Math & Science when making knives.

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RazrBreed

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Do knife makers(both production and custom) use math and science to make the knives, or do they mostly go by instinct, or possibly a combination of both.
 
Instinct? Like, chewing off the excess steel and G-10? :D

I am going to move this to Shop Talk, where real knifemakers can answer for themselves.
 
It depends on what the maker wants, on one hand; on the other hand, its science either way (manipulating the structure of steel with heat treatments, etc..)

A maker using a simple forge, designing a blade as they forge it is using mostly instinct and experience. A maker making a folding knife of stainless, that they planned out in a CAD program, keeping their measurements exact to ridiculous degrees, is using a bit more math and science.
 
I well I do a lot of reading, and I see that lets take for instance, Spyderco they have a machine that will pretty much break the knife. It just keeps putting torque on the knife to try and simulate a real situation. This is to see how much the knife really could take.

The same thing could be done with a bunch of mechanical engineering equations.
 
Some makers like Cashen are very much into the science of knifemaking, both in terms of steel and shape of the knife, some makers are not.

-Cliff
 
There is a lot of math involved. Some folks don't realize that they are using math, but they are.

Some knife makers use charts, tables, formulae, and calculations, often on paper (I'm one of those).
We also mentally calculate ( instinct?) the volume of a forge chamber, the soak time of a piece of steel and the amount of dilution for ferric chloride etchant. When looking at the color of steel, we compare it to a mental chart of colors vs temperatures.

If you just start heating up any old piece of steel, stick it in something to cool it off, and make a pointed object out of it, then you could be called a non-math maker.

If you heat 5160 to 1475F, soak for 5 min., quench in toughquench, grind with 60/120/220/400 grit, know that you want the handle to blade ratio to be around 3/5....then you are using math.

The first example will yield some sort of knife....maybe OK....maybe not.
The second example will not guarantee a good knife ( but the chances are much better), but you will have an idea where you went wrong if it isn't right.

Stacy
 
I agree with Stacy, but with a bit of a caveat. Just because we use math and science to produce a better product doesn't mean that instinct isn't utilized heavily. I may know that letting the edge heat to 400F while grinding after HT is bad, but my fingers aren't thermometers. My gut tells me when to stop and cool the blade off. I may know that I want to approximate the golden ratio in blade/handle length, but some guys just have a "feel" for what balances well and looks right. A sense of design is something that some folks just have. Freehand grinding compound curves on handles and achieving symmetry takes a certain mindset and touch at the grinder.

Maybe "instinct" is the wrong word, but there is definitely a sixth sense that some knifemakers have (or have developed) that makes custom knifemaking as much an art as it is a science. If you embrace both and deny neither you're more likely to make a truly quality piece of workmanship.

just my $.02...

-d
 
bladsmth said:
There is a lot of math involved. Some folks don't realize that they are using math, but they are.
Click to expand...

I'm just getting to the point now where I don't have to figure as many things out on paper as I used to. I can pretty much look at and hold a blank while I'm roughing and figure out where the balance point will be when I grind it down and add scales and bolsters. There is a point where the math becomes instinct. In other words - there is no substitute for experience and criticism. I'm a bit luckier than some people starting out as I already had a working knowledge of metallurgy from welding that I'm continuing to expand upon, and I've had some people with experience to learn from and bounce design ideas off of (my uncle Kelly, and recently, the guys at this forum). There is a lot of science, metallurgy, and math in making but that doesn't mean you have to be a scientist, engineer, or mathmatician to start out making, although it sure wouldn't hurt:D .


Nathan
 
Intinct, No. Habit Yes.
Stacy Points out that we use math allthe time and he is correct, the human brain is designed to caculate position and trajectories without using the active conscience part of the mind. Knifemaking is a learned skill and can be done with a lot of math and science actively involved or not. It depends on how the maker got his start. Some makers draw out the knives very carefully and then follow with the lines on the steel and remove all the material not in the lines. Some makers just walk up to the grinder and do it. It really is a matter of pratice until the correct behaviors become habit.
Thanks,
Del
 
RazrBreed said:
Do knife makers(both production and custom) use math and science to make the knives
Click to expand...


