Busse and Kin Edge angles

TheMtnMan said:
Dannn Rob, I cant get over how Sweet those Mirror Edges look.
I think I might just send you my display CS WTF to put one of them Mirror edges on it.
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Thank you sir --- not sure I'll have too much free time in the near future for that kind of awesome job!!! Haha but feel free to check in with me. Congrats on your legendary knife!!
 
Rob_Mob said:
Thanks for the kind words ---- But -- No, Not at all --- that user and I have a history of back and forth exchanges. That user has a history of trolling Busse/Bussekin products. That user has a history of borderline harassing people. That user makes broad claims and then refuses to put his money where his mouth is. That user laughs and chastises people who believe anything over 15 degrees each side is suitable.

You definitely misunderstood me. There are plenty of people who legitimately believe in more acute angles and I applaud them. I myself have tried acute angles on certain knives. I do believe it is silly for someone to bash Busse/Bussekin products for not being able to match straight razor edge angles and chop through seasoned wood without edge damage.

Anyone who knows me knows that I'm a nice, patient, and understanding guy ---- but I have no patience for people who behave in a predatory way and intentionally antagonize people. The only thing worse than that kind of forum member is a forum member who does all that and then refuses an opportunity to validate his claims. Look up his thread history --- I'm surprised he hasn't been banned.
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Lol, thanks for the reply. Guess I read the initial post a bit too literally without knowing the whole context. I nearly spit out my coffee :eek:

I have some thoughts on the larger discussion, but I'm having a lazy Sunday at the pool with my kids, so I'm going to get back to that. :)
 
Apophis said:
Lol, thanks for the reply. Guess I read the initial post a bit too literally without knowing the whole context. I nearly spit out my coffee :eek:

I have some thoughts on the larger discussion, but I'm having a lazy Sunday at the pool with my kids, so I'm going to get back to that. :)
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No worries my friend haha . . . Hope you enjoy the quality time with the family!! Cheers!
 
Rob_Mob said:
I WANT TO PROVE YOU WRONG ---- I challenge you -- do you accept??
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Just put him on ignore. He has a history of taking makers knives to very shallow anglea. Having the blades regrouped, then bashing makers when the heavily re-profiled steel fails!

I usually disagree with everything he posts........
 
SpyderPhreak said:
That, or finish with a strop, which basically does the same thing on a smaller scale.



Yep! :cool: People don't think about the keenness of the apex. Given the same thickness behind the bevel, a 40-degree edge finished to a sub-micron apex will seem sharper than a 20-degree edge poorly finished to a multi-micron apex. Not only that, the 40-degree edge is a lot stronger. As I previously stated, there is very little reason to sharpen at less than 30 degrees on a large blade. I agree that ~35-40 degrees seems more optimal overall, IF properly sharpened. :thumbup: Nice edges BTW!!! :D :cool:
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40 degrees with a highly polished apex will lose that apex performance faster compared to a coarser edge. 40 degrees requires so much effort while cutting I consider it unsafe for any slicing use, which is a big loss of utility for a knife... Also, the reverberation into the hand makes thicker edges much more tiresome to use (but not a huge difference in chopping performance on heavy blades though, although on borderline lighter blades the chopping performance difference of thinner edges is really apparent).

Even for strength while chopping wood, I find claims of more open angle edge "strength" dubious... Thinner edges sink deeper into the wood with less deceleration, and that lower deceleration means lower yaw: This alone tends to make thinner edges more deeply "pinched" by the wood, which helps holding the edge together.

Thinner edges of 12 per side will usually hold up as well or even better in wood than thicker edges or 17 per side, unless a dirt particle is encountered in the bark: So yeah, in rough field conditions with a lot of contaminates, and after a lot of use, the thinner edge might one or two visible, and very narrow, flaws that the thicker edge doesn't... However the thicker edge might have more serious damage in terms of broad-ranging micro-folds all over the place, from yawing and harder decelerations, with a less wood-pinch protected edge... This means that restoring the edge might require going deeper, or the edge will eventually completely chip or fold over. Mind you, a wire edge can still cut for a while if you are lucky...

Gaston
 
SpyderPhreak said:
lol :rolleyes: Sorry man, I don't buy it. Between it being 440B and your claim that it is 0.020" behind the edge (I think that's what you meant), there's just no way. That would mean the edge bevel is nearly three times as tall as it is thick (almost 0.060"). No way 440B wouldn't have folded over at 20 degrees inclusive while chopping seasoned Maple. Unless the dent in the small log in the background of that pic is what you chopped 1,000 times... :p It's MUCH more likely that there was a micro-bevel of 30-40 degrees at the edge of that 20-degree bevel.
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There is inevitably some rounding off near the apex, but again, see my post above: Thinner edges sink deeper, and if you keep the forces mostly straight they are not that fragile because of this... They will even occasionally pry out some wood chips sideways with no damage, after the glancing impact from a missed hit (but not from deliberately applied lateral forces), because the wood chips are still clinging around the edge and support it against the lateral forces that occur when a glancing blow happens.

