Cliff Stamp
BANNED
- Joined
- Oct 5, 1998
- Messages
- 17,562
This is a large brush blade owned by Andrew Lynch, similar in design to the Blackjack Marauder. It is hand forged to shape, without excessive grinding to finish. The blade shows evidence of the forging as there has not been a complete regrind to produce a smooth finish. The spine for example shows hammer marks as does the primary profile. As to exactly what you would call it, it isn't exactly a bolo, nor a khukuri, but sort of what you would get if you melded them together, but I am going to refer to it as a bolo anyway.
Here is a shot of it and a few other blades of similar general design to get an idea of its general size :
http://www.physics.mun.ca/~sstamp/images/al_bolo_bm_pab_ak_side.jpg
From top to bottom; an 18" Ang Khola khukuri from Himalayan Imports , Andrew's bolo/khukuri blade, a PAB from Strider, and a straight handled Battle Mistress from Busse Combat. Andrew's blade is a lot slimmer than the other blades and it is also more narrow as well, and is the only one with a distal taper. More details on those other blades can be seen in the reviews.
The mass of the blade is 700g and the balance point is four inches from the center of my grip, it isn't a light machete by any means. For reference the Battle Mistress is 660g and is balanced closer to my hand, three and a half inches, so you would expect it to be more neutrally balanced than the bolo - which is saying something. However the bolo feels lighter in hand than the Battle Mistress. The much wider grip on the bolo spreads out the force and thus there is less pressure induced. The blade came with a wooden scabbard, which does not hold the blade tight (turn it upside down and the blade will fall out), but is common on a lot of traditional blades.
The knife came with a very slight secondary edge bevel which I removed by blending the edge bevel back into the primary grind. I used a large x-coarse Japanese waterstone (5lbs) by hand and it quickly blended the bevels together, about a half hour or so. The edge was then sharpened using a couple of finer waterstones (1000 and 4000 grit). While I did not change the edge angle, the edge was weakened by the lightening of the shoulder which will reduce its ability to resist lateral loads. However this blending will also raise its cutting ability slightly. The main reason I did it was because on blades with convex grinds, secondary edge bevels will lead to edge thickening very quickly. I also ground the face of the guard a little as it was left almost sharp. Even then though it would not be something to choke up on for precise work as it is much too thin.
Before I did any heavy work I did some whittling on hard wood dowels to gauge its cutting ability ability. This was an unknown steel (probably spring), from an unknown maker of unknown RC, so it could have fallen apart on harder work quite quickly, so you start off light and work up. Anyway, the bolo pointed the dowels in 10.5 +/- 0.6 slices, which is very strong performance, the best I have seen in a knife this size without extensive modifications. I then did some chopping comparisons against the Gransfors Bruks Wildlife hatchet. The bolo had 91 +/- 3% of the hatchets raw chopping ability. You would need to be paying very close attention to notice the small difference in performance.
However beyond raw penetration, there was a large difference in feel and how they chopped through the wood. Specifically, the bolo had a higher tendency to glance. When the hatchet meets the wood there is a smooth transition as the edge cuts into and then through the wood. With the bolo, since the edge is curved it is more difficult to get a straight cut and it tends to pop out easier. It is just a matter of experience, after spending some time with the blade this ceased to be a problem. Most people will comment on this when they use such blades, like khukuris, for the first time.
However the handle leaves a lot to be desired. While it it nice and wide, it is boxy and gets slick quickly. There is also not a lot to drive off of at the end of the grip, nor much of a guard to prevent your hand from going forward. Though on blades of this class you don't generally do a lot of hard stabbing motions. I generally preferred to work with grip tape on the handle to increase security as even with a light rain the grip became slippery.
A khukuri of similar length as the bolo, such as the Ang Khola in the above, will have better penetration in the wood (~ 20%) and be much more fluid because of lower binding. So for felling and bucking I would readily prefer the khukuri. The khukuri is also much stronger and is a better splitter and pry bar. Of course such a blade is overkill for lighter vegetation and generates an extreme level of fatigue on lighter grasses and such. It is like swatting flies with a hammer. You can do it, but it tires you out quickly.
For general utility, the Battle Mistress is a superior choice as the curvature of the bolo makes some things very difficult. Trying to slice something on a cutting board (or whatever) for example is near impossible, and the additional blade length makes more precise work more awkward. The bolo truly excels chopping through light woody vegetation, such as limbing small trees. It is just a bit too heavy for grasses and such, though much better than the khukuri, and a bit too light for truly thick wood, but for limbing it is simply excellent.
