Strider PAB chopping & comfort?

[RokJok]

Cliff Stamp and other Strider PAB owners or users,

Allow me to ask about the performance of the Strider PAB since I find its general blade/handle configuration aesthetically appealing. Is it as nice a limbing chopper to drive as it appears to me? Or does more of the weight need to be moved out toward the tip for chopping? What changes would you recommend for the blade size or geometry? While the cord wrap would no doubt be secure, how is its comfort level, particularly for those cord bends on the sides chewing into your hand?

In the picture Cliff linked to the BK&T Patrol Machete thread, the PAB appears to be hollow saber ground about half-way up the blade. If that is its geometry, I'd expect the penetration curve to be high with moderate applied energy at first, but falling off rapidly once you got to the concave part of the hollow grind. However, for limbing out small branches up to about 1", you would be all the way through the branch before you got to that thicker part of the grind. Also, if it has a thin edge, have you incurred any damage to the PAB?

However, in the picture below the primary grind looks like a flat grind rising nearly to the spine. Has the PAB blade come in different geometries over time?

IMHO for an idealized chopper it sounds about right to fabricate a combination of the PAB's blade shape at 12" long, full flat ground in 3/16" INFI (or 52100/L6/A2 differentially heat treated maybe?) with distal taper, full convex edge or the Busse asymetrical edge, and driven by a PAB-angled handle with pommel swell like the BK&T handle with Cliff's suggested gentler transition in selective ROKJOK (tm pending )beadblast finish. And as Cliff noted about the BK&T PM handle, do not have holes in the scales whose edges can chew at the hand under high pressure gripping.

The selective beadblast would be to texture the bottom surface and about the bottom half of each handle scale, where the fingers contact the handle. But leave smooth the top part of the scales where the knuckles, particularly at the base of the thumb and trigger finger, and palm of the hand contact the handle. By leaving the top half of the scales smooth the texture wouldn't be chewing (e.g. rubbing raw spots) on the fulcrum contact points of the hand that have the least padding between the handle material and the bones of the hand. Those are the contact points where a little slipping could be advantageous.

To reiterate the initial question: How good is the PAB for limbing work? Thx in advance.

 

[Cliff Stamp]

Rokjok :

... does more of the weight need to be moved out toward the tip ...

The balance is quite far ahead, which allows it to have the impact energy of a heavier blade like my SHBM, which is about 20% heavier. This was one of the many things I really liked about the PAB, its chopping ability to weight ratio, was very high. The small tang, allows the shedding of unnecessary weight.

What changes would you recommend for the blade size or geometry?

This is one of the main failing points for me, the hollow grind which had two main disadvantages. First off, as seen with the WB, once the edge durability has been exceeded, you can blow a piece out of the primary grind, for a heavy hacker, this is not what I would want. Secondly, while the chopping ability was on lumber (2x4's) was very good, about 80% that of the GB Wildlife hatchet, on actual fresh wood the binding was too great. On heavy chopping I actually had to beat the knife out of the wood with another piece of wood, it would get stuck so badly. This was the reason that I sold it, without this functionality it was not useful as a brush knife. Now I of course could eliminate the binding by simply chopping lighter, but then the ability falls behind many to one over something like the SHBM.

So, the geometry I would change, ideally to a dual convex taper. This has the primary convex grind coming down from about 2/3 height to form the edge, and then running the other 1/3 of the way up (at a much larger radius of curvature) to slim out the spine. This increases cutting ability, reduces wedging, and greatly raises impact toughness. In terms of blade size, for general brush work I prefer a large blade for reasons of reach, about 14" is my personal preference, as beyond that it becomes too much for knife-like work and thus I would want an additional smaller blade, this of course, is very person dependent. If I could not get the dual convex grind, then a full flat grind would be a close second. My only concern here would be again binding. Will Kwan has used the full-flat CS khukuris, and they bind rather badly.

While the cord wrap would no doubt be secure, how is its comfort level, particularly for those cord bends on the sides chewing into your hand?