Gaston
 
I'm with Rob on this also being s/o who prefers 19 or 20 dps for most large, "hard use" type knives. I put it in quotes because the phrase is subjective but I take it to mean chopping, batoning and other such activities. Maybe I could go some degrees lower with no issues, but for me, I would rather err on the side of extra meat than a possible edge failure. I find 19 - 21 or so to be a "jack of all trades" edge that can perform a variety of tasks generally rather competently. For smaller knives like Spydercos, 15 degrees per side is fine and I suspect 12 would be all right too. Of course my Spydercos are slicers as opposed to choppers and that is important to consider when deciding on an edge angle.
 
Well, 12 degrees per side? IS that all? Pretty weak steel. INFI has gone down sub 10 degrees and held up better. I am sure my battlemistress could probably chop a lile and a randall in half and still spread peanut butter on my bread. Easily. But here is a quote that has been around for 15 years.

Cliff Stamp said:
As of late I have been doing some chopping with a BM-E (early one bought when they first came out), and my SHBM. Now my BM isn't exactly standard, it is 0.275", no clip to the point, and weighs 660 g. I have also significantly changed the edge profile, so I wasn't looking at the raw performance as much as looking at how they handled, to check out the new grip mods mainly. More on that later.

I started off cutting some fresh wood, mainly pine, that went ok. Later on I switched to scrap lumber as I didn't have as much free time, and had to fit in chopping whenever I got a free half hour or so. This is when the surprises started setting in. I could not keep a working edge on my BM. The edge would constantly roll to a visible degree, you could see it bend or ripple. To be specific these were just barely visible by eye, the steel was 0.005" to 0.010" thick behind the bend.

Now the ripples were easily removed with a little pressure, no chipping as I would have expected. However I was not overly pleased by having to stop chopping every half dozen blocks (I was using mainly 4x4 and 6x6 posts), to fix the edge. Now I knew that the edge was much more acute than standard, but from memory, the last time I checked it, it wasn't that thin that I would expect the the damage to set in this frequently.

The last draw was when I went back to fresh wood and during bucking some spruce I whacked the knife into a knot in the worst possible way. It was kind of "movie-like" as I oculd sort of feel the chop happening in slow motion. I knew it was going to be bad and when it hit the knot I didn't have to check the edge to know it was going to be dented. Sure enough it was rippled to this time about 0.020" thick.

I straightened it with a nail set and a hammer and then adjusted the profile slightly by adding a convex taper to the last one mm or so of edge. I then checked the edge profile to see how much I had thickened it. It spec'ed out at ~11 degrees per side in the last bit of edge. This took me back because that is where I thought it was before I just altered it.

So I check the primary edge profile and it is ~8.5 degrees per side. Ok, now I understand why it was rippling so easy (relative of course, it only got damaged on knots with full heavy swings). This was a flat bevel, no convex taper, on a heavy blade balanced knife. Not bad at all. And of course, no chipping and all damage was easily repaired with the aid of a large hammer.

For those curious, I checked my notes on the ~8.5 degree mod, I did this to check just how much damage would be induce with wood working as I figured that INFI would set a solid benchmark. I was trying to figure out just how low you could go and still be functional. I seems that a sub mm micro-bevel would be enough for all but the worst impacts.

-Cliff
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^^^ Thanks Cobalt. That's the exact anecdote I've had in mind this whole time. While there wasn't any permanent damage, fixing the edge like that becomes tiresome, and may not be possible in the field.

Again, based on my experience (I only gave one example), there's just no good reason to go less than 30 degrees included on a large blade IMO, especially if there is a high likelihood of true hard use. ~35-38 degrees seems to be about an ideal compromise (yeah, that word...) between sharp, edge longevity, edge durability, and ease of field maintenance in the real world. Hit a rock or torque the edge in a knot at 20-25 degrees? Have fun fixing that edge! :rolleyes: Do that a few times and you'll have lost a significant amount of steel from your blade. No thanks!

