another newbie question

[lukek655]

i was recently given some rather large industrial hacksaw blades. they measure about 1 1/4 inch from botom of tooth to top. they aren't a bi-metal blade that I can tell, my problem is that after grinding to shape and adding bevels with a bench grinder(all I have at the moment) I can't get any drill bit to dril holes. they got really hot while grinding any chance I hardened them while grinding. A new file skates off. should I go back and anneal them or what? HELP

 

[raylaconico]

You didn't harden them while grinding because hacksaw blades are already hard. They should be annealed before you try to drill a hole.

 

[lukek655]

thanks, it is some decent steel, at least going by the old spark test. i'll keep y'all updated on their progress.

 

[ciphery]

good luck on the anealing as most hacksaw blades are air hardeningHSS and nearly imposable to soften up.