Bad heat treatment on axe?

[joenineo]

So, took a tomahawk out the other day to do some chopping (clean up) at our local club. Seemed to be going ok, but it looked like I was wrong! ...

So, in your opinion:
1. Bad heat treatment?
2. Poor grind that I put on it (ie too narrow)?
3. Poor technique?

Interested in your thoughts.

I have since hammered it back down and reground the edge back to where it was (I hope) ...and yes, I probably hit a couple of nails in my initial chopping, but the bigger "roll" seemed to me to be more like hitting a knot - and I really didn't expect that result.

I think its (1) .. so I guess I'm going to have to heat and quench it myself during the summer.

Joe.

 

[Broch]

The problem is that tool steel is tempered at between 200 and 400 degrees C resulting in a hardness of between 60 and 50 HRC. You can easily reach these temperatures when grinding dry, especially at the very edge, and completely ruin any hardness on the edge. If the axe is made of a carbon steel it will need reprofiling and an edge putting on, then quenching from around 800 degrees, then tempering at around 250 ish to achieve a hardness of around 58 HRC - if that's what you're aiming for.

 

[Stew]

I would guess (and it is just a guess as looking at pictures opinions are limited) that it's a bit on the soft side. That is a hefty roll! If you have the kit to reheattreat it wouldn't hurt then you'll know what it is. I'm guessing you don't have the means to check how hard it is now?

 

[joenineo]

using. Unfortunately not. However, when I say regrinding .. I am talking about file re profiling, not using a belt.

 

[Janne]

What brand is it?

 

[Broch]

using. Unfortunately not. However, when I say regrinding .. I am talking about file re profiling, not using a belt.

OK, that won't overheat it but, as Stew says, it looks as though it's on the soft side. If it files easily it is too soft for anything other than splitting small logs and will never hold an edge unless it is heat treated (assuming the steel is good enough).

 

[Stew]

OK, that won't overheat it but, as Stew says, it looks as though it's on the soft side. If it files easily it is too soft for anything other than splitting small logs and will never hold an edge unless it is heat treated (assuming the steel is good enough).

Good thought - using a metal file to reshape will give you a sense of how hard it is. It's never something I attempt to do as I have belt grinders to use so it's also not something I think of.

 

[Robson Valley]

Looks like a fine wood carver's gouge that hit something very hard.
What do you suppose the total included bevel angle is for that blade?

The bevel must change to support the edge, depending on the job.
The trick is to measure that and keep it that way.
Exactly the same logic applies to different kinds of kitchen cleavers (eg tomato vs bone.)

 

[joenineo]

Brand - can't remember to be honest - got it states-side one year. As to bevel angle - not too sure... will need to measure that one... but yes, I figure I need some better heat treatment there.