Cliff Stamp
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- Joined
- Oct 5, 1998
- Messages
- 17,562
Specifics :
The Howling Rat is 185 g and balances about a half a cm behind the handle, neutral and very light in hand. It has a high sabre flat grind, with a small strip of unground steel along the spine. The blade is is 0.031 - 0.038" thick behind the edge, which is ground at 17-18 degrees per side. For a general use knife that angle is a solid choice, robust enough for anything outside of hardened metal, however I would cut the edge thickness down just a little. About 0.020" thick behind the edge would leave it robust enough for light to medium knot work (batoning), and any cutting work outside of heavy twisting which could induce the edge to ripple [not a concern with the current profile].
However this would lower the durability to the point that you could possibly damage it deeply [into the primary grind] on extreme hard contacts with rock or hardened metal, and it would prevent the edge from being able to take significant lateral loads, and thus its usefulness as a an overall utility tool would be lowered. The overall gain in cutting ability would be a matter of a small percentage (around 20% on binding material like woods, much less on things like ropes etc. ), so the higher thickness could easily make a lot of sense to some in regards to large durability gain vs small cutting ability loss. The major performance gain with the more narrow bevel would come in regards to ease of sharpening, as that is essentially proportional to the width ratio, so it would sharpen with about 50% less time with the much thinner bevel.
Stock testing :
The Howling Rat is shaving sharp but could be a little sharper. Under magnification (20x) the edge is smooth, so there were no rough spots, just a little roll. It scores 160 (29) g on light thread, and 1.30 (70) cm on 1/4 inch poly. For comparison, the top performance of the thread on knives of this geometry is ~100 g and about 0.25 cm with the poly [very few knives come this sharp]. Thus the push cutting sharpness is decently high, but the slicing aggression relatively low. The knife is also significantly sharper near the base of the blade than the tip. As a further test of slicing aggression, using rolls of cotton fabric as a test medium, I did some cutting with with the Howling Rat and an Opinel and Twistmaster. Both folders had very aggressive finishes, left rough by a 100 grit AO belt and both could cut the fabric on a slice with much less passes than the Swamp Rat knife. However when I just pressed all the blades through the material the Howling Rat jumped ahead. This is the tradeoff of blade finish, leave it coarse and the slicing ability jumps ahead but the push cutting ability goes down.
On to various stock work which goes beyond sharpness and into cutting ability and thus is influenced by the geometry of the blade, the Howling Rat cuts through 3/8" hemp requiring 30-32 lbs at the base and 32-34 lbs near the tip. There was little aggression on a slice taking ~28 lbs on a 2" draw, thus no significant reduction as compared to a pure push cut. It does well on whittling, taking 10.1 (0.8) slices to point a piece of 1" Basswood. The tip is of a decently robust nature, however the point penetration is still very high due to the military or penetrator tip (a short sharpened section of clip). It got on average 627 (8) pages into a phone book on a vertical stab. This is significantly better penetration on a per mass basis than the Camp Tramp (about 50%), which you would expect given the slimmer tip. All of these results (except the lack of slicing aggression) indicate well above average performance.
For comparison, I also did similar work with a 52100 MEUK made by Allen Blade and modified by Ed Caffrey. This blade is similar to the Howling Rat in size and shape [see its review for more details] with the essential difference being that the primary grind comes down to a much thinner edge. On the MEUK the blade is ~0.005" thick behind the edge which is ground at ~20 degrees [it is very difficult to measure the edge bevel precisely as it is so narrow]. The MEUK cuts the hemp rope at 29-31 lbs near the base and a much reduced 19-21 lbs near the tip. The true power of the thinner edge is exhibited on the hardwood dowel cutting where it takes only 4.5 (0.7) slices to form a point. The cost of this higher cutting ability is in the fragility of the edge profile. If the edge ever came into a forceful contact with hard bone, rock or hardened metal it could get damaged up to a quarter of an inch deep into the primary grind with the same level of impact on the Howling Rat not inducing damage exceeding the extent of the edge bevel.