Sincerely,
A Drunken Ape ;) :p :D

Let's Drink!!! :thumbup: :thumbup: :thumbup:
 
Rob_Mob said:
No worries my friend haha . . . Hope you enjoy the quality time with the family!! Cheers!
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Thanks brother! We had a great day. Luckily I had some "me" time in the woods yesterday as well :D

I snapped a few pics along the way, but this is the only one that wasn't blurry. It was stupid humid and I was drenched the whole time my boy and I were out:

2rdhsmp.jpg


Granted, that was some pretty soft deadfall, but I'd say that DT is about dialed in where I want it. :thumbup:
 
If it's safe to quote Cliff, I have a good one, rather than poorly explain it in my own words, but basically in my experience as primary and edge bevels go thinner and lower, performance can go up quite notably, but of course durability goes the other way (at a non-linear rate, no matter the steel/ht) and user skill and the specific work involved become much more important. As for what is best/worst, works best for what, etc... well, it just depends ;)


Here is the quote. He talks about Sal and Spyderco folders, but it could just as easily be any manufacturer:

Sal is a contracting agent for Spyderco meaning what he says can be held accountable for and thus he has to be conservative for the simple reason that if he wasn't there could be significant warranty / customer service costs. The strength of an edge is dependent on the edge angle in a nonlinear fashion. To be specific an edge which is ground at 20 degrees per side is almost ten times stiffer than one which is ground at 10 degrees per side. If you were Sal which angle would you recommend given the fact that any time someone damages a knife and decides to make a claim against you then you have to pay for it and if the claims get too frequent it can have a serious negative impact on the business.

Does the edge retention, cutting ability, etc. increase at 10 dps vs 20 - for a lot of work yes. However if you are not cutting clean materials, if you are using your knife as a tradesperson does, if you are not a collector of knives but someone who just carries them to cut things then the damage will increase dramatically when you hit a heavy staple, when you cut into a piece of heavy wire, if the knife is dropped, if someone cuts hard into a sandwich and rams the knife into a plate etc. . In general in the video's the guy doing the promotion has to ride a fine line between making the knife durable enough to reduce warranty claims and not compromising too much on performance.

He likely realizes that anyone who is seriously interested in altering the angle to maximize cutting ability / edge retention is also going to realize the durability issues that arise and not make a warranty claim if a knife which was severely reground gets damaged. Take a look at what happened in regards to warranty.service with the Nilakka for example. There were some very experienced people using that and still they damaged the edge considerably because they didn't take into account the very low strength and durability of a 5 dps edge with a micro-bevel. Spyderco's response was simply to thicken the edge profile to prevent the damage and compromise on cutting ability/edge retention to limit warranty claims.

Remember if you say something or do something it is one knife, yours, if Sal says or does something it can mean a lot more than you can do it and he (and Spyderco) become liable for what results. If Sal said something like "In general you could find that reducing the edge angle to even below 15 dps could increase performance significantly." do you not think that a lot of people might do that and then be surprised with the 10 degree per side edges had vastly reduced durability in heavy cutting. For a lot of people heavy cutting doesn't mean cutting open a cardboard box, you can do that with razor blade utility knife, it means cutting drywall, shingles, sods, etc. .*

Now if you want an interesting perspective on edge angles and sharpening, read the bible on axes by Cook and you will find that he recommends ~15 dps as the edge angle for a full size felling axe. In general you only see people going up to 17 dps for very hard woods, and only going above it still for non-cutting patterns (swampers, splitters, etc.). Now ask yourself - is the edge on my 3" folding knife going to take the same loads as a felling axe? If it isn't, then you likely don't need the same edge angle as one...*
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speaking of angle and everything, what would be a good angle for the 1311? right now i have the "factory" angle

what about the ak47?

is there a good guided system for these long blade or not?

(same question for when B13 will arrive...)
 
The larger blades have more leverage and consequently much more impact energy. So you want more steel behind the edge on a larger blade. On a 13 inch blade, I would say 18-20dps would work fine with hard woods. On soft vegetation, like jungle I would go thinner, like 14-15dps. This is just my taste. Everyone has a different idea and opinion. All this is assuming a tough carbon steel. If I have a stainless steel large blade, I go to a larger angle.
 
In general, I make my edges as acute as possible to start with, as it is easier to go obtuse from there. It will always be tending to more obtuse as you sharpen anyway. I have no measure of the included, but I would bet I'm around 30 deg included angle. It works for what I need.
 
Rob_Mob,
My internet search skills suck apparently. I love your edges. Idolize them in fact. Where can I see them in action? I'm not a good tracker when it comes to this googley stuff. But I want to see them rock and roll. Dems definitely sharp.

Edit: RCB2000... You on the old CZ forum? I mean like back in 2002 or so? Your name looks mighty familiar.

Much love to the good peoples of this forum. Peace and goodnite.
 
crowbardog said:
Rob_Mob,
My internet search skills suck apparently. I love your edges. Idolize them in fact. Where can I see them in action? I'm not a good tracker when it comes to this googley stuff. But I want to see them rock and roll. Dems definitely sharp.

Edit: RCB2000... You on the old CZ forum? I mean like back in 2002 or so? Your name looks mighty familiar.

Much love to the good peoples of this forum. Peace and goodnite.
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If you owe him money, yes, it's me :D
No, not me, sorry!
And yes, Robs edges are insane
 
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