Sciencing Sharpness – Part 4 – Failing to Improve the Measurements

My mother was ordering some things from an online drugstore and I jokingly said if she could order me a nylon thread too. And surprisingly, the shop did carry a 0.25 mm nylon thread. It arrived today. I have immediately run an experiment to evaluate if it delivers better results than my old, PVA glue-impregnated thread. And sadly, it does not.

I made 25 measurements with both threads with a razor and then with the testing knife sharpened at 10°. And the results are interesting, but not good.

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The nylon thread performed statistically significantly better for the razor – the values were less spread out. But when it came to the knife they were both about the same, with no statistical significance whatsoever. And there were outliers in both sets. A disappointment, really. A lower spread would allow me in the future to get useful results with fewer measurements per each test, this way I am somewhat stuck with making at least ten measurements.

At least all four sets had normal distribution which means that averaging multiple measurements should give precise-ish results.

I think that the biggest problem is the scale’s lack of a Hold function and the frequency at which it renews the display. Well, it is still useful and the thread did not cost too much. And it is easier to span.

Sciencing Sharpness – Part 3 – Angle vs. Sharpness

It is not good for my ego to have the predictions mostly correct again, but this time there were things that surprised me a bit.

I have included a sharpening angle of 10° which I never use in praxis because it is not recommended for the N690 steel due to reduced edge retention at that angle (tendency to chipping), but that would not be a problem in this test and it is a data point of knowledge in case I make some carbon-steel sushi knives or razors in the future.

Now the boxplot:

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So I got the prediction about how the cutting force will rise mostly correct. Mostly, not completely.

ANOVA test has found no significant difference between the first four angles but I am sure there would be one if I had performed more measurements and/or refined the testing method. The Lookandsee test does indicate a slow rise in cutting force from around 25 gf to around 50 gf.

The jump at 30° is a bit more sudden than I expected. I suspect that it is a fluke. And then the rise at 40-45° was a lot less than I expected.  It seems that the 90° cutting edge is still significantly better than no cutting edge, which would be somewhere around 3-4 times worse with a cutting force of around 1000 gf. I did not expect that. The best-fit function is quadratic. This is less drastic than the predicted exponential growth, although still significantly faster than simple linear growth.

So in conclusion, it does appear that my opinion that whilst there is a difference at angles 10-25°, it is not big enough to matter for casual knife users is substantiated. The angle 30° performed slightly worse than I expected, and the angle 45° performed significantly better than I expected.

I am going to think about all this some more and then I decide how to proceed from now on.

Sciencing Sharpness – Part 2 – Grit vs Sharpness

Notwithstanding dangerousbeans’s comment at the last article, I did find in my steel offcuts pile a blade that broke after it was nearly completely finished, with etched logo and all. That means learning about the sharpening properties of exactly the steel that I use in exactly the state it is in a finished product. In different steel, the results might come out a bit differently, which means I am mightily glad that I could do my tests on this – an absolutely ideal testing specimen.

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I have sharpened the blade stub at a 15° angle which is the angle at which I usually sharpen kitchen knives, and always those that I make from N690 steel. (When tasked with sharpening store-bought knives from unknown steel I occasionally sharpen them at 20°, especially if it is clear from the state of the knives that the customer is not particularly careful about their use.)

I established the bevel with 120 grit and then I progressed from 180 and 240 grit Zirkorund and then Trizact belts (in the evaluation translated into grit equivalents) from A 65 all the way to Trizact A6. I only differed from my usual sharpening procedure in one way – I used fresh belts, instead of old ones. Normally for sharpening, I am using old belts because sharpening is extremely rough on the belt and destroys it very quickly.

The measuring method is wildly imprecise – the testing thread is not homogenous, the angle at which I put the blade on it is not always precise, I do not always hit the center, I am not pushing with constant speed, the kitchen scales do not renew the measured value with sufficient frequency and probably several other variables. I have experience with such measurements from my previous job though and there are ways to get relatively reliable, reproducible, and usable results even so. One of those ways is to make lots of measurements – that is why I took 12 measurements, discarding two of the most egregious outliers and making the evaluation with the remaining 10. There are mathematical methods for discarding outliers but for my personal purposes, the Lookandsee method suffices. (Thirty or fifty measurements would be better, but I am not going for exact values for individual grits, I am going for a comparative assessment between those grits. Anyway, not going to write a boring lesson about measuring).