[the MEUK was not used for heavy tip work as the tip is quite weak and easily bent due to a combination of soft spine due to a differential hardening and very slim geometry]
Sharpening :
After the stock testing, the knife was honed on CrO loaded leather, pushing very hard on the strop. The blade took a hair popping sharp sharpness, a slight improved compared to the initial finish. The slicing aggression was still low as you would expect given the strop compound. The blade was later tested on the fabric and on the rope with a 600 grit DMT finish [just a couple of passes on a rod] which showed a many to one improvement on slicing ability but a loss (not as extensive) on push cutting ability. For this kind of work, as Joe Talmadge has described in the past you don't need to leave the entire edge rough, I just sharpened a one inch section of the blade near the choil with the 600 grit DMT rod. That section then gets stropped along with the main section of the blade, and then retouched as necessary with a couple of passes on the rod to finish.
Chopping :
The blade has little mass and a neutral balance and thus can't chop effectively even with snap cuts around the end of the grip. There is simply nothing there to get power behind on a swing or with a wrist snap. However it can be used with a baton and thus is able to handle small woods [up to say 2.5 inches] without a large amount of effort, but you are still working many to one times slower than with something like the Camp Tramp for example. The smaller blade length on the Howling Rat hampers baton work on larger woods as multiple relief cuts are needed, and splitting even medium sized piece of wood (3-4" thick), means multiple splits are necessary. When splitting that size of wood or larger, you work around the round taking off sections until you have reduced the width to something you can split readily. You really want something longer for that class of wood, the blade length should ideally be a couple of inches longer than the maximum wood diameter to provide some free blade length so hit with the baton.
Kitchen :
On soft materials like meats, fruits and most vegetables, the Howling Rat once properly sharpened will do as well as any of the kitchen knives I own, and I own very extreme optimized blades. With the NIB finish, the blade was unable to cut well foods like plums, tomatoes and such, as there would be a lot of slipping on the tough skin because of the give of the underlying very soft tissue. On thicker foods which are solid enough to cause binding or wedging on the knife, the Howling Rat does fall behind an optimized kitchen knife. For example, it cuts through a medium size carrot with 5-7 lbs (same as the Camp Tramp), for comparison, a Japanese utility knife, at the extreme end of kitchen cutlery does it in 2.5 - 3 lbs. The force is still very low however and isn't significant enough to cause fatigue, it does limit the size of the slices you can make, you can't very very thin slices as they will break, so no see through slices for fancy presentations.
Handle :
The grip is made of a dense rubber like material which is more durable than Kraton, but far less than Micarta or G10. It has a decent texture (I would prefer it more aggressive but this does induce a trade off in regards to comfort] and deals with shock better than the more dense grip materials. It is contoured in all dimensions and is smaller in all dimensions than the handle on the Camp Tramp. It has a couple of problems though. The front of the grip is rather squarish and this really limits how much force you can use when cutting as the corners are high pressure points. Ideally the front of the handle should be blended into the blade so as to give a nice form fitting shape for an overhand grip. A longer guard would also be nice for more security in extreme circumstances. The rear butt hook is well shaped providing a strong combination of security and ergonomics.
Sheath :
The sheath is Cordura with a Kydex insert. It came with a significantly looser fit than the Camp Tramp, though not enough to induce any rattle. Nice pouch on the sheath with an elastic tie down. Secure and quality stitching.
Reprofiling :
I had intended to alter the primary grind until the edge was down to around 0.020 - 0.025", and then take it out for some really heavy wood work, knots and such, and if it fared ok there, whack it into something really bad like a nail into a piece of wood. Plans being wonderful and all, when I started grinding I bled the edge back into the primary grind before I knew what I was doing, force of habit I guess. Now the knife was a basic replica of Luke's modified BA3 I described awhile back. Just as seen on that knife, the changed profile induced a large increase in cutting performance, but I would not want to hit the edge off of anything hard now. This combination doesn't seem that coherent to me, I would prefer the original profile, or a very different overall one like the Deerhunter from A.G. Russell, more optimized designs. It is out on loan now to get some use on it with the new profile, mainly durability reflections.
