Ask A Knifemaker

Ask A Knifemaker: The Truth About Blade Shapes Part 1 – Flat Bevel Blades

snody wharny

In our first discussion, we talked about different blade alloys. It takes three main components to talk about the cutting performance of any knife: alloy, heat treat, and today’s subject: blade geometry. The broad subject of blade geometry encompasses many different parts of the blade. While I want to cover all the popular blade profiles, I think it’s best to break them down and talk about one family at a time. Today let’s discuss all the flat beveled cousins. The wharncliffe, sheepsfoot, reverse tanto and coping blade shapes are all related, and will do a variety of tasks well suited to their design . . .

OK so let’s all get on the same page and talk about the anatomy of a blade. Thanks to customtacticals.com we have this handy dandy diagram.

Image courtesy www.customtacticals.com

This diagram happens to show a spear point, but what defines the flat-bevel category of knife blades is a flat (or near flat) cutting edge with the spine dropping to meet it at the point. This makes for quite a few interesting possibilities for the primary grinds, but universally these blades share finer, more delicate points with more tip control. The flat, predictable edges respond well to utility tasks and give the user greater confidence when bearing down, that the edge will cut predictably. Sometimes the “belly” of more sloping curvaceous grinds allows the knife to slide, slip, and in general act more erratically when placed under pressure.

sheepsfoot2

Historically these blade shapes have been in use for hundreds and thousands of years. Typical specialty uses would be whittling and fine carving, fisherman’s/sailor’s utilities, farm tasks, first responder/EMS emergency duties. Why would such a diverse group of people come to love this blade profile? Well the experienced sailor or fisherman use the sheepsfoot blade to allow efficient cutting without the danger of stabbing themselves on a less than stable boat deck. The high sloping spine of the sheepsfoot makes for a poor stabbing tool. This is also very useful for firefighters and EMS personnel when cutting passengers from a car wreck where the goal is to cut the seatbelt, not the people underneath.

Not all of the sheepsfoot’s flat, beveled cousins are terrible at stabbing duties. The reverse tanto and Wharncliffe make extremely thin, fine points that will pierce most mediums with ease. The reverse tanto usually has more tip strength for impact while the Wharncliffe will have a finer edge/point for increased control.

With the advent of modern supersteels, blades can be ground thinner and still hold up to the strength of thicker blade designs. I know that for me, there are very few blade shapes that can compare with the slicing ability of a Wharncliffe. When you slice with a drop point, bowie or spearpoint blade, the tip is usually doing very little work. As the blade slices, the belly of the ground edge cuts the material. This makes for a very smooth draw cut, but a flat bevel will drag that thinner, sharper tip straight through. A properly maintained flat bevel cuts like a laser beam and because you can see the tip at all times, it allows for a level of tip control not possible with other knives.

Wharncliffe3

So if you’re a die hard drop point or tanto fan, right about now, your’re probably asking yourself, “Why?” Well I can tell you, every knife has a purpose and every knife user must make decisions as to the blades they choose to match the cutting tasks they have. For me, I EDC a Wharncliffe style straight bevel blade, because my daily pocket knife tasks require laser accuracy in an easy to touch up blade shape.

I don’t normally make production knife recommendations but as a knifemaker, I have been impressed with the CRKT Eraser, designed by Liong Mah. The $80 street price makes it easy to get a great modified reverse tanto blade in AUS8. The knife is beefy and secure with G10 and aluminum bolsters. I’ve been carrying one for months and love it. If you’re in the market for something different, you can’t go wrong with a Liong Mah design.

CRKT-Mah-Eraser 4

Let me know what your thoughts. I’ll be answering questions in the comments below.

Discussion

12 responses to ‘Ask A Knifemaker: The Truth About Blade Shapes Part 1 – Flat Bevel Blades

  1. Great article. I usually carry a knife with a lot of belly and a fine since my cutting tasks involve a lot of skinning and other slicing motions. For example, I have been EDCing a Cold Steel Police folder now almost exclusively for three years. The reason I go with the belly is for the smooth slicing motion with lower friction “draw cut” you mentioned, but you are right in noting that the tip , except for making initial incisions, does very little work. When I sharpen my knives it is always because the belly has gone dull while I can still shave with the tip. You are also correct to note that tip control on knives with a lot of belly is significantly reduced. I typically notice this deficiency with my knives during food preparation. For instance, when I’m cutting sausages fresh from the grill, since I cannot drag the tip through the cut, I end up with a lot of sausage peices still connected with each other by the sausage skin which I failed to cut at the bottom. Same goes with peppers and onions. The other blade that I use a lot of is a what Eye Brand calls the Spey blade on their Trapper model. It keeps me from getting stabbed when working mounted on a horse or when working with cattle but, since it is a very blunt, symetrical, spear point type chape, the cutting edge sweeps up toward the spine toward the tip meaning that it has the same deficiencies in the tip cutting control department as my other speer, and clip point knives with a lot of belly.

