surface plate

I doubt you will able to find a raw plate that has that sort of accuracy. It would have to be machined in some form or other. Also, unless the place the place will be used is highly temperature controlled you probably wouldn't want to use a metal plate or anything else that will expand or contract with temperature changes.

thanks for the response

but if i have to machine a surface plate of such tolerance than would u please suggest me any one of methods, if u have any idea. i think i am gonna use graphite for surface plate..

I couldn't even begin to suggest a surface material for such close tolerances. All I know is that any type of metal plate wouldn't be able to have such tight tolerances without a very temperature controlled environment.

You can buy them Guest, but the cost for that size would be large... also the weight of the cast iron would be in the region of several tonnes and would need a room with substantial foundations so as not to cause movement etc...

Far cheaper to get a custom one made for your particular job... Then you can have several set points at your tolerance without the mass of a huge flat casting...

If you still need to get hold of a one piece surface plate of that size then start enquiring about snooker table manufacturers and what their tables need in the way of special flooring and then double that figure to get something close to what you are asking for.

John.