That is better than I would have expected but in reality no where near enough for a machine tool such as a mill or a lathe even if you do manage to get it as good as 0.02mm. I think I remember you saying it was a granite cutter you have, that kind of accuracy is more than likely much better than you need
Hood

thanks a lot
can u help me for the accurate and best way for home switch r it limit or proximity switch or photocell or other

probably an optical switch would be the most accurate but it would depend on the environment whether it would be the best. If there is a lot of dirt and dust then and optical would need to be enclosed and the flag operated by a plunger which exits from the side of the encosure so that dust isnt a problem.
 You may be better with a prox switch if it is no magnetic material you will be cutting, they can be accurate as well.
Hood