View Full Version : scandinavien grind pros and cons?


MSoerensen
08-11-2003, 05:40 PM
i would like to hear some pros and cons about the scandinavian grind.

berettaman12000
08-12-2003, 12:42 PM
Me too!!

Jerry Hossom
08-12-2003, 01:45 PM
Are you speaking of a fairly thin blade, flat ground to about half it's width?

MSoerensen
08-12-2003, 05:56 PM
this is what i am talking about
the blade length is 3" and the thickness of the blade is approx. 1/8".
http://www.naturgalleriet.dk/foto/knivmageri/f-klinger/Fuldtange/060301.jpg

JensJ
08-13-2003, 03:27 AM
I personally like it on traditional scandinavien knives-thin blades, relatively short , 'zero-edge flat ground'. Very sharp and strong enough for normal use. But-you have to sharpen the whole bevel, not just a small secondary bevel, or after some time the cutting performance will go down.

But on everything else I think the cutting performance is increased by a high grind (hollow, flat, convex-they all work if the geometry of the blade is right).

Jerry Hossom
08-13-2003, 11:06 AM
There's a lot of emotion and some national pride attached to this discussion, so I'll be careful. This is my personal view only, and is based solely on what I know about knives and my personal experience with them.

I think that blade design is a compromise, based on minimizing the amount of steel needed to make a knife and placing a higher burden on the owner to keep it effectively sharpened, as is noted above. It is not easy to sharpen that entire bevel, and almost impossible to do so properly and/or quickly in the field. The use of a secondary bevel offers advantages in both regards. In an age of very modern steels, which are less prone to chipping, greater strength, and offering improved wear resistance, I think the full flat grind or a hollow grind with a secondary bevel are just much more practical. There is the added advantage of being able to use heavier steel to start with, leaving a thicker spine on the blade for strength all the way to the point; that being especially true with hollow grinds that don't require a distal taper.

As a cutting implement, you have several considerations. The fineness of the edge, the strength of the edge to resist chipping, and the drag induced by the blade behind the edge. The first two are defined by the edge bevel angle and are always a compromise of one versus the other. I personally prefer a convex edge, which is somewhat less fine but better resists chipping. It's my belief that micro-chipping is a major cause of dulling, and convex edges resist micro-chipping very well. Drag is a major component of how well a blade cuts. You can test this very easily, by simply knocking the corner off a secondary bevel by sharpening at an angle about half that of the secondary bevel to create a semi-convex edge. You'll be amazed at how much better the knife cuts, especially in hard materials. The less contact there is between the blade and the material being cut, the less the drag, and the better the blade moves through the material.

Again, this is just my personal philosophy, but I believe there are only two components of a blade that matter. The spine for strength and the edge for cutting. Everything in between is just weight and drag. In that design, given modern steels, there is just too much in between, though on a knife this size weight hardly matters; drag still does...

berettaman12000
08-13-2003, 11:18 AM
Jens...those are some beautiful customs! Who made the custom in Foto 15? Thanks!

JensJ
08-13-2003, 01:59 PM
OT for berettaman: I made the knives in the album-I'm just a hobby knifemaker:) Glad you like them.

Jerry Hossom
08-13-2003, 02:17 PM
I like them as well - simple, clean and very functional designs. Nice!

JensJ
08-14-2003, 01:22 AM
Thanks Jerry, for the nice comments-they mean a lot to me.

To come back to the thread topic: I agree with everything you said.
It would be very interesting to hear more about the history of this blade/grind combination, when it was first used and so on. Also first hand experience from a 'real world' user of these knives in the field...any Scandinaviens around here?

Jerry Hossom
08-14-2003, 12:07 PM
There are a great many outdoors survival folks in the US who swear by these knives. I think for light cutting they work great, though it's helpful to have some long hours out of the field to reset the edge if/when it dulls.

