High-hardness choppers

[Twindog]

The bottom line:


Geometry cuts. For choppers, length, mass and acute edge are the magic combination. No surprise, that’s just what I found.


But edge stability (wear resistance and resistance to chipping and rolling) is also important. In my tests, the 10xx steels don’t have the edge stability of modern high-tech steels. The surprise for me was how well super high hardness steels with excellent heat treats — such as Bluntcut’s W2 and 3V heat treats with a hardness of 65 Rc did amazingly well.


And I found that heat treating is really king. A good heat treat in a potentially chippy steel like S30V can easily outperform anything in 10xx.






Discussion:


My homestead is deep in the rainforest of the Olympic Peninsula in Washington state, so I am blessed with the need for big choppers.


I used to use 10xx hardware-store machetes to do most of my chopping, but those machetes were never stout enough for rainforest realities. Their big advantage was a cheap price, which was a critical attribute in my younger, poorer days. But their edge stability was poor. I was constantly repairing damage with a file.


When I could financially swing it, I purchased a 3V chopper from a knife maker. It had a 12 inch blade and was a big improvement over the hardware machetes. But its edge tended to chip out when chopping heavy brush. In a discussion thread, Jerry Hossom was surprised that 3V steel would chip. He asked to examine the blade, and in return he would sharpen the blade. What he noticed was a strange quality to the steel. Something was wrong with the heat treat, but he put an amazing edge on the blade. Even with that premium convex edge, the steel chipped on chopping salmonberries — a woody plant with thick stems that likes to grow in incredibly dense thickets along river bottoms out here in the Pacific Northwest.




Below: chipping on my custom 3V chopper after bushwhacking salmonberries.

I asked Luong (Bluntcut) if he would examine the chips and tell me what was what. He found a poor heat treat was the problem, with the chips showing overly large gain and grain boundaries clogged with impurities. He offered to do a reheat treat, which bumped the hardness up from 60 Rc to 65 Rc. I’d never heard of 3V being heat treated that hard, and reheat treats are a crap shoot, but Luong knows more about steel than I do by a long, long shot. So I said, let’s do it.


He broke off the tip of one of his 3V knives to compare the grain structure to my 3V chopper, confirming that I had a bad heat treat.


http://i.imgur.com/J66LWV3.jpg


When he sent me the 3V chopper back, he also included his W2 test chopper with an experimental heat treat to test. I decided to test a bunch of choppers along with Luong’s W2 chopper and the new heat treat on the 3V chopper.

 

[Twindog]

Here are the players:


From L to R: Condor, 3V reheat treat, Busse, Senegal, Fiddleback, W2 test knife

Luong’s W2 chopper at 65 Rc. The spine thickness on this 11 inch blade is 0.3073 inches. The edge width at the shoulders (SEW) is about 0.027 inches. This beast chops with power.


Luong’s reheat treat of my 3V chopper at 65 Rc. The spine thickness on this 12-inch blade is 0.1375 inches, and the SEW is 0.037 inches. This is a thin blade that packs power and penetration.


Busse’s Bushwhacker Battle Mistress in Infi steel (58-60 Rc). The spine thickness on this 10.5-inch blade is 0.2075 inches. The SEW is 0.053 inches. This is a fairly agile blade with proven steel.


Bark Rivers’ Senegal in A2 steel (58 Rc). The spine thickness on this 14-inch blade is 0.1925 inches. The SEW is hard to measure because of the convex edge, but at the same depth as the other blades it runs about 0.027 inches. This is a beast of a chopper and hits with massive power.


Fiddleback Forge’s custom machete in 1075 (maker does not publish Rc hardness). The spine thickness on this 16-inch blade is 0.089 inches. The SEW is about 0.033 inches at the same edge depth as the other blades. This is a light blade that is really meant for lighter brush. It’s agile and an excellent slasher, but way out of the league of the other choppers. I included it for reference. I love this machete.


Condor’s khuki in 1075 (56-58 Rc). The spine thickness on this 9,75-inch blade is 0.297 inches. The SEW is hard to measure because it’s an extremely convex grind, but it’s about 0.06 inches at the same depth as the other choppers. This is a different knife design, but a classic design and I wanted to include it for comparison.

 

[Twindog]

The tests:


I was interested in edge stability, mostly because of the problems I had with my custom 3V chopper and because of Luong’s super-hard heat treat. I also wanted to see how the different blade geometries handled various tasks common to homesteading work in my area.


There were four tests:


1 — Chopping a heavy branch of big leaf maple, a hard wood. This branch was green. I was mostly interested in how fast the various choppers could go through it.

