Axe Sharpening and Grit

FortyTwoBlades said:
It's false attribution. What you are seeing/experiencing is not the result of hardening at the edge. Just because they do one thing and get a particular result does not mean that it is due to the reasons they state. Heat would not harden steel, and it is not work hardening from displacement of the crystal structure. There is not a mechanism at work in that method that is able to induce an increase in hardness. The closest thing there is would be if any burr or wire edge is present it will work harden and break off due to being folded back and forth a bunch of times, but that isn't going to produce an increase in performance vs simply sharpening to a fine apex without developing a wire edge in the first place.
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Well there's enough people with a deep understanding of sharpening who believe in it, suggesting to me that it shouldn't just be carelessly tossed aside as 'non-scientific'. Kochanski says that proper stropping will burn off the burr. I suspect that this heat allows the burr to soften enough that it will tear off more cleanly, which is in effect the same as hardening. 'Hardening' is not being used in the same sense as 'tempering'. It may mean keeping the edge as close to its ideal temper as possible, which may mean hardening or softening, depending on the context; or even removal of the burr, which can act as a too soft or too brittle edge (and in function carries the steel away from its ideal hardness).

Are you not effectively hardening (really, softening) the steel when you warm the edge before chopping in the winter? The same can be said of a build up of brittle steel at the edge due to incomplete sharpening practises, the steel has, in effect, been made too hard.

Significant amounts of chopping will warm the edge of the axe, enough to make a difference in the steel I cannot say for sure, but the difference between -20C and 0C produces a noticeable difference in the performance of steel. And there are those who say not to let an axe become too warm to the touch - chopping and stropping can approach this. And crucially, this slight difference would make the process of stoning and stropping the steel slightly different because of the change in steel at the edge, if ever so slight.

Similarly, there are people in timbersports who say not to leave the axe in the sun because the heat will soften the steel and the edge. Minor changes can have a greater effect on steel than we believe or what might be studied in science. The language is simply less rigid than the scientific; that does not make it wrong.
 
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Chignecto Woodsman said:
Well there's enough people with a deep understanding of sharpening who believe in it, suggesting to me that it shouldn't just be carelessly tossed aside as 'non-scientific'. Kochanski says that proper stropping will burn off the burr. I suspect that this heat allows the burr to soften enough that it will tear off more cleanly, which is in effect the same as hardening. 'Hardening' is not being used in the same sense as 'tempering'. It may mean keeping the edge as close to its ideal temper as possible, which may mean hardening or softening, depending on the context; or even removal of the burr, which can act as a too soft or too brittle edge (and in function carries the steel away from its ideal hardness).

Are you not effectively hardening (really, softening) the steel when you warm the edge before chopping in the winter? The same can be said of a build up of brittle steel at the edge due to incomplete sharpening practises, the steel has, in effect, been made too hard.

Significant amounts of chopping will warm the edge of the axe, enough to make a difference in the steel I cannot say for sure, but the difference between -20C and 0C produces a noticeable difference in the performance of steel. And there are those who say not to let an axe become too warm to the touch - chopping and stropping can approach this. And crucially, this slight difference would make the process of stoning and stropping the steel slightly different because of the change in steel at the edge, if ever so slight.

Similarly, there are people in timbersports who say not to leave the axe in the sun because the heat will soften the steel and the edge. Minor changes can have a greater effect on steel than we believe or what might be studied in science. The language is simply less rigid than the scientific; that does not make it wrong.
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Except these things have been studied--at great length--and myths abound in the realm of edged tools. I once spoke with an old duffer who was highly experienced in trail maintenance who thought that after a number of years his machetes lost their carbon (for some mysterious reason) and had to be "re-tempered" by heating them up red hot in a fire and sprinkling borax on them...to...uh...put the carbon back in them...Yes, that is really what he claimed! The real reason his tools were going soft was because he was heating them up in a fire. :p

"Experience without theory is blind, but theory without experience is mere intellectual play."
~Kantian maxim

What Mors, by your description, seems to be noting is actually removal of a wire edge by work hardening--working the wire edge back and forth until its fatigue limit is reached and it shears off. But the resulting edge isn't appreciably harder than when it was initially heat treated, and will still benefit from some additional light finish-honing because the removal of the wire edge will have left a somewhat ragged apex compared to what can be achieved by further honing. Additionally, even if there were somehow a gain in hardness at the edge, hardness achieved through work hardening (such as peening the edge of a European scythe blade) does not increase the wear resistance of the steel--but it does increase its resistance to deformation while simultaneously reducing its toughness. That's not what happens under normal sharpening, though.

