Cliff Stamp
BANNED
- Joined
- Oct 5, 1998
- Messages
- 17,562
Yesterday, I did some rope cutting on the Opinel with the edge profile as indicated in the above. I was expecting slices at less than 10 lbs initially, and to at least reach 500 cuts before the force exceeded 20 lbs. However it took ~18 lbs to make a cut at the start, and after about 50 or so cuts the force was at ~20 lbs. I tried the same sharpening process, only slower this time, on a couple of other knives and the sharpness was horrible on each of them. Specifically, while you could get a strong bite, it required a huge amount of force. In retrospect I should have expected this as I noticed this connection awhile ago. In short, there is a practical limit to the aggression you can get with coarse edges as if you go too rough the amount of force required is far too much. The best result I have seen so far was from a slightly worn 100 grit AO belt. I intend to polish the primary on the Opinel and do some cutting with it at various finer finishes.
Chad :
Plain leather and canvas loaded with paste can align without generating the level of burr of a smooth steel and without removing the micro-teeth as buffing compounds will.
[stropping]
You can avoid this by using a high end strop. It should be pressed leather and thus very smooth and dense. Most modern cheap strops are soft and deform easily.
[710]
My main problem with that knife isn't because of what it is specifically, but what it could be. M2 is a very wear resistant steel capable of getting to 64-66 RC and has a very fine grain. It would be near ideal for an optimal cutting knife focused on light use work and high edge retention (Opinel). The 710 is, I have no doubt, a very solid work knife capable of handling a broad range of tasks, however for that role, something simpler like A2 or even 52100 would have allowed the same performance without the drawbacks of heat treating and machining M2.
In regards to the edge profile, since you are not chopping, you can go really thin and thus allow a much more obtuse edge (and therefore durability) at the same level of cutting ability. The 52100-MEUK I have has an edge of 20+ degrees but will easily out cut knives with much more acute edges because its edge is much thinner (0.005"). I can use it roughly (like splitting knotty wood) without harm. Last time I checked Benchmade was still running their edges quite thick and thus not what I would want performance wise, even if I spent the time to thin it out, which isn't attractive considering the price point. If one comes up cheap on the secondary market I'd look at it seriously, probably re-profiling it bring the main bevel up and down, probably going full convex, and in any event, making the edge thinner.
As well, sabre-grinds on folders really boggle me, and I have concerns about the axis lock after hearing multiple reports of problems. Yes you can just send it back for single spring failures, but since I am in Canada that isn't as easy as it sounds and it is obviously not as robust as simpler designs like lockbacks and the Compression lock. I have settled on the Opinel for a light use folder and am still looking for a more serious work piece. It would be nice if Spyderco would put out a Compression lock folder with a 3/16" blade, full flat grind, right down to at least 0.01" with a 15 degree edge made out of a sensible tool steel, barring that, S30V.
The Sebenza does have a very high performance cutting profile, but I have ergonomic and security problems with frame locks, similar to liner locks. Right now I prefer lock backs and compression locks. As well, with a heavy use folder, I would not want a high hollow grind for durability reasons.
It is the ideal system as then you can also optimize the handle as well as the blade for the given tasks. One of the other reasons that I am really leaning towards multi's as of late is that they are more traditional and don't give off the "weapon" vibe that one handed openers do.
[full size Spyderco Calypso]
I have used the small one extensively and would mirror your comments exactly. Last time I seen it the clip had broken off, taking a huge chunk out of the Micarta, beats me how that was done, same guy mauled the clip on a SOG X-Ray Vision. The lock was still rock solid. Mine was AUS-8 which I found rolled too easily, the VG-10 one should be harder and a very nice upgrade. I which they would come out with a truly optimized one, say ATS-34 or BG-42 at 62-64 RC with a very thin edge and acute angle and promote it as a totally optimized pure light use cutting tool.
My perspective is pretty much the same. For aggressive edges, the first thing I try is some stropping on plain leather or canvas and if that doesn't work a few passes on a smooth steel followed by a couple of strokes on a diamond or ceramic rod to remove the burr and rounded carbides. For polished edges I just strop on CrO.
[Ontario machetes]
I saw the exact same failure with two of them. Very odd when they show high flexibility and in general very durable edges so I don't see fracture growth under impact as being likely. I would guess it is probably a heat treat problem resulting in chains of segregated carbides or impurity clustering at grain boundaries. It could also be just localized problems in the steel, maybe they are just buying low grade. Considering the prices, its not that great of a leap to assume they are cutting costs somewhere.
Yes, exactly. This is one of the greatest misconceptions about cutting performance, as people often comment that "shaving edges" as they are not aggressive. You can get really aggressive edges to shave if they are sharpened with care. I think Joe Talmadge was one of the first people to clearly illustrate this, as most people just assume that coarse edges can't shave. I fluked into it a few times by accident before I realized what was going on as I had just believed the common perception. Improper edge alignment is probably the single biggest problem with NIB edges. Most of them can see performance gains of ~100% with just a couple of passes on a rod or some stropping to align the edge and remove the burr.
Yes, the only other consideration here is the depth of damage and propagation. Under impacts for example, chips are much more likely to spread than dents, this is of course only relevant for large chopping knives.
GREENJACKET :
Yes, the extended lifetime is a large advantage as is the fact that the edge is stable unlike steeled edges which will relax to being blunt over time even without any use.
Yes, I also under cut the edges on my machetes as I don't really care if the edges does get dinged up, and the increase in cutting ability is worth it. For a high end blade you don't want to do this as you will wear it out fast, but for a $10 who cares. Get the best performance you can and buy a new one every now and again.