I used it extensively in the fall of 2001 (through few cords of wood) and it easily outperformed the Battle Mistress for such work having a longer reach and a higher cutting ability for such work. The curvature acts to lock the vegetation in and there is no slipping along the edge. This in fact acts to increase the edge holding ability. It quickly became the blade I would choose for such work.
In regards to edge holding ability, and edge durability, while I started off very light, just working on soft woods, eventually I moved up to hacking through the hardest and knottiest wood around, which was seasoned dead fall, and which you can't cut as much as just break apart. The edge only tended to get damaged near the tip, and even there it just tended to get flattened. This isn't to such an extent that you could see it from the side, but you could note light reflecting. This could also be from dirt contacts as it only happened once in a while, however tips are often run softer on larger blades like these.
Lately (spring and summer 2002) I had been using a couple of large blades which I had modified to give the maximum level of limbing ability. The edges on these blades had been slimmed down significantly by me, often taking hours or work on a belt sander. They were ground down to the point at which they would dent if reduced further (as I did, and they did). I then ran the bolo against these blades to see how my impressions held up, as they were better cutters that what I was using last fall. The bolo held its own in terms of raw cutting ability, the only drawback was the boxy handle. After not working with the blade it for so long, and going heavy for around three hours, my ring finger started to show signs of irritation.
Getting specific about geometry, the very edge on the bolo is actually slightly more obtuse than on the other blades I was comparing it to (custom RTAK, Jungle knife etc. ). However the bolo was able to cut as well as them because of the nature of the primary grind which is dual convex. The blade tapers from about 2/3 height down to form the edge, and then back tapering along the upper 1/3 to reduce the spine thickness. This is the optimal shape to reduce drag. The concave blade curvature is also the ideal one for limbing. I recently thinned out my Battle Mistress again, and now it offered a greater limbing ability than the bolo, however the edge had to be ground much more acute, and the bolo still has the advantage of additional reach and the hooking action.
Here is the main profile of the bolo :
http://www.physics.mun.ca/~sstamp/images/al_blade_profile.gif
and a close up of the edge :
http://www.physics.mun.ca/~sstamp/images/al_edge_profile.gif
In short, the cutting ability is high, and the durability enough for the most extreme wood cutting as even hardened knots could not turn it. This is the only blade in a long time that I did not modify significantly from its NIB profile. The handle however could use some extensive work as it is not overly ergonomic nor secure. The sheath, while I didn't have any problems with it, would also probably not hold up to any kind of significant impacts without cracking, and could probably warp or split in humid extremes. It held up better than Kydex to the cold though. The blade will also rust rather easily if you don't oil it, which is expected for forged carbon steels. It is a simply excellent performer for cutting light to medium brush, boxy handle and all.
-Cliff
Here is a shot of it and a few other blades of similar general design to get an idea of its general size :
http://www.physics.mun.ca/~sstamp/images/al_bolo_bm_pab_ak_side.jpg
From top to bottom; an 18" Ang Khola khukuri from Himalayan Imports , Andrew's bolo/khukuri blade, a PAB from Strider, and a straight handled Battle Mistress from Busse Combat. Andrew's blade is a lot slimmer than the other blades and it is also more narrow as well, and is the only one with a distal taper. More details on those other blades can be seen in the reviews.
The mass of the blade is 700g and the balance point is four inches from the center of my grip, it isn't a light machete by any means. For reference the Battle Mistress is 660g and is balanced closer to my hand, three and a half inches, so you would expect it to be more neutrally balanced than the bolo - which is saying something. However the bolo feels lighter in hand than the Battle Mistress. The much wider grip on the bolo spreads out the force and thus there is less pressure induced. The blade came with a wooden scabbard, which does not hold the blade tight (turn it upside down and the blade will fall out), but is common on a lot of traditional blades.
The knife came with a very slight secondary edge bevel which I removed by blending the edge bevel back into the primary grind. I used a large x-coarse Japanese waterstone (5lbs) by hand and it quickly blended the bevels together, about a half hour or so. The edge was then sharpened using a couple of finer waterstones (1000 and 4000 grit). While I did not change the edge angle, the edge was weakened by the lightening of the shoulder which will reduce its ability to resist lateral loads. However this blending will also raise its cutting ability slightly. The main reason I did it was because on blades with convex grinds, secondary edge bevels will lead to edge thickening very quickly. I also ground the face of the guard a little as it was left almost sharp. Even then though it would not be something to choke up on for precise work as it is much too thin.
Before I did any heavy work I did some whittling on hard wood dowels to gauge its cutting ability ability. This was an unknown steel (probably spring), from an unknown maker of unknown RC, so it could have fallen apart on harder work quite quickly, so you start off light and work up. Anyway, the bolo pointed the dowels in 10.5 +/- 0.6 slices, which is very strong performance, the best I have seen in a knife this size without extensive modifications. I then did some chopping comparisons against the Gransfors Bruks Wildlife hatchet. The bolo had 91 +/- 3% of the hatchets raw chopping ability. You would need to be paying very close attention to notice the small difference in performance.