In your cold weather example you are conflating hardness and toughness. While typically linked, they aren't direct opposites.

It is true that vague statements are not inherently wrong so long as their meaning can be clearly ascertained, but by the same token it is still possible for them to be completely wrong even when that meaning is made known. It can be of great value to study the advice, traditions, and practices of professionals and experienced tool users, but it is also important to take a large grain of salt when doing so. Unless they happened to also be engineers or metallurgists it's unlikely that they'll have a full understanding of exactly what does or doesn't go on with their tools from a scientific basis. Some of these things they'll have hit on correctly through a keen process of observation, testing, and evaluation, but others they'll likely either be blind to or have arrived at some confused and incorrect conclusion with because they lack a measure of theory equal to their experience. This could be corrected by either studying the work already done by others or by using scientific methods to do the legwork themselves.

TL/DR version: Some people know how to make an axe nice and sharp, yet don't know the why of it. :)
 
Good lord. I'm all for understanding the science and getting better results from certain methods but I think we need to keep a few things in mind. It's fund to geek out on all of this stuff but let's be honest: at the end of the day if you sharpen an axe using your preferred method the real, tangible, difference between methods is negligible at best. An axe sharpened with a bastard file vs an axe honed to 6,000 grit will both chop down a tee. Will the honed axe "stick less" and "penetrate millimeters deeper" yes. However, the average user probably won't notice much difference.

What would be interesting is to see if the time taken to hone an axe to 6,000+ grit would outweigh the extra time an axe sharpened with a bastard file would take to chop through a tree.

Diminishing marginal utility comes to mind... But then you have to factor in the pleasure one gets from a mirror polished axe edge honed to 12,000 grit and the pleasure of chopping down a tree, etc.

In my (admittedly limited) experience, I would say sharpen/hone to your hearts desire (whether that be 12,000 grit or 250) and then chop chop chop. In reality you probably won't lose a whole lot of time.

(I'd like to thank Wild Turkey Rare Breed for inspiring this post)
 
Ultimately, from a general purpose standpoint, all that needs to be done is for the edge to be brought to an apex at an appropriate angle, and with any resulting burr or wire edge removed.

Even a bastard-cut file or coarse silicon carbide stone will produce a serviceable edge on an axe. Going finer will produce better results, but is not strictly necessary for most users, and it won't do you much good unless you took care of the preceding steps first, anyhow. But the more heavily you rely/depend upon the tool, the more worth it it will be to take it finer. For those using the tool with high intensity, frequency, and time on task, small performance gains rapidly add up. For occasional or casual use, it's largely a drop in the bucket as long as it's apexed, burr free, and a proper angle for the context of use.
 
Tymowens said:
Will the honed axe "stick less" and "penetrate millimeters deeper" yes. However, the average user probably won't notice much difference.

What would be interesting is to see if the time taken to hone an axe to 6,000+ grit would outweigh the extra time an axe sharpened with a bastard file would take to chop through a tree.
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A more appropriate test would be to see how much time is gained in chopping as many trees as can be chopped until the tool needs sharpening again. The amount of total energy expended honing the edge will be gained back tenfold in energy spent chopping. A finely honed axe cuts like a dream. Anyone will feel the difference right away.
 
Square_peg said:
The amount of total energy expended honing the edge will be gained back tenfold in energy spent chopping. A finely honed axe cuts like a dream. Anyone will feel the difference right away.
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Yup! Though it's possible to get edges with a bastard file that dry shave.
 
FortyTwoBlades said:
Yup! Though it's possible to get edges with a bastard file that dry shave.
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True, i finish with a little Nicholson made in USA 6" bastard file, very light pressure, not much more than the weight of the file. Has to be a high quality file.
 