Here is the boxplot of those ten measurements per each grit:

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And it looks like my prediction from yesterday was bang-on. Which is satisfying to my ego, but also boring in a way. It would be much more exciting if it were different.

What you see here is the cutting force going rapidly down from ~270 g at 180 grit to ~ 75 at 400 grit. At this point, the blade is capable of cutting freely hanging paper. Then it falls some more to ~40g  at 800 grit and more or less stays there till the end (the knife is shaving-sharp at these stages). The slight increase at 1200 is a fluke that would most probably go away if I have made more measurements and/or invested time and resources in refining the method. I made ANOVA test and there is no statistically significant difference between the last three fine grits.

So in conclusion, sharpening knives beyond 1000 grit indeed appears to have very little practical value. At 800 grit the blade is already shaving-sharp and polishing the edge further only costs more time without noticeably improving its cutting capabilities. With more precise measuring method there might be a difference, but it would be very, very tiny. I think that I can replace the last two belts with a leather belt infused with stropping compound and get the same result. And since time is money, I will do exactly that.

Sciencing Sharpness – Part 1 – Predictions

I hope to use my new sharpmeter to get some knowledge about, well, sharpness. And since I am going to be playing at science whilst doing so, I have decided that I will write down the predictions for my tests. The tests will not be blind, because I will be doing both the sharpening and testing and there will still be some subjectivity to these tests, but nothing is perfect. I am doing these tests to gain some knowledge and I will share that knowledge for free but there will inevitably be bias.

The first test that I intend to perform is the influence of grit on edge sharpness. I think that after establishing the bevel with 180 grit the cutting force will go down significantly with the next steps, but it stops changing significantly above 400 grit. My reasoning for this is the fact that it is possible to get a knife shaving-sharp with ca 320 grit stone and at 320-400 grit usually the wire edge/burr falls off. I think that I have mentioned in the past in comments somewhere – either in Marcus’s place or here – that going above 1000 grit in sharpening makes little sense function-wise, although I cannot find the comment now. I will go up all the way to trizact A6 belt (the equivalent of 2000-2500 grit) in the experiment.

The second test that I intend to take is the influence of the sharpening angle. There was a heated debate between me and Marcus on this issue a while back -click-  and I really want to test it (caveat from the first paragraph applies doubly). I expect the force needed to cut the thread to rise exponentially, i.e. slowly from 10-25°, then some more for 30° and even more for 40° and again even more for 45°. I won’t test sharpening angles steeper than 45° because it makes no sense IMO since a 45° sharpening angle means a 90° edge. I know from praxis that knives sharpened at 15°, 20°, and 25° can be shaving-sharp. I do not know much about the 30° angle, since that is extreme and I only sharpen hatchets and axes at that angle and I never even tried to get those to shaving-sharp. They do cut paper though.

So, sometime this week I shall heat the workshop again, sharpen some steel offcuts (probably pieces of old hacksaws) and go measuring.


It is freezing here and I still do not have the slightest inclination to do something useful. But I need to heat the workshop occasionally to prevent it from completely freezing. Not that it would be super bad, except that maybe ice forming in the cooling receptacle near the grinder could damage it. Anyhoo, yesterday was a workshop heating day. I could not do anything super useful – it took me hours to raise the temperature to a bearable level and soon after I stopped feeding the stove, the temperature got down quickly again. But I could use the time to do something small and simple so I have made a device for measuring knife sharpness (I did not invent the concept, I saw the principle somewhere on the interwebs sometime ago).

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It is simple and consists of two main parts. One part is a board with four legs and a 35 mm hole in the middle. A tiny table that can be put over my kitchen scales.

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The second part is a small wooden cylinder with a cutout and two screws on each side of it.

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I can span a thin thread between the two screws and when the cylinder is put on the scale through the hole in the middle of the tiny table, I can cut the thread safely for me, the scale, and the furniture.

