Secondary Bevel on a Chisel Grind?

T

tpeterson

Joined
Apr 2, 2012
Messages
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Hi All,
I just started making knives this year and working on my first Kiridashi.
The question I have is on the grind.

What are your opinions / best practices when it comes to a secondary bevel on a chisel grind?

Or, do I keep a single bevel to make it easier to sharpen?

Thanks!
Troy
 
The blades edge design is contained within the name itself. Chisel; the name of this style of blade grind comes from the original tool; the chisel.

Some one may chose to add a secondary grind at the edge of the blade, if so it is no longer a chisel ground blade. I can think of no real reason to add a secondary grind at the edge; when all it takes to make any chisel ground blade more keen is to make the angle of the grind more acute.

I know someone who puts a hollow ground edge on his convex ground blades; whats the purpose, got me.
 
There are many knifemakers who make Zero Chisel ground blades. They cut like crazy but can take awhile to sharpen.

You can also make a shallow chisel grind with and edge at 15-20*+/-. It is much easier to sharpe, cuts like crazy and has little parasitic drag from the other side. It is pretty common and companies like Emerson, Strider, Snody and others have great success with them.

Heck Seal Team 6 were carrying Emersons with Chisel grinds with a secondary edge when they terminated Osama :)
 
tpeterson said:
Hi All,
I just started making knives this year and working on my first Kiridashi.
The question I have is on the grind.

What are your opinions / best practices when it comes to a secondary bevel on a chisel grind?

Or, do I keep a single bevel to make it easier to sharpen?

Thanks!
Troy
Click to expand...

The answer depends on what you want in the knife.

I think a near zero bevel with a small microbevel can be a great way to go on many types of knives.
 
Wow!
I love the community here guys.

I posted this yesterday and already have 5 replies!

Thanks for the input. I have my bevel at 20deg, so i think I'll keep it a sing bevel instead of going with a secondary.

I figured I should keep it a single, but I kept seeing so many examples online with secondary, so I thought I'd ask.

Troy
 
As far as a purist definition is concerned, many pro woodworkers like a microbevel on their chisels and plane irons. Does that mean they're no longer a chisel? :confused:

Daniel Fairly Knives said:
The answer depends on what you want in the knife.
Click to expand...

Yup! Use the knife for whatever you designed it for. If the zero edge holds up to your satisfaction, you're golden. If it's chippy or rolls, consider adding a microbevel.
 
I say yes on the secondary bevel. I do a hollow grind with a micro bevel. If you did a hollow to a "zero" edge it would be tough for the customer to sharpen. Picture a hollow ground "scandi" edge, wouldn't work very well. A zero convex edge is also a good way to do it.
 
The consensus I think; different task require different edges, along with differing geometries. With this, mix in different expectations for a given bevel and edge. Some combinations cancel each other out; like the convex bevel sporting a hollow ground edge. The convex bevels add strength, the hollow ground edge takes away from that strength. There are quite a few of these combinations around.

Looking at it as a woodworker, I prefer no added angle on the edge of a flat ground chisel. Most task in a wood shop use the flat ground bevel surface along with the edge. Looking at it as a knife maker and user, I see it differently. The task that can be accomplished with a knife blade, are many compared with the few that are asked of a chisel.
Also, sharpening a flat chisel in the woodworking shop takes seconds, on a horizontal disk, holding the proper angle. Same for a most any blade, including knife blades. If you can't sharpen it, its worthless. :(

This discussion leads to the obvious, elephant in the room; [I despise the phrase] Can you take the same liberties with a "Scandi" ground blade; after all it's two chisels back to back. For this reason I grind few Scandi style blades; its to hard for the average knife user to sharpen.

For me, making original knives, with appropriate grinds, carrying the proper edges for their required usages, is a challenge. That's what makes knife making so satisfying; the challenge!

Happy grinding, Fred


PS. If a chisel ground blade has a secondary grind at its cutting edge; it is no longer a chisel grind; its a flat ground bevel with a secondary grind at its edge.
 
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Most all single bevels actually have a small secondary bevel. It is often referred to as a micro-bevel. By leaving the edge at a single acute angle, it will chip easily. These chips are minute, and often referred to as micro-chipping. A tiny secondary bevel will eliminate or lessen this.

