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View Full Version : Knife construction discussions, part 1: Forged vs. stock removal



UglyJoe
03-13-2011, 05:39 PM
Hey guys,

Since there has been a lot of participation on this board from knifemakers (Thanks guys!), and there are a lot of very knowledgeable people on the boards, I thought it would be cool to have a series of threads on the benefits/drawbacks of some of the different techniques used to manufacture knives, from the perspective of both the ease of the manufacturing process, the scientific/metallurgical properties of the finished knife, and the significance to the end user, as well as to the idea of what it means to be "functional art". Topics that I think would be really cool to cover include laminated vs. solid steel knives (always love a good san-mai vs. solid steel debate), the benefits/drawbacks to honyaki knives, damascus knives (where the edge is actually damascus and composed of two separate steels), the heat treatment process, and anything else you guys want to talk about.

AS A NOTE: I don't want to turn this into a bashing of one way of doing things or otherwise want to offend a maker if they make things one way or the other. This is intended for friendly, intellectual debate.

First up, I'd like to discuss the "starting point" of making knives. I know, I know, the first real thing is to decide what steel you are using and what kind of knife you are making, but IMO the first real decision when it comes to the manufacture of any knife is if the blade will be forged from stock to it's basic final dimensions or if a piece of relatively thin knife stock will "simply" be ground/cut out to the final profile the knife will have. This debate arises from the large amount of stock-removal knives that have come to the market recently. i've been interested by the fact that many makers have introduced relatively expensive knives that use the stock removal technique.

The traditional opinion is that blades generated by stock removal or stamping are inferior to forged knives. I don't know how this opinion came to be, but my guess is that stock steel was at one time simply inferior, with uneven carbon content, high impurity, etc. The forging process allows (as far as I understand) the maker to work out impurities as well as gain a more even distribution/manipulate the amount of the carbon content, etc., as well as to simply realize early on in the process if they have a bad bar of stock and abandon work earlier in the process. I don't know how much this holds true anymore, and would like to here opinions on available stock steel nowadays, etc.

So, what are the opinions out there from our members? Is the forged/stock removal dichotomy something you think about when purchasing a knife? For the makers out there, do you consider the forging process to be paramount to the final quality of the blade, or is it secondary to a good heat treat with the correct stock steel for what you want? For those of you that have used a lot of knives with high frequency (calling Chef Niloc!), have you found knives of one kind or the other to perform better from a steel standpoint (not geometry/profile) based on if they were forged or not? For those of you that have sharpened a lot of knives, do you find any difference between the two? Any metallurgists out there have any insight onto what effect forging the blade from stock has on the final structure and properties of the steel?

I have a lot of opinions on these subjects, but would like your opinions first. I've blabbed enough in this post as it is.

Chef Niloc
03-13-2011, 06:36 PM
I have great knives made both ways, that sad my two best (IMO) are forged to shape.

UglyJoe
03-13-2011, 06:47 PM
What about the two best do you like more, and can that be in part attributed to the forging process?

Larrin
03-13-2011, 07:20 PM
Most knife makers are kidding themselves if they think they can improve the steel by forging it. You have to remember that the stock removal makers are using steel that was forged too, forged by the steel company instead of the bladesmith. The forger just forges it down from slightly larger stock. There are more things that can be messed up in the steel than fixed. The chances that the grain and carbide structure have been improved are pretty slim in most cases, especially with forges at approximate at best temperatures and then using a simple anneal. This leaves forging to shape as the only way left to improve the knife. However with the way knives are shaped and used there isn't really any improvement to be had.

RRLOVER
03-13-2011, 07:35 PM
I am glad to here this Larrin,now i can buy some 52100.I was under the impression that the grain and carbide structure was improved by forging.

Pensacola Tiger
03-13-2011, 07:40 PM
Hey, Larrin, welcome to KKF! Glad you're here.

Dave Martell
03-13-2011, 07:50 PM
From what little I know about forging I would agree with Larrin on this.


BTW, welcome Larrin. :)


Good thread idea Joe.