The first time I used the PAB, the day before I had worked over my hands heavily and I was at about 50% strength and my hands were tender. In this condition the PAB was completely useless for any kind of heavy work. I could not grip the blade tightly enough to keep the knots stable, and thus they were banging around and doing a job on my already weakened grip. Taking the SHBM, this wasn't an issue. The only problem with that was the well known "Busse pinky" effect where the rear Talon keeps smashing into the side of your pinky. Switching to the GB Wildlife hatchet, none of these problems were evident. That being said, when my hand wasn't pre-chewed, I could use the PAB fine, except for heavy stabs which would cause heavy enough impacts that I would not want to do more than a dozen or so without stopping. The only knife I could not use when at 100% was the TOPS Steel Eagle. However my hands are tougher now than a couple of years ago and I am fairly curious if I could use it now. Anyway, the PAB grip is very secure, it is one of the very few grips that I could use with full force even when my grip was severely compromised with soap / oil etc. . The others on this very short list are the Reeves Project and Tops Steel Eagle. The PAB is more abrasive than the Reeves but not as abrasive as the TOPS.

However, the cord grip was the other main thing that made the knife not functional for field work for me. In the beginning I was very impressed with its security. However it quickly became obvious that it had a huge disadvantage which was that it was impossible to clean. Around here in late summer, and you get some heat and rain, the sap on many of the felled trees which you are cleaning up starts to rot and turns into this slimy, oily mixture. Once this gets into the cord is goes very slick and the handle becomes non-functional. If the grip has simple scales, then the sludge can be scrubbed off. However it goes into the cord and is very difficult to remove. I wrapped the handle on the SHBM with cord (simply wrap) and it quickly had to be removed and re-wrapped as it got gunked up. This is not something that I would want to do with the PAB on a regular basis. However an epoxy + cord wrap might not have this problem, as it should be far easier to clean. That being said, I do think that in general you are better off with an actual shaped grip with an aggressive texture as the other main failing of the PAB grip is that it has no end-hook to drive off of and the cord can easily be cut with a smashing impact if you glance when using the tang as a hammer.

[sabre-hollow PAB]

I'd expect the penetration curve to be high with moderate applied energy at first, but falling off rapidly once you got to the concave part of the hollow grind. However, for limbing out small branches up to about 1", you would be all the way through the branch before you got to that thicker part of the grind.

Yes, exactly, on small brush, it had no binding problems and worked well.

[/quote]Also, if it has a thin edge, have you incurred any damage to the PAB? [/quote]

The edge was at ~22 degrees per side, and the blade was about 0.035" thick behind the edge. This is vastly over built for a wood working knife, thus no damage will be seen even on heavy wild swings into small diameter hardwoods (I tried it for several hours). On that class of blade you can go down to <15 degrees per side, and 0.025" thick behind the edge, which gives a decent safety margin. With more skill and clean wood you can approach 10 degrees per side and 0.020" thick behind the bevel, that geometry doesn't leave much room for error. That being said, of course as a "combat" grade knife, you would expect the PAB to have a more durable edge requirement than a knife that is just being used for brush work, so you are going to trade off cutting ability for durability, and thus put more metal at the edge.

However, in the picture below the primary grind looks like a flat grind rising nearly to the spine. Has the PAB blade come in different geometries over time?

The Striders were sabre-hollow at first, but now many are full flat.

IMHO for an idealized chopper it sounds about right to fabricate a combination of the PAB's blade shape at 12" long, full flat ground in 3/16" INFI (or 52100/L6/A2 differentially heat treated maybe?) with distal taper, full convex edge or the Busse asymetrical edge, and driven by a PAB-angled handle with pommel swell like the BK&T handle with Cliff's suggested gentler transition in selective ROKJOK (tm pending )beadblast finish. And as Cliff noted about the BK&T PM handle, do not have holes in the scales whose edges can chew at the hand under high pressure gripping.

That sounds like a very nice blade for light to medium brush work. The distal taper is something that needs to be carefully considered. If you want to be able to handle woody brush work, then you can't have too much taper as it will leave the edge on the tip too thin which can be problematic for heavily ingrown brush. However if you leave the black stock uniform a you approach the tip, you lose a lot of light brush clearing ability. It is yet another decision you have to make about what you want the blade to be able to do. Same thing for the stock, 3/16" with a full grind will bind much more readily than 1/4" so consider the amount of thick wood chopping ability you require, you can't do everything in one blade.

