heres a good discussion topic

V

vaquero57

Joined
Nov 12, 2000
Messages
131
Okay I have jheard all kinds of opinions in the past about how thick to leave a blade before quenching it. I have heard people say they have had problems warping and breaking blades that were too thin when they quenched. My very first knife was a small hunter and I believe it was about 1/32" thick when I heat treated it. No problems. Since then I read all this stuff about this subject so my blades have been left at about 1/16" before. But I get tired of spending an entire evening(2-3 hours) finishing off 1/16" on the belt grinder. That does not include rubbing. So this next hunter I will heat treat tomorrow with the torch is back to 1/32" to see if I can pull it off again. If I can then the amount of finish grinding I have to do on this blade will be minimal. What does everyone feel about this subject. Does pre thickness have to do with type of steel, thickness, and size? or am I just getting lucky?

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" I am a shootist."
Clay Allison
" Does this mean we are bladists?"
Vaquero57
McAlpin Bladesmithing
 
vaquero57,I agree with you.I heat treat O-1 and 1095 with a torch and have never had a problem with warping or breaking.I finish the knife to 220 grit with about a 1/32" edge or less. Dave
 
Thinking about it, I'm not sure that warpage and such is the entire picture. I think there is also the "cutting factor" involved with leaving the blade edge overly thick. I view it as a protective shroud surrounding the material that will be the cutting edge in the finished product. Call it sacraficial material if you like, but after having experimented with blades that are thin verses blades that are thicker going into the hardening cycle, the blades that are left thick tend to out perform those that are thin. I'm sure much of the results have to do with steel type, individual methods of hardening, and even the care of how the heat is applied to the blade, but a couple of hours at the grinder, plus another one or two rubbing, is normal procedure in my shop.

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Ed Caffrey "The Montana Bladesmith"
ABS Mastersmith
www.caffreyknives.com
 
I use 0-1. So are you saying Edd that when the blades are thin the carbon all burns out of them? If you are getting a good soak all the way through the metal then how is thin steel gonna release any more carbon then thick steel. I do not put the heat directly on the point or the thin stuff anyways. I hit the thicker stuff and let the heat soak into the thinner areas. If you eventually grind down to that point then should not the carbon content still be there at the surface at that point just like if you already had it ground down? I guess what I am referring to is the protective shroud Ed. In theory it makes perfect sense. But in reality if it is protectying the inner steel, then is it safe to say that trhe inner steel is not hot enough. Get what I mean? Anyways if you sharpen 3-4 times then you should have the bad stuff gone by then right? By the way Ed this is Cory. How did your Elk hunt go? Deer season for shotgun starts this weekend in Iowa. Can't wait. Maybe get a bigger buck this time huh? Yeah right with my luck I might only see a coyote.
 
Not sure my opinion counts as a relative newbie but I take the edge to about .020 before heat treat and I haven't had any problems. The advice came from people I respect a great deal.


my $0.02

Rob!

 
Your opinionn better count Rob!! I am a newbie too and I hope mine counts. We have alot to learn but don't rule us out as being stupid right. .020 is 1/50"! that is smaller yet than my 1/32 I was worried about. If the people who told you were knowledgable than use it if it works. Bottom line is this for everyone here; There are sometimes different ways to get the same thing accomplished and the goal of each person should be to find out what works for him or her. If we took everything that anyone ever told us as gospel than throughout history we would never have made any progress as alot of progress has become from going against the grain. I will try this way of mine and see what happens. It might change too if I ever do a large blade who knows. Any other opinions?? Technically my friend Bruce Evans told me that with a thin edge the cartbon can get burned out it and it will take 3-4 good sharpenings to get down to the good stuff where a decent edge will hold. I was on one makers sight the other day and he was advising his customers of this so they would not be alarmed if their knives did not hold the best edge for the first few sharpenings.

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" I am a shootist."
Clay Allison
" Does this mean we are bladists?"
Vaquero57
McAlpin Bladesmithing
 
I always leave the edge thick and grind to finished size also. I think the carbon content is affected up to .010" deep on any part of the blade that is hardened. The scale is like dead skin and needs to be removed. Oxygen is the killer here. If the blade is heated in hot salts, there is no oxygen to damage carbon. Warpage is at a minimum too.
Ed Fowler wrote an article for Blade Magazine a few years back, He says "Keep it thick" I always use new belts to regrind which cuts the 2 hours down to 20 minutes or so. The blades can be ground straight at this time if there is warpage also.
I dont think my customers want to sharpen their knives 3 or 4 times before they start to hold an edge. They will using my name in vain while standing on a dead elk in a driving horizontal snow storm.
 
Like I told Cory,I have learned this from experience by using my own knives .And when you are going to show off a new knife to someone that has a deer down and your new knife has to be sharppened as much as the Wal-Mart knife it gets kind of embarrasing.I also feel that the customer shouldnt have to go through the multiple sharpening prosess them selves so,I will alwys spend that extra time regrinding the blade after the heat treat so my customer doesnt have to.
I know that for a begginer (really new) that is on a limited budget can not afford to go through any more belts than they have to but I believe that if they do they will make people happier and start selling more knives sooner than if they make the customer do the final sharppening work.....Bruce
Just my 2 cents worth here....

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Bruce Evans Handcrafted Knives
The soul of the Knife begins in the Fire!!!!!
Member of,AKTI#A000223 and The American Bladesmith Society
 
i leave them thick before heat treat because its easier to do some finish work with a sharp belt. than it is to put metal back on if there are some problems.LOL also 98% plus of my customers want the keys to there new knife and drive off.i have only had a few in my short 3 1/2 years at it, that wanted to put there own edge work on.

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Laurence Segal www.RHINOKNIVES.com
 
Cory,
The two areas of "soaking" and oxygen combine to mess up from 5-15 thousandths depth of your blade material. I'm talking about steels that would normally be considered hardenable via forging methods. I personally think soaking any of the routinely forged steels is a mistake. Slowly bring it to critical, and then get it into the quench. Soaking only encourages grain growth, and the oxidizing process (which would not be wrong to be called "burning"). The "protective shroud" that I spoke about eairlier is the material that gets eaten up by the scale and oxidation. By leaving the blade overly thick in all dimensions, you will still get the full measure of hardness, but you will also be lessening the chances of blade/edge warpage, as well as the protection from oxidation.
About the hunt.....not bad, snow was thigh deep on me, and about all I got of an elk was their rumps headed over the ridge. I took a nice 4x2 mulie, and my dad downed a forkhorn. Waterfowling was shot! We had an early, hard freeze, and all the birds headed south.



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Ed Caffrey "The Montana Bladesmith"
ABS Mastersmith
www.caffreyknives.com
 
You guys are probably right but on this one I had to even up the edge and balance it out and then had to regrind the edge profile a little and then finish the bevel again. I would guess from my lack of experience lol that I probably ground enough off to clean it up wouldn't you guys think.

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" I am a shootist."
Clay Allison
" Does this mean we are bladists?"
Vaquero57
McAlpin Bladesmithing
 
I've often heard that soaking is bad because it promotes grain growth but what about air-hardening steels like A2? Some say soak two hours following the specs and some say heat to critical and cool. Either way, A2 is a good blade steel, I think. Anyone know the answer?
 
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