Does anyone know what these steels avg carbide sizes are?

N

Nathan Akins

Joined
Jan 31, 2015
Messages
91
13c26
O1
Shirogami 1

I'm looking for the best wood carving knife steel and I have determined that with optimum ht, low edge angle, mirror polished and a hard, very fine grained/carbide size steel.
I have determined that,once the avg carbide gets lower than a certain point, it would be unnoticeable for ease of push cutting wise.
Does anyone know what those numbers would be? Definitely smaller than 2um avg right?

Nathan
 
Nathan Akins said:
13c26
O1
Shirogami 1

I'm looking for the best wood carving knife steel and I have determined that with optimum ht, low edge angle, mirror polished and a hard, very fine grained/carbide size steel.
I have determined that,once the avg carbide gets lower than a certain point, it would be unnoticeable for ease of push cutting wise.
Does anyone know what those numbers would be? Definitely smaller than 2um avg right?

Nathan
Click to expand...

I recommend that you peruse Steve Elliots wood-planer testing page: http://bladetest.infillplane.com/html/microstructure.html

<2um is a good round number that characterizes carbide size for a wide variety of steels. But carbide size has nothing to do with ease of push-cutting, that is a matter of edge-geometry, specifically a keen apex and thin behind it. D2 and 440C steels, known for occasional large aggregates of carbide spanning >20um, can be honed to just as fine if not a finer edge than steels lacking such large aggregates... IF using proper honing equipment and techniques. Also carving wood has less to do with low edge angle than it has to do with low edge thickness. In Steve's tests of blades requiring a much keener edge than you are likely to need carving with a knife, he maintained his blades at >15-dps (30 inclusive) below which he observed an unacceptable increase in edge-degradation through deformation/chipping from lack of structural support (i.e. low thickness behind the apex). Keep in mind that he wasn't carving soft/fluffy wood like pine or balsa, so your needs might not demand such strength, and also note that damage was confined to the very apex, so you could easily sharpen at a lower angle so long as you add a microbevel to sustain the edge.

Regarding the steels you've selected, any one of those would be good for woodcarving... and so would a vast number of other steels, you needn't be so restrictive and especially shouldn't get the notion into your head that those three are somehow "the best" for such a task. A good carving knife can be made from O1 or from D2 or from M390. The reason to chose O1 over the others is price/performance - D2 and M390 don't really offer any advantage in wood-carving. The reason to choose 13C26 (or 420HC or 440A) over O1 is corrosion-resistance.

Choose a steel that has been HT'd well and achieves >60Rc if possible... though lots of us get by on Buck's 420HC at ~58Rc. Honestly, the most important factor in a good woodcarving knife is the handle - get something that is comfortable... then worry about blade-steel. That's my $0.02
 
Wouldn't there be less edge stab ability with larger carbides? And carbide size doesn't affect push cutting ability? And how does those steels get just as sharp? Super fine stripping compound? But I'm still curious to see what those steels avg carbide steels are. :)
 
Nathan Akins said:
Wouldn't there be less edge stab ability with larger carbides? And carbide size doesn't affect push cutting ability? And how does those steels get just as sharp? Super fine stripping compound? But I'm still curious to see what those steels avg carbide steels are. :)
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You can find etched micrographs online with a little bit of searching. Most PM steels have carbide aggregates <2um. With proper heat-treatment, the steels you listed would have carbides <1um and at fairly low volume. D2 and 440C are known for producing larger aggregates due to the manufacturing process and high carbide volume, but aggregation is sporadic/non-uniform in ingot steels so even they present a lot of smaller carbides. Carbides are many times harder than martensite and so are capable of taking a much finer/thinner edge but this requires shaping of the carbides with sufficiently hard and sharp abrasives applied well, e.g. SiC, CBN, diamond, etc. This is the challenge with high-carbide blades - they require more skill or better equipment to shape the apex to a fine finish (due to their high abrasion-resistance) than simpler steels.
Again, push-cutting is a matter of edge-geometry, i.e. how the apex is shaped. All this requires is the proper tools/skill to shape the apex. The BEST push-cutting blades are designed for microtomes and are >96% carbide (tungsten or diamond) compared to only ~15% carbide for D2. Regarding "edge-stability", you need to present a working definition of what you understand that term to mean. High-carbide blades at very thin geometry are more "brittle" than low-carbide steels... which is NOT to say that they are "fragile", only that when subjected to the same levels of stress in excess of the steels yield point, the higher-carbide blade will crack/chip sooner than the lower-carbide blade that deforms more before cracking. When you set either to a proper geometry (edge thickness and apex angle) to support the steel, neither will suffer.
 
Nathan are you looking to make a knife? If so look at the steel makers sites to find grain size. There are several very good wood carving knife manufactures. To name a few - NorthBay Forge, Cape Forge, and Helvie. Of these only NorthBay lists the steels he uses - W1 and W2 - his blades are forged and they keep a very good long lasting edge. If you are looking for a pocket carry knife to carve with then Queen uses D2, ATS-34 and others I would go with the D2 they can be found at a reasonable price. GEC uses 1095 and as mentioned about there are Buck knives USA vintage that can work.
 
Thanks for all the help! So this is what REALLY maters in ease of push cutting: edge geometry(thing angle thin blade good apex) hardness, mirror polished, and what else. I would have thought carbide size had something to do with it. Thanks again
 
Nathan Akins said:
Thanks for all the help! So this is what REALLY maters in ease of push cutting: edge geometry(thing angle thin blade good apex) hardness, mirror polished, and what else. I would have thought carbide size had something to do with it. Thanks again
Click to expand...

