How sharp can it be?

[Fred.Rowe]

Each and every knife sold, whether a custom, bench made or factory blade, should be presented to the new owner along with the blades bevel angles and the specific "original" angle at which the edge was sharpened. If the new owner doesn't have this information, how can he select the correct angle to "touch up" the edge when the blade dulls slightly or God forbid, if the blade is chipped, how does the owner chose the angle that "matches" the original.
I think you can assume that the angles that were chosen by the designer/maker of the knife were chosen to compliment the blades geometry and intended use. If this is true then matching the original angles is mandatory. If these "original" numbers aren't reproduced during touch up or resharpening; the new owner could be destroying what the maker of the blade took so much time to create.

Any knife blade can be sharpened; but only to the degree dictated by the blades geometry.

Would you like to know what angles were used to grind and sharpen the blade you are buying? If so let makers know when you purchase a new knife; I'm sure they would be happy to give you this information.

Happy grinding, Fred

 

[sunshadow]

That information is easily attainable if the edge/bevels are originally done using a jig or fixture like the Bubble Jig or a Lansky system and are consistent from one end of the knife to the other and are not in any way convexed (like the people slack belt sharpening or paper wheel burning do) for those sharpening freehand or doing a complex bevel things get more interesting and less quantifiable, for instance a full height flat grind on a slightly distal tapered blade with a Loveless style drop point profile, that ends up being very complex geometry. Food for thought

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[watercrawl]

If the new owner doesn't have this information, how can he select the correct angle to "touch up" the edge when the blade dulls slightly or God forbid, if the blade is chipped, how does the owner chose the angle that "matches" the original.

I've never cared about this as a buyer.

I think you can assume that the angles that were chosen by the designer/maker of the knife were chosen to compliment the blades geometry and intended use.

Not necessarily. As a buyer, I would never assume a knife maker know exactly how I plan to use the knife. My focus is mainly on kitchen knives, so that's where my comments come from...but:

How can a maker, or a buyer, know precisely what edge angle to put on a knife? First, how can a maker have any clue as to how a knife will be used? Is the end user a push cutter, or a rock chopper? Does he use finesse, or is a quick and dirty user that abuses his knives more for the sake of quickness? Does the maker make the knife like they think it should be made and risk making it really thin for the end user resulting in a knife that the buyer hates because it chips too easily? Or does he make it a little thicker?

As a buyer, you can tell the maker certain things about your cutting style. However, you've never used a knife made by me, with the steel I use, HT'd the way I heat treated it...so how do you know what will work for you in the end?

You can get close...sure. However adjustments are almost mandatory. A knife buyer and a knife maker should both be aware of this IMHO.

Now, for a spec knife...one made without a specific buyer in mind....all of that goes out the window.

This is all said concerning the edge angle...not the angle the knife is ground at. I have no idea why anyone would care what angle a knife is ground at unless they intended on taking it back to the grinder.

Just my $0.02 on the subject any how.

 

[james terrio]

Interesting points, and certainly one of the reasons many people get into handmade/custom knives to begin with - so they can choose the edge thickness and geometry best suited for them.

I generally put fine convex edges on my personal knives, because they cut very well and are super easy to touch up on a belt. But by default, I sharpen for-sale knives with a Lansky system, specifically because it's easy for the customer to match. I will happily change that to a convex by request, no charge.

 

[Nathan the Machinist]

There is no one single edge angle perfect of all the uses a knife may be used for. Even for a particular application, there is frequently not one perfect angle for the entire length of the blade. Some folks might want it thinner at the tip and belly for some cuts, and thicker up near the guard for heavier cuts. Some folks prefer the exact opposite.

A particular knife may perform all of its intended tasks well at 15 per side. But if the new owner plans to use it for lighter cutting and wants the improved cutting performance he may elect to reprofile it to 10. Or if he wants a more durable edge and is less concerned with cutting efficiency, he may go up to 20.

It is folly to assign one angle to a particular knife when the uses and users vary so much. For this reason, I usually sharpen a new knife relatively acute so it will be easy to steepen the edge angle if it doesn't hold up to the new user. Many makers (and most factory) take the opposite view.

A lot of folks like a micro bevel or a convex edge.

So, I think this is a great big grey area.

 

[silver_pilate]

I think it's a matter of different strokes for different folks. Some collectors/users are very specific in the type and angle of edge they want on a blade and often sharpen using various systems out there so that they can control the angle. Others are more free-style. I'm personally a bit more within the free-style crowd.

