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WE ARE MANUFACTURING OF GRANITE / CAST IRON SURFACE PLATES AS PER IS 7327-2003 AS PER IS STANDARDS. WE ARE SELECTED QUALITY GRANITE STONE AS PER IS 7327-2003 PROPERTIES.
Surface plates complying with this part of ISO 8512 shall be made from stable, workable rock presenting a wear-resistant surface which does not tend to scratch steel surfaces. Igneous rocks such as diabase, gabbro and various other granites have been found suitable; they are commonly referred to STANDARDS.
The thickness of granite surface plates shall be such that when a concentrated load is applied about the centre of the plate, the loaded area shall not deflect below the remaining area of the plate by more than 1 pm/200 N. The limiting value for deflection applies to surface plates of size 400 mm x 250 mm and larger.
The top (working surface) of grades O and 1 plates shall be finished by lapping, whereas grades 2 and 3 plates may be finished by lapping or left as ground. However, an item placed on it shall not wring to the surface of the plate.
Two flatness tolerances are applied, one for the working surface overall and one for any local area of 250 mm x 250 mm of the working surface. A border zone, the width of which shall not exceed 2 “A of the shorter side with a maximum of 20 mm, may be excluded from these requirements for accuracy provided that no point on the border zone projects higher than the remaioder of the working surface of the plate.