After viewing some knives on the Chopper/Camp webpage from Takach Forge the following was requested :
That 1095 machete pattern looks very nice for grasses and smaller brush
and the O1 chopper for large wood, though I would prefer a handle such
as you have on the 1095 chopper as that looks to allow a forward and
partial rear grip and the end flare looks solid for security. The only
thing I would really not be interested in is the heavy recurve chopper
because some of the wood we have locally is exceptionally soft such as
alder and clear white pine. This wood is not much more than balsa and
I can easily work it up to 3-5" thick as i can get 2"+ penetration and
a recurve won't clear the chips easily and I like my blades to have a
flexible enough design to work on all the local woods available.
I would also prefer to leave the handle unpolished, just with the shaping grit
as that will enhance the texture and it will wear smooth and polish in time
from friction during work, and I simply like the look. And as well leave the
blade with the as forged texture as on the min-machete pattern where it is
un-ground as I prefer the rustic look as well and it will enhance the patina
which will form in use. I would also like a dangler like you have on the
damascus blade as it gives me more flexibility in movement and in the case
where I do fall/slip etc. the blade can move out of the way instead of being
driven up against my hip/side.
... something simple like 1084 or 5160 on the larger knives as I don't
need the wear resistance of the higher carbon steels like 52100/w2, etc. .
Blade should be about 12", 2" or so wide. Handle about a hand and a half
long to allow multi-position grips.
This is what resulted :
This review consists of :
Basic specifications :
Initial impressions :
The initial sharpness of this blade was above average for a blade of its size and type of use. As noted in the video on the right it easily slices newsprint with very little draw and is almost at the point to do a push cut, and once one is started it can continue a cut with a very slight angle. For some more numerical measures of sharpness :
Using the knife alongside a
#1260 Mora using light force to slice
some pine there was a fairly dramatic difference seen in cutting ability.
The picture on the right shows the two piles of shavings made with
both knives making a hundred slices. It is obvious that :
Now this knife obviously isn't designed to be a kitchen knife, it is made from much thicker stock and is far heavier and more forward balanced. If compared to a couple of even semi-decent kitchen knives the difference in performance is obvious.
It is ease to see which peels are made by which knife (they are in the same order from top to bottom as the above list). The Chef's knife makes thinner peels as the edge is much thinner and the paring knife can peel the potato with one curl as the blade is very narrow.
This knife however isn't likely to be picked over a chef's knife in the ktichen, but as it can work with a forward grip there is no real issue in preparing a few vegetables for a meal at camp. Of course in general the thicker cross section of this blade does increase the forces used in cutting over an actual kitchen knife but the results might not be as obvious as might be expected :
The interesting thing here is that when the foods are fairly small and relatively soft then the force difference though slight is noticeable. But as the vegetables get much larger and stiffer the difference actually gets much smaller. On the turnip cut the Chicago Cutlery Chef's knife actually wedges significantly whereas the forged brush knife actually causes the turnip to split and thus it opens up and reduces the force. Now not all chef's knife bind but this is a point that it isn't as simple as a slimmer knife will cut better as it clearly doesn't here.
As a more direct and sensible comparison for a camp knife, using the custom and the North 49 mini-hatchet to take down a small chicken :
The knife did come with a high polish and this is generally optimal for brush and wood chopping however it still is possible to cut even difficult to cut materials such as crusty fresh bread as noted on the picture at the right.
Now for such work a more coarse edge has better edge retention, and for very hard crusty bread a much rougher finish from say an X-coarse DMT stone would be more ideal and allow a much more efficient cut but such a very rough edge would blunt quickly in chopping.
It is possible of course to leave a bit of the edge in front of the handle fairly coarse to start such cuts and this would also work well on slicing ropes and such - this would though impede carving ability.
Moving on to some meats, the brush knife easily cut up a smoked sausage into very fine strips for a sandwich and then some small cubes to be cooked with eggs. Again the main thing here is :
Materials cut :
In general, the main issue for utility is :
But again it has to be kept in mind this is a purpose build bush knife, intended to be a heavy machete. It can do very fine curls of wood as noted in the image to the right, but it is fairly awkward to do it compared to a small specialized wood carving knife. But if you are just making a few shavings vs carving a spoon - well that might not be a significant issue in any case.