Back off topic for a second. Jens, the more I study your knives the more I appreciate the form/function relationships. How the hand works with the blade and what the blade is really intended to do are often overlooked in knifemaking. Obviously, you've thought about these matters carefully in shaping your designs.

berettaman12000
08-14-2003, 12:59 PM
Jens, you ought to serious consider making customs for money, I've purchased customs in the past that were not as well made as yours appear to be!
I have purchased a couple of factory puukko's in the past and I wasn't satisfied with the blade's performance, am currently looking for a forged puukko from someone who knows how to properly forge a blade.

Keep up the good work and please post pics of your new customs!

JensJ
08-14-2003, 01:32 PM
Thanks again, you two:D

I really try to form my knives so that they 'work', even though they are very small. Most are 3-finger knives, so I spend a lot of time designing a handle shape that is still secure.
I have only hand tools-and I still have a long way to go, especially filing the blade (but thats also the most difficult part of knifemaking when grinding with machines). At my rate, I make about 2-3 knives a year (I'm working on number 11 at the moment, I posted a picture in the 'outpost' further down), so doing this 'commercially' is not really an option at the moment (even though I actually sold some of the knives in the album).

Jens.

edit to add something not OT: berettaman, if you are looking for a custom puukko, do a web search for scandinavian makers-there are lots of them doing extremly good work...or get in touch with Morten, whos thread has been hijacked:rolleyes:

MSoerensen
08-17-2003, 04:09 PM
i have found a page that list some pros and cons do you agree and why?

scandinavian grind (http://www.ragweedforge.com/grind.html)

Jerry Hossom
08-17-2003, 04:55 PM
I disagree for the reasons previously given. I also think the gentleman's arguments are rather dated in view of current sharpening methods (i.e. ceramics) and a bit biased.

Daniel J
08-19-2003, 01:38 AM
As a cutting implement, you have several considerations. The fineness of the edge, the strength of the edge to resist chipping, and the drag induced by the blade behind the edge. The first two are defined by the edge bevel angle and are always a compromise of one versus the other. I personally prefer a convex edge, which is somewhat less fine but better resists chipping. It's my belief that micro-chipping is a major cause of dulling, and convex edges resist micro-chipping very well. Drag is a major component of how well a blade cuts. You can test this very easily, by simply knocking the corner off a secondary bevel by sharpening at an angle about half that of the secondary bevel to create a semi-convex edge. You'll be amazed at how much better the knife cuts, especially in hard materials. The less contact there is between the blade and the material being cut, the less the drag, and the better the blade moves through the material.

Again, this is just my personal philosophy, but I believe there are only two components of a blade that matter. The spine for strength and the edge for cutting. Everything in between is just weight and drag. In that design, given modern steels, there is just too much in between, though on a knife this size weight hardly matters; drag still does...
Jerry, are you advocating a full hollow grind (like a straight razor)? :D
I'd tend to side with the scandanavian POV as far as woodworking goes, but I'm sure you've got far more experience than I do when it comes to hunting blades...

Jerry Hossom
08-19-2003, 09:18 AM
Originally posted by Daniel J

Jerry, are you advocating a full hollow grind (like a straight razor)? :D
I'd tend to side with the scandanavian POV as far as woodworking goes, but I'm sure you've got far more experience than I do when it comes to hunting blades...

Not necessarily a hollow grind, but certainly not a chisel grind which is basically what the Scandinavian grind is. I guess I'm not sure what you mean by "woodworking". I was speaking of field use. If the edge is shaped properly, what's between the edge and the spine doesn't really matter much. For camp chores, I use a grind that is hollow at the top, transitioning into a wide convex grind and edge at the bottom.

BTW, I whole-heartedly subscribe to the philosophy and interests expressed in your bio... :)

MSoerensen
08-21-2003, 04:38 AM
jerry earlier in this thread you said

It is not easy to sharpen that entire bevel, and almost impossible to do so properly and/or quickly in the field.

well i have read a lot about some different grinds, one of the things said about a full convex grind is that it is almost impossible to sharpen without a slackbelt grinder, so i would like to hear if you are able to sharpen your blades properly/quickly in the field. and how you do it?

