There are four grades of surface plates.
Granite surface plate grades.
Granite surface plate have more rigidity for the same depth with the absence of corrosion.
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.
Grade s aa and a are the flattest with a flatness tolerances better than 0 00001 in for a grade aa plate.
Laboratory grade aa and a room inspection grade b and the fourth is workshop grade.
Workshop grades being the least flat and as the name suggests they are intended for use in tool rooms.
Types of surface plate.
Plates that have ledges are used for clamping purposes only.
Cast iron surface.
Surface plate grades and it s types basic terminology in surface measurement.
Flatness is define by the distance between peak and depth point of surface.
Our granite surface plates are manufactured in three ledge types as well as standard sizes and grades.