Using the blade for some brush work alongside a small axe and the Buck Hoodlum a few thing were obvious fairly quickly :
After extended work with it, the blade grind was modified to thin out the edge and create a dual grind :
This thickness is still enough for the blade to have the strength to cut even harder and occasionally knotty wood without issues. It easily handles moderate sized wood efficiently and in many cases can be more effective than a small axe due to issues of reach and blade length.
The grip stands out immediately as a one of the strong points of the knife mainly due to the versatility. It has a very long handle length which allows a forward hold which puts the center of mass very close to the handle for fine work. At the same time, the handle is long enough to shift to a rear grip which increase the effective blade length by almost 50% and turns the blade into an effective short machete.
For a larger blade this is critical because the center of mass has to be forward to give power chopping ability but this same factor will make it very fatiguing to use in the hand for more precision cutting. The ability to shift the grip to create a more neutral and then blade heavy balance as desired really expands the scope of work of the knife.
For personal preference, the micarta is a bit smooth and it was sanded with some coarse sandpaper for improved traction. The edges of the handle were also sanded down a little to increase comfort in heavy impacts. The grip does however have that desired rectangular/oval type cross section meaning it is wider than it is thick. This stabilizes the grip in hand and minimizes turning.
Nominal composition of 1084 :
The first thing that is obvious is that this is a high carbon steel. Looking at the diagram to the right, 1084 has much more carbon than is necessary even for full hardness in steels. The extra carbon which isn't dissolved in the martensite is used to form cememtite, or iron carbide, which increases the wear resistance over a steel such as 1060 which could obtain similar hardness.
The other thing which is obvious is that it only has a small amount of
alloying elements which increase hardenability and so it will require a very
fast quench, either water or a very fast oil.
Note in the isothermal transformation diagrams to the right how the small amount of Chromium and the much larger amount of Manganese in O1 (just under 1.5%) makes a severe impact on the hardenability.
The O1 shows a severe weakening or suppression of the diffusion based transformations (pearlite) during the cooling and thus can take a much slower quench. This reduces issues of warping and quench cracking which is why slower quenching steels can be favored by makers/manufacturers.
Note that in addition to Carbon and Manganese, 1084 will typically contain Silicon, Phorphorus and Sulphur. The last two are impurities and are present in all steels, Silicon will in general as well as it is commonly used as a deoxidizer and will be present in the original ore.
Silicon does serve as an alloying element in steels as it dissolves in
ferrite and strengthens it. It also enhances corrosion resistance, commonly
used in austenetic stainless steels. It is also very significant in regards to
its effect on carbide formation as it suppresses it both during the quench and
during tempering. However in order for
these effects of silicon to be significant, they require more substantial
amounts than what is typically found in 1084.
In regards to the carbon content of 1084, it is very close to the eutectoid point for the iron/carbon system whihc is ~0.77%. This is a fairly technical point but has some implications for the knife maker.
As noted in the diagram on the right, a steel close to the Eutectoid point will, upon heating, transform from from ferrite+pearlite to pure austenite. Steels which have a lower carbon content will transform to austenite but will still contain ferrite and steels which have a higher carbon content will contain cementite instead of the ferrite.
Again, this is a technical point, but it is of interest to those hardening the steel.
In regards to the actual properties of 1084, it will have physical properties similar to other carbon and low alloy steels. Often times much argument will be made about small changes in steels which imply large differences but the metallurgical data doesn't reflect such extravagant claims. For example, it is true that in general 1095 will have a slightly higher amount of cementite than 1084 which will give it a higher wear resistance, but how much is likely not to be significant. In some detail, from research looking at the wear on steels in grinding ore, here are the relative wear rates of 1040 carbon steel vs 1090 carbon steel : 1
Note that this is comparing a very large difference in carbon content, from
0.4 to 0.9%, much larger than say 1084 vs 1095 and yet the wear factors of the
tooling change by less than 10%.
If this seems odd then realize that the volume of cementite (iron carbide) in these pure carbon steels is relatively small. For example the picture on the right is of DIN 12206 which is a 1.5% carbon steel. Even in this much higher carbon content there is still only approximately 5% of carbide by volume of the steel.