The main downside is that my kitchen scale does not have a “Hold” or “Max” function so the measured values are not super precise. Another problem is the used thread – a very thin fishing line would be probably better since this one has a tendency to get damaged during spanning. Or perhaps a very thin copper wire – I might try to extract some strands from leftovers from speaker or ethernet cables. But when being very careful with spanning the thread and doing the cut slowly and carefully, the setup gives useable results and I did learn some things.

Here is a boxplot of 10 measurements with the three cutting implements in the photos – a fresh razor blade, a paper-cutting-but-not-shaving-sharp sharp knife, and a blunt table knife (I used the non-serrated part which is about 1 mm thick),

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The razor had an average cutting force of ~6 g, the sharp-ish knife ~60 g, and the blunt knife ~ 1000 g. The less sharp the blade the bigger the spread but even with sometimes ridiculous outliers, there is a definitive and statistically significant difference between these three and it does give me some information and opens future opportunities. I would like for example to examine the relationship between sharpness and sharpening angle, to get some hard data to back up my opinion that anything between 10-30° works just fine. My prediction is that the relationship is not linear and as the angle gets steeper, the cutting ability gets exponentially worse.

I did learn one thing – my “Not a Masterpiece” was sharpened at a 20° angle and the only knife that actually scares me – the bigger knife from the two-knife applewood set – was sharpened at 15°, yet both measured within the same range as the razor. Although the applewood knife completely failed to register on the scale one time, thus my suspicion that it is the sharpest knife I made so far might be true.

Of course this only tests edge geometry, not blade geometry. I could use a similar setup to test the influence of blade geometry on cutting force too, but I do not have a reliable medium to do so yet. All things that I have thought of so far are either expensive (cork, rubber, silicone) or have highly inconsistent properties (fruit & veggies). But maybe I will think of something to test blade gomtry too.

New Tool In Da Shoppe

Last year at around this time my circular saw gave up the ghost and I had to buy a replacement despite not exactly swimming in money. I have put the tool through its paces this summer and it stood up well to all the tasks that I could throw at it, although some objections to the design remain, and some other flaws were made obvious in that time. Nevertheless, the tool appears to be durable and sturdy enough.

This year the demons haunting my shoppe struck again.

I have complained several times about my craparooni bandsaw. I went through the bands rather quickly. The last time I mentioned this, it was suggested that I might not be tensioning the bands enough. So after it snapped another band, I tried to increase the tension a bit. It resulted in the saw band stripping the rubber band covering the driving wheel. That was it, the last drop at which my patience with this cheapo piece of crap has reached its limit. I have moved it to the attic where it will await whether I think of some use for it. In the meantime, I have bought a new band saw from the same manufacturer as my table saw. I am not happy about the expenditure, but I need it and I cannot spend half my time repairing.

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I really hope the band won’t snap after just a few cuts. It is bigger and stronger than the previous one, so it cuts faster and there is a lesser risk of the band getting caught and stopped because the wood deforms during the cut a tiny bit.

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My shop vacuum did not fit into the dust collector exhaust but the problem was easily resolved with various pieces left over from previous vacuums etc. – I fixed a fitting tube directly to the exhaust and in the other end I glued in a reduction for my shop vacuum.

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Despite being bigger, its cut width is not bigger than on the previous one and I could make 2 mm veneers easily. Excellent.

There was, however, one big no-no with this delivery. There was a loose screw and a nut in the package and I was wondering what they are doing there since they were not on the schematics and list of parts. After some searching around I found that they are missing from the band tensioning mechanism and that the other screw in the pair is also loose and on the verge of falling out. That is not something that should happen, ever. Other than that, I have no big objections so far although I only tested it for about half an hour.

The Nutkraken

It is the season when the walnut tree is shedding its bounty. We still haven’t eatet yet all the nuts from last year and it will probably take some time to eat them, possibly a whole another year. And this year’s harvest promises to be even bigger than last year’s. Thus I have some nefarious plans with the nuts this year.