Ref :
http://www.swampratknives.com/
-Cliff
The Howling Rat is 185 g and balances about a half a cm behind the handle, neutral and very light in hand. It has a high sabre flat grind, with a small strip of unground steel along the spine. The blade is is 0.031 - 0.038" thick behind the edge, which is ground at 17-18 degrees per side. For a general use knife that angle is a solid choice, robust enough for anything outside of hardened metal, however I would cut the edge thickness down just a little. About 0.020" thick behind the edge would leave it robust enough for light to medium knot work (batoning), and any cutting work outside of heavy twisting which could induce the edge to ripple [not a concern with the current profile].
However this would lower the durability to the point that you could possibly damage it deeply [into the primary grind] on extreme hard contacts with rock or hardened metal, and it would prevent the edge from being able to take significant lateral loads, and thus its usefulness as a an overall utility tool would be lowered. The overall gain in cutting ability would be a matter of a small percentage (around 20% on binding material like woods, much less on things like ropes etc. ), so the higher thickness could easily make a lot of sense to some in regards to large durability gain vs small cutting ability loss. The major performance gain with the more narrow bevel would come in regards to ease of sharpening, as that is essentially proportional to the width ratio, so it would sharpen with about 50% less time with the much thinner bevel.
Stock testing :
The Howling Rat is shaving sharp but could be a little sharper. Under magnification (20x) the edge is smooth, so there were no rough spots, just a little roll. It scores 160 (29) g on light thread, and 1.30 (70) cm on 1/4 inch poly. For comparison, the top performance of the thread on knives of this geometry is ~100 g and about 0.25 cm with the poly [very few knives come this sharp]. Thus the push cutting sharpness is decently high, but the slicing aggression relatively low. The knife is also significantly sharper near the base of the blade than the tip. As a further test of slicing aggression, using rolls of cotton fabric as a test medium, I did some cutting with with the Howling Rat and an Opinel and Twistmaster. Both folders had very aggressive finishes, left rough by a 100 grit AO belt and both could cut the fabric on a slice with much less passes than the Swamp Rat knife. However when I just pressed all the blades through the material the Howling Rat jumped ahead. This is the tradeoff of blade finish, leave it coarse and the slicing ability jumps ahead but the push cutting ability goes down.
On to various stock work which goes beyond sharpness and into cutting ability and thus is influenced by the geometry of the blade, the Howling Rat cuts through 3/8" hemp requiring 30-32 lbs at the base and 32-34 lbs near the tip. There was little aggression on a slice taking ~28 lbs on a 2" draw, thus no significant reduction as compared to a pure push cut. It does well on whittling, taking 10.1 (0.8) slices to point a piece of 1" Basswood. The tip is of a decently robust nature, however the point penetration is still very high due to the military or penetrator tip (a short sharpened section of clip). It got on average 627 (8) pages into a phone book on a vertical stab. This is significantly better penetration on a per mass basis than the Camp Tramp (about 50%), which you would expect given the slimmer tip. All of these results (except the lack of slicing aggression) indicate well above average performance.
For comparison, I also did similar work with a 52100 MEUK made by Allen Blade and modified by Ed Caffrey. This blade is similar to the Howling Rat in size and shape [see its review for more details] with the essential difference being that the primary grind comes down to a much thinner edge. On the MEUK the blade is ~0.005" thick behind the edge which is ground at ~20 degrees [it is very difficult to measure the edge bevel precisely as it is so narrow]. The MEUK cuts the hemp rope at 29-31 lbs near the base and a much reduced 19-21 lbs near the tip. The true power of the thinner edge is exhibited on the hardwood dowel cutting where it takes only 4.5 (0.7) slices to form a point. The cost of this higher cutting ability is in the fragility of the edge profile. If the edge ever came into a forceful contact with hard bone, rock or hardened metal it could get damaged up to a quarter of an inch deep into the primary grind with the same level of impact on the Howling Rat not inducing damage exceeding the extent of the edge bevel.