Everyday ! :D Whether its cutting a simple guard slot or writing a complex program in G code math comes into play each & everyday for me. Science? I get the benefit of science every time I harden & temper a blade. Anodizing Ti, etching a Damascus Blade ? Yes, our trade is filled with both, whether done consciencely or not ;) I wanted to add that since having come to BF I have met some of the most knowlegable people I have ever had the pleasure to come in contact with, yes, there are some "smart cookies" here bro ;) We're talking very "Einstein Like" :D (I don't include myself in that group) ;) I just take advantage of their smarts :thumbup: ;)
 
Knifemaking involves the use of math on at least two levels:

The actual making of the knife is an exercise in applied physics. Algebra, geometry, and trigonometry are required to work through proportional spacing, balance, and various design elements, meteric conversions, heat treats, machining, and everything else. As someone mentioned above; the maker may not be aware that they are using these tools, nor do they necessarily break out paper and pencils; but, they do.

On another level, you need to be able to manage your business. To handle material purchases, logistics, communications, sales, inventory, and financials; and, there is certainly some math there.

n2s
 
One major affliction of bladesmithing is that it is a medieval craft still going in the 21st century. This isn’t really a problem once you manage to come to grips with the traditional tools and methods versus the modern dilemma, but the basic materials still give issues.

In the history of working iron/steel intentional alloying is a very recent thing, for around 2000 years steel was just iron with carbon, as simple as one can get. If you wanted toughness you made it softer. With this you got a couple millennia of tradition and techniques, secrets and tricks. For all those years gut instinct and following the ritualistic methods of a master worked fine since any steel encountered would be iron and carbon. The carbon levels would vary wildly (even within one blade) but with experience this could be dealt with.

Then along comes alloying and everything changes, now two different steels may not only have different carbon levels, they may not even behave like they same metal at all. Suddenly toughness is not solely a function of Rockwell hardness (a quick browse of this and many forums will show how little smiths get this one to this day). Steel can now have elements in them that hog up enough carbon to make a very high carbon steel act like a lower carbon one. Different times at different temperatures are required for each individual alloy and the old universal recipes are all but useless. If you have to walk a path blindfolded it is not too much of a problem if the path is but one, straight and wide. But if you are in a maze you had better take the blinders off and find your way, or find a really good line of B.S. to make it look like your aimless wandering has a purpose.

Those who want stick to traditional methods need to find very close approximates to tradition materials in order to have the same success as the ancients. Those who want to work with modern alloys and get the most out of them had better embrace some science, if they are not a really slick salesman.
 
Science - and then a dose of humility that requires instinct to cope with. There's a lot of science involved in steel selection and shaping that steel as well as heat treating it. Having said that, we (I?) have frequently "re-specified design parameters" - sometimes because it "feels" wrong and sometimes because of an unexpected sneeze while grinding. :rolleyes:

The amount of paper to put in a foil heat treat envelope is stoichiometry - HA! That would just be sicko! :D

Perhaps we should add philosophy to the question of 'science or instinct'?

Rob!

....oh yes - and add beer too! ;)

Rob!
 
Humans are tool makers and for the last few thousand years we have been called on to make all sorts of knives and edged weapons. The form in which they were built was arrived at by observing the function they were asked to perform. The makers would ask themselves, what did or did not work in the past or maybe something entirely new was called for. "Sometimes we learn from our experiences and go on to make a better mousetrap".
When new technologies arrived on the scene makers countered with new blade designs; Drawing both from past experience and creating anew from our imaginations.
In todays knife community we are possessed of some of the finest makers in our history. [imho] There are thousands of makers with a vast knowledge of steel and materials. People with backgrounds in design, metallurgy, jewelry and art. There are many makers that have come from the fields of science and math. We have access to wondrous machines. Todays makers are blessed.
When you put the question forward; whether we use math and science in our knife making today, my first thought was that we have always used both and much more. We do so, even more today.

My .o2 cents, Fred

Edited to include: Sitting in the shop with your feet up on the anvil; dreaming!
 
It is a combination of instinct and engineering. There is the calculations for heat treatment, the size and thickness of materials being incorporated into the knife, use of adhesives and other materials.

The instinctive part is the shaping of the knife; the blade, handle and how it feels in the hand. Making the knife come alive and feel good in the hand, knowing how much weight to remove or add, and the overall appearence too. Some may refer to this as the artwork of the knife, that makes it stand out from the factory knives.
 
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