drawbacks of a ground blade compared to a forged blade...

Don Hanson III said:
There are too many variables to say one is better than the other. No absolutes...

Thermal cycles and fine grain are key to performance. Not all steel that comes out of the mills is ready to heat treat.
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BINGO!

We have to try and keep discussions like this one in proportion. In many single instances, one method will exceed the other. As a whole, it probably is a wash.
My favorite explanation is the shelf bracket forged from a bar. The block to make it by stock removal would be around 95% wasted. In the case of many ( most as far as I am concerned) high alloy and tool steels, stock removal almost surely would win over forging.
 
From what I've read, the main disadvantage to stock removal is that the knife blade has to fit within the stock at hand. For example a 1/16 x 3/4 x 7" bird and trout knife needs that size stock or larger. And if a knifemaker does not have that stock on hand, it will require more stock removal to get the blade finished from a larger piece of metal. Forging that same blade could use 3/16" drill rod or 1/4" square rod or even a 9/16" ball bearing? The ability to use a multitude of sources seems to be a distinct positive for the forger. What about the amount of time that it takes to make the blade and the potential exposure to airborn particulate matter?

Meanwhile, I think I'll take a blacksmithing class. :)
 
I never understood the need to forge a bar of flat stock. Its flat, why make it unflat. Now when I look at at a one inch thick section of 2 1/4 inch round stock, I see a hundred possibilities. The forging process is the height of creativity. Its fluid, the forger is constantly making adjustments as the blade takes shape. I believe this is what draws so many people to it. Its a real challenge as well as an ongoing learning experience. Carrying out heat cycling while the blade is being forged can add a lot, to the final product as well.
Its all good.
 
I totally agree that the practical use of flat bars basically eliminates the need to forge to shape 95% of most knife shapes.

I have been having a discussion with Tai over this thread, and many may be surprised to know that he is on the scientific side of the argument for forged blades. He has been using big words and all :)

Here is my response to a recent email,m from him. It deals with his point about anisotropy....known as grain direction to most of us. It refers to the directionality of the grain caused by rolling the steel, and any subsequent manipulations. :

Tai,
I am really pleased to see your take on the grain structure and directional control (Anisotropy) of the grain caused by forging. This is where science aids art. Just as a wood carver can shape a longer lasting statue by observing the grain, a forger can shape a better blade by the same technique.
However, the difference in grain in steel between a hot rolled bar made into a stock removal blade and the same bar made into a forged blade is not nearly as large. The refinement of the gain in anisotropy induced by forging is there, buy it is not a large increase. The proper grain refinement done on the blade in a good HT will refine the grain nearly as much on a stock removal or a forged blade. In an analytical ( laboratory) sense, the forged blade will still be better.....but the average user almost surely couldn't tell.

The exception for this is in extremely fine edged, high hardness blades....made from hyper-eutectoid steel. That is why the Aogami Japanese kitchen knives excel in cutting by most users observations. The edges are forged thin, and the grain refinement as well as the potential grain size is very small. This allows a much harder blade with a very fine grain edge.

As you point out, this increase is very dependent on the skill of the smith. Just pounding out a blade may not make much difference....and the HT will determine the things that govern 99% of how the blade comes out.
Stacy

NOTE:
The comparison of a Japanese kitchen blade is used to show that steel selection, alloying ( or lack of it) and superb HT ( which includes superb forging in many cases) is what takes one blade far beyond another. The slight, imperceptible differences between two blades made by the two methods we are discussing is not the same thing.

I will reiterate my feelings on stock removal vs forged:
"Make your knives the way you want....and heat treat them like each one was going to be placed in the Smithsonian for future generations to see how well a knife can perform."
 
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Three years in, and I still have questions. Kinda makes me happy.

Why does everyone keep posting that you can't make damascus without forging? Isn't using a hydraulic press closer to what the mill does than traditional forging? Secondly, aren't all the benefits of forging discussed here lost when you anneal?
 
zaph1 said:
Three years in, and I still have questions. Kinda makes me happy.

Why does everyone keep posting that you can't make damascus without forging? Isn't using a hydraulic press closer to what the mill does than traditional forging? Secondly, aren't all the benefits of forging discussed here lost when you anneal?
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Using a hydraulic press is forging. But I personally would rather use a power hammer.