It is a matter of usage for me. Some axes get the file or coarse stone only, others get dressed to finer hone. If I know it is getting rough treatment, a file is all I do. If it is likely to be treated gently, I'll make it nicer. The finer finish is more durable in terms of lasting longer and cutting better, but makes no difference in terms of mechanical damage like knots, Dirt, rock, etc.

For example. My felling axe is finished to ~1000 grit on a fine stone, wheras the $10 hatchet I use to chop black locust saplings off below ground level gets a file... Axes for limbing and bucking get some middle treatment.
 
I wondered about the durability of a refined edge vs the more coarse edge? My recent edge got the fine edge because I wanted to see if this is more efficient in splitting. Gives a better return on spent energy.
I may not take it to this level every time still, I'm learning. A file is very coarse and removes a lot of metal. Maybe I could ruin my axe quick. Thanks guys for sharing your experience. DM
 
It depends on specifically what you mean. In the case of the degree of refinement of the apex only, a more refined edge will last longer in the kind of cutting action used by an axe (push cuts.) If referring to thin vs. thick edge angle, the thinner angle will maintain sharpness longer when subjected to abrasive wear, but the thicker angle will be more resistant to dulling by deformation.

A file removes a lot of metal compared to a bench stone, but not nearly so much that you risk ruining an axe.
 
David Martin said:
I wondered about the durability of a refined edge vs the more coarse edge? My recent edge got the fine edge because I wanted to see if this is more efficient in splitting. Gives a better return on spent energy.
I may not take it to this level every time still, I'm learning. A file is very coarse and removes a lot of metal. Maybe I could ruin my axe quick. Thanks guys for sharing your experience. DM
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I rarely use a file unless I'm re-profiling or restoring an axe edge. Once I get them to where I want, I usually just hone the edge with a dual-grit rectangular stone with some honing oil (and I finish with a ceramic flat stone and a strop). I use the long stone as I prefer to bring the stone to the axe, and I can scrub the edge with the stone in a circular motion while keeping my fingers clear. If the profile is set well (convex) following the Ax to Grind guage, it will last through quite a bit if it's good steel. My refurbed Council Tool 5-lb Dayton came with a decently thin edge, but needed a bit of filing, followed by the stone. I split quite a bit of wood last season with it, and it definitely didn;t need to be filed...it only needed a very light touch-up with the stones to keep it shaving sharp.
 
Ok, good. That's what I was hoping. I like bringing the stone to the axe as well. Just a light touch up is what I was hoping as well. I use 2X8" and 2.5X11.5" stones which work well. Thanks, DM
 
FortyTwoBlades said:
It can be of great value to study the advice, traditions, and practices of professionals and experienced tool users, but it is also important to take a large grain of salt when doing so. Unless they happened to also be engineers or metallurgists it's unlikely that they'll have a full understanding of exactly what does or doesn't go on with their tools from a scientific basis. Some of these things they'll have hit on correctly through a keen process of observation, testing, and evaluation, but others they'll likely either be blind to or have arrived at some confused and incorrect conclusion with because they lack a measure of theory equal to their experience. This could be corrected by either studying the work already done by others or by using scientific methods to do the legwork themselves.

TL/DR version: Some people know how to make an axe nice and sharp, yet don't know the why of it. :)
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Nice summary... As an engineer with background in some of these areas, and a strong interest in historical methods and hand skills I spend a lot of time talking with the hands on folks and learning and watching... and yes more often than not they have the "why" something works wrong, even when they are better at the doing than I will ever be.

Just because someone is good at chopping with an axe or sharpening it, doesn't mean he knows anything about smelting the steel its made from.

For me the key take aways on finish are: finer finished edges push cut better, and stay sharp longer, meaning lower effort in cutting and fewer times sharpening
 
It's absurd to say that these folks didn't know the why of it, they developed all of the best practises for sharpening. Their explanations simply use different language.

Now everyone knows the why of things, or thinks it is the why, but can't sharpen worth a lick.
 
Chignecto Woodsman said:
It's absurd to say that these folks didn't know the why of it, they developed all of the best practises for sharpening. Their explanations simply use different language.

