Jump to content

HT False Edge.


guarnera
 Share

Recommended Posts

I'm making a Bowie / Fighter with a 10 1/4" blade with a 8 1/4" false edge. The blade is 5160. Usually for 5160 I would do a full quench, temper at 350F, which would give me about a 60Rc and then draw the back to a nice blue color giving me a spring temper to the back of the blade. Now with a long false edge I'm not sure how to handle this. The false edge isn't sharp, But if someone wanted to they could sharpen it, I guess. So do I forget about the false edge and draw the back of the blade? Or do I full harden and temper the whole blade a little softer, say like 58Rc? Or any other suggestions. Please don't say clay it to harden both edges and have a soft center. This is 5160 not 10XX or W1 or 2. Thanks for your suggestions.

 

Tony G

Link to comment
Share on other sites

If you want both edges hardened then you have no choice but to full quench and then oven temper it. It's the same process you would have to do with a dagger.

Everything I need to know I learned from the people trapped in my basement.

 

 

I'm out of my mind but feel free to leave a message.

Link to comment
Share on other sites

with a fine tip on your torch, you can draw the centre of the blade to blue, as long as you dont go too close to the tip. if you set the blade in a quarter inch of water to prevent the edge from softening, then as the colours creep towards the false edge, you can quickly flip the blade and quench the false edge. but even at a blue heat, the false edge should still be hard enough to sharpen, maybe low 50's. i've made workhorse blades from leaf springs, and full tempered to blue, and they perform fine. i think our insistence on rc 60 for edges is a bit overkill in many cases - some of the best knives i have ever used (old sabateier kitchen knives) are tempered to about 50 on the edge, and they work great as long as you keep them honed.

Jake Cleland - Skye Knives

www.knifemaker.co.uk

"We can't solve problems by using the same kind of thinking we used when we created them."

"Everything should be made as simple as possible, but not simpler."

"Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe."

 

Albert Einstein

Link to comment
Share on other sites

I am with Jake on this. If you draw the back down and some heat bleed into the back edge, it is not going to ruin the knife. The odd slash you may do with the back edge does not demand the same edge holding as the main edge.

 

An alternative to using a flame for tempering, is to se a pair of tongs with a rod of steel welded to each side of the jaw. If you bring this up to yellow heat, you can pinch the areas you want to heat and let the heat bleed into the blade. This is a pretty controllable process, but keep a tub of water nearby if you need to suddenly stop heat from spreading further.

You can pre heat the whole blade to below tempering range to save some time, but be prepared to re heat the tong a couple of times before you are done.

 

You may use a flame to draw the spine and use the tong for just the point section of the blade.

 

I make many of my sword blades in (equivalents of) 6150 or 5160. I take them to about 57-58 HRC without doing a selective tempering of the spine. With these through hardening steels at this hardness the blades are not brittle and can be whacked into angle iron, cutting into the iron, without damage to edge or breaking of blades. You make your blades harder and that can of course change things.

 

With a fine grain size, perhaps you may not even need to do a selective tempering? Have you tested to see what kind of abuse you can put a fully hardened and owen tempered knife through without it failing?

Link to comment
Share on other sites

My philosophy is to keep it simple and eliminate as many variables that could cause problems. If I am going to make a knife with a false edge that I intend to use then it will be the same hardness as the main edge. It make no more sense to have two different hardnesses on a functional false edge knife as it does a dagger.

 

Why would anyone make a dagger with a different hardness on one side?

 

I don't want a customer coming back and asking me why one edge seems to go dull faster. Even if I explained to them the dual HTing they may sell it to someone else and it will still have my name on it. A name that would appear to be associated with a bad heat treating.

Everything I need to know I learned from the people trapped in my basement.

 

 

I'm out of my mind but feel free to leave a message.

Link to comment
Share on other sites

My philosophy is to keep it simple and eliminate as many variables that could cause problems. If I am going to make a knife with a false edge that I intend to use then it will be the same hardness as the main edge. It make no more sense to have two different hardnesses on a functional false edge knife as it does a dagger.

 

Why would anyone make a dagger with a different hardness on one side?

 

I don't want a customer coming back and asking me why one edge seems to go dull faster. Even if I explained to them the dual HTing they may sell it to someone else and it will still have my name on it. A name that would appear to be associated with a bad heat treating.

 

 

Thank You all for the reply's. I will have to agree with Mr. Finnigan on keeping it simple. A full heat treat and temper back to 57-58Rc sounds like the way to go. I know I really don't need and probably shouldn't have a 60Rc edge on a big knife like this. But when I do a spring temper on the blade (less edge) I don't mind leaving the edge a little on the hard side because I fell you can because the spring tempered body will absorb shock and let you get away with it. I wouldn't go over 60Rc. And this is going to be a 1800's gentleman's dress bowie (if it turns out), So I figured a 60Rc edge would be fine since it is actually a fighter and wouldn't be used for camp work. However, wanting to have the option open for the owner to be able to sharpen the false edge if they want, then I think Mr. Finnigan's suggestion to do a full harden and temper to 57-58Rc makes the most sense. Thank you all for your suggestions.

 

Tony G

Link to comment
Share on other sites

My philosophy is to keep it simple and eliminate as many variables that could cause problems. If I am going to make a knife with a false edge that I intend to use then it will be the same hardness as the main edge. It make no more sense to have two different hardnesses on a functional false edge knife as it does a dagger.

 

Why would anyone make a dagger with a different hardness on one side?

 

I don't want a customer coming back and asking me why one edge seems to go dull faster. Even if I explained to them the dual HTing they may sell it to someone else and it will still have my name on it. A name that would appear to be associated with a bad heat treating.

 

This would be the clincher for me, along with the KISS principle.

Cheers Bruce

Barnett Custom Knives

www.barnettcustomknives.com

 

Australian Knifemakers Guild Secretary/Treasurer

American Bladesmith Society Apprentice

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...