No, the benefits of forging are not lost when you anneal. I don't anneal, I just normalize.
 
Forging is the manipulation of the shape of the steel by pressure. It can be done cold, but is usually done hot in the areas that we deal with. It can be with a hammer or a press.

Don't know 'bout y'all, but to me a bladesmith of necessity is forging his blades, but a knifemaker doesn't necessarily.
 
Fred.Rowe said:
I never understood the need to forge a bar of flat stock. Its flat, why make it unflat. Now when I look at at a one inch thick section of 2 1/4 inch round stock, I see a hundred possibilities. The forging process is the height of creativity. Its fluid, the forger is constantly making adjustments as the blade takes shape. I believe this is what draws so many people to it. Its a real challenge as well as an ongoing learning experience. Carrying out heat cycling while the blade is being forged can add a lot, to the final product as well.
Its all good.
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For me Fred I buy a lot of bar stock in 1/4 by 1 inch and I can turn it into something I would most likely need 2 inch stock to create. Plus all the cycle's I can run it through to get a really nice blade.
 
Bano119 said:
Lost a sale today of a custom knife when the customer realized that it wasnt forged. Any thoughts on drawbacks of a ground blade from flat stock? I asked the customer but he hasnt replied, so I thought I'd post...
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The original question deserves a simple answer, none. There are no drawbacks. Using either method an outstanding knife can be created. Are the knives created by forging or stock removal better than one or the other? No. they are simply different ways of obtaining a cutting tool. Are there knife makers who prefer one method over the other? You better believe it. Does the maker who uses one or the other method have the right to say his chosen method is better than another’s, I don’t think so. Is there scientific proof that one or the other method produces a better knife; I have not seen any objective scientific proof one way or the other. I have read a lot of articles that purport to address this question saying one method is better when compared to the other, but I’m not buying it. Do some knife makers claim that there way of making a knife is better, Of course. I personally believe that any knife maker who says that either method is better than the other is just practicing salesmanship and if a person chooses to buy that sales pitch that’s there privilege. As a knife maker, my stand is the following, I choose to use stock removal because it meets my needs and I am proud of the blades I make using it. Most importantly I enjoy making knives. To me that is the bottom line.
 
I think I need to do some more reading here. How exactly does the metallurgy work for altering the grain structure to be finer (or directed properly) during forging? And is this mainly true for simple carbon steels? My limited understanding of the whole process suggests that the HT is the most important part of altering the grain structure of the steel, so why is it that you can't get the same results out of a stock removal blade that you can with a forged blade? Brad at Peters seemed pretty convinced that forging was detrimental for more complicated steels such as 3V, because you don't get even distribution of carbides unless some sort of additional stress relief or normalizing cycle is performed.

Can someone tell me if I've got this right? My understanding of a lot of these terms is pretty weak. When you normalize, you stabilize the structure of the steel, right? I'm somewhat unclear on what that means. For more complicated steels, I understood that to mean you were looking to even out the distribution of the elements in solution throughout the piece, so you get even formation of carbides, etc. Not sure how that translates to grain structure, exactly. I had thought it was about making all the crystals the same size. Would that affect what you accomplish during forging, and if so how? If my understanding of normalizing is correct, wouldn't the triple normalizing cycle undo the edge-packing or whatever it's called that Stacy is describing?

Then, during the HT, what are we shooting for? Martensite? That's got a needle-shaped grain structure, if I'm reading it right, so is that why the grain structure would be better during forging of a curved blade? So that the needles follow the edge as much as possible or something? Why would that not be true regardless of knifemaking method? I thought the martensite forms during temper, and why wouldn't it naturally follow the edge of the material then? I would be interested to see a microscopic view of the edge of a well-forged blade vs a stock removal blade. Is there such a thing? Where are the most gaping holes in my understanding? This stuff is very interesting to me, but quite confusing, especially because there seems to be a lot of disagreement among knifemakers about the way it works, from the articles I've been reading since this thread started, trying to understand it all. (Wow, that was a LOT of question marks...)

Thanks for the interesting discussion, sorry to interrupt it with my noobish questions...
 
Martensite forms starting at around 400F as the steel cools from austenitization during the quench. It does not form during the temper except from any small amount of Retained Austenite that converts ( this is why you need two tempers). During the temper the martensite is made less brittle.