Jerry Hossom
08-21-2003, 08:44 AM
Almost anytime you sharpen a knife on a stone you get a convex edge, unless you're using an angle guide like a Lansky or the grind itself as on the Scandanavian blades. For field sharpening of my blades I recommend a ceramic rod, run along the edge. What's immediately behind the edge is defined by the maker/manufacturer. If that is convex, then the sharpening process will tend to follow that same contour. If you screw it up because you're in a hurry, you'll have to work a little harder when you get home.

A convex edge is really not "almost impossible to grind without a slack belt grinder", but it's a lot easier with one. They are certainly not "almost impossible" to sharpen. Fact is, convex edges and blades have been in use for centuries. Bill Moran finishes all his knives with hand sharpening on a stone, and he does it quickly. Barbers have always maintained the edges on hollow ground razors solely by stropping. Those edges are convex.

I think there is an area of confusion that's been created by the association of woodworking tools with knife blades. Both need to be very sharp, but the role of the edge geometry is very different. The only thing they really have in common is the need for a reasonably fine angle to provide effective cutting. A chisel and other such tools, however, need a flat bevel to work properly because they depend on that bevel for accuracy in the direction of the cut. Knives don't have that requirement, at least not to the same degree. Maybe if I were using one to carve wood, I'd think differently, but I don't use a knife for that purpose. I see people buying $300-500 sharpening systems for sharpening knives, primarily because they hold the blade at a precisely fixed angle and are therefore fairly foolproof. For the same money, or even a LOT less, they could buy a small belt grinder and sharpen knives better and faster with little trouble. For about $20 you can buy cardboard sharpening wheels to mount on a $30-40 bench grinder that will sharpen knives very quickly and with almost any kind of edge you want to put on it.

Consider this. Virtually all the professional knifemakers in the world have equipment that will allow them to shape a blade and the edge anyway they want. The choice is entirely theirs. Some base their choices on what their customers want; some on what they think is best based on their personal experience. Regardless of how they arrive at the decision, the vast majority use full grinds and convex edges.

MSoerensen
08-21-2003, 11:34 AM
then i have some questions for you.

how can it be that the sami people who live in the northern norway finland and sweden, and uses their knives for a lot of different purposes havent choosen another style of knife if the full convex grind are so much superior to the scandinavian grind in everything else than woodworking?

and there is a lot of hunters in the scandinavian countries who still uses knives with the scandinavian grind, why would they do that if they were so hard to sharpen in the field?

not that i have anything to compare the scandinavian grind to convex or full grind, but i have had a hollowground knife blade which was impossible to keep sharp. this is compared to a frost blade, which i s very cheap, the frost knife didnt cost more than the knife blade which were bought in the us.

maybe it was just me who didnt know how to maintain that knife, but i have a lot better experience with the scandinavian grind.

i am not writing this to irritate someone. i just want to know as much as i can about this grind because i like knives with this kind of grind.

Jerry Hossom
08-21-2003, 12:33 PM
It doesn't matter where a knife is made nor its design. A bad knife is a bad knife, and a good knife of any design will usually outperform a bad knife. Why don't some people change? If I could answer that question I could probably rule the world... :)

You can sharpen a scandi blade in the field quickly at the expense of creating more work when you want to restore the edge to its original condition. You simply apply a secondary taper, slightly steeper than the primary grind, but eventually you have to pay that back by grinding away more steel to get back to the original edge. In truth, it's impossible for me to answer your question without knowing how those who use Scandi knives actually use them, for what tasks, and how do they perform those tasks compared to what I'm familiar with. I also don't know their mindset about using them preferentially to other blades. Tradition means a lot to people. I'm not very fond of Bowie knives but a lot of people use them. For many years I used a little 3" Shrade hunter, because someone told me it was a good knife. I kept it sharp and it served me very well for many years. At the time, nobody could have told me there was a better knife for what I wanted to do.

One of the many problems when people compare designs, manufactureres, steels, grinds or any other feature of a knife is that unless you actually compare a great many, and know that each knife tested is made to the highest level it's able to attain, you really don't know if what you're seeing is a problem of the design, the manufacturer, the steel, grind or any other individual attribute of the knife.

