Granite Surface Plates | Surface Plate | Gmt Surface Plates

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GRANITE SURFACE PLATES

It contains the specifications for rectangular or square granite surface plates in four accuracy levels, with desired sizes ranging from 160 mm x 100 mm to 2500 mm x 1600 mm. That is grades 0 through 3. According to their grade, it applies to granite surface plates that are brand-new, those that are already in use, and those that have been refurbished.

Material

The surface plates must be constructed from durable, workable rock that doesn't tend to damage steel surfaces and has a wear-resistant surface. For the purposes of this standard, surface plates composed of stable igneous rocks, such as diabase and gabbro, that have a uniform texture, are sound, are finely grained, and are devoid of cracks and fissures must fall under the category of granite surface plates. It is not permissible to repair surface flaws. The granite's color is unimportant, but each plate's color must be consistent.

Preferred sizes

The table below shows the preferred sizes when taking them into consideration. The side lengths of plates must be within 5% of the specified nominal size. ...
... All measurements and tolerances are in millimeters. The pertinent requirements of this standard must be followed, though, if plates of other sizes are necessary.

Support

A Granite surface plate needs to be supported at three spots, ideally 20 percent of the plate's length in from the ends. The remaining support should be centered, with the other two supports placed 20% of the width away from the long sides. Only three points can firmly rest on any surface other than a precise one. Safety feet must be added to plates that are larger than 1000mm X 630mm.Only precise leveling is required if the plate is properly supported. To maintain the accuracy of a properly supported plate, leveling is not required.