I recently came into a 1245mm x 750mm cast iron surface plate. Unfortunately moisture had got under the cover and a lot of spots where heavily pitted the plate also had a number of scratches in it. It weighs 280kg so before I unloaded it at my place I took it to get surface ground it should be back within a week.

I would eventually like to scrape if flat enough to use to scrape straight edges and the like. I am investigating methods that allow scraping plates from smaller reference surfaces. I know this is possible and in fact a common on really large machine tools. I have found this video which shows the use of only a straight edge and an autocollimator to scrape a surface plate https://www.youtube.com/watch?time_c...ature=emb_logo unfortunately its not in English so the explanation of the technique is not clear.

Can anyone explain the method used here and are does anyone else know of other methods for scraping a larger plate from smaller reference?

Regards

Eric


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