Many people say stainless steel makes lousy knives. Some will say thay've had bad luck with a stainless hunter from a particular company; others will swear they are good knives. If you understand the process these companies use, you can understand how two knives out of the same batch, with the same steel, same design, same grind, and looking exactly the same in every way, can easily be very different in performance, ranging from good to terrible. The only way you can really compare anything about two knives is to make two blades exactly the same in every detail except the one element which you are testing. If the hollow ground blade you tested had kousy steel or maybe just a bad heat treating cycle, the results of your testing would reveal only that. It wouldn't tell you anything about the merits of a hollow grind. Maybe it wouldn't stay sharp because you were unfamiliar with how to best sharpen it, so the edge you applied was one that was easily dulled, regardless of the knife being otherwise sound. I'm not saying that to question your sharpening skills, just observing that there are many many variables in a knife and you seldom know which is resposible for good or bad performance.

Mass produced knives in Scandanavia, using good Swedish steel, might just be made better than mass produced knives from Taiwan. Maybe there's better control of the heat treating process. Maybe there's better automated equipment. Maybe the workers are more skilled or conscientious. Maybe the design IS better.

And maybe it's as simple as these are the knives the Scandanavian peoples are familiar with and like, having used them since childhood, and being familiar with how to best use and maintain them.

Hell, some people think Green Herring is better than fried trout... :)

Daniel J
08-22-2003, 05:31 AM
Jerry, the majority of (good) straight razors made in the past 150 years have been of a full hollow-grind cross section.
Barbers do maintain them primarily through stropping, but that maintainance would be very difficult on a convex edge, IMHO.

The main purpose of a hollow-ground razor is to allow a perfect-angle sharpening method (alot like the scandanavian grind being discussed) without spending all that time honing away the steel from the sides of the blade.
It also cuts down on weight and lets the razor sing, but the maintainance aspect is the most important one for someone who shaves with it several times a week. The strop isn't used the same way you would use a strop with a secodary-beveled edge, it's always at the same angle. (spine resting on the strop/hone, edge just touching.) This allows for a super-precise edge without requiring the hands of a surgeon. :D

That's why I think the lansky system is great as well- if you can sharpen the same edge the same way every time, you'll reduce the amount of sharpening you need to do overall; and you'll get a better slicing edge as well.
Camp knives/butcher's cleavers/etc. are obviously a different matter; but for cutting paper, leather, vegetables, softer wood, meat, etc. you want a precise edge with no variation in angle. Obviously a covex grind could do all of those things, so I suppose it's a matter of deciding which feature is more important- the durability or the precision...

I find it hard to keep up with you, Jerry, you keep saying such insightful things... Personal experience is the definition of all of our knowledge- every answer we recieve must be checked and re-chacked against memory in order for the mind to accept it. When I think of blade shapes I like most, the two that come to mind are the Boye drop-edge utility knife and the classic Loveless hunter. Can you guess which how-to book was my first? Can you guess which custom maker I read about most in my early blade-fanatic years?

(BTW, which philosophy in particular do you agree with? Being unskilled due to lack of experience and not having the willpower/time to go out and get it; therefore resorting to the repetitious regurgitation of third-hand information on internet msg. boards in order to feel a sense of accomplishments in the arts? ;))

Jerry Hossom
08-22-2003, 08:20 AM
Daniel, I believe I said straight razors were hollow ground, and having seen them used and sharpened in barber shops for much of my life, I've observed that most barbers stropped by whipping the blade edge back and forth on the strop, which will inevitably lead to a convex edge. In fact a strop doesn't really work if the blade is flat or near flat against it.

The next time you use your Lansky, take an older knife, maybe an old kitchen knife you're not fond of and sharpen it at a fairly steep angle, then see how it cuts. Then lower your Lansky to the shallowest angle you can achieve and knock the corner off that bevel. Retest. See the difference. This is an approximation of a convex edge. It's the same edge angle, just different cutting dynamics. If on your good knives, you knocked off that same corner, you'd get a similar improvement in cutting performance. If you were to polish it all into a smooth parabolic curve you'd see dramatic improvement in cutting.