2 — Chopping hardened 3/8-inch oak dowels, a moderate test for edge stability.

3 — Chopping into a 4x6 Douglas fir block to test for edge penetration.


4 — Chopping thin bailing wire as a more extreme test of edge stability.

5 — Chopping though heavy salmonberry brush to test chopping performance and edge stability.

First up was the maple chopping, listed in order of performance, from worst to first:


6th by a long shot was the Condor khukri. It’s heavy geometry was slow to work through the branch. The blade profile was too thick to be effective.


5th was the Busse BWBM. It wasn’t too bad, but it lacked the mass and geometry to compete with the others.


4th was the thin 3V chopper. It was very good, but green maple yields better to heavier blade geometries.


3rd was Luong’s W2 test chipper. It’s not a long blade, so it lacks some of the leverage, but it hits with power.


2nd was the Fiddleback machete. The long length gives it leverage to amplify the thin blade geometry.


1st was the Senegal. It has both length and mass. This sucker can chop.


None of the blade suffered edge damage.

 

[Twindog]

Next up was the oak-dowel chopping. This test was easy to all the blades. The clear loser was the Fiddleback machete, which suffered edge damage.




The third test was penetration into a 4x6 block of Douglas Fir. None of the blades suffered edge damage, but the penetration was far different.


6th was the khuki, which had great difficulty sticking in the block. It’s geometry was too thick.


5th was the Fiddleback machete, and I’m not sure why, perhaps because it lacked mass.


4th was the Busse BWBM.


2nd was a tie between Luong’s W2 test blade and the Senegal. Both put it to the Doug fir block.


First was the long, thin 3V chopper. It’s length and thin profile buried deeply into the block.




The really tough test was the bailing wire cutting. I didn’t try the Fiddleback machete because it had already failed on the oak dowel test. All blades suffered edge damage on this test, although not too severe.


5th was the Senegal. It’s A2 steel suffered a dent/roll easily worse than any of the other blades.

4th was the khuki, which suffered slight damage.


1st was basically a tie between Luong’s W2 chopper, his reheat treated 3V chopper, both of which suffered very slight damage, and the Busse Bushwhacker in Infi steel. This result surprised me because Luong’s blades were much harder than the rest, so normally they would have been exceptionally vulnerable to this test, especially with a thin edge geometry. Luong does a great heat treat.


The Busse BWBM actually suffered the least damage, but not by much. This classic steel known for its ultra toughness was suffered slight damage, just a bit better than the other first-place steels. I put it in a tie because it had such an advantage in geoemety over the W2 and 3V choppers. The BWBM had a much thicker edge width - far more stout than Luong’s knives.

 

[Twindog]

The last test was bushwhacking through heavy salmonberry. This was a subjective test. My girlfriend did the test with me, and we independently came up with almost identical results.

6th was the khuki, which to be fair is not meant to be a heavy brush chopper.


5th was the Busse, mostly because it had a shorter blade. It, too, is not designed as a machete, despite the name.


4th was the Fiddleback machete. It is awesome for light brush, but not as good for thick, woody brush. It suffered edge damage, the only blade to do so in this test.


3rd was Luong’s W2 test knife, which was surprising because it’s not a long blade. It’s power hitting really helped against the thickest stems.


2nd was the long, thin 3V chopper. Its length and thin profile made it efficient at chopping.


1st was the Senegal. Although heavy and not something I’d want to swing for long, it’s length and mass was murder on thick, woody branches and stems.

 

[Twindog]

Post Script:


I wondered about the edge damage suffered by every chopper in my test. So I decided to put some high-end knives to the same test.


From L to R: My custom hunter in 1095, Crusader Forge in S30V, Gilson in M4 (64 Rc), Carothers 3V at about 60 Rc.

Nathan Carothers’ 3V field knife is highly respected — and it’s blade was very sharp. It, too, chipped, maybe a bit worse than the Infi and Luong’s 3V and W2, but it was close.
]

My 1095 hunter is hand forged and has passed my toughness tests before, but the wire test was murder on its edge.

The Crusader Forge in S30V had minor chipping, not much. The Gilson M4 at high hardness (64 Rc) also had very minor chipping.

 

[GREENJACKET]

Testing and using is the only way to find a choppers limitations. The wire test to me is a tricky one, as it really requirers a different approach to a wood chopping/chipping edge, or even wood cutting edge.
In the past my choppers of all kinds tend to have a softer steel and heat treatment so they don't snap or chip badly. These big blades sure do take some forces, way way higher than more standard mid sized blades. Getting a temper so they don't snap and also with an edge that lasts is well difficult.