Howevah, all plans include cracking the nuts first. We do have a small hand-held nutcracker, but that is good only if you want to crack a few nuts for a snack, not when you need to go through a bucketful every day. I have tried to make a small lever nutcracker from an old drill press. It worked, but not great. So this year we brainstormed some ideas with my father about how to proceed and this is what I came up with later in the workshope when looking for suitable materials to materialize our idea – behold the mighty Nutkraken:

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I made it in about 5 minutes from a piece of board, two armrests salvaged from my father’s old armchair, a 10 cm piece of 4 mm fencing wire, and a bottle cork.

The armrests are connected on one end with the fencing wire. That end not only had pre-drilled holes. The armrests have an S – curve that has a nice short curve on the connected end and a long one on the other, making a nice indentation for the walnut and more than enough space for fingers. The lower arm has attached a perpendicular piece of board to it to stabilize it and to allow for it to be fixed to the table via clamps. After some testing I have added the bottle cork so the nuts do not get totally obliterated, making it easier to separate the shells from the meal. With a bit of additional work it could even be made to look pretty, but I probably won’t bother with that. I usually don’t with tools.

My father enjoys his new toy greatly and he cracked and shelled a bucket of nuts yesterday in no time. Those were low-quality nuts, and I intend to test some things with them first either today or tomorrow before I proceed to mangle the good-quality nuts that start falling next week. I will let you know the results of my sciency experimoments promptly.

The Nutkraken works magnificently. No sprain on wrists and fingers, no over- or under-crushed nuts, no problems whatsoevah.

A Big Commission – Part 2 – New Magnetic Thingamajig

My magnetic chuck for grinding bevels  works well and I am still using it but it is unsuitable for establishing the bevels on a huge blade like this. I have actually been thinking about this for some time, and the kukri commission was in the end just a suitable excuse to play for two days with magnets and exercise my grey matter a bit.

The thing I came up with was a combination of a magnetic jig and the sharpenatrix. That alone could not work because it does not allow me to get as close to the belt as I need. And also it has a fixed length, so in certain positions, the blade like the kukri would actually be partly above the tallest point on the belt. Thus I established that I need:

  1. a telescopic arm
  2. a switchable permanent magnet

Both of those things can be bought, sometimes even in conjunction. But they are really expensive and for my purposes, even the cheapest and smallest ones are needlessly bulky and heavy. Yes, at long last, finally a chance for me to just dick around with various scraps and it is really economic use of my time!

After some trial and error, I have gotten the best results with just two magnetic arrays from two broken speaker magnets and four flat pieces of mild steel from a broken clamp.

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The magnets are oriented in both arrays with the north in the same direction on both sides of the pipe in the middle. And since they were broken into irregular pieces, I have glued them in with a mixture of steel dust and epoxy to better facilitate the transfer of the magnetic field into the steel. With one exception – the side that is going to hold the workpiece has a bit of brass between the steel bars, so the magnetic field does not extend there all the way to the surface between them. The piece of stainless steel non-magnetic pipe in the middle allows me to connect the two magnets with an axis around which they can swivel freely. When the poles of both arrays are aligned, they repulse each other but the whole assembly sticks to steel on the sides very strongly. When they are misaligned, the whole thing is nearly non-magnetic all around.

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Here you can see me testing it. A threaded copper rod is fixed to one of the magnetic arrays and will connect it to the telescopic arm later on. A stainless, non-magnetic steel rod is also fixed (riveted) into that magnetic array. The second array can rotate freely on the top. At this stage, I got my first bonus – both extreme configurations are stable without the need for any mechanical locking mechanism and the outward magnetic force builds up/disappears quickly, not gradually.

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Now you can see it nearly finished. The telescopic arm consists of several parts:

  1. the 8 mm copper rod with stainless steel nut fixed into the array
  2. thin 12 mm steel tube lined with 10 mm brass tube in the upper half to ensure a tight fit for the copper rod.
  3. 10 mm steel rod with thread at the end on which the ball from sharpenatrix can be screwed
  4. 2 screws go through threads in two pieces of thicker tube and through all the tubing to lock both the steel and the copper rods in fixed positions. There are brass inserts under each screw to ensure they do not scratch the surface of the rods. Hopefully.