Please note, carving is much more than just push-cutting, it is wedging and leveraging, i.e. inducing significant lateral stress on the blade edge unlike shaving your face or cutting through meats and fruits in the kitchen which induces very little stress (unless you embed in a bone or hard seed-pit). What this means is that taking the edge too thin for carving stiff wood, e.g. thin like a razor blade, can result in serious deformation and/or chipping. The carbides exist primarily for abrasion resistance, but at very thin geometries they can compromise the fracture-toughness of the blade. Those ultrafine-edge microtome blades I mentioned are used in a very controlled manner on materials that do not induce lateral stress the way wood does - i would not recommend a ceramic blade for carving despite it's incredible push-cutting prowess, it doesn't have the requisite ductility to resist apex damage when carving. And carving wood is not generally a highly-abrasive task unless we're talking about wood-planers as in the link previously provided, so a high carbide content is not really an advantage in use and can be a disadvantage when trying to restore a dull-edge because of its abrasion-resistance.

For a good carving knife you want a blade that is sufficiently hard to resist lateral deformation and compression (i.e. 60+Rc), sharpened to a fine polish and keen apex (low diameter) at an angle that provides sufficient thickness to stabilize that apex against rolls/fracture (e.g. 15-20 dps microbevel) to a shoulder thickness that is low enough to allow good penetration but stout enough to prevent gross fracture of the blade (e.g. >0.010") when leveraging the wood being carved. And most important of all...

... comfy handle. :cool:

Here's a thread where whittling/carving knives were discussed - the main contributor uses a Cold Steel Mini Tuff-Lite (AUS8 steel at ~58Rc) for everyday carving: http://www.bladeforums.com/forums/showthread.php/1089873-Good-knife-for-whittling-and-carving
 
I have to make a comment here . I don't like the idea of prying out the wood .It's too easy to damage the edge when doing that ! Push or slice cleanly as far as needed to avoid bending or breaking the edge , it doesn't take much to mess things up. A carving tool also must be chosen as a balance of time between cutting and ease of cutting - that's your choice . A fine grained /small carbide steel is one you should be looking at . Such as the CPM steels or similar European ones . S35VN ,3V might work well also Fallkniven's 3G type [don't think it's avaiable for chisels etc. ]
 
Don't get hung up on numbers and stats.. Find a maker with a good reputation and actually talk with him in person or over the phone. After a short conversation, any maker worth his salt, should be able to ask a few questions and make you whatever you need with the proper steel and geometry for the intended task of the knife.
It really is that simple.
 
Some good discussion here. I buy from companies that publish which steels they use, but that's just because I'm a steel nerd.

Drake uses o1. I have two of their tools, the general carving knife has a very acute apex (zero grind), but is tempered springy. I did get a little waviness along the edge, but that has disappeared with sharpening. Couldn't say if it's due to "fresh steel" or a very slight increase in edge angle.

Deepwoods Ventures uses 1095 (forged rod stock). I have several knives from this company. Not as acute, probably closer to 30° (inclusive), but excellent cutting.

Cold Steel mini tuff lite (aus8 as mentioned). The knife comes with an excellent edc edge but I brought mine down to something between 25-28. I have had a little edge deformation, but nothing that couldn't be very easily fixed. The handle, for me, is terrible for carving, but it's an easy fix if you don't mind making the knife a pseudo fixed blade (non closing).

The other knife I bought for carving duty is a GEC halfwhitt. 1095 and it has been fine.

As others have pointed out, choose your knife by handle design first. If you plan to carve for more than 10 minutes at a time, this cannot be overstated. Out of the above, the Drake tools feature the most ergonomic handles for me.

As for steel, don't get too caught up in it. Yes you can have a knife made from a super wear resistant, high Vanadium steel, but good (easy) maintenance is part of carving. I typically strop on green ChromOx every 15 minutes or so. Doing this I can keep the blades razor sharp almost indefinitely. Lateral forces should be avoided at all costs because they produce unwanted results in the project, not just the steel. That said, it does happen, especially on the tip if you are careless. I have not had a failure at all from lateral forces. I carve basswood (soft) and a hard type of poplar.

Nothing wrong with looking at the science when choosing your carving knife, but it's easy to transfer edc knife steel ideals to focused tools when it's really a different animal.
 
This is what happens when you put a high lateral load on the edge. This knife is D2, and I thinned it out too much.

http://i137.photobucket.com/albums/q203/sodak_photos/testing/queen_4180.jpg

A small microbevel took out the damage and gave the edge enough thickness to be able to repeat the test with no more damage, but lesson learned. I was carving a piece of fatwood, using the same motion that you would use to scoop ice cream.
 
How thin was your D2 edge?

Out of curiosity, I just scoop some dry pine & black oak with D2 blades I tested today - no problem.
cross link - http://www.bladeforums.com/forums/s...est-amp-arms-exercise?p=14484421#post14484421

sodak said:
This is what happens when you put a high lateral load on the edge. This knife is D2, and I thinned it out too much.

http://i137.photobucket.com/albums/q203/sodak_photos/testing/queen_4180.jpg

A small microbevel took out the damage and gave the edge enough thickness to be able to repeat the test with no more damage, but lesson learned. I was carving a piece of fatwood, using the same motion that you would use to scoop ice cream.
Click to expand...
 
bluntcut said:
How thin was your D2 edge?

Out of curiosity, I just scoop some dry pine & black oak with D2 blades I tested today - no problem.
cross link - http://www.bladeforums.com/forums/s...est-amp-arms-exercise?p=14484421#post14484421
Click to expand...
Way too thin. I don't remember exactly, but it wouldn't surprise me if it were under 0.015 inches, I was really pushing it back then. It cut very well, but needed a little more support. If I could have had it re-hardened to 61 or so, it might have been ok, but a different steel probably would have been a better choice...

To be clear, this was completely my fault, not the knife's fault. I still use it today, and it's a great performer.
 
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