David Boye's book was the one that inspired me most as a beginning knifemaker. I found Loveless' book a bit daunting. I ended up just doing things that seemed to work for me.

Most of my knife knowledge is experiential. I'm too much of a cynic to accept rules as fact. It's been my experience that at least 50% of what's stated on most knife forums is incorrect compared with my personal findings (CKD being a notable exception). I often disagree with some of the best knifemakers I know. Likely, we are both wrong. The quest for the perfect blade continues and will forever...

Daniel J
08-22-2003, 11:35 PM
Barbers have always maintained the edges on hollow ground razors solely by stropping. Those edges are convex.
That was the comment you made; sorry if I misunderstood you. From personal experience, a straight razor should always be stropped/honed with as shallow an angle as possible; most (http://www.bladeforums.com/features/faqrazor.shtml) razor literature (http://web.archive.org/web/20010221021014/razorcentral.tripod.com/honr.html) says to roll the blade over the spine at the end of a honing/stropping stroke to prevent the development of a secondary angle. I'm sure plenty of professionals learned to do it differently for the sake of speed; lots of those professionals have also switched to disposable blades...

I understand the benifit of a convex edge, I like to shapen lots of my knives to a similar edge. (larger or utility-oriented ones.) But I think that for woodworking especially, the sigle-angle edge will actually provide less resistance. Think of an airfoil: the curved surface generates more airflow because of ... more surface area. The flat angle of a scandanavian knife generates less drag.
But, as you've been saying alot around here, chipping is a large part of what makes an edge dull. With a tougher steel in a fine enough edge, you'll simply find the edge rolling over. I was using an old straight razor (I got several more than I needed from an e-bay auction) for slicing heavy leather/kydex one time, and it didn't stay sharp for long! Obviously this is a matter of using a super-fine edge for something it was never designed for. But knives with a steeper angle work very well indeed for that sort of work.

The quest for the perfect blade continues and will forever...
There is no perfect blade. A machete is a crappy craft knife. A rotary slicer is the worst tool possible for bush clearing. A woodcarving chisel sucks at cutting seatbelts.
IMHO, we need to stop worrying about making one knife to do everything and start working out a system that will do what it's supposed to do, and be there when you need it. (IE reasonably lightweight and simple to carry.) Multi-blade carry systems have been around for a long time, but they've been almost abandoned recently.

Jerry Hossom
08-23-2003, 09:50 AM
Originally posted by Daniel J
... But I think that for woodworking especially, the sigle-angle edge will actually provide less resistance. Think of an airfoil: the curved surface generates more airflow because of ... more surface area. The flat angle of a scandanavian knife generates less drag.

Depending on what you're cutting and how, that edge actually generates more drag. The convex edge reduces the effective frontal area of the airfoil, since the edge breaks contact with the material being cut as soon as it reaches the top of the parabolic curve. That might happen after the edge has penetrated only 1/8" or so, depending on the elasticity of the material being cut. A blade is an airfoil, but what you're cutting is not a fluid. Some of the analogies apply though. Imagine a symmetrical airfoil (a blade) with a large ridge at the top of the leading edge. That would create huge drag. That's what you have with the shoulder on a flat beveled edge. Also, since what you're cutting is either a solid or a semi-solid, the distance it's in contact with the sides of the blade generates still more drag. In the case of the knife shown that looks to be about 1/4", maybe more. A convex edge, particularly on a hollow grind, likely only extends back 1/8", and after that there is NO contact with the material being cut - No drag induced by the sides of the blade.