Factory machete's tend to be far too soft for forestry. Lack of stiffness and the vibrations are the reasons I've stopped using them.
Heavy beefed up Bolo's or Machete can work. I have a Blackjack Marauder II that does it. Plenty of steel behind the edge and the edge rarely ever chips. I once witnessed an Al Mar Pathfinder fail with a huge, I mean huge, chip out right into the grind of the blade, all because it was heat treated too hard. Too soft and they just sqidge in as found with the heavy military machete's/bolos.
I find Kukri's tend to small chip on the edge as do village parangs. Leaf spring steel village forged blades can only take so much. The trick is to sharpen them when working all the time to keep damage reasonable.

One problem with the heavier tougher blades is that they often aren't keen enough to catch the cut of thin springy vegetation as for bushwhacking. So many are given a chopping chipping edge that just can't cut this thin stuff. Here a keen edge is required. Thicket come in too many thicknesses and toughnesses. Too heavy a blade on this stuff is tiring, very. I have found a great tool in the Skrama for this work, see my report elsewhere.

Your tests seem to suggest what I have found. Industrial wire damages fine edges, best to use wire shears. The harder the wood the more obtuse the edge to get metal behind it. Too hard a wood and too fine a grind and the steel will ripple or crescent fail as the Pathfinder did. Hard wood really needs an axe grind edge to chip out material rather than cut out the wood.
Thicket then something keen to catch the cut but also enough steel in the grind to take the abuse. Weight and reach is important too. Again look up Skrama.

When it comes to sexy steels and heat treatment then what works on a knife best probably won't for a big chopper; choppers have a whole other set of rules. Its taken me a while to find big choppers that I have confidence with; many I've tried have been lacking. In truth I've been pretty disappointed with what is offered by the factory manufacturers. I ave found a couple as above that I use before reaching for the axe. I now match the tool to what they are up against.

Lastly, I once tried to cut some trip wire wire with my knife. That wire might be thin but it can strip an edge off any edge, stupid tough and hard.

 

[BluntCut MetalWorks]

Thanks for excellent review, Twindog :thumbup:

Others - please keep in mind and or consideration, these high hardness choppers are hard & tough, unlike conventional ht where extra hardness goes along with extra brittle.

Here is my latest video of 66+rc 3V chopper - [video]https://youtu.be/HH_EYiL0zF8[/video]

As GreenJacket mentioned about chopping very hard wood need thick geometry. In the video, I chopped knotty olive & lignum vitae argentine - both are very hard. Soft or brittle edge will suffer damage (roll or chip). My 66+rc passed these tests -> deductively, this edge must be very strong/hard & tough (impact load) to passed these tests.

As for chopping bale wire - you don't know your tool capability until subject them beyond their limits. Ideally edge geometry need to be normalized - e.g. 0.025" behind edge thick & 17dps. Edge damages will be worse for edge with low hrc & easy to chip. Imply, infi won't fare that well. Keep in mind, thickness/cross-section is cubic in volume stiff/strength. So 20dps is 2.3x volume strength over 15dps.

 

[WILLIAM.M]

Excellent review!!!

 

[trestle]

Excellent review and pics, thanks for posting. I keep meaning to get out west and connect with you. I wonder how the edge of a 12" Fiddleback machete (thicker stock than the 16") would have done on the dowel and salmonberry tests. I like your custom chopper, great looking shape.

 

[Twindog]

Thanks. I was mostly interested in seeing how well Luong's heat treat would hold up on a reheat treated blade that was misheat treated before. My understanding is that reheats are difficult. But Luong did a great job. The 3V chopper is now what it was supposed to be in the first place. His test W2 blade is awesome, too. Once before I bought a custom Bowie in W2 after watching a knife maker chop nails in half with his W2 chopper. But on mine, by a different maker, the steel suffered damage chopping clear-grains, bark-free and knot-free Doug fir. Heat treat is really the key.

I was especially looking for a way to test edge stability without wrecking the knife. The wire test was harder than I thought, but it brought out edge issues quickly without doing much harm.

The Fiddleback was a little disappointing, but I like it a lot. It has a good feel and works well on light vegetation. I think it shows that steel is important, as well as the heat treat. The small hunter in 1095 chipped/rolled easily, while a similar knife in M4 at high hardness didn't.

Mostly, I got to know my blades a lot better. They all have strengths and weaknesses. Now I know what they are.