A graver is sharpened to a very sharp edge, and then a tiny secondary bevel is added to thicken the edge and make it tougher. The same principle applies to extremely sharp sashimi blades. After making the blade screaming sharp, a few strokes at about 5° more than the edge angle will make for a more durable and long lasting edge.
 
It's fun to split hairs :) I'm not being a smart-alec; I honestly enjoy thinking these things through with you all, and often learn a lot from that process.

Among the fans/users of "scandi" zero grinds, a hugely common comment is how easy they are to sharpen, since you can just lay the bevel right on your stone or whatever. (naturally it takes a bit longer, since you're removing more steel; but if done often enough the amount is still small and it's very simple to do right).

A bit of research reveals quickly that in general, actual Scandinavian folks almost always put a small micro bevel on their blades... which makes it no different than any other sabre or partial flat grind. I generally dislike that style simply because they're not as acute as a full-flat grind on the same width/thickness blade. These days we're blessed with lots of alloys and HT protocols that can support fine, acute edges... so why not take advantage of that?

I do like very thin edges, whether chisel, full-flat or convex, and find that a small micro-bevel is very easy to set and maintain, and helps with edge-stability while allowing the overall blade to cut really well, as Stacy described.

I can't speak about hollow grinds since I have very little love for them in general, and no experience at all making them.

Anyway! Back on topic... my main hesitation about "chisel-ground" knives is that they're difficult to use with the off hand, and sometimes are ground completely bass-ackwards. But there's no question that a chisel-grind can make for a really sharp, aggressive and controllable knife when done right. :thumbup:
 
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I was thinking about this on the yanagi WIP you posted. My understanding is the bevel is sharpened, a small secondary bevel is added for strength, then they are blended back together. Either that or I'm wrong completely and those knives have extremely low bevel angles, with grinds from 1/2 to 3/4 of the width all the way to the edge. Were I to make one, which I've been planning for months, I'd put a very small microbevel on it, just barely visible, to reinforce what would otherwise be (on my design anyway) a final edge angle of 7 to 10 degrees total.
 
It should also be noted that "chisel" grind has nothing to do with a real chisel. In the fast paced ever changing knife market it simply means "single bevel" or ground on one side( flat, hollow, or convex) Much like the term "Tanto" coined by cold steel in the early 80's during the Sho Kosugi Ninja movie boom. Tanto describes a knife with an aprox. 45 degree armor piercing tip no matter what length. Those of us who studied classic martial arts like Iaido, Aikido and so forth know that a Tanto refers to a very particular blade type, not the Americanized version.
 
JBS TOOLMAKER said:
It should also be noted that "chisel" grind has nothing to do with a real chisel. In the fast paced ever changing knife market it simply means "single bevel" or ground on one side( flat, hollow, or convex) Much like the term "Tanto" coined by cold steel in the early 80's during the Sho Kosugi Ninja movie boom. Tanto describes a knife with an aprox. 45 degree armor piercing tip no matter what length. Those of us who studied classic martial arts like Iaido, Aikido and so forth know that a Tanto refers to a very particular blade type, not the Americanized version.
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I must disagree; if in conversation, someone speaks of a grind they just executed, stating it to be a chisel ground blade, I don't think anyone would ask if it is a flat, convex or hollow ground chisel grind. The understanding being that it is, in fact, a single bevel blade with a flat chisel grind. There are dozens of different grinds, each with its own moniker.


Every blade will have a micro bevel at its exact edge; steel properties say its so. Even razor blades have micro bevels.

Regards, Fred
 
All of my chisel ground knives have a secondary bevel.

I add a secondary bevel for ease of sharpening and increased edge durability.

I have zero ground a few knives, but did not feel that the edge was particularly durable.

The average person has minimal sharpening skills, and will have difficulty trying to sharpen a zero ground blade. Eventually they are just going to give up, and add a secondary bevel.
 
I'm with Jonathan, I tried zero ground knives and mine were very chippy and delicate. I want my customer to be able to sharpen these knives without laying the entire bevel on the stone. What a pain in the ass, and a quick way to ruin the original finish.

Alot of my knives are a single bevel, with a secondary edge on the bevel side, and even a tiny microbevel on the flat side. I've also tried sharpening a bevel on the flat side that terminates into the primary grind. very interesting, and very sharp. Cuts nicely too.

Here's one of my kiridashi's with a secondary bevel on the grind side, and the burr knocked off the flat side with a leather belt. VERY sharp.

IMG_0002-2.jpg
 
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