Edge thickness before HT

[alexmin]

I grind my edges to about 0.05. I've just found today that O-1 is shallow hardening steel so it's possible to grind off hardned layer.
My question is how thick is this layer?

 

[Jeff Clark]

A knife blade is thin enough that it will harden all the way through. You don't need to worry about your edge.

 

[Stacy E. Apelt - Bladesmith]

What Jeff said.
Shallow hardening steel applies to castings and heavy stampings like industrial parts.Knives have a width to thickness ratio too large to make hardening depth relevant.IOW - it all gets hard.

 

[flatgrinder]

I good rule of thumb is to leave the edge at 0.5mm prior to HT.

 

[David Schott]

I tend to leave mine a little thick. That being said, I dont remember the last time I warped a blade. I don't find grinding hard steel to be that bad. I actually feel like I have a bit more control, actually. I use the new norton blaze belts and they eat hardened steel pretty easilly.

I leave mine about a dime thickness...

 

[Kevin R. Cashen]

I grind my edges to about 0.05. I've just found today that O-1 is shallow hardening steel so it's possible to grind off hardned layer.
My question is how thick is this layer?

I would verify your source of information, while some things can be relative (O-1 could be considered shallower hardening than a true air hardening steel), when it comes to knives O1 is a deep hardening steel, while something like 1095 would be shallow hardening. It shouldn't be possible to grind any of the hardness off from O1 in knife cross sections as it will harden completely all the way to the spine.

Depending upon your heat treat set up, however, you may need to still worry about that thickness. If you have decarb you will need to do the opposite, i.e. grind the soft stuff back unitl you get to the good hard stuff. More obvious however will be the tendancy for that really thin edge to distort in heat treat, depending upon how you quench.

But if it really is O-1 don't worry about hardness you should have it everywhere.

 

[David Schott]

I've found that with 0-1 its nearly air hardening, fully through 1/4"....my bits skitter across tangs that were not even quenched most of the time...

 

[alexmin]

Guys,

thanks for explaining.

Alex

 

[Michael J. Spangler]

i leave the edge about .050 or sometimes thinner before HT.
i find keeping the blade cools saves me 90% of my troubles in warping. it seems when i get those big ol hot spots when grinding is right where those warps end up. other than that i've gone as this as about .015 before on a straight razor before HT. and had no warping.
all in O1 of course

 

[NWA]

I'll throw in my.02 I use O-1 with a flat ground profile and I have found that
.025" thick at the edge works very well for me. If I decide to do a hollow grind I like to leave the edge at .030" thick (min) I usually finish the knife after HT to a edge thickness of .020"-.022" Again this is what works for me.




Nick