Tbh, the jury is kinda still out on that one. You'll see scientists and professors disagreeing all the time, whether it's metallic bonding or air pressure. I remember reading someone said that if you leave them stuck for long enough, they weld.
@@old_iron_axe_and_tool The point of gear tooth curvature is to ensure maximum and consistent contact surface area. The smoothness only minimises the torque loss. It's fairly simple - let's assume your contact time is infidecimally short. If your contact area is smooth, the pressure created from the slave gear antagonising the master gear will compress the crystalline structure of the metal, creating a temporary contact plane where the work will be done. If your machining is exceptional, the plane will be flatter, which in turn means you can push more force through the system without damaging the gears. If we assume minimal material deviations, friction would be at it's lowest the smoother the surface is. An ideal gear will have a one dimensional line where the work is done.
Great points. What I really want to know though is what is that handle you have on the flying fox behind you? Red paint on the swell looks to be in the 25” ballpark…. What is that handle?
@@elliottwooding9931 Ehh, that's concrete that's exposing the surface of the (much smoother) rocks inside the concrete. Bit of an apples to oranges comparison. A rougher surface _of different material_ might have less friction, sure. But the comparison is between differing roughness with the same surface material.
@here_be_dragons9184 racing axes actually make great splitting axes. Look at the older competition tassie patterns. Highly sought after for splitting.
@old_iron_axe_and_tool i just got recommended this video and I'm not entirely sure why but i just want to say i really respect ur replies to people in the comments. Great video too
A high center line definitely reduces surfaces area, which makes an axe less sticky, but forging marks don’t count, as you said. Only major changes in geometry has minor changes in cutting, but yes a polish head helps. It’s why racing axes are polished.
Good job at explaining a bit of a controversial topic with old / vintage axes now ,I only go to 360 grit on the edge and the rest is just wire wheel and light oil. I've seen the whole topic go crazy here in the UK in just 3 years!
10:58 Simply, it's the function of the tool or intent of use that the purchaser wants that matters. If someone wants a splitting axe to use, then by all means polish it. If it's for collecting, leave it. Any other kind of axe, use discretion.
@1:47 I know nothing about axe heads. However, any physics class will tell you that friction is a function of contact patch and force (aka surface area absolutely matters). This is why drag strip cars have really wide tires for power delivery, for example. When you polish a surface, you are increasing the contact patch (aka "reducing the parts that aren't touching"), and therefore increasing the surface area of the surfaces that are touching. There are, of course, many other factors involved with friction, such as the materials involved. There are things like drag, which I would guess would come into play here. Basically, my guess (before watching the vid to be clear) would be that the forge marks in the axe head could act like a cheese grater. Removing the cheese grater effect will absolutely improve your chop. When I hear "polished axe head," it makes me think that it's a mirror finish. I wonder if a sandblasted finish would stick in a tree less than a mirrored polish. Trees have a lot of water, and you know that your hand experiences a lot of friction on your bathroom mirror (due to contact patch). However, your hand will stick less to frosted glass. edit: Ok you got into "sticktion," which is great! The sandblast matte finish might help reduce sticktion because it hopefully will interrupt water's hydrogen bonds. OR it might give it more surface area to grab onto lol, so tbh I dunno... but it'd be interesting to see it tested haha
Thank you for reading my disseration lol edit: @9:45 I do some knife sharpening, and the exact same concept applies to sharpening scissors. If they're too polished, than the thing you are cutting just slides away lol
> friction is a function of contact patch and force (aka surface area absolutely matters) I don't think "contact patch" here means what you think it means. The actual "contact patch" that affects friction is the material in physical contact, at a microscopic level, that forms transient bonds (e.g. van der Waals) or physically catches (in terms of peaks/valleys). It's not the total area that _looks_ like it's in contact to our eyes, and for hard surfaces, contact patch tends to be proportional to normal force (which is why friction is proportional to normal force). What polishing does is reduce the peaks/valleys contribution to friction, and thus it reduces the coefficient of friction. > Trees have a lot of water, and you know that your hand experiences a lot of friction on your bathroom mirror (due to contact patch). However, your hand will stick less to frosted glass. This effect is pretty specific to hands (and fingerprints in particular), not general surfaces. Our fingers have evolved this texture specifically to maintain grip on different surfaces (including very smooth ones, like smooth rocks), and friction becomes more complicated when soft materials like rubber or skin are involved. Don't think wood is elastic in the same way.