A really strong combination would be such a light brush blade for all manner of clearing, a small folding saw for felling, and the GB Wildlife hatchet for heavier chopping and pounding. It obviously depends on the types of wood in your area, softer woods like Pine are no problems even for blades with a lot of distal taper so you could ignore the hatchet, and probably would not even need the saw for felling, as even 3-5" fresh pine can be chewed though quite quickly with a decent large blade. The Martindale "Jungle Knife" is such a bush blade that I have been thinking about lately, and the Golok more slanted towards woody brush :

http://www.cutsforthknives.com/cutsforth_knives_martindale_machete_005.htm

Your comments about selective texture are interesting, on the custom I had made awhile ago, I had the sides checkered, however the top and bottom is smooth :

http://www.physics.mun.ca/~sstamp/images/parrell_parang_side.jpg

It is working out decently well, however the checkering isn't as aggressive as it could be, again personal preference plays a large role here. The Reeve checkering is my personal preference so far. I would make several changes to the design though based on experience since I had it made, and will probably go back to Parrell this fall to have another blade made :

http://www.vikingmetalworks.com/

To reiterate the initial question: How good is the PAB for limbing work?

If you are just limbing, then the Tramontina bolo is a more optimized, the hump is an excellent club for dead/frozen limbs :

http://www.physics.mun.ca/~sstamp/images/camillus_bush_hog_bolo_bm.jpg

The NIB edge and the handle may need some work. I have cut the end-hook down on mine, I may have to go further still. You need enough hook to get a good drive, but not so much that the impact is too sudden. The big problem with the Tramontina for wood work is that it binds heavily having no primary grind. This is where the above custom parang comes in, it has a dual convex taper and doesn't bind significantly. Right now though, the edge profile is too obtuse, I need to take it down to about 75% of where it is now.

-Cliff

 

[chad234]

Cliff,
I am suprised by your comments in regards to the Tramotina Bolo. I had one, and was very unimpressed.
The steel was very soft and thus very prone to impact damage. As an example, I was clearing some shrubs and vines out of the fencing in my backyard (standard cyclone fence), I was basicly just swiping the bolo along the fence surface, taking out any branches and vines. I'd have to stop every three to four minutes and hit the edge with a file. The spots where the edge contacted the fence (which is darn soft metal) were heavily impacted, but I was not being very careful and there was a lot of lateral pressure applied to the edge....... I hit a nail sticking out of a wooden fence post and it caused a large dent in the edge, basicly large enough that repairing the damage would take more time than the bolo was worth. Last time I saw it was in my ex-wife's garage......
After blowing out the Tram, I switched to an Ontario machete (USGI 18") and the results were much better. The Ontario kept its edge for the 45 minutes it took me to finish, and was easily sharpened using a DMT course diafold and then a ceramic rod. There was no damage (though I was also being more careful with my swings), and its not like the Ontario USGI machete is a high performance benchmark......
The price difference between the two was slight, I think the Tram was $5 or so and I had picked up the Ontario at $8.99 (which I suppose is a big difference percentage wise, but in the real world a couple bucks ain't a big deal...)

One suprise in the Tramotina product line is their kitchen knives. I have used several in a commercial setting and they held their edge as well as any other commercial "kitchen" cutlery I have used.

On that class of blade you can go down to <15 degrees per side, and 0.025" thick behind the edge, which gives a decent safety margin. With more skill and clean wood you can approach 10 degrees per side and 0.020" thick behind the bevel, that geometry doesn't leave much room for error