SpikeC
03-13-2011, 07:50 PM
I don't forge, but Larrin's comments are spot on as far as I can see. Modern steel manufacturing is pretty well controlled, industry would be in trouble if that were not the case. If you are starting with iron sands, forging is the way to go, but when I buy a chunk of O1 I'm pretty sure that it is as good as it is going to get. If the metal is heated way up and whacked into shape, what is happening to the carbon and other alloy constituents? And how will that affect the way the stuff heat treats?

UglyJoe
03-13-2011, 08:22 PM
Most knife makers are kidding themselves if they think they can improve the steel by forging it. You have to remember that the stock removal makers are using steel that was forged too, forged by the steel company instead of the bladesmith. The forger just forges it down from slightly larger stock. There are more things that can be messed up in the steel than fixed. The chances that the grain and carbide structure have been improved are pretty slim in most cases, especially with forges at approximate at best temperatures and then using a simple anneal. This leaves forging to shape as the only way left to improve the knife. However with the way knives are shaped and used there isn't really any improvement to be had.

Very interesting. So in your opinion, it's the heat treat where the knifemaker really shines as far as quality of his steel? I find this particularly interesting with respect to the ABS Mastersmith testing. I've heard of some very good knifemakers failing these tests - particularly the one bending the knife to 90 degrees without it breaking - and have always assumed that it was the quality of the forging process, as well as the heat treat, that set those blades that passed the test vs. those that didn't apart. Of course, I'm going on complete ignorance on this, as I don't know what the rules are regarding what kind of steel and forging methods are allowed for ABS submission. Does anyone know this?

I've always thought that it was the forging that really mattered here because heat treating is (as far as I know) a more exact science, with most of the common steels having very specific instructions from the manufacturer on how to best heat treat the steel. I assumed that if heat treating was the main factor in the steel quality, there would be a lot more ABS mastersmiths, although I'm completely ignorant of any politics/expense that goes into getting ABS certification, and wither or not many makers simply skip it because of them.

UglyJoe
03-13-2011, 08:23 PM
From what little I know about forging I would agree with Larrin on this.


BTW, welcome Larrin. :)


Good thread idea Joe.

This one will probably be pretty short... it's the clad vs. solid thread that I think will be a little more entertaining....

Marko Tsourkan
03-13-2011, 08:59 PM
Yep, but the mythology is missing and a guy with a hammer looks better in pictures than a guy sitting comfortably in front of 2x72 grinder. :)

That said, I am buying 52100 this Saturday. Mario if you need some let me know and I 'll pick some for you at NJ Steel Baron hammer-in.

M

Larrin
03-13-2011, 09:24 PM
Very interesting. So in your opinion, it's the heat treat where the knifemaker really shines as far as quality of his steel? I find this particularly interesting with respect to the ABS Mastersmith testing. I've heard of some very good knifemakers failing these tests - particularly the one bending the knife to 90 degrees without it breaking - and have always assumed that it was the quality of the forging process, as well as the heat treat, that set those blades that passed the test vs. those that didn't apart. Of course, I'm going on complete ignorance on this, as I don't know what the rules are regarding what kind of steel and forging methods are allowed for ABS submission. Does anyone know this?

I've always thought that it was the forging that really mattered here because heat treating is (as far as I know) a more exact science, with most of the common steels having very specific instructions from the manufacturer on how to best heat treat the steel. I assumed that if heat treating was the main factor in the steel quality, there would be a lot more ABS mastersmiths, although I'm completely ignorant of any politics/expense that goes into getting ABS certification, and wither or not many makers simply skip it because of them.
The only reason forging would be a factor with the ABS knives is if they screwed it up and left it with a large grain size. It's all about the heat treating with the ABS test because you have to have a soft spine to pass the bend test with a hard edge for the cutting test. The scientific studies on heat treatment go out the window when most guys are using a torch for all or part of this heat treating process. Many of them use the torch either to temper the spine without softening the edge after heat treating the rest of the blade or to heat the edge to austenitizing temperature without heating the spine at all (leaving it at the annealed or normalized hardness). Also, you must remember that after the forging there are several heat treating steps required before final heat treatment to repair everything done in the forging. This includes normalizing and annealing. I would argue these heat treating steps are as important if not more important than the actual forging procedure. Of course the best case scenario is to do all of the steps properly.

