Workshop grades being the least flat and as the name suggests they are intended for use in tool rooms.
Granite surface plate grades.
Our granite surface plates are manufactured in three ledge types as well as standard sizes and grades.
Flatness is define by the distance between peak and depth point of surface.
Asme b89 3 7 defines standardized tolerance grades for surface plates.
Surface plate grades and it s types basic terminology in surface measurement.
Cast iron surface.
Granite surface plate have more rigidity for the same depth with the absence of corrosion.
The highest accuracy plates are called grade aa and they are often found in calibration laboratories.
Grade s aa and a are the flattest with a flatness tolerances better than 0 00001 in for a grade aa plate.
The middle grade plates grade a are often used in inspection areas.
Grade b plates are the lowest accuracy plates and they might be found on shop floors.
There are four grades of surface plates.
Plates that have ledges are used for clamping purposes only.