who wrote....."I have a feeling that most older chisels were in the .9-1% carbon range,  and the alloy was only enough to improve the iron carbides and add some toughness to the matrix,  as I've never had a vintage tool that resisted sharpening stones. The idea about carbon content is based on having looked for carbides in worn edges on chisels and plane irons from ward.  There is little to nothing visible whereas 1.25% carbon steel makes a dense pattern of iron carbides in a worn matrix.  The odd thing is that they do nothing for wear resistance,  and even the small amount of chromium in 52100 increases wear resistance measurably and you can feel it on the stones, too."

It would be a dandy project to get some of these old tools and analyze their composition. It is trivial to do if you have the gear. I known where some is located....call Chuck Kettler....