Granite plate is precision measuring tool made by natural stone material. It has the ideal datum to inspect instruments, precision tools and mechanical parts, especially for the high-precision measurement. Granite plate originated from underground high quality rock. Through eons' natural aging, its form is very stable. Don't need to worry about deformation caused by normal differences in temperature. Granite plate through strict physical test and the selected granite material has close grain and hard texture. As granite is nonmetallic material, so there is no magnetic field reaction and plastic deformation. The hardness of granite plate is high, therefore precision retaining ability is good.
Granite plate: when using stone tool, it just drops several rubbles at most when knock by heavy objects. Granite plate is better than high quality cast iron and steel precision measuring datum part, so it can get high and stable accuracy.
Characters and advantages of granite plate:
1. Through eons' natural aging, the structure of stone is symmetrical. Coefficient of inertia expansion is dinky. Innerstress all disappear. No deformation. So the precision is high.
2. Good rigidity, high hardness, high abrasive resistance.
3. Won't has scratch. No homothermic condition limitation.
4. No magnetization. It can move smoothly when measuring.