As the carbon content drops so does the volume of carbide. In steels such
as 1084 or 1095, the carbide volume will only be a couple of percent.
Comparing something like 1084 vs 1095 then in regards to wear resistance is
talking about a very small fraction of a percent difference in carbide volume.
If the other aspects of the steels are similar, which are strongly influenced
by the initial steel quality and the heat treatment, the performance of 1084
vs 1095 is likely to be near identical.
What is the significant difference then in 1084 vs the lower carbon content steels such as 1045 or similar alloys such as 4340? The critical aspect is the toughness and in particular the ductile to brittle transition. This is important in steels as it is the temperature at which steels will fail in a brittle mode vs a ductile one. This means that they will crack with little or no deformation.
In high carbon steels, the ductile to brittle failure point is actually at high temperatures, above room temperature which means that when fully hardened they tend to break when over stressed with little deformation and crack cleanly. It also means that the amount of energy they absorb is severely reduced. However as noted in the figure in the right, the low to mid carbon steels have a ductile to brittle temperature which is below zero which means they are more suitable for impacts and harsh work in colder weather.
In regards to this knife, what was seen? The knife was generally durable enough to resist fracture in the hardest of wood working and generally blunted on the micron level in a combination of rolling and wear. Based on that observation then, there would be little benefit in going to a lower carbon steel as there is no significant failure due to lack of toughness. There could be benefit in using a harder steel for more strength, or a more wear resistant steel to reduce abrasion and prolong edge holding - but care would have to be taken to not compromise on the performance due to decreasing toughness.
In regards to sharpening, as there was very little damage to the apex, and generally none to the edge during wood work, there was little work in regards to sharpening. As this is a low carbide steel with only a small volume of cementite and no alloy carbide it grinds very easily even on natural stones. As it has a decent working hardness and quality hardening from the maker, it also sharpens easily to a fine finish and has no significant issues with burr formation.
In general after a significant session of chopping it is usually maintained by a Naniwa Aotoshi 2000 grit stone and then finished on a higher grit stone as a higher polish is generally preferred for wood working. If there is any visible damage to the apex from grit contact then the apex will be cut back with a light pass and a more coarse stone, a Naniwa Superstone 400, or similar used to reset the edge bevel.
Periodically, the blade grind itself is worked on a very coarse stone, the Sigma Power 120, or TASK, to ensure the edge bevel does not thicken and this maintains the cutting ability, ease of sharpening and general over all performance. As Murray Carter is fond of noting, make sure proper care is given to all of the grinds on a knife, not just the edge bevel.
Knife sheaths have two very broad types based on the purpose for them. It seems rather obvious to the point of being pointless what a sheath is for but there is a significance difference and it has a severe influence on design. The most basic type of sheath is a simple carrying case. The sheath it is just there so the knife doesn't have to be carried everywhere by the handle - this is that type of sheath. The other type of sheath is there to keep the knife secure, to allow it to be carried in various ways, points of attachment. It is not that kind of sheath. That kind of sheath has to be far more complicated to ensure retention and attachment methods.
As this was going to be used as a heavy machete, then there was no really need for anything but a simple case, this was clear in the original design request and it does that exceptionally well.
It is a custom ultra-low ride from Robert Jones with a dangler. The height was set at the exact personal height for a natural draw and the dangler keeps the blade from hanging up and also prevents the blade from jamming in a fall. The wide and open mouth also allows ease of securing the blade even while wearing heavy gloves. It is made from thick leather, even stitching and has a solid welt.
In short this is a very solid blade of its type and the maker was excellent to work with. There were no issues found in the material or execution of the design. After extensive experience with this knife, if it was to be made again a few changes would be made to customize more to personal preferences :
Comments can be emailed to Some chopping and splitting
or on the YouTube Playlist.
1 : The Effects of Carbon Content, Matrix Hardness and Microstructure on the Wear of Steel Grinding Balls During Wet Copper Ore Grinding
Most of the pictures in the above are in the
PhotoBucket Album.
| Last updated : | 12/02/2012 |
| Originally written: | 28/01/2012 |