The knob was only added so I do not poke myself with the sticking screw during work and it turned out to be a second bonus – it allows me to hold onto the blade with one hand and comfortably hold and switch on/off the magnet with the other.

With that, the arm was not finished yet, but it was functional, so I went on and tested it. And it worked really well. Not ideally, but it did help a lot, especially with a complicated grind like this. Kukri changes the blade width over the lenght of the blade, so to reduce the weight, keep it strong, and optimize the cutting capability towards the end of the blade the primary bevel has to be steeper on the wider portion of the blade than on the narrow part. So I had to grind it in two steps. The first step was to establish the less- steep bevel on the whole blade (approx 5°).

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The second step was to establish the steeper bevel on the wide portion of the blade whilst carefully feathering it into the narrow portion. The grind on the intermediate portions is a bit funny-shaped, which I will have to correct with a file. Later during polishing (this will only go to 100 or perhaps 120 grit), it will smoothen out, I did make blades like this already, although not of this size and not with a belt grinder.

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I made this grind in about an hour, which is speedy, especially considering that I was working with a new jig. I slipped up on two parts on the other side before I figured out how to best use it, but nothing that would not be corrected in polishing.

As a final touch, I have encased both arrays in alluminium housing so they do not gather steel dust. And I painted ON/OFF markings with a sharpie to have visual clues during work.

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If it were a bit stronger, I would not have those two slip-ups that I had, but it is strong enough to be useful – it has over 2,5 kg lifting force, which is in my opinion impressive given that the initial magnets on their own have barely lifted anything.

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Overall I am very pleased with the result. I now know how to make small switchable permanent magnets. I still have some ordinary black magnets to play with, but I will probably also buy some small neodymium magnets and build myself a variety of magnetic holders with high force. Even a small flat magnetic plate can cost several hundred €. With some care and planning, I think I could make a useful one myself for a fraction of the cost in just a few days.

Why Relying on Algorithms is Bad

About two years ago, I got into playing chess online and I also watch chess videos since then, usually at dinner or lunch. One funny thing that happened last year in the online chess community was that a live stream interview between the (then) most popular chess YouTuber Agadmator and chess Grandmaster Hikaru Nakamura was banned for hate speech. Apparently, the algorithm has interpreted the phrases as “white is better here”, “black is defending”, “white attack” and similar as incitement to violence, and completely failed to recognize that the talk is about a board game.

At the same time, open racists and transphobes were spouting and often keep spouting their bile on YouTube completely unimpeded under the guise of “Humor” or “Just Asking Kwestchions”.

Today the algorithm struck marvelously again.

I do not remember precisely when I have seen so-called fractal burning of wood on YouTube, but I think it was some time last year. I thought that it looks cool so I researched how it is done. And I have immediately gone to the conclusion that cool looking it might be, but I certainly ain’t doing that, not even for a big clock. And YouTube channel “How To Cook That” has published an excellent video a few weeks ago explaining why fractal wood burning is not a good craft hack for woodworkers:

And of course, an excellent youtube video cannot go unpunished – the algorithm yanked it for allegedly promoting harmful and dangerous acts. And while it was banned, that same algorithm has actually recommended to me a video showing the hack in action. Marvelous work – a warning about dangerous practice gets banned as promotion of said practice and an actual promotion of it gets promoted. Logic straight as a corkscrew.

The video has been reinstated after YouTube got pushback, but I do wonder how many really good and possibly important videos get yanked and never get back because the channels that made them were small and did not have millions of subscribers to cry foul on their behalf. Because let’s be real – YouTube gets an actual human to do the review only when there is an outcry, otherwise, they do not bother.

I think that overreliance on algorithms has great potential for actual harm. Human social interactions are so complex that there are humans out there (like me) who are barely able to navigate them. I do not think that AI is there yet.

I Think This Will Cut It

My new circular table saw arrived today. I haven’t got round to using it yet, for I had some time-sensitive work to do in the garden, but tomorrow I am definitely going to use it because I have bought a small bedside table that needs some modifications to fit into my living room properly.

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It is not the most prestigious and expensive tool imaginable, but it was fairly expensive so I really, really, really hope it works well. I was putting off this purchase for as long as I could, but I needed a