A bar of steel from the mill has been rolled out from a huge ingot. It has been thinned and stretched from a couple feet thick to 1/4" in most knife use bars. This gives the grain structure a directionality called anisotropy. The directional strength is one factor of anisotropy, as we all are familiar with in wood. In steel, the directional strength is not a significant factor of anisotropy, but there are other things in the way the grains are aligned, and also concerning the impurities in the steel. These impurities ( sometimes called stringers) are aligned along the "grain" of the steel, and that is a permanent situation. Forging helps reduce these impurities by breaking them up, and spreads the distance out between them.

What is meant by the forged blade having greater strength due to anisotropy is seen in a hidden tang. If the tang is forged to shape and taper, the "grain" follows that shape. This will be somewhat ( very slightly) stronger than a tang ground out of a bar with the "grain" going off the curve.

As you point out, the HT is 99.5% responsible for the blades final condition. While there is that 1/2% that can be affected by forging, the difference isn't necessarily a 1/2% better blade. It would take a laboratory and serious examination to see any real differences.

I believe Kevin Cashen and Roman Landes have some micrographs of different structures and things like anisotropy in steel. You might want to contact them for more in depth study. Be forewarned, if my words cause you to blink and rub your eyes, theirs will make your head hurt.

Funny anisotropy story:
A friend was taking karate classes with his son. The instructor was doing a foot-kick board breaking demo and had him hold the 12"X12" squares of 3/4" pine because he is a lot bigger than the kids. Sensei broke one board, then two, and then went to three. My friend is an engineer, and knows what the grain direction does to strength. He picked up three boards, but turned the middle board 90° to the other two. The instructor kicked the stack...and bounced right off it. He tried two more times, and then realized what was going on :) . After re-arranging the boards to match grain direction, they broke easily.
 
That's an excellent story. Starting to all come together a bit. I hadn't thought about the impurities either. So...what are your thoughts about whether this is true for all steels, or mainly for the simpler carbon steels?
 
My thoughts are that only the carbon steels are worth forging. Whatever gain that can be attributed to the forging, and not the HT will be very small.

It takes either a fool or someone with a very specific reason to forge stainless or high alloy steel. I would expect a forged blade in these steels to lose not gain in quality. These losses could be quite significant. IMHO, any steel with a high alloy ingredient list should be stock removal only in anything less than a large factory setting and equipment.
 
When I was in motorsports, we noted an improvement with forged cranks when the RPM of a 5l or larger engine needed to spin faster than 6000RPM. I had a 5l mustang that redlined at 7200rpm. Unless you were pushing those performance boundaries, the gain from the anisotrophy were meaningless and the extra money was wasted. Even the forged pistons for less than 11:1 compression engines were falling out of favour years ago, as the alloying elements gave most of the benefits of the forged pistons (these were aluminum) without the downside. Grain direction would probably make more of a difference in a pry bar than a knife, but it would be a minimal improvement. At extremes, there is a measurable gain, but it is a small one.
 
What a great thread, there's a whole seminar on metallurgy here for the reading!

There's one more thing about forged blades: Many of the aesthetic touches that we feel make a nice looking knife are by products of "forging logic."
The ricasso so beloved by the ABS, the "bowie" blade shape, on smaller knives called a Clip, the visual contrast between a curved cutting edge and straighter spine- these all occur almost spontaneously as you pull a cutting edge out of a hot steel bar.

There's no practical reason not to grind the same shapes out of flat stock, but I think our idea of what a knife should look like came from millenia of forged blades.
 
Great thread. It is this type of discussion that keeps bringing the best of the best here to BF.
 
Fred.Rowe said:
I never understood the need to forge a bar of flat stock. Its flat, why make it unflat. Now when I look at at a one inch thick section of 2 1/4 inch round stock, I see a hundred possibilities. The forging process is the height of creativity. Its fluid, the forger is constantly making adjustments as the blade takes shape. I believe this is what draws so many people to it. Its a real challenge as well as an ongoing learning experience. Carrying out heat cycling while the blade is being forged can add a lot, to the final product as well.
Its all good.
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this x1000000

I tried getting into forging with flat stock , but it bored me to death.

Then I took a break and did stock removal and that started to bore me so i went back to forging but instead got some o1 rods and its a totally different ballgame.
 
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