I am suprised by the acute edge bevels you are advocating for a blade to be used mainly for chopping, at a 30 (or 20!!!) degree included angle, I can see a high chance for edge damage being caused by lateral pressure on the edge from glances or direct damage from inclusions. I might try something that thin in my garage after I had cleaned the wood, but not in the field (where inclusions are more likely, small rocks, sand, I have even chopped into wood and found bits of barbed wire!!!)
Another factor to be considered is the type of chopping that is being done, I have found that sometimes (often) limbing (which is what Rokjok was asking about) is actually more stressful on a blade than felling. If you are felling, it is usually fresh, soft wood but limbing the wood is often dead, dried and hardened.
Another factor is the individual tree, trees with tight growth rings seem to be much tougher on an edge than one with wide spaced growth rings, even of the same species (maple, oak, spruce, etc).
Of course the level of acuteness that an edge can be run at and maintain durability is largely a function of the type of steel being used, and the heat treat. While Paul Bos heat treat is top of the line, ATS34 would not be my first choice for a chopper (though Strider seems to have good success with it), for this application I would greatly prefer A2, a very fine grained and impact resistant tool steel.
I understand that Strider is switching to .25" S30V, and am very intersted to see the performance of this steel in real world contexts.....
I have no experience with Strider knives (other than playing with them at shows) but the grinds were even, and the warranty seems to be very strong. Since these knives were designed by people with real world experience, who stand by their product and are willing to provide a strong warranty, I think it is safe to say that you can use the knife with confidence.
Take care,
Chad

 

[jefroman]

Just a note--any Strider Knife can now be ordered with either a full flat grind or a hollow grind.

Jeff

 

[Cliff Stamp]

chad :

[tramontina]

The steel was very soft and thus very prone to impact damage.

This is the worst problem with low end knives, the QC cotrol is horrible, I could have experience with the best ones (only a few) and you the worst ones, thus we are both shaking our heads in wonderment at what the other is describing. This is why in general I would strongly recommend avoiding all such low end blades for actual functional users. I pick them up to look at various geometries, and get functional customs made based on experience. I have not hit anything hard with the Tramontina yet, but will eventually and will see how it goes, first just on some knotty wood. I did take another one apart awhile ago though and had no complaints.

I am suprised by the acute edge bevels you are advocating for a blade to be used mainly for chopping

The main reason that chopping angles have exploded that the steels used are much much more brittle, due to both alloy content and hardness. I am not talking about small percentage changes, but many times to one effects. Consider that felling axes for fresh wood were routinely sharpened at 15 to 20 degrees included. A knife of course will experience much lower energy impacts. While that geometry sounds insane compared to the current "22 degree per side" standard, this was what was used, and experience trumps theory. Wood type as you mentioned was a factor, on the harder woods, especially the knotty ones you increase the angle, making a stronger convex sweep toward the edge.

However, not all has been lost, there are many makers today who offer very high performance cutting blades which ride very close to the optimum limits. Check out, for example, the bevels on a knife from a maker like Ray Kirk. His bowie edge was out cutting my SHBM 2:1 on wood whittling, and I had slimmed down the BM edge a couple of times, and NIB it was well under 22 degrees per side. I limbed out a half a truckload of wood (2-4") with that bowie with no significant problems (the other half was done with the SHBM).

This is why the forged ABS guys have such reputations for high cutting abilty, they grind *so* much thinner and more acute edges. They also use much tougher steels, an obvious requirement. Note the concrete pounding with his knife did nothing but impact the edge. It is extremely difficult to initiate a large scale fracture the metals they use. I should point out however there are lots of non-abs guys with very high performance edge geometries, Wilson, Schott (MIA?), Boye etc. .

I can see a high chance for edge damage being caused by lateral pressure on the edge from glances or direct damage from inclusions.

Direct damage is insignificant when compared to lateral impacts, it just forces minor sharpening, and is so localized it can be pretty much ignored. Generally it takes many such impacts before I will consider removing them as they don't significantly degrade the gross performace. It is much better for a blade to take a very hard direct hit, than a much softer lateral one. I could have for example banged the PM off of a rock many times and it would have only remove the very edge. Lateral loads can completely wipe out a blade, technique of course is key and directly influences just how far you can go geometry wise (as does steel, the other factor you noted). As the geometry slims down, your force drops and your control rises, thus high cutting blades, when used so as to take advantage of their geometry, will have greater durability than the raw cross-section will predict, as you don't need to pound on them as hard.

I have even chopped into wood and found bits of barbed wire!!!

