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saws and in particular the steel in them.  I would suggest, based on 
what has been written, that more reading on metallurgy, steel making 
and the history thereof would be a better use of your time that 
posting.  I am posting some comment in the hope of clearing up this 
discussion.

Saws for hand wood working are and have been almost exclusively made 
of what is know as high carbon or spring steel.  Variation in what is 
known as alloying elements (e.g. Cr, Ni and only if very high Mn & 
Si) have little to no effect on properties of these steels as used. 
Leaving aside the back saw carbon content and hardness for latter, 
the result presented as typical of what would be expected and my 
feeling was so what.

The next point is the question of the use of the word quality with 
regard to steels (tool) before the Second World War.  Trade names 
were used to indicate what they consider the important considerations 
with regard to carbon steel which included: iron source (effected P 
content), what process was used to make them (e.g. cast steel which 
was made in small well controlled batches), surface conditioning 
prior to and during forging or rolling, and in generally those 
factors which were believed to affect uniformity and toughness of the 
steel.  Steel were purchased (produced), based on experience, with 
particular trade name steels, because it was not known exactly what 
effected toughness and useability. and therefore experience was the 
only guide.  In some cases trade names also indicated aim carbon 
content but this has no bearing in this case.

Therefore it would have been much more informative if the initial 
work by Eric had included those factors effecting quality 
specifically S and P content, microstructure (including inclusion 
type and content) and perhaps analysis for the gasses. Back to the 
back saw, I think that the carbon content and hardness differences 
just indicates that there was more variability in steel circa 1850 
than latter.

If desired, by enough galoots, I could go thru all the responses that 
have been made, on a point by point basis, but I doubt it is worth 
the time required.

jim
(James ME Wallbridge P. Eng.) Libertarian, Metallurgist, Wood & Metal 
Worker, Fly Fisher,  Resident of Calgary,  Canada's new head office 
location of choice.  Permission is hereby given to use any 
information herein, as an attributed quote, unless the body of the 
message states otherwise.