Like James, many of my knives have a convex edge bevel. If the edge is a convex edge, it can be touched up at home by the buyer with something like fine sand paper on a spongy mouse pad with a bit of practice. For flat ground edge bevels, I've never really been concerned to know the angle on any of the knives I own. When sharpening, I use a sharpie marker and color the edge bevel. If I'm using a sharpening system, I adjust the angle until I'm removing all of the sharpie coloring on a pass, or if by hand, I adjust the angle I'm sharpening until I achieve the same result against the stone.

--nathan

 

[Shaw Blades]

I was reading Bo Bergman's book knifemaking and he discusses the edge of the angle should vary from 10 to 30 degrees depending on its intended usage. Closer to 30 degrees for hunting and 10 degrees for carving softer woods. Do you guys think this is something to take with a grain of salt or does that still hold true to modern technology?

 

[spareparts]

I was reading Bo Bergman's book knifemaking and he discusses the edge of the angle should vary from 10 to 30 degrees depending on its intended usage. Closer to 30 degrees for hunting and 10 degrees for carving softer woods. Do you guys think this is something to take with a grain of salt or does that still hold true to modern technology?

I take guidelines with the grain of salt. Depends on the knife and the task. On a hunting knife 30 degress is good (I prefer 22-25 degrees) if you are cutting through joints, bone, tendons but for skinning and opening up the body cavity I prefer closer to 15 for more scalpel like sharpness and precision to avoid cutting in to intestines and other tissues. But then again, I'll take multiple knives and won't rely on one knife to do the whole job. Depends alot on your touch and your experience in dealing with whatever medium you are cutting in to and cutting with.

I'm no expert but I've been hand honing since I was about 8 years old. If you develop some hand skill you can feel when the angle of the original edge matches up with the stone for touching up. On a bench stone it should kind of feel like your sliding the blade on glass. If it feels sort of gritty (for lack of a better term) then you're not holding it at the correct angle, kind of hard to explain years of experience in a simple text. If the edge is completely shot and you have to take it back to a course stone then it doesn't really matter because you can cut a new edge to what ever angle you like. If you don't know what angles you like for a given knife/task then you need to do more cutting until you figure it out. Now I use and Edge Pro to get an accurate angle initially but do touch ups free hand with bench stones.

 

[sunshadow]

i make some of my knives with an edge geometry in the neighborhood of 22-25 degrees near the handle and 10-14degrees a the tip so that the areas people really lean into for heavy cutting has a very durable edge, but the areas near the tip that are used for very fine work are extremely sharp

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[Nathan the Machinist]

i make some of my knives with an edge geometry in the neighborhood of 22-25 degrees near the handle and 10-14degrees a the tip so that the areas people really lean into for heavy cutting has a very durable edge, but the areas near the tip that are used for very fine work are extremely sharp

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I'm the same way. :thumbup: Of course I'm told I'm doing it wrong by the tactical crowd who like a really thick tip for punching holes in (what I would presume to be) skulls, steel doors etc, while having a thin edge towards the ricasso for cutting the seat belts, belay lines and bomb fuses they're cutting all the time. Personally, I'm more likely to hammer a knife through a (deer) ribcage towards the ricasso, where a bit thicker edge helps. And a thin tip on a drop point (and the edge held facing out) helps unzip the game efficiently. But that's just me.

I put thick tips on all of the wife's kitchen knives, because that is where she bludgeons the plates with them.

 

[Talesin]

More information from the makers/factory is nice, but it is something I can live without. I do all of my sharpening free-hand and use the sharpie method like someone else mentioned. When it comes to people who buy and use knives that don't know how to sharpen, well, then I don't think it really matters because they aren't concerned with it anyway.

I don't know how you guys use the lansky system. I bought one a while back and absolutely hated using it. It probably had something to do with the stones not being flat but I could not put a decent edge on anything with it, and this was after spending a couple of hours flattening the stones I had. I taught myself how to free-hand sharpen and I can regularly get knives to be shaving sharp with ease. I guess it's because with free-hand I get a better feel for the steel as opposed to the lansky where all I feel is the stone.

As far as acuteness or obtuseness of edges, I find that it really depends on the steel and the task at hand. I haven't graduated to putting compound edge grinds on my knives, but in most cases 15-20 degrees works for most of my everyday tasks.