However beyond raw penetration, there was a large difference in feel and how they chopped through the wood. Specifically, the bolo had a higher tendency to glance. When the hatchet meets the wood there is a smooth transition as the edge cuts into and then through the wood. With the bolo, since the edge is curved it is more difficult to get a straight cut and it tends to pop out easier. It is just a matter of experience, after spending some time with the blade this ceased to be a problem. Most people will comment on this when they use such blades, like khukuris, for the first time.
However the handle leaves a lot to be desired. While it it nice and wide, it is boxy and gets slick quickly. There is also not a lot to drive off of at the end of the grip, nor much of a guard to prevent your hand from going forward. Though on blades of this class you don't generally do a lot of hard stabbing motions. I generally preferred to work with grip tape on the handle to increase security as even with a light rain the grip became slippery.
A khukuri of similar length as the bolo, such as the Ang Khola in the above, will have better penetration in the wood (~ 20%) and be much more fluid because of lower binding. So for felling and bucking I would readily prefer the khukuri. The khukuri is also much stronger and is a better splitter and pry bar. Of course such a blade is overkill for lighter vegetation and generates an extreme level of fatigue on lighter grasses and such. It is like swatting flies with a hammer. You can do it, but it tires you out quickly.
For general utility, the Battle Mistress is a superior choice as the curvature of the bolo makes some things very difficult. Trying to slice something on a cutting board (or whatever) for example is near impossible, and the additional blade length makes more precise work more awkward. The bolo truly excels chopping through light woody vegetation, such as limbing small trees. It is just a bit too heavy for grasses and such, though much better than the khukuri, and a bit too light for truly thick wood, but for limbing it is simply excellent.
I used it extensively in the fall of 2001 (through few cords of wood) and it easily outperformed the Battle Mistress for such work having a longer reach and a higher cutting ability for such work. The curvature acts to lock the vegetation in and there is no slipping along the edge. This in fact acts to increase the edge holding ability. It quickly became the blade I would choose for such work.
In regards to edge holding ability, and edge durability, while I started off very light, just working on soft woods, eventually I moved up to hacking through the hardest and knottiest wood around, which was seasoned dead fall, and which you can't cut as much as just break apart. The edge only tended to get damaged near the tip, and even there it just tended to get flattened. This isn't to such an extent that you could see it from the side, but you could note light reflecting. This could also be from dirt contacts as it only happened once in a while, however tips are often run softer on larger blades like these.
Lately (spring and summer 2002) I had been using a couple of large blades which I had modified to give the maximum level of limbing ability. The edges on these blades had been slimmed down significantly by me, often taking hours or work on a belt sander. They were ground down to the point at which they would dent if reduced further (as I did, and they did). I then ran the bolo against these blades to see how my impressions held up, as they were better cutters that what I was using last fall. The bolo held its own in terms of raw cutting ability, the only drawback was the boxy handle. After not working with the blade it for so long, and going heavy for around three hours, my ring finger started to show signs of irritation.
Getting specific about geometry, the very edge on the bolo is actually slightly more obtuse than on the other blades I was comparing it to (custom RTAK, Jungle knife etc. ). However the bolo was able to cut as well as them because of the nature of the primary grind which is dual convex. The blade tapers from about 2/3 height down to form the edge, and then back tapering along the upper 1/3 to reduce the spine thickness. This is the optimal shape to reduce drag. The concave blade curvature is also the ideal one for limbing. I recently thinned out my Battle Mistress again, and now it offered a greater limbing ability than the bolo, however the edge had to be ground much more acute, and the bolo still has the advantage of additional reach and the hooking action.
Here is the main profile of the bolo :
http://www.physics.mun.ca/~sstamp/images/al_blade_profile.gif
and a close up of the edge :
http://www.physics.mun.ca/~sstamp/images/al_edge_profile.gif
In short, the cutting ability is high, and the durability enough for the most extreme wood cutting as even hardened knots could not turn it. This is the only blade in a long time that I did not modify significantly from its NIB profile. The handle however could use some extensive work as it is not overly ergonomic nor secure. The sheath, while I didn't have any problems with it, would also probably not hold up to any kind of significant impacts without cracking, and could probably warp or split in humid extremes. It held up better than Kydex to the cold though. The blade will also rust rather easily if you don't oil it, which is expected for forged carbon steels. It is a simply excellent performer for cutting light to medium brush, boxy handle and all.
-Cliff