Yes, it is the same thing around here, you are clearing a lot and suddenly hit nail or piece of fence that was removed generations ago. Nails are a real killer as well, mainly from kids building cabins. If this is a real common problem you just put a more obtuse small secondary bevel (sub mm).

limbing (which is what Rokjok was asking about) is actually more stressful on a blade than felling

Yes, many times to one. The main factor is the lower contact area which directly raises impact pressures, but secondly because they bend, snap, vibrate and do all kinds of nasty things that a tree trunk does not. Limbing dead wood branches is one of the worst things you can do with a knife and requires that the blade be *far* over built for felling, angle isn't important, but the supporting thickness must be significantly greater. A true dedicated felling axe, will not be used for limbing such branches but will be used like a hammer to beat them off. If you are going to limb with it, you use care and notch-cut the wood, no complete cuts. Besides wood type, heavy ingrowth is the other key factor as it makes selective chopping very difficult and thus glances become very likely.

As with everything, experience is key, I can't recommend strongly enough that personal experience can't be avoided without great waste. The first thing I would suggest is getting a couple of low end knives and seeing how far you can push them before they fall apart. This knowledge will allow you to eliminate a lot of waste on your higher end blades which obviously should have much greater performance demanded of them. If you have the money of course you are better off going straight to customs from the outset and just getting the off the shelf models so you don't have to deal with the hassle of the QC problems of the low-end production. The latter is why I recommend getting a few, as if you pick the wrong one you can end up with a very skewed perspective. Something like the RCM would be a great place to start as its not that expensive (~150$ last time I checked) and will have a *much* tighter QC, and thus lower performance variance than Ontario, Tramontina etc. .



-Cliff

 

[ExamonLyf]

Interesting posts guys...thanks! Sadly.., of 3 Striders I've tried so far.., I haven't really liked any of them .. maybe just me.., but the edge geometry selected for various models in combination with the profiling just doesn't work well for me so far....


"Hunters seek what they [WANT].., Seekers hunt what they [NEED]"

 

[RokJok]

Many many thanks to all for the information and offering such granular examination of the questions asked. I believe it'll work to keep the overall config of the PAB as a launch point for getting a 1/4" thick, full convex custom made. The most likely options are in INFI from Busse or in A2 from Trace Rinaldi. Or just do both, right? While I'm waiting to win the lottery to pay for the blades, I can think some more about the handle configuration.

With my deep appreciation,
Greg

 

[Cliff Stamp]

I forgot to mention in the above that there is a huge difference between limbing a felled tree and just whacking the limbs off trees that are still standing to make room, or gather wood. The difference is in how they are cut. When you are working on a felled tree, you start at the base and move towards the tip, always chopping at the underside of the limb. The wood will naturally bend to allow the edge to pass through. If you are clearing brush, this is very difficult to do as you are swinging from a much weaker range of motion. It is much easier (on you) to use the same swing, but this has the blade hit the limb in the opposite way and the limb will not want to bend to allow the blade to pass here and thus the impacts are much worse on the edge. For dedicated felling, you usually have a thicker bitted axe to remove such limbs, or roots and even bark to make life easier on your felling axe. This allows you to run the felling axe much thinner, and thus raise its cutting performance. Same rule in general, the more tools you have, the more optomized each can be.

Rokjok, I would definately be interested in a picture of that blade once you get it made and your perspective on its performance after you get some use into it.

-Cliff

 

[DancesWithKnives]

RokJok,

As you know, I'm a fellow Infi fan. However, in addition to Infi and A2, I'm curious whether you would consider 3V for a big hacker? I don't own anything in 3V but am interested in it.

Thanks!

 

[RokJok]

DWK, Thanks for the nomination of another steel to add to the list. I hadn't considered 3V since I'm pretty unfamiliar with some of the newer alloys, so will have to research it when the time comes to make the decisions. FWIW, this is a really long-term possible blade for me. By the time I actually get around to ordering it, INFI & 3V may be passe'. Or I may have moved on to chainsaws as the limbing tool of choice.

Cliff, Definitely true about being easier to clear branches from the roots toward the crown of the tree, rather than vice versa. Massive resistance when chopping into the crotch of a limb compared to chopping up from the bottom of the limb.

 

[DancesWithKnives]

RokJok,

Good point----we may be using light sabers by the time I can afford the Hossom short sword I would want in 3V. Jerry told me that the 3V would be tougher than 154, S30V and A2 for the Eskrima-stick-size sword that he makes. However, he also said that it is expensive and a bear to work. 3V would increase the cost of the short sword by about 50%.