h a l f b a k e r yA dish best served not.
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Chainsaws blunt fairly quickly and are a pain to sharpen. My idea is ablative/sacrificial cutting edges that are stacked together. When one cutting edge gets dull/blunt the cutting edge is removed, revealing a fresh sharp cutting edge.
I'll describe a simplified version of a chainsaw tooth blade where
each blade is a flat metal plate. More complex tooth designs (closer to what a typical chainsaw tooth blade looks like) may be possible.
The plates are parallelogram in side cross section. To imagine the parallelogram, start with a long and thin rectangle. Now tilt/shear the rectangle so it has an acute interior angles of 30°(the cutting edge) and an obtuse interior angle of 150°. The metal plates could be quite thin, possibly as thin as a disposable razor blade (0.1mm).
Each metal plate has a rectangular hole in the middle.
The hole in the first plate has a horizontal rectangle shape. The hole in the next plate has a vertical rectangle shape. The hole in the next plate has a horizontal rectangle shape. And so on, with alternating orientation holes.
Through all the holes is a shaft that freely rotates. At one end of the shaft is a pivot beam (see-saw).
From a front perspective, when the see-saw is unaligned (at 90°) with the hole in the first plate, the see-saw holds the first plate in place (the shaft has a spring bias pulling the underside of the see-saw against the top plate). When the shaft is rotated 90°, the see-saw is aligned with the hole in the first plate. This allows the plate to slide over the see-saw and to be ejected, and then the see-saw abuts and holds in place the next plate (which has an unaligned hole).
The see-saw is necessary because of the tilt of the blades. The see-saw is pivoting from 60°, to vertical, to -60°, to vertical with each 90° rotation.
I've got a few ideas about the ejection mechanism. The simplest ejection mechanism is a short screw-thread on the shaft just below the see-saw. When the shaft is rotated 90°the screw thread engages with corresponding slots in the periphery of the hole. This lifts the plate on the front of the stack from the other plates behind.
So when the plates are stacked together, they form a strong block with a sharp edge at the front. To sharpen the blade, the shaft is rotated 90°using a tool such as a screwdriver. The blades should always be 'sharpened' together to keep the chainsaw balanced (so the user would need to rotate typically 40 shafts each 90°) . Some kind of housing/collector could be used to collect the ablated blades.
If having a see-saw protruding from trailing face of the blade is a problem (e.g. saw-dust/swarf getting impeded), each blade could be non-flat with a circular recessed portion, so that the top of the see-saw was flush with the face of the blade.
a few sketches
https://photos.app....l/coNG3dK6XLAfd8zg6
[xaviergisz, Mar 17 2026]
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You could brand name it "Shark's Teeth" (+) |
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[+] for idea and shark teeth name because I think shark teeth grow back, ablative sort of. If I’m mistaken I have no idea where I got that idea. |
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Close, I think they are preloaded and there's always a next set ready to emerge when one is worn out / torn out. Like humans should be if the design team hadn't been pulled off the dental project early and put to work on the giraffe. |
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Okay, good, at least I was in the ballpark. If there was nothing even close to that it’d be like “I thing donkeys tails grow back, it’s where they get mops from.” |
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//Like humans should be if the design team hadn't been pulled off the dental project early// |
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You have to be pretty tooth-prioritizing if you're rapidly removing large sections of live sea creatures with your mouth. |
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Humans cleverly avoided this by using a bit of stone attached to a bit of wood to quickly transition a dangerous wild animal to a much safer horizontal pile of pre-processed meat. Then, using bits of stone, humans separated out the tooth-breaking bits, the nasty bits, the tasty bits and the bits for making nice jackets. Then a relatively quick process of partial thermal degradation (more stick utilization). |
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Then they figured out how to maintain teeth and even screw new ones into their heads. |
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The stack of thin plates will not be as strong as a solid tooth. One hit with a nail or rock and all the plates in the stack will be splayed out all over. |
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The idea of a replaceable wear surface could be useful on the guide bar though- specifically the bottom section near the powerhead, where lubrication is least and cutting is most. This area wears out unevenly, making for crooked cutting. Filing this area to restore the shape works for a while until the groove becomes too shallow and the tips of the drive links start to grind at the bottom of the groove. So if you had replacement sections of guide groove it would make bars last almost indefinitely. |
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I agree that a stack will not be as strong a a solid tooth. This is envisaged for the occasional gardener rather than a lumberjack, so the convenience of easy sharpening will outweigh those downsides. |
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One way to protect the underlying ablative layers is to make each ablative layer on two sides of the tooth. So imagine a layer with a cross section in the shape of the number 7; the short arm of the 7 is the cutting face, while the long arm of the 7 is the top surface. |
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A similar mechanism as described before could be used to secure the top surface. To reduce the inconvenience of having to rotate two separate shafts to sharpen a tooth, the two shafts could be coupled via a bevel gear, so a turning one element would release both sides of the ablative layer. |
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claude made me a few sketches, but i still didn't get it...
so it made me a step-through slide presentation. Neat. |
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I thought the idea was to bring your sacrifice, along with your chainsaw. |
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I tried to get sketches done by various AI tools, based on the description alone. None of the AI tools were able to correctly illustrate it, so I've added a few basic images to help visualise. |
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I'm having a bit of an existential crisis as to my understanding of why chainsaw blades would wear out? Wood is sooo much softer than a reasonable steel. I can only think that the mechanical necessities of making a blade mean that it must be thin, then you have impacts that progressively fold the edge over - then maybe fatigue comes into play. |
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We can grow diamond in the lab reliably now. If we progress to growing it into any shape we like, so many human problems will simply go away. |
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I'd add another bun if I could for the artwork. |
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Nothing makes an HB post more enjoyable than getting an illustration of the idea. |
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I like this, and it bleeds into something I'd thought to market someday, but I'm getting old and I'm probably not going to get around to this one... so... here. |
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Design a chainsaw so that there is a file set to the optimum angle which engages each tooth as it passes over-top for as long or little a duration as the operator feels appropriate at the flip of a switch. |
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Fast. Way easier than conventional methods, and should have been thought of more than fifty years ago. |
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Sharpening a chainsaw by hand sucks. Totally Zen but a huge waist of time. |
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How about a bunch of radial saw blades, or even a linear oscillating motor in place of a chainsaw? Chainsaws were invented back when combustion motors were required to power them. Nowadays we've got electric motors for all kinds of power tools. With electrification could come better kinds of geometries than the mere primitive chain of the chainsaw. |
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Well that reminds me of something else I've never posted which I might market before I die. |
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I'mna keep this one for now... but you'll love it if it ever get's made. |
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