Busse and Kin Edge angles

R

rattlesnakerocker

Joined
Oct 13, 2015
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I've noticed that on all of my Busse and Kin knives the edge angle gets more obtuse as you move from the ricasso to the tip. For example, I was checking my Chop House ( Thin cut ) today and it went from 20 degrees at the ricasso to 30+ degrees at the the tip. This makes sharping with a guided sharpening system problematic unless you are willing to re-profile. What do most of you do to deal with this inconsistent edge angle ?
 
Depending on the particular knife, I either leave it thick at the edge for tip strength or thin it out with the rest of the knife.
 
I have been re-profiling. It's quite a bit of work initially, at least on my Wicked Edge, but I really like the results on the few I have done so far.
 
every Busse and kin blade I have all had to be re-profiled, and in some cases, reground. I have not received one yet that could even cut paper from the factory as received.
 
I tend to sharpen until the original edge is worn away. That is to say, until the only scratch pattern visible on the bevel is the one from my diamond plate.

If I'm feeling REALLY ambitious, I use my harbor freight 1x30 belt grinder and get a nice convex going, then use the diamond plates to get a nice secondary bevel
 
Ratman79 said:
every Busse and kin blade I have all had to be re-profiled, and in some cases, reground. I have not received one yet that could even cut paper from the factory as received.
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Can't say that is the case with any of mine. They will cut paper, although some of them aren't exactly exhilarating at it. Most of the time, if the blade is sharpened by Beef, the edge will cut paper quite well.
 
The custom shop blades I have don't need any touching up, but most of my combat grades have required a complete reprofile to be as sharp as I would like, which took forever on the edgepro (My battle saw was the last big blade I did by hand.... and it'll stay the last!) leading me to purchase a worksharp, which does the brunt of my sharpening now.
 
I pretty much run everything between 8-12 degrees per side, which sounds excessively low to most people. That being said, 12 degrees per is plenty of strength for heavy use such as chopping or digging… while 8 degrees is more suited for lighter work. These edges will fail on cutting metal, but to my thinking you either have a knife or a cold chisel… you don't get both. Run you edges thick/obtuse enough to stand up to cutting metal and you've got a pretty miserable geometry for cutting anything else.
 
I've never specifically re-profiled any of my blades. For a long time I was afraid to be aggressive and in many cases would make things duller than they were, but over the years I've been getting better at using hones and rods freehand on both my kitchen knives and my Busses. With the big blades I tend to get a very sharp, but somewhat toothy edge. Not mirror polished they way some of you guys get it. It may even get a little snagged on thin paper, however they can score a pork belly like a razor blade, then chop fire wood, then back to kitchen duties with ease.
 
Out of my ten plus Busse knives, all came sharp and took little effort to get to 40 inclusive. Most of then needed light stropping from the box to get scary sharp! My last two Busse blades, the Steel Heart Ergo and Ratwieler came light saber sharp. The only one that I was disappointed with was my Tglb, it was so thick behind the edge that it doesn't cut, it scrapes. I will eventually get it reground.
 
I can tell you all with 100% certainty --- that Busse knives do not come 20 degrees each side from heel to tip all the way through. The reason why I know this is because I have reprofiled sooooo many

However, they are wonderful and super durable. Fortunately, where there's more -- there's room to create an edge specific to your liking. I certainly have found what type of edge is to my liking! Cheers!!
 
If you are using a sharpening system, simply raise the angle near the tip, or sharpen it by hand to accommodate the variance in angle from heel to tip.

This will conserve the most metal.

Over time with repeated sharpening, it will even out.

This is a function of changing geometry on the knife that includes tapering of the spine towards the tip as well as changes to the width of the face of the blade from spine to tip.

If you do not accommodate the changing angle while sharpening, you will notice the edge widen towards the tip. Nothing wrong with that per se, but you'll grind off alot more than necessary.

My own philosophy is to accommodate the change in angle or thin only slightly there, and then as you use the knife keep working at it.
 
TripleT said:
If you are using a sharpening system, simply raise the angle near the tip, or sharpen it by hand to accommodate the variance in angle from heel to tip.

This will conserve the most metal.

Over time with repeated sharpening, it will even out.

This is a function of changing geometry on the knife that includes tapering of the spine towards the tip as well as changes to the width of the face of the blade from spine to tip.

If you do not accommodate the changing angle while sharpening, you will notice the edge widen towards the tip. Nothing wrong with that per se, but you'll grind off alot more than necessary.

My own philosophy is to accommodate the change in angle or thin only slightly there, and then as you use the knife keep working at it.
Click to expand...

Yes -- if metal conservation is the goal, if maximum durability is the goal, and if minimal reprofiling is the goal ---- however, if consistency, improved geometry, and maximum sharpness is the goal --- then you definitely should reprofile to ensure uniformity.

To each their own though. Either way -- cheers!
 
I freehand all my knives. Sometimes I go hard on them and knock the edge shoulder down a bit if it's a bit too thick. I just do what works for me and get the knife sharp when it needs it.
 
I use different methods; Ken Onion Work Shop, DMT diamond stones, ceramic stones, strops, and even a cloth wheel. I can get my edges to carve receipt paper (most of the time), sometimes even shave arm hair; sometimes it takes more work than I like... but hey, so it goes. All that matters is that they get sharp and cut what you need cutting. But yeah, I wish the edge angles were a little different out the gate. The one example of perfect geometry and crazy sharpness was when I sent in my TGLB for re-sharpening/ profiling, and to get it made into a clip point. Beef did a wicked job.
 