 

[GREENJACKET]

I'm a user but have great admiration for those trying to make big blades that can go beyond the norm. I recognise its really difficult. Most manufacturers play safe as any big failure doesn't do their sales much good.

Generally to catch the cut of springy stuff requires a very keen edge. Hard wood a more solid edge to chip out pieces. Different techniques for different materials. Few blades can do doth. How keen can we let the steel go before it can't take any more?

Which is the reason for testing and trying different steels and those steels with different heat treatment. There is a hobby somewhere in there in its own right. Be it custom or factory most makers can make a good blade, but few can make a big chopper that can still hold real keenness without the possibility of failure. Add both wood and scrapyard challenges and those blades are going to be tested. Its difficult.

High hardness choppers is a real challenge.

Because no one has really beaten the challenge I tend to play safe and take several tools that are good at one specific task. My bushwhackers, my wood choppers, and metal guillotines/steel snips.

Nice review.




w ch

 

[bodog]

Nice review man. Enjoyed reading it

 

[Twindog]

As a final test, I dug out my Zero Tolerance 0180 in Vandals 4 Extra steel. I bought this after reading Bodog's review on this super tough steel.

I did the standard wire test, and the damage was extremely slight. I could see the damage only under magnification or in just the right light. The blade still cleanly sliced notebook paper after whacking the edge on the wire very hard. The big choppers, of course, were hitting the wire with much, much more power just because of their greater mass and length; so I can't call this a winner. But it is awesome steel. Hard for me to imagine going back to traditional steels.

 

[DeadboxHero]

Thanks Twindog great read.

I appreciate the time

 

[sodak]

Thanks Twindog, this is great!

 

[black mamba]

Very informative, I really appreciate the effort!

 

[BluntCut MetalWorks]

Vanadis4E is very tough for a high carbide volume steel, result reflected that. Outside of edge geometry, bale wire chopping task is fair (physics wise) for all test blades - big & small. Wire is a softer version of nail, in my testing - there is a narrow range threshold of pass/fail edge geometry. Range for blind-folded chopping nail on solid metal backing: 0.015"BET+16dps to 0.018"BET + 18dps. Wood backing: 0.018/18dps - 0.02/20dps.

As a final test, I dug out my Zero Tolerance 0180 in Vandals 4 Extra steel. I bought this after reading Bodog's review on this super tough steel.

I did the standard wire test, and the damage was extremely slight. I could see the damage only under magnification or in just the right light. The blade still cleanly sliced notebook paper after whacking the edge on the wire very hard. The big choppers, of course, were hitting the wire with much, much more power just because of their greater mass and length; so I can't call this a winner. But it is awesome steel. Hard for me to imagine going back to traditional steels.

 

[Twindog]

I was talking with a highly respected knife maker, and he said a more telling test would be trying to chop a 10d (3 inches) nail in half. I had resisted tests that hard because I didn't want to destroy all my good knives. But I did try it with my Busse Bushwhacker in Infi, which is a modified A8 steel known to be extremely tough, and the re-heat treat that Luong did to my 3V blade.

I didn't try any of my other choppers because I knew they would all fail. I had already sent Luong's W2 test chopper back to him, and wouldn't have done it on that blade because I didn't own it.

The results: I put the 10d nail on my big block of Doug fir, just as with the bailing wire test. I hit the nails as hard as I could. I could not cut them in half, but they cut part of the way and then bent. This was the same experience I had with the wire, except that Luong's re-heat treated 3V chopper and his W2 test choppers were able to cut the wire in half on several of the blows. Both the nails and the wire end up being driven into the wood.

After my mightiest blows, the Bushwhacker showed no damage. It suffered more damage from the bailing wire, so that wire must be tougher than I thought. The re-heat treated 3V chopper had a few very small rolls (not chips) that could be seen under a 22x loupe. Infi obviously deserves its reputation. The re-heat treat by Luong also is also incredible. The 3V blade he re-heat treated chipped badly under just salmonberries before Luong's magic.

Remember, the geometry on the 3V chopper is much more acute than the geometry of the Bushwhacker, making it more vulnerable to damage from this kind of abuse.

Kind of blows my mind that highly acute 3V at 65 Rc would roll before it chipped. Amazing.

 

[trestle]

I would say Mr. Luong has an excellent protocol for his heat treatment of thin 3V. As for the 10D nail, when I used to frame houses we called those "the correctors" because they could literally move and hold framing that needed aligned or straightened. That's a tough test of those blades, no doubt about it, and the results are impressive.