Surface area in contact definitely doesn't matter. More surface area reduces the pressure since it's the same force over a larger area. The surface area cancels out of each side of the formula, which is why the formula for friction doesn't include it. It's just normal force and friction coefficient. Cars having wide wheels are just to have more material and reduce wear, and probably for added stability. In real life scenarios, less surface area would increase wear, and it also might cause the harder object to dig into the softer one, increasing drag. So even though surface area is out of the friction formula, in real life applications where things rub together, it's generally preferred to have bigger surfaces, like wide wheels on cars, or bigger brake pads, etc.
You slept in your physics classes then. For a given coefficient of friction, the normal force is the only thing that affects the force of friction. The coefficient of friction is of course not constant due to a wide variety of reasons but it's close to constant to hard materials like metals. The reason why racing tires are wider is because rubber in those tires is very soft and the effect of friction "saturates" with enough normal force. The coefficient of friction actually drops the more load is put on the tire. Wood is not rubber and the conditions in wood chopping aren't as extreme for this nonlinearity to really make much of an effect.
Just found your channel and am super impressed with your knowledge. I have a son that LOVES splitting wood. He will appreciate the polished head idea cuz of our axes getting stuck! 👍🏽Thanks for sharing.
I split my billets of cordwood with an old 3# ax that has a stunt edge that I keep sharp. I polish the first inch to penetrate better. I leave the face "rough." If I don't split on the first shot, I lift the ax and wood to give it another shot. The unpolished face holds the wood as I lift it. Works very well!
Anyone who argues that a non polished axe performs better has never watched pro dog competition choppers. Where their axes can reflect the sunlight so well that they could probably burn down houses with the power of the reflection being so clear. You dont see some bad dude out there with an axe that has ridges and bumps and any of that. Why? Because if it was what was best, they would ALL do it. Plus, we know from pretty much any other cutting object out there that rusty or non smooth surfaces bind easier. Also, if we wanna talk about friction in a polished vs non polished. A rough surface that has less contact area is going to have a higher friction/pressure point, vs a load spread out over a larger surface, which will have less pressure.
I've noticed this recently especially while splitting the bottom rounds from big Douglas fir trees. Using a polished bit is noticably easier to pull out of the wood. I'm glad i have a decent collection to pull from and use the right axe for the job instead of polishing my user vintage axes. I also find using the flick helps if I'm getting really stuck
When splitting tough rounds in my old age I like to spray the axe headwith any available lube. Keeps it from getting stuck and probably splits a little better too.
I basically like my axes to be smooth (not Shiny ) but i leave the pits and big scars in them to keep the age and avoid polishing on the makers mark as much as possible
In my old age I have taken to spraying my axe head with whatever available spray lube when splitting tough rounds. It keeps the ax from sticking and probably helps with the splitting.
It's like any collectible, you don't unpackage it if your intent is to ever sell it at for a higher price, you put it up on the shelf and dust it when you take it down and savor it (or gloat). If you intend to use it on your model train track then unbox it as a hobby piece (or for axes - a working tool) not a collectable.
Yeah I agree. I've started buffing all my user edges. Not the full head but a portion of the bit. One day RU-vid will let us upload pictures and I could show everyone.
I thought you were saying Grant vs Brooks when talking about boutique axes. But I assume it's Gränsfors bruk? Take a closer look at their axes and you will find that they are polished differently according to intended use. Notably the splitting axes make a good point in your case as the bit is smooth almost all the way to the handle. I get a bit defensive as I'm from Sweden I guess but I think it shows deep knowledge and great craftsmanship to know where to put in what amount of effort. I find it way more more lazy, greedy and manipulative to sell an axe of low quality steel polished to a mirror shine all over because people like the looks of it. ¯\_(ツ)_/¯
Polished head reduce surface friction when the head is moving through an other medium(the wood being cut). The better the polish, the firther it will go. See that in this way. The surface is a texture with millions of little bump and crevaces. Even if the surface is polished like a mirror, there is bump and crevaces. It's just that they are very very small and "flattened out". But there is... Unpoliched surface "grind" against the other medium it goes through. Doing so the wood doesn't extract metal chip (like a file do), it extract kynetic energy, one little surface bump at a time. The flatter the bump are, less energy is dissipated, which keep the momentum of the axe in the direction it goes. When the axe come to a full stop, it's because all the kynetic energy have dissipated in the wood. Static friction is related to surface quality(amount of bump). The higher the bumps, the higher the static friction. And yes, at a certain level if the surface is too soft, it create vaccum and two metal part will stick together. It's because the bumps are so small and flatten than air(which is a fluid) can't flow between the bumps. So when you approach the two parts together, the air is pushed away, untill there is mostly no air remaining... this is why they call it "molecular bounded".
