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Granite Surface Plate

18“ x 12” ( 450mm x 300mm ) Grade AA Granite Surface Plate

It is flat to within 1 micron.

It is to be used as a surface for accurate measurements and for testing flatness with engineers micrometer or bearing blue ( not the blue used for marking out surfaces ).

Scratching the surface will ruin it so it is not to be used for lapping, cutting, bashing, or as a general purpose bench surface.

It is HEAVY, 30kg, and not attached to the small crate it's standing on.

Explanatory A4 Label for the top cover of the surface plate

Side warning label for the surface plate cover

Instructions

Do not allow dirt or dust to get on the surface, it will scratch the plate and ruin it. Wipe with a clean dry lint free cloth every time it is used, before using it and before placing anything on it.

Make sure any metal surfaces are smooth before placing them on the surface plate, check by feeling the surface with your finger or the back of your hand, smooth with fine emery if necessary.

Place items on the plate carefully to avoid chipping or scratching the plate.

Do not attempt to polish out or otherwise remove scratches. Granite plates do not form a raised burr like metal plates and any attempt at repair will ruin the local flatness.

Clean off engineers blue with Isopropylalcohol and let the plate dry.

Keep the plate covered when not in use

Hand scraping info

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