The main differences between cast iron surface plate and granite surface plate are raw materials and processing methods. The raw material of cast iron surface plate is cast iron which is usually gray cast iron or alloyed cast iron. The normal processing method is finish-milling or hand-scraped. The surface of scraped surface plate can store lubricant oil and hold dust, so the reliability and stability are improved in some extent. The cast iron surface plate can regain its precision grade through re-scraped. We can test the cast iron surface plate which is processed through finish-milling by spirit level. Scraped surface plate can inspect the components’ flatness by coloring method; it is accurate, intuitive and convenient. It’s smoothly to pull the gauge stand and workpieces on the scraped surface plates’ surface, so it provides the workers with convenience and measuring precision. The quality of raw material and heat treatment of Cast iron surface plates influences the using performance greatly.

The granite surface plate is made of granite. The granite has the features of fine particles and dense structure. The processing method is saw cutting, drilling and then well planed. The granite surface plates are wear stability; the advantages are precision stability and easy maintenance. On the other hand it can not withstand banging and impact, it is high humidity and easy to deform. The hygroscopicity is 1%.