Mr. Old Iron, I watched that intial short before you posted this video. I found all of this information interesting from the title to the description...The part about phycosis and the lack of need for an axe driving the current "craze"...your personal cords split this year and all the comments thus far...all the scientific facts stated...very interesting sir...
Hey Brian. Testing will be up soon. I already know how much it helps, but the good people of youtube don't quite understand. Kinda conflicting with the current style today but oh well.
@@old_iron_axe_and_tool I am better than I’ve ever been. Wild story that’s best told over the phone or in person! Man I’m absolutely loving what you’ve built! This is of course right up your alley but damn, you’re killing it brother!!
Another way of reducing friction would be to reduce the surface area of the part of the axe in contact with the wood. Fluting/scalloping the flats of the head would do this.
Wood is not soft enough for the nonlinearity of friction to make a noticeable effect so the added friction from the shape of the surface might totally overpower the effect.
Another purpose for polishing that seems counterintuitive... A friend of polishes his knife blades to a mirror polish... He removes as many of the fine scratches from the factory polish as he can. The reason: Blood is corrosive. When he cleans game he can wipe the blood off. The blood doesnt settle down in the fine surface scratches and invite corrosion. He states that it makes maintenance and corrosion prevention much easier.
I'm pretty sure the added friction from two completely smooth (polished) surfaces is due to contact surface area. When you have a single smooth, and single rough surface the rough surface will only be in contact on the high points of the rough. Where as two perfectly smooth surfaces will have contact almost completely across the entire surface. It's why lubricants are so important to create a barrier between the two. This is in high speeds though. BUT - in the point of polishing, you're essentially working with the same structure of aerodynamics. You're giving it less places to grab and a smoother path of entry vs a rough surface that would in theory grab.
It's not because of the contact area as metal friction is very linear making the surface area cancel out in calculations. Highly polished surfaces made of similar metals weld together when rubbed so the additional friction comes from having to break bonds between atoms that form between the two surfaces.
Many years ago (70) when I was an apprentice and collecting the tools I would need in my trade. I perchased a two sided sharpening stone. It was a 3 inch circle. When I showed one of the jounymen who worked in lumber camps said it was an axe stone. Can you tell me more
Respectfully sir, are you talking about puck maybe? Not trying to be smart here, all mayor axe producers also have a sharpening stone with two sides in shape of a puck
And what makes it an axe stone (or puck) as far as I understand is mainly shape. Comfortable to hold in one hand while holding the axe in the other when sharpening out in the woods where you would work. As axes are very rarely straight like a chisel and the shape of the edge is usually slightly konvex to be more sturdy they lend themselves very well to freehand sharpening and honing. Secondly stones like this would generally be rougher than those used used by say a furniture maker or a chef because the needs are different.
Painting axe heads is a relatively new phenomenon... And its mostly used to hide imperfections from poor quality work. Forge scale is another thing, but a polished head slips through wood fibers more easily.
I've been using Presto Black and like the finished results best. However it's messy. Brownells Bluing paste is the cleanest to apply but it has a blue tint. presto Black is BLACK.
Well i polish some and wire some i do not really care what all the fuss is about i do not like my tools rusty vintage or not. But hell om trying to use my tools or atleast pass ir in to someone that Will use it
Only part where you got it wrong is where you said "multiply by 2 because there's 2 surfaces on either side of the axe". Those surfaces add up to make a bigger surface, which doesn't matter, as you said, friction is only dependent on the normal force and the friction coefficient.
Traditional octagon handles are thinner than normal handles, and that can be good and bad. I like octagon handles because I feel they're more accurate. The lines give you a known point that let's your hands know better what direction the axe is aiming. I especially prefer them on my throwers.
i have an old ball peen hammer im afraid to polish it up cause it dates way back to colonial times. i gonna have it appraised at a historical museum before i do anything . thanks
just look at all them rusty, stinky ol' axe heads hanging there. better call the scrap yard and pay them to come get 'em. tell you what mack, i'll take 'em off your hands no charge.
So he ain't too wrong about the rusting this leaving it Rusty to sell it because most of the time when I'm looking for a new axe I look for a rusty one one that I can work on and work with and then learn how to do it myself I don't like in the shinier ones because the shinier ones if you ain't careful some of them have a belly groove in it where they tried polishing it