    The CRKT eraser you highlited actually looks like it might be a good knife for me to consider though. It looks like it has just enough belly for the kind of slicing and skinning that I do while being flat enough that I might gain the point control I currently lack. The spine dropping down to the point also makes for a very fine point that looks like it might actually be very useful for initial incisions and for making turning cuts in flesh, e.g. when making the incision around the anus while field dressing an animal. I am also a big fan of AUS8 steel from me experience. I have found it to behave much like many carbon steels that I have used when properly heat treated. It takes a very fine edge, which it does not hold as well as some harder alloys, but it is also very easy to strop back to a razor edge, even in the field.

    It looks like I might be trying out a CRKT eraser in the future to fix that problem wit hanging chads I continually get during food preparation and such.

  2. To read my above reply you might wonder “wow, why doesn’t this guy just take the knife with him fitted to the task at hand? If he’s going hunting, why not take a hunting knife, if he is doing food prep, why using any of the other knives in the kitchen?” As such, you might think I expect too much of my primary EDC knife. Well yes and no. See, I often drop in on situations that I didn’t plan when kitting up in the morning. For example, I might be at the law office in the morning and then get a call mid-day that I need to pick up some hunters from their stand on my way in to the house and deal with whatever game they have on the ground when I get there. Sometimes when guiding hunters there are multiple animals on the ground needing processing, meaning it’s a multi-man job, and someone else’s mystery metal knife takes a dump on them. Then I let them use my purpose-built hunting knife, and my EDC gets pressed into service on the animal I’m working on. Sometimes I go to someone else’s house, and in the course of helping cook, I learn that they have never sharpened any of their kitchen knives, or worse they have those horrible serrated ever-sharp knives that are poor even at being a hack-saw. Instead of using a dull knife and butchering the meal, I’ll pull out my edc (wash it of course) and press it into service. So yes, I do expect my EDC to be able to do everything, but I don’t only use it for everything. If I’m going hunting, I take my hunting knife and my EDC. If I’m cooking, I use my kitchen knives but I have my EDC if I’m cooking away from them. If I’m working cattle, I have my Eye Brand Trapper, and my EDC. If I’m butchering, I have my boning, paring, and skinning knives in the meat room, but I have my EDC too. It’s about built in redundancy, but also about not being able to always anticipate in the morning what duties I might need to fulfill in the evening. As such I am in constant search of an EDC which can do everything from field-dress and process game animals, which be used for self defense, and or as a box cutter or for kitchen tasks if need be. Do I think, that’s asking too much? Well if it was the only knife I ever intended to use, then yes, but as a back-up or fail-safe, I think it is reasonable to seek out a knife for EDC that is good at as many different tasks as possible.

  3. Good review. That was very interesting. I’m a fixed-blade full-tang man yet I am starting to get intrigued to consider buying a folding or flip-out knife such as this one.

  4. “Built in redundancy” is one of those excellent design goals that usually either taken too far or not far enough. Balancing utility with a clean design capable of filling multiple roles is VERY difficult. I really like the CRKT Eraser design because it really can bridge quite a few roles blade shape wise.

  5. good article. I like the blue benchmade knife in the top picture but could not find it (or a blade that matched that style) in the current catalog.

  6. I use a SOG Agency Model for most kitchen chores for which a longer blade is the choice. It works well for stuff that doesn’t require a thin blade for slicing (like mushrooms), and I just like the way it feels in my hand.

  7. Thanks for the great article. I have recently started carrying a Wharncliffe bladed folder and really like the blade design. I almost always carry a GEC #72LB or GEC #53MFT both sporting wharncliffe blades and some of the nicest stag I’ve seen in production knives. You are correct with the fact that a thin profile Wharncliffe cuts like a laser.

Leave a Reply

Your email address will not be published. Required fields are marked *

Pingbacks & Trackbacks

  1. Walter Sorrells Video: Grind geometry explained | The Truth About Knives