Ever use a French Chef's knife? Ever had something you're slicing pile up on the sides of the blade, until it finally drives you nuts and you have to stop and clean it off? All that material on the side of the blade is causing drag. The edge on that knife is very fine, and the frontal area is pretty small, maybe 1/8" max on a good knife. It cuts pretty efficiently, but it still suffers from drag. So too does any zero ground blade. (I don't want to wander into philosophies on food cutting knives in this thread - we can start another for that if wanted. I'm just using that as an example of blade geometry induced drag. )

As for that straight razor that didn't cut leather, you assumed the problem was the blade/edge geometry. As I stated earlier, you really don't know why that razor failed the task. It might well have just been a lousy straight razor that wasn't a very good at being a razor either, for reasons that had nothing to do with its shape. Maybe it was just bad steel. Extrapolation in the world of knives is risky. Logic fails when a second variable remains undefined.

Daniel J
08-23-2003, 05:22 PM
Hmmmm... fluid dynamics... I think I need to do more testing...


But I'm sure that the razor failed because of abuse. The fine edge rolled over when put up against tough surfaces. Splitting protein molecules in facial hair is one thing, slicing kydex/harness leather against a stiff cutting board is another entirely.

C L Wilkins
08-24-2003, 02:05 PM
Most knife designs are a result of necessity and/or culture. Some good, some not so good but they all serve the basic purpose of cutting or stabbing, regardless. I have no idea what the main purposes are of a scandinavian knife. Some designs are steeped so far in tradition that everyone has forgotten their original purpose! Take a look at a traditional design such as the "Bowie" nowadays. There are better designs but we still have the traditional aspect of them. A machete or bolo is another example. So is a scimitar, kukri, katana, or a French chef's knife for that matter. Did you catch something in that list? All from different cultures.

I realize this thread is concerning scandinavian knife design however with the topic moving towards uses and designs I found this to be rather interesting at this site. (http://www.knifecenter.com/knifecenter/sharpen/instrazor.html)


I have studied straight razors over the past few months and even if you just casually study them you can soon appreciate the complexity of their design. There is more than one size wheel used in the manufacture of high end straight razors, sometimes even three different size wheels are used for "hollowing" different parts of the blade. Some razors are still flat ground.

Actually, once a razor is stropped it should be allowed to "rest" for 24 to 48 hours so the "fin" will straighten. Straight razors "once upon a time" were generally sold in sets of two or three, sometimes one for each day of the week due to this.

An exerpt from the link above is as follows:

DESCRIPTION OF STRAIGHT RAZOR ANATOMY Orientation used in the description: the handle to the right, blade to the left, cutting edge pointing downwards. Kopf/Point/Bout/Punta: the left end of the blade. Blade, with a Ruecken/Back/Dos/Lomo, the part of the blade opposite the cutting edge, and a Schneide/Cutting edge/Tranchant/Corte (pointing downwards). Erl/Tang/talon/Espiga: the complete non-cutting metal part fixed to the blade, serving as a grip for the index, middle, ring, and little finger. Doppelansatz/Double stabilizing piece/Double piece stabilisatrice/Doble pieza estabilizadora: two close parallel vertical rims situated where the tang continues to the cutting part on the knife. Sometimes there is only one stabilizing piece. Kranzangel/Decorated tang/Talon decore/Espiga decorada: some sort of art where the blade stops and the tang begin. Schale/Handle/Manche/Cacha: the the part of the razor that contains the blade when closed. Sometimes it has an Einlage/Inlay/Marque/Marca (text, mark on the handle). Steg/Center plug/Rivet central/Remanche estabilizador: the middle plug on the handle; Hohlung/Hollow ground/Evidage/Filo Concavo: the biconcave form of the blade in transection view. Goldaetzung/Gold etching/Gravure doree/Grabado dorado: the mark or text on the blade. Zeichen/Trade mark/Marque/Marca, the mark/text graved on the tang. The Ridge/Der Wall: parallel to the back and the edge, running from point to the stabilizing piece, is a thickening of the blade, the purpose of which is to stabilize against torsion in the horizontal plane, and to give the edge elasticity. The stabilizing piece gives the blade torsion resistance in the vertical plane. If the ridge is close to the edge, it is called =BC hollow ground, the lowest grade of hollow ground; if it is close to the back, it is called 1/1 or full hollow ground; =BD and =BE are in-between. More on grind types below.