[the MEUK was not used for heavy tip work as the tip is quite weak and easily bent due to a combination of soft spine due to a differential hardening and very slim geometry]
Sharpening :
After the stock testing, the knife was honed on CrO loaded leather, pushing very hard on the strop. The blade took a hair popping sharp sharpness, a slight improved compared to the initial finish. The slicing aggression was still low as you would expect given the strop compound. The blade was later tested on the fabric and on the rope with a 600 grit DMT finish [just a couple of passes on a rod] which showed a many to one improvement on slicing ability but a loss (not as extensive) on push cutting ability. For this kind of work, as Joe Talmadge has described in the past you don't need to leave the entire edge rough, I just sharpened a one inch section of the blade near the choil with the 600 grit DMT rod. That section then gets stropped along with the main section of the blade, and then retouched as necessary with a couple of passes on the rod to finish.
Chopping :
The blade has little mass and a neutral balance and thus can't chop effectively even with snap cuts around the end of the grip. There is simply nothing there to get power behind on a swing or with a wrist snap. However it can be used with a baton and thus is able to handle small woods [up to say 2.5 inches] without a large amount of effort, but you are still working many to one times slower than with something like the Camp Tramp for example. The smaller blade length on the Howling Rat hampers baton work on larger woods as multiple relief cuts are needed, and splitting even medium sized piece of wood (3-4" thick), means multiple splits are necessary. When splitting that size of wood or larger, you work around the round taking off sections until you have reduced the width to something you can split readily. You really want something longer for that class of wood, the blade length should ideally be a couple of inches longer than the maximum wood diameter to provide some free blade length so hit with the baton.
Kitchen :
On soft materials like meats, fruits and most vegetables, the Howling Rat once properly sharpened will do as well as any of the kitchen knives I own, and I own very extreme optimized blades. With the NIB finish, the blade was unable to cut well foods like plums, tomatoes and such, as there would be a lot of slipping on the tough skin because of the give of the underlying very soft tissue. On thicker foods which are solid enough to cause binding or wedging on the knife, the Howling Rat does fall behind an optimized kitchen knife. For example, it cuts through a medium size carrot with 5-7 lbs (same as the Camp Tramp), for comparison, a Japanese utility knife, at the extreme end of kitchen cutlery does it in 2.5 - 3 lbs. The force is still very low however and isn't significant enough to cause fatigue, it does limit the size of the slices you can make, you can't very very thin slices as they will break, so no see through slices for fancy presentations.
Handle :
The grip is made of a dense rubber like material which is more durable than Kraton, but far less than Micarta or G10. It has a decent texture (I would prefer it more aggressive but this does induce a trade off in regards to comfort] and deals with shock better than the more dense grip materials. It is contoured in all dimensions and is smaller in all dimensions than the handle on the Camp Tramp. It has a couple of problems though. The front of the grip is rather squarish and this really limits how much force you can use when cutting as the corners are high pressure points. Ideally the front of the handle should be blended into the blade so as to give a nice form fitting shape for an overhand grip. A longer guard would also be nice for more security in extreme circumstances. The rear butt hook is well shaped providing a strong combination of security and ergonomics.
Sheath :
The sheath is Cordura with a Kydex insert. It came with a significantly looser fit than the Camp Tramp, though not enough to induce any rattle. Nice pouch on the sheath with an elastic tie down. Secure and quality stitching.
Reprofiling :
I had intended to alter the primary grind until the edge was down to around 0.020 - 0.025", and then take it out for some really heavy wood work, knots and such, and if it fared ok there, whack it into something really bad like a nail into a piece of wood. Plans being wonderful and all, when I started grinding I bled the edge back into the primary grind before I knew what I was doing, force of habit I guess. Now the knife was a basic replica of Luke's modified BA3 I described awhile back. Just as seen on that knife, the changed profile induced a large increase in cutting performance, but I would not want to hit the edge off of anything hard now. This combination doesn't seem that coherent to me, I would prefer the original profile, or a very different overall one like the Deerhunter from A.G. Russell, more optimized designs. It is out on loan now to get some use on it with the new profile, mainly durability reflections.
Ref :
http://www.swampratknives.com/
-Cliff
