Tony called our attention to a type  _machinist scraper_ 

> But see
> 
> http://store.apextoolgroup.com/nicholson-
21667n-3-1-4-machinist-s-scraper.html">http://store.apextoolgroup.com/nicholson-
21667n-3-1-4-machinist-s-scraper.html
> 
> for a Nicholson bearing scraper of the same form as  your Hirsch tool. 
 
Now, note that ad says "MACHINIST SCRAPER". No where does it say a word about
bearings !!!
 
If the bearing was wide, that scraper would not be of much use. On a wide
bearing, you'd only be able to scrape with the curved part right near the tip.
It could readily scrape narrow bearings such as the poured babbit in early auto
engines, but only up a width corresponding to the straight part of the edge.

> The answer may come down to whether your find has a convex, flat or  
> hollow grind on the faces.
 
This, I think is "the rub".  The convex creates a "relief" on the back of the
blade which I think is vital to scrape Babbitt to a smooth surface. The flat-
sided, sharp-arrised scrapers may in indeed be scrapers, but they are not
_bearing_ scrapers. They will do general scraping such as deburring, but aren't
going to make a fine surface on Babbitt. That's my uninformed opinion and I'm
sticking to it! (But, see below, because open-minded John just found a
counterexample.)
 
Now, just to muddy the very waters I indended to clarify, I present this for the
Porch's perusal:
 
http://www.csosborne.com/brscr
ape_1.htm
 
and, the "killer" reference:
 
http://www.csosborne.com/no29B.htm">http://www.csosborne.com/no29B.htm
 
Because, here, BOTH hollow-ground ( concave ) and flat-sided triangular scrapers
are referred to as "bearing scrapers".  !!!
 
So, now I think we are all, all of us, correct. 
 
 
 
 
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