TYPES Flat and hollow-ground: Derbes Messer/Flat ground/Le rasoir plein: the cross section of the blade is a triangular shape; Hohl/Full hollow ground/Creux/Concavo: biconcave cross-section; Something in between (1/2 or =BE hollow).

BLADES Round point/Rundkopf: the point is rounded. Square point/Gradkopf: the point is square, forming a spike at the transition between point and cutting edge. Something in-between: Franzkopf Blade sizes (width) are: 3/8", 4/8", 5/8", 6/8", 7/8".

PRINCIPLES OF STRAIGHT RAZOR GEOMETRY In the beginning straight razor blades were wedge shaped, the sides of the blade were straight lines, not concave (hollow). These blades shaved as perfect as the later hollow ground blades, if sharp, but had some disadvantages. First, they were heavy, compromising balance. Second, due to the wedge shape, the sides of the blade above the cutting edge instead of the edge itself, primarily touched the hone surface while honing. Third, after years of daily use, the regular honing caused rapid thickening of the edge width, thus making sharpening increasingly difficult and time consuming. Therefore, the next step was to clear the blade sides from the hone surface, in order to reduce weight, and to use the back as a guide for keeping the correct angle of the cutting edge, with which it forms one plane. This was done by grinding away metal between the cutting edge and the back with a wheel, resulting in a biconcave, hollow ground blade (at first without a ridge), combining an extremely thin blade with a very small cutting angle under 15 degrees. The disadvantage of this second step without a ridge was, that the ultra thin biconcave blades were unstable in the direction perpendicular to the plane of the blade. Therefore the third step was to create a ridge parallel to the cutting edge, dividing the blade in two parts: an upper part between back and ridge, and a lower part between ridge and cutting edge. The ridge is created by grinding the raw triangular basic form with successive different wheel diameters: the greater wheel for the part between ridge and back; the smaller wheel for the part between ridge and cutting edge.

The result consists of two hollow grind blade divisions separated by a thicker ridge, with hardly visible smooth transitions. The closer the ridge is to the back, the more the type goes from =BC to 1/1 hollow grind. The ridge presents stability and vibrations which add to cutting performance, which can be identified by transversely rubbing the thumb carefully over the edge, causing a ringing sound. The ridge is not that thick that it touches the hone, of course, and you can hardly see or feel it. The three parts (two concave parts separated by the ridge) are identified under a sharp light: the ridge diverges the light and is therefore identified as a linear shadow, parallel to the edge. The full hollow grind blades have the ridge at about a little below halfway between back and edge; lower grades of hollow ground just behind the edge, or somewhat further to the middle of the blade. A full (1/1) hollow ground blade keeps a very thin edge even after a lifetime of honing and stropping; a =BC ground blade edge rapidly thickens after years of honing, because of the proximity of the ridge to the edge.

RECOGNIZING A double stabilizing piece (two vertical rims between tang and blade) implies 1/1 (full-) hollow ground, but some full hollow ground blades have no stabilizing pieces at all, but instead a smooth transition between blade and tang. Theoretically, you might confuse a single stabilization piece (which indicates less than 1/1 hollow ground) with these types of full hollow ground blades but there is a difference which can be seen with the full hollow ground Bismarck or Renaissance (DOVE) types of blades. The Bismarck shows a smooth transition between blade and tang, lacking any rim, and therefore is easily identified as full hollow ground. The Renaissance has one rim, which might indicate either less than 1/1 hollow ground (cheaper) or full hollow; the fact that the rim is ot confined to the blade, but runs through into the tang, identifies this type as full hollow ground. If the transition from tang to blade shows one vertical rim that is confined to the blade and exactly vertical, it must be a flat ground or =BD-3/4 hollow.