UglyJoe
03-13-2011, 09:34 PM
The only reason forging would be a factor with the ABS knives is if they screwed it up and left it with a large grain size. It's all about the heat treating with the ABS test because you have to have a soft spine to pass the bend test with a hard edge for the cutting test. The scientific studies on heat treatment go out the window when most guys are using a torch for all or part of this heat treating process. Many of them use the torch either to temper the spine without softening the edge after heat treating the rest of the blade or to heat the edge to austenitizing temperature without heating the spine at all (leaving it at the annealed or normalized hardness). Also, you must remember that after the forging there are several heat treating steps required before final heat treatment to repair everything done in the forging. This includes normalizing and annealing. I would argue these heat treating steps are as important if not more important than the actual forging procedure. Of course the best case scenario is to do all of the steps properly.

Interesting. In a lot of ways it sounds like most of the knives that pass the ABS test aren't knives you would want to use for anything besides passing the ABS tests anyway.

Marko Tsourkan
03-13-2011, 09:42 PM
Interesting. In a lot of ways it sounds like most of the knives that pass the ABS test aren't knives you would want to use for anything besides passing the ABS tests anyway.

Short of using it as a meat cleaver, I don't see a use for a knife that cuts nails with its heel. The tip should be OK to use.

If I recall it correctly, Devin was refused ABS membership because he has done the requirements for the test on a knife from stainless steel, which ABS bylaws say can't be done. I guess, paradigm doesn't shift often with ABS.

M

Larrin
03-13-2011, 10:38 PM
Interesting. In a lot of ways it sounds like most of the knives that pass the ABS test aren't knives you would want to use for anything besides passing the ABS tests anyway.
That's certainly true.

Dave Martell
03-13-2011, 11:16 PM
That said, I am buying 52100 this Saturday. Mario if you need some let me know and I 'll pick some for you at NJ Steel Baron hammer-in.

M


Say Hi to Aldo from me.

Delbert Ealy
03-13-2011, 11:54 PM
One thing that is seldom pointed out is that every bar of steel out there has already been forged. It is inherent in the steel manufacturing process. You buy a bar of 1/8" stock, well that bar started out as a part of a melt that was several tons(for a small one it could be much larger) the steel is rolled and formed into the final recatgular bar shape. Forging is just a way to move the metal around to give you a desired shape different from the starting point. It was used by many smiths to conserve steel.
As Larrin pointed out a person can do much more damage to a piece of steel by forging, than by stock removal.
Economically speaking it does require more of an initial investment to forge blades, given that you need a forge, anvil, hammer ect in addition to all the tools you need for stock removal. There are very rare circumstances that a forged part may perform marginally better than a stock removal part, but knives are not one of those.
I should point out that I am a damascus maker and i do forge all the steel I use and sell, however I do not forge all the blades I make. It all depends on the design of the knife I am making. There are some instances where forging makes sense, and is quicker, and there are some where it is easiest to stock remove.
There are many good people on both sides of this debate and it has been going on for as long as I have been making knives.
It is interesting that the ABS test has come into this conversation. The real purpose of the test is to test the knifemakers ability to heat treat their blade in an exacting manner, to test their skill at heat treating, not to heat treat a blade for use in the real world. Some people believe that the ABS test blade is the ultimate blade, unfortunately there is no blade that does all tasks perfectly. If there were, then there would only be one knife that each of us would buy and I would have to go back to flipping burgers. :)

StephanFowler
03-14-2011, 12:43 AM
The only reason forging would be a factor with the ABS knives is if they screwed it up and left it with a large grain size. It's all about the heat treating with the ABS test because you have to have a soft spine to pass the bend test with a hard edge for the cutting test. The scientific studies on heat treatment go out the window when most guys are using a torch for all or part of this heat treating process. Many of them use the torch either to temper the spine without softening the edge after heat treating the rest of the blade or to heat the edge to austenitizing temperature without heating the spine at all (leaving it at the annealed or normalized hardness). Also, you must remember that after the forging there are several heat treating steps required before final heat treatment to repair everything done in the forging. This includes normalizing and annealing. I would argue these heat treating steps are as important if not more important than the actual forging procedure. Of course the best case scenario is to do all of the steps properly.

