"EW" wrote in message
...
I'm assuming that new lawn mower blades are sharpened, then hardened
before
sold. Question: after sharpening the blades on a bench grinder (after
much
use) is it necessary to harden them for longer life, and if so, how?
Thanks.

My dad was a certified pressure-vessel stick welder. Rather than hardening
his mower blades, he used to hard-face them with a tungsten rod. The host
metal would slowly wear away until there was mere foil holding the (almost)
intact tungsten edge in place G.

Most commercial mower blades (you know, the really thick, heavy ones, like
on Scags, Dixie Choppers, etc) are hardened in and around the cutting edges.
The bodies are left at a tougher temper, especially around the hub hole.

LLoyd