Collins with chip in blade

[markv]

i'd re-profile it like as illustrated above.
good practice for future repairs and cleanups.
all good
thanks for posting

buzz

 

[Square_peg]

It makes a fine paper weight just as it is.

 

[FortyTwoBlades]

That's a good point, but with the shallow hardening steels commonly used, they can do the same thing to a lesser extent. The surface/cheeks cool faster than the thick interior, so the center may still be soft a little further down.

Industrial definitions for "shallow hardening" are way less shallow than one might think. I'm seeing specs for a maximum through-hardening of 60-63mm for 1045, which is roughly 2.5" deep. With simple oil quenching I'm seeing a through hardening max depth of 1/4" as a figure, which should get you pretty far back into the bit without issue.

 

[Steve Tall]

Industrial definitions for "shallow hardening" are way less shallow than one might think. I'm seeing specs for a maximum through-hardening of 60-63mm for 1045, which is roughly 2.5" deep. With simple oil quenching I'm seeing a through hardening max depth of 1/4" as a figure, which should get you pretty far back into the bit without issue.

Indeed, the USFS specs for axes (1999 revision) calls for Rc 54-58 for at least an inch back from the edge, and these values are specified for the entire thickness. The hardness testing itself is done in the middle, along the centerline of the cut sample, at 1/4", 1/2", and 1" from the bit edge.