Now everyone knows the why of things, or thinks it is the why, but can't sharpen worth a lick.
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No...SOME knew the why of it, many didn't. Same as today. And many more knew the how of it rather than the why. They knew the practices, but not the mechanisms by which the practices produced the results they did. Did it matter at the end of the day? Not really, because their tools were sharp. But those that didn't understand the real reasons behind things doing what they did, just that they did them, was that they often falsely attributed the results they got to some conjured up explanation that was completely inaccurate, and sometimes engaged in extra steps or labor they could have avoided if they had only known that it didn't actually contribute to their end result. A quote from Nikola Tesla comes to mind:

quote-if-edison-had-a-needle-to-find-in-a-haystack-he-would-proceed-at-once-with-the-diligence-of-the-nikola-tesla-287671.jpg


Now, as I noted, some DID understand the theory behind the practices, because they had studied them by close examination as well as research into the studies of others. But the majority didn't, or only knew part of it, and so many a man with great skill in sharpening explained their methods in false terms despite still producing an excellent end result. They had struck upon something that worked...they just sometimes didn't know why it worked despite possibly claiming to.
 
I recently caught the axe bug. I am a welder/metal worker by trade so I use some power tools.

First when I get a new axe I grab a fine single cut file and put an edge on it. Then depending on the axe I may or may not mess around with some DMT diamond paddles the Spyderco stones. You don't have to be to fussy about all of this my last Husquvarna that bought I timed my self and I had it easily shaving hair in ten mins and that was with taking the time to drink some beer and make sure all of the factory grind marks were filed out of the edge.

When I'm ready to take the next step I primarily use hook and loop ScotchBrite pads to remove all grind marks and polish the cheeks. You can do some mild re-profiling with the brown and the red pads as well. Care must be used but so long as you stay just back from the edge and don't bare down I rarely have had them get even uncomfortable to touch. I almost hate to say this but if some major stock removal has to happen one can use a sander flap wheel on the grinder. Don't use the dry! Lubricate by waxing the grit. And remember that higher grit gives more heat.

Once that's all done I put on a buffing pad and mirror polish with green then white compound.

Now you should be able to fine hone with no burr. Or use cardboard wheels on a bench grinder. If you hone you can strop with green compound if you like.

It sounds like a lot but it only take 45min and they are pretty after you get done.
 
Sorry after reading all the post I got off the original topic.

I am with a lot of the other people here I think, I don't think that the pure polishing of the edge really affects the cutting ability that much on an axe. Just thinking of the function of why when a ultra fine edge is NEEDED it is precision and quality. Think surgeon, sushi chef and fine woodworking tools.
An axe does not fall into any of these. What a polished edge does do is protect the edge both from oxidation and tearout/chipping.

And there is a pretty healthy dose of pride taken as well. I don't really think that's a bad thing. I mean who says someone is stupid because they take to good care of there car or house, right?
 
Years ago I did some cut testing on smaller blades and then applied to larger ones. I lived on a heavily overgrown lot of several acres and had plenty of opportunity/need to figure this out.

Comparing an edge finished at 80 grit and one taken up hair whittling on a barber hone, the common wisdom that rough finish draw cuts better, fine one pressure cuts better. The 80 grit edge cut rope and heavy canvas with far less applied force with a draw than the fine one with either a draw or press. Of course the 80 grit had a very tough time pressure cutting anything tough.

The part of my testing that stood out for me, swinging at some green ash branches about the diameter of my thumb. The rough edge barely penetrated all the way through the bark, the super fine edge nipped the same branch off clean, barely slowed down as it did so. Sharpened up my first gen Fiskars hatchet up to a hard Arkansas and stropped. It lasted four or five camping trips and still shaved arm hair. Proof enough for me, this formed the backbone of my edge retention theory - whatever finish and cutting strategy allows for cutting with the least amount of force directed back at the steel (toothy/draw, polished/pressure cut, something between), will yield the longest lasting edge for a given job - all other things being equal.

IMHO, even if the fine edge is somewhat overstropped, it will still chop better than a more cleanly formed rougher edge (up to a point) - less friction right at the edge = more retained inertia as it chops in. I find this edge unacceptable for my EDU knives, but on hatchets and machetes is a must.
 
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