Yeah, and it was being done a lot further back than "the turn of the
century". Sir Joseph Whitworth was one of the first to publicize flat and
straight edge making, but it didn't originate with him, probably. For
details, get one of Lindsay's books, "English and American Tool Builders"/

Bob Swinney

"Dave Baker" wrote in message
...
Subject: Early surface plates: How were they made?
From: (Chris Lindquist)
Date: 21/08/03 20:43 GMT Daylight Time
Message-id:

I've been trying to find out exactly what process was used for
originating a surface plate in the good old days. I expect it involved
careful hands and a large amount of scraping, but what provided a
reference for "flat"? And how flat was flat around the turn of the
century?

I'm not planning to try this at home, of course. My Chinese granite
plate is plenty flat enough, thanks. But I've been going through my
books looking for an answer to this chicken-and-egg question without
finding a solution.

Can anyone help?

By lapping 3 plates against each other with grinding paste until all three
are
flat. The same way as reference plates are made now. The ancients could
make a
plate as flat as we can now. The technique requires no special technology.


Dave Baker - Puma Race Engines (www.pumaracing.co.uk)
I'm not at all sure why women like men. We're argumentative, childish,
unsociable and extremely unappealing naked. I'm quite grateful they do
though.