.

CI surface table
CI Surface table

The accuracy of this surface plate is +/- 0.002 mm to +/-0.005 mm for the surface plate diagonal of 150 mm.

CI surface plate available in 2 grades,

Grade-1 (Maximum flatness is 5 microns for 300mm*300 mm plate)

Grade-2 (Maximum flatness is 20 microns for 300mm*300 mm plate)

Glass Surface Plate

Glass surface plate commercially available. These are comparatively light in weight and free from burr and corrosion.

Accuracy varies in the range 0.004 to 0.008 mm. They are available in size of 150mmx150mm to 600mm*800mm.

Measurement of Surface roughness

Inspection and assessment of surface roughness of machined work-piece can be done by different measurement techniques.

  1. Pocket Surf
  2. Electronic Level

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