A old friend of mine once told me that he made himself a granite surface plate using a combination of lapping and scraping 3 pieces of broken granite worktop. Apparently he was able to bring it to an “astounding level of flatness” (in his own words).

Whilst I don’t have the time or patience to do this I still think its very interesting and would like to know more.

Whilst I understand the principle, does anyone know anything about the process or is able to point me to a guide/book/website.


Cheers

Liam Mc

Have a look at this description, it is pretty simple if you already have a reference surface plate - it is basically what I've done in the past (I've only done metal ones though).

http://gfish.livejournal.com/187606.html

Or I believe photocopier glass is flat enough to basically be a surface plate for most uses and can be had for next to nothing from a scrap photocopier.

Regards
Hugh

Depends on how much you need to do but whenever I've needed to surface small items (bike carbs etc.) I've visited the local glass shop and bought an off-cut of plate glass.
Combined with valve grinding compound - coarse and fine the results are pretty good.
HTH.
Cheers, Pewe10
PS No news on the Animal - sorry.

Yes, standard plate glass is all that is required.

Thanks guys, interesting stuff.


Animal has gone @Pewe

I believe that the point of using 3 plates is that you don't need a separate reference plate. You start with 3 plates, make them as flat as possible with the resources available (mill, surface grinder, etc.) then use one against another across all of the plates. Plate A is used with blue against plate B, then A against C, B against C, over and over until you end up with 3 good surface plates.

Found a description! linky - there's a vague description near the bottom of the page.

I do know that scraping a surface is a skill I don't have - I tried it once, and found it much much harder than it looks when an expert does it (like many skills!)

[Edited on 8/7/14 by David Jenkins]