 

[butcher_block]

guess im lucky as kitchen knife ppl havbe even gone so far as asking me not to put an edge on so they can do it them selves and straight razors set there own angle

 

[Justin King]

double post

 

[Justin King]

Does anyone else find it ironic that we are (some of us at least) evolving to require a jig and a table of precise angles in order to sharpen our handmade knives?

 

[Fred.Rowe]

Does anyone else find it ironic that we are (some of us at least) evolving to require a jig and a table of precise angles in order to sharpen our handmade knives?

I think its in a knife makers blood, to get the most out of his creations. Whether its fit and finish, design, heat treat, blade geometry and of course, ultimately blade performance, all get scrutinized, all should and are pushed to the limit. We are perfectionist.

If there is anything ironic about knife making its that we are absorbed with the title hand made, while all along we strive for machined perfection.

Fred

 

[Frank Niro]

I believe Nathan has said it all ! Frank

 

[james terrio]

For this reason, I usually sharpen a new knife relatively acute so it will be easy to steepen the edge angle if it doesn't hold up to the new user. Many makers (and most factory) take the opposite view.

Really excellent point, it's much easier for a client to "beef up" a thin edge than to have to completely re-do a thick one. I tend to shoot for thinner edges (even on "tactical" knives) than most anyway, because the steels and HT protocols I use allow it without being weak... so why not? Thinner cuts better.

If there is anything ironic about knife making its that we are absorbed with the title hand made, while all along we strive for machined perfection.

That's also true! The other ironic thing is that a great many machine-made knives look to me like they're about half-done, and half-vast at that, in terms of fit/finish, sharpness, bevels matching etc. Again, that's one of the big reasons I got interested in handmade stuff to begin with. The upshot is, I feel when a person is paying a good deal more for the skill and labor involved in a handmade knife, it better be pretty dang good. Even if it's a plain-jane model with no bells and whistles, it has to be crisp and clean, and outperform Wally-World stuff.

In any case, it's up to either the maker's personal style, the client's preferences or a combination of both. There's lots of ways to skin this cat, and that's part of what makes it fun

 

[Justin King]

I think its in a knife makers blood, to get the most out of his creations. Whether its fit and finish, design, heat treat, blade geometry and of course, ultimately blade performance, all get scrutinized, all should and are pushed to the limit. We are perfectionist.

If there is anything ironic about knife making its that we are absorbed with the title hand made, while all along we strive for machined perfection.

Fred

I don't want to pick a fight, but I do think your assertions are out of place. I strive for hand-made quality, not machined perfection. I have never used or needed a special sharpening system to take the error out of sharpening, and you seem to imply that I am remiss in that regard.

If the precise edge angles on your knives are a marketing point, then by all means use that with my blessing to sell your knives. But please don't drop it in my lap like a challenge, or use it to publicly point out the errors of others (as you percieve it). The right way/wrong way mentality detracts from the diversity and beauty of our craft.

 

[sunshadow]

I don't want to pick a fight, but I do think your assertions are out of place. I strive for hand-made quality, not machined perfection. I have never used or needed a special sharpening system to take the error out of sharpening, and you seem to imply that I am remiss in that regard.

If the precise edge angles on your knives are a marketing point, then by all means use that with my blessing to sell your knives. But please don't drop it in my lap like a challenge, or use it to publicly point out the errors of others (as you percieve it). The right way/wrong way mentality detracts from the diversity and beauty of our craft.

I think this whole thread was started by the OP as a thinly veiled marketing thread for his Bubble Jig which (if I recall correctly) allows you to set up precise angles relative to gravitational vertical so you can easily reproduce bevel angles. When I was making stock removal knives in the typical style that most factory (and a lot of handmades) are done with a flat area near the spine and a bevel that is a uniform height and angle coming up from the edge to meet that flat, a device like the Bubble Jig would have been really handy for making uniform height and geometry bevels, thankfully I have taken my style into a more fluid direction, so I no longer make knives to look machine made, and my geometry is based more on the form of the blade when I am done with the hammer than any rote geometry, and the edge is a matter of how aggressively sharp can I make this with the steel and heat treat I am using and have this edge stand up to my customer's use. I try to keep as many variables under control in my metallurgical process so I can be as free as possible with the rest of it

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[tryppyr]

Craftsmanship takes many forms, even for something as deceptively simple as a knife.