Absolutely correct, I have passed my J.S. performance test and will be submitting my presentation knives at the Blade show this year. I have a lot of love and respect for the ABS but at the same time I am very good friends with a lot of stock removal knifemakers.

there is no one best way to make a knife,
I forge because it's fun. I would get too bored just cutting out a shape and grinding. the hammering is the best part.

but I also had to learn that all of the heat cycles I was putting the steel through greatly increased my chances of screwing it up.

any knife is only as good as it's heat treat.


Interesting. In a lot of ways it sounds like most of the knives that pass the ABS test aren't knives you would want to use for anything besides passing the ABS tests anyway.

I sure wouldn't, I've never made another knife like I used for my test and I don't plan too

StephanFowler
03-14-2011, 12:44 AM
The real purpose of the test is to test the knifemakers ability to heat treat their blade in an exacting manner, to test their skill at heat treating, not to heat treat a blade for use in the real world. :)

This is EXACTLY the way I've heard it from several MS over the years.

UglyJoe
03-14-2011, 01:30 AM
Well, this topic was less interesting than I hoped it would be. And here I was thinking that a forged knife was far superior to a stock removal knife. Hopefully someone else who thought the way I did feels differently now. Still, there is something romantic about a forged knife... just not enough more romantic that I can see myself shelling out extra $$$ for a forged vs. stock removal blade. Cool beans.

Eamon Burke
03-14-2011, 01:38 AM
I am a cook, so I'll try to create an analogy in that regard.

I have every intent of creating knives in the near future, but one of my concerns is how to label them. I do not feel that if the characteristics that make a knife great(instead of good) are in the steel itself, then I can't really take credit for making the knife. I wouldn't open a can of Campbell's soup, throw some basil in it and tell someone I made it.

That said, there is significant investment and risk in heat treating steel, considering without VERY expensive equipment it is easier to screw up a great hunk of steel you got, perhaps stock removal is a more democratic solution. The geometry and overall design of a knife is at least as important as the steel's heat treat(both of which far outweigh the steel's composition IME), so that is something to consider. I know if someone is making knives with steel heat treated, or even sourced from a respectable origin, I would consider the knife a good buy if well designed. Perhaps it is just as valid as making a tomato soup in the winter with canned tomatoes.

After all, I don't know how it must feel to spend years learning to handle the raw steel, purchasing very specialized, high-dollar equipment, master centuries old techniques to massage a hunk of steel into a performing object--and then have someone say "That has too much belly for me, no thanks."

spaceconvoy
03-14-2011, 01:55 AM
On thing you can't get with a stock removal knife is the characteristic thicker machi of a forged knife... Well, you could in theory, but you'd end up removing more stock than you'd have knife left over. Not that this has any effect on performance at the edge, but it feels dead sexy :D Plus I thought this thread could use some aesthetic balance, since we've only talked about performance issues so far.

Dave Martell
03-14-2011, 10:47 AM
I'm sure that you can make some designs/shapes through forging that aren't easily duplicated through stock removal.

UglyJoe
03-14-2011, 10:57 AM
Not to mention a lot of clad combinations aren't available as normal stock from a manufacturer. And I don't think that anyone sells stock that's two layers for traditional single bevel knives.

obtuse
03-14-2011, 11:00 AM
I think either knife can be exceptional, one isn't greater than the other. There are a lot of good makers doing either style. Most forged knives are carbon steel, while most stock removal knives are stainless. Some materials just lend themselves to different treatments. Tradition vs. Modern techniques, I appreciate both.

Marko Tsourkan
03-14-2011, 05:07 PM
Not to mention a lot of clad combinations aren't available as normal stock from a manufacturer. And I don't think that anyone sells stock that's two layers for traditional single bevel knives.

In Japan you can get laminated stock (including damascus) either for double-beveled or single-beveled knvies. Even some established smiths use them to cut down costs and stay competitive. They do forge them down though.

M

spaceconvoy
03-14-2011, 05:23 PM
http://cgi.ebay.com/Japanese-Damascus-YANAGIBA-knife-270mm-SHIMATANI-Blue-s-/250782612664

Like this one, probably