Do I have Carbon Steel or ?

[Doug Wolf]

I have an old "Habor Freight" 1"x5/32" wood skew blade about 4" long that I want to use for a scraper blade in my hollowing bar for wood.
I cut the first piece off of the end about 2" back with a hacksaw. I started to make another 2" cut just before the tang and the saw blade lost most of its teeth. I ended up scoring the blade with a file and snapping the blade into. I was able to drill a 3/16" hole in the middle of both pieces with a high speed twist drill.
Why was the tang end of the blade "harder" than the sharp end? I hadn't gotten it hot when I sharpened the scraper, so I don't think it lost its "temper", I just think it never had any.
Anyway, now I've got my two pieces but I'm concerned they are not going to hold an edge. Can I heat treat them to make them harder? Are they worth the trouble? Should I start over with some better material?
Thanks for any help you can give me.

[Chris Fournier]

This sounds like work hardening to me. I've ruined a few saw blades in a similar fashion.

[David Weaver]

Maybe the tang end was heat treated and never tempered.

[Steve Ryan]

You can tell the type of steel by a spark test if you have access to a chart. Different steel type have a tell tale spark from a grinding wheel. Sounds like the piece was hardened but was given an un even temper. I bought some chisels once that refused to hold an edge. Got nicked and minor edge bend over when pounded into a laminate counter I was demolishing. Sharpened it up and the same thing happened. After a while it held an edge. I guess that the original gring overheated the edge and ruined the hardness at the end.