Maggot Brain said:
I pretty much run everything between 8-12 degrees per side, which sounds excessively low to most people. That being said, 12 degrees per is plenty of strength for heavy use such as chopping or digging… while 8 degrees is more suited for lighter work. These edges will fail on cutting metal, but to my thinking you either have a knife or a cold chisel… you don't get both. Run you edges thick/obtuse enough to stand up to cutting metal and you've got a pretty miserable geometry for cutting anything else.
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Um, really??? :confused: It IS excessively low, and that is one of the craziest things I've ever read here. INFI / SR-101 at 58-60 Rockwell C does not have enough stability to support that thin of an edge under heavy use without some pretty serious edge damage. :rolleyes: Maybe at 62-64 RHC, but then the steel will begin to chip out under any amount of lateral force. You WILL get edge rolling and eventually tear-out with that kind of geometry if you try to baton and/or chop with it, especially on hardwoods. A 20-25 degree edge (inclusive) will hold up under a lot of others kinds of normal use, but not the kind of heavy usage that you're talking about (chopping and digging).

How do I know? BTDT. I sharpened my custom shop Bowie RMD to that kind of edge, and in bit of a drunken chopping session one evening, chopped up a bunch of seasoned Red Oak. The next day, once sober, I was shocked to find that my edge was pretty well trashed. No chips or tear-outs, but it was pretty rippled along nearly its entire length, and I couldn't fully repair the edge by steeling it back straight, Instead, I had to grind away some steel to get it back to normal, and reduced the included angle a bit to ~30 degrees while I was at it.

And below 20 degrees included??? :eek: Come on man, seriously? :rolleyes: Maybe if you're using you Busse as a sushi knife... :p Even many razors are set to a final edge angle of 30 degrees. A ~15 degree straight razor will even have a final edge angle of 25-30 degrees due to micro-convexity after stropping. Don't believe me? I suggest you take a gander at the Science of Sharp. There is little reason to put an edge less than 30 degrees inclusive on a knife much larger than 4-5", especially if it is expected to see hard use. Even in general, at less tan 30 degrees on most steels, the edge is either going to get damaged, or you are going to be sharpening it all the time.
 
Maggot Brain said:
I pretty much run everything between 8-12 degrees per side, which sounds excessively low to most people. That being said, 12 degrees per is plenty of strength for heavy use such as chopping or digging… while 8 degrees is more suited for lighter work. These edges will fail on cutting metal, but to my thinking you either have a knife or a cold chisel… you don't get both. Run you edges thick/obtuse enough to stand up to cutting metal and you've got a pretty miserable geometry for cutting anything else.
Click to expand...

Exactly my thinking, yet the last time I mentioned this, I was told by a Busse fan:

breavis5694 said:
INFI is made of all that you hope to be Gaston, as such it will always be out of your reach. 12 degrees is stupid, i can't say that any nicer.
Click to expand...

Now that I know at least someone sharpens INFI to a reasonable thinness, I suppose this means it can actually take it... I have seen many knives by top end custom makers that fail chopping Maple even at 15 per side (and I mean fail in less than 20 strokes): A big RJ Martin in S30V would do micro-folds (a very modest failure that could be detected only as a tiny sideway fold that barely grabs the nail material as your rub the nail, but still unacceptable for ONE hit...), an ACK in 440C at 12 degrees per side (heavy curling), and another 440C knife by Vaughn Neeley, also at 15 degrees per side (crumbling).

Knives that held up included Randalls, Colin Cox, Al Mars in Aus-6 and especially 2 Liles (unmarked if D-2 or 440).

Nice to know then that INFI can actually hold up at useable thin angles. I never could understand anything over 15 per side... Even 15 is really the outer end, more like a good dagger's angle.

Gaston
 
Gaston444 said:
Exactly my thinking, yet the last time I mentioned this, I was told by a Busse fan:

breavis5694 said:
INFI is made of all that you hope to be Gaston, as such it will always be out of your reach. 12 degrees is stupid, i can't say that any nicer.
Click to expand...

Now that I know at least someone sharpens INFI to a reasonable thinness, I suppose this means it can actually take it... I have seen many knives by top end custom makers that fail chopping Maple even at 15 per side (and I mean fail in less than 20 strokes): A big RJ Martin in S30V would do micro-folds (a very modest failure that could be detected only as a tiny sideway fold that barely grabs the nail material as your rub the nail, but still unacceptable for ONE hit...), an ACK in 440C at 12 degrees per side (heavy curling), and another 440C knife by Vaughn Neeley, also at 15 degrees per side (crumbling).

Knives that held up included Randalls, Colin Cox, Al Mars in Aus-6 and especially 2 Liles (unmarked if D-2 or 440).

Nice to know then that INFI can actually hold up at useable thin angles. I never could understand anything over 15 per side... Even 15 is really the outer end, more like a good dagger's angle.

Gaston
Click to expand...

See my response above. In such thin cross-sections, most steels will fail in some manner below RC 62 when chopping, etc. At higher hardness, they will fail with very little lateral force, as they become brittle. They may be great for other things like kitchen duty, animal skinning, etc. but not for heavy use.
 
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