I doubt it, you would have to go above the tempering temperature and I was holding onto the blade during the process.
Yes, this happens often when people try to "fix" something without really understanding the intention of the design.
I have broken a couple CS knives, and they will snap suddenly, the Twistmaster is quite thin though so I expect it to flex quite a bit before it snaps. The blade mount, since its only plastic, may in fact just be broken apart before the blade is over stressed.
Will do.
-Cliff
Chad :
Plain leather and canvas loaded with paste can align without generating the level of burr of a smooth steel and without removing the micro-teeth as buffing compounds will.
[stropping]
You can avoid this by using a high end strop. It should be pressed leather and thus very smooth and dense. Most modern cheap strops are soft and deform easily.
[710]
My main problem with that knife isn't because of what it is specifically, but what it could be. M2 is a very wear resistant steel capable of getting to 64-66 RC and has a very fine grain. It would be near ideal for an optimal cutting knife focused on light use work and high edge retention (Opinel). The 710 is, I have no doubt, a very solid work knife capable of handling a broad range of tasks, however for that role, something simpler like A2 or even 52100 would have allowed the same performance without the drawbacks of heat treating and machining M2.
In regards to the edge profile, since you are not chopping, you can go really thin and thus allow a much more obtuse edge (and therefore durability) at the same level of cutting ability. The 52100-MEUK I have has an edge of 20+ degrees but will easily out cut knives with much more acute edges because its edge is much thinner (0.005"). I can use it roughly (like splitting knotty wood) without harm. Last time I checked Benchmade was still running their edges quite thick and thus not what I would want performance wise, even if I spent the time to thin it out, which isn't attractive considering the price point. If one comes up cheap on the secondary market I'd look at it seriously, probably re-profiling it bring the main bevel up and down, probably going full convex, and in any event, making the edge thinner.
As well, sabre-grinds on folders really boggle me, and I have concerns about the axis lock after hearing multiple reports of problems. Yes you can just send it back for single spring failures, but since I am in Canada that isn't as easy as it sounds and it is obviously not as robust as simpler designs like lockbacks and the Compression lock. I have settled on the Opinel for a light use folder and am still looking for a more serious work piece. It would be nice if Spyderco would put out a Compression lock folder with a 3/16" blade, full flat grind, right down to at least 0.01" with a 15 degree edge made out of a sensible tool steel, barring that, S30V.
The Sebenza does have a very high performance cutting profile, but I have ergonomic and security problems with frame locks, similar to liner locks. Right now I prefer lock backs and compression locks. As well, with a heavy use folder, I would not want a high hollow grind for durability reasons.
It is the ideal system as then you can also optimize the handle as well as the blade for the given tasks. One of the other reasons that I am really leaning towards multi's as of late is that they are more traditional and don't give off the "weapon" vibe that one handed openers do.
[full size Spyderco Calypso]
I have used the small one extensively and would mirror your comments exactly. Last time I seen it the clip had broken off, taking a huge chunk out of the Micarta, beats me how that was done, same guy mauled the clip on a SOG X-Ray Vision. The lock was still rock solid. Mine was AUS-8 which I found rolled too easily, the VG-10 one should be harder and a very nice upgrade. I which they would come out with a truly optimized one, say ATS-34 or BG-42 at 62-64 RC with a very thin edge and acute angle and promote it as a totally optimized pure light use cutting tool.
My perspective is pretty much the same. For aggressive edges, the first thing I try is some stropping on plain leather or canvas and if that doesn't work a few passes on a smooth steel followed by a couple of strokes on a diamond or ceramic rod to remove the burr and rounded carbides. For polished edges I just strop on CrO.
[Ontario machetes]
I saw the exact same failure with two of them. Very odd when they show high flexibility and in general very durable edges so I don't see fracture growth under impact as being likely. I would guess it is probably a heat treat problem resulting in chains of segregated carbides or impurity clustering at grain boundaries. It could also be just localized problems in the steel, maybe they are just buying low grade. Considering the prices, its not that great of a leap to assume they are cutting costs somewhere.
Yes, exactly. This is one of the greatest misconceptions about cutting performance, as people often comment that "shaving edges" as they are not aggressive. You can get really aggressive edges to shave if they are sharpened with care. I think Joe Talmadge was one of the first people to clearly illustrate this, as most people just assume that coarse edges can't shave. I fluked into it a few times by accident before I realized what was going on as I had just believed the common perception. Improper edge alignment is probably the single biggest problem with NIB edges. Most of them can see performance gains of ~100% with just a couple of passes on a rod or some stropping to align the edge and remove the burr.
Yes, the only other consideration here is the depth of damage and propagation. Under impacts for example, chips are much more likely to spread than dents, this is of course only relevant for large chopping knives.
GREENJACKET :
Yes, the extended lifetime is a large advantage as is the fact that the edge is stable unlike steeled edges which will relax to being blunt over time even without any use.
Yes, I also under cut the edges on my machetes as I don't really care if the edges does get dinged up, and the increase in cutting ability is worth it. For a high end blade you don't want to do this as you will wear it out fast, but for a $10 who cares. Get the best performance you can and buy a new one every now and again.
I doubt it, you would have to go above the tempering temperature and I was holding onto the blade during the process.
Yes, this happens often when people try to "fix" something without really understanding the intention of the design.
I have broken a couple CS knives, and they will snap suddenly, the Twistmaster is quite thin though so I expect it to flex quite a bit before it snaps. The blade mount, since its only plastic, may in fact just be broken apart before the blade is over stressed.
Will do.
-Cliff