PURPOSE OF TYPES In general: the higher the grade of hollow grinding, the easier it is for the customer to keep the blade in perfect condition with relative ease (stropping and sometimes honing). Flat ground: in general for heavy and less perfect shave, for contour shaving, hospitals, etc. Full hollow ground for thorough and precise shaving. 3/8", 4/8": hospitals, eyebrows, and a very soft beard. 3/8" and 4/8" are mostly flat or half-hollow- ground. 4/8", 5/8": preferred for daily shaving, specially 5/8" which has more torsion resistance. For persons with very large hands and/or handicap the 6/8" and 7/8" were originally designed, but they also have very good torsion resistance and shaving characteristics.

Taken from www.knifecenter.com

Craig

Daniel J
08-25-2003, 02:04 AM
I'm going to go a bit further off-topic here... Or maybe not...

Craig, IMHO (and it's not necessarily any more valid than yours, I've only been using a straight since early this year) there is one reason and one reason alone why we're told to let a razor "rest" this semi-theoretical super-fine burr along the edge of the razor- because someone thought they could sell 3-day sets.
It worked- they're very collectible, too.
They expanded on the idea and started selling 7-day sets- why would anyone need to rotate 7 identical razors? I can't think of a single reason... Unless perhaps you shave your entire body in a rotational pattern during the course of a week?

The literature we see at knifecenter is almost directly from Dovo, IIRC. Not only does this lead to a poor translation, (:rolleyes: ) It also means that they're going to tell you what will make you want to buy more razors.

(If you want to find out some more about straight razors, this yahoo group (http://groups.yahoo.com/group/straightrazorplace/) has some serious enthusiasts, and even some professionals.)

So, what does this prove?

That Scandanavian knives aren't the only grey-area of our collective knowledge when it comes to rock-hard facts. That's why I like groups that encourage experimentation and learning from a maker's POV- it really opens up your eyes...

C L Wilkins
08-25-2003, 02:26 AM
Nevermind.

Daniel J
08-25-2003, 03:50 AM
Nevermind what?
Any question or answer can be valuable depending on how much thought you're willing to put into the evaluation of it, and how much experience you have with the subject.
Your comment about the differences in knife styles used worldwide is an excellent point- these ideas and concepts came from somewhere; so we can't discard them without sitting down for a good while and examining the facts.
As far as the micro-fin on straight razor edges; I'm inclined to dismiss it; and my personal experience doesn't give me any reason to go against intuition. But it does make me curious- has anyone ever done real research? At what level of finishing might we see this phenomenon occuring? Could it apply to a few particular steels more than others?

I think it would be cool to have an organized, professional thinktank of knife professionals and researchers do real, in-depth research into these sorts of questions. Right now, it's up to us and our low-budget testing methods, with experienced input from really cool guys like Hossom and Cashen, to name a very few.

Keep posting stuff for me to read and think about, Craig! It's the only excuse I have not to do 'real' work! :D

Jan Dox
08-26-2003, 04:44 PM
I like the look of Scandinavian knives, but I prefer a convex grind myself. The scandinavian grind looks easier to manufacture, as most blades are fairly thin <1/8" the primary angle is small.
The shapes are very old and tested in time.
At home the bevel was easily restored on a big (handpowered) waterstone and in the field a secondary bevel was formed if neccessary. This is easier than maintaining a nice convex edge without a belt grinder.
Another factor for this grind could be that , with laminated blades (hard core and softer sides) the core had better support and less risk of breaking the weld between the layers of steel under stress. (Not all smiths could produce top quality laminated blades I suppose and we must keep aware we are talking about relatively thin blades here).

my2cents,

Jan

Mut
09-19-2003, 04:48 AM
Hi Jens.

I am a maker and user of hidden tang nordic Knives. I personally think that the edge holding capability has a lot to do with the person who forged it. I have used some blades that are a little thicker than others and they hold the edge well.

There is also a new sharpening tool available here for sharpening knives in the field. It'd be soet of belt kit. You turn the blade and run the diamobd wheels along the cutting edge and they sharpen the blade really nicely. I use one whilst I an fishing all te time.

It is made by helle i think.

As for blades though, hand forged tend not to hold an edge as long as the factory produces. Something to do with steel types I would think.

just my opinion.