On 13 Oct 2003 11:54:19 -0400, Allan Adler wrote:
If I understand correctly, what I need to do hand scraping is:
(1) a piece of metal to scrape
(2) a 3 cornered scraper
(3) bench level with milled surfaces (instead of an expensive surface plate)
(4) Prussian blue oil paint

A 3 corner scraper is used to scrape or deburr internal holes (diameters).
It is not used to scrape flat surfaces. For scraping flat surfaces, you need
something that looks more like a paint scraper, except that the handle
will be stronger and longer, and the cutter blade will be high speed steel
or a tungsten carbide insert.

You can grind the end of an old file to the correct profile to make a
cheap scraper, though the high carbon steel won't hold up as well as
a carbide insert, and the file body may be too brittle to withstand the
required pressure. You could also make a holder for a carbide insert,
though that would require a bit more work. You can buy commercial
scrapers, though it is a bit of a specialized tool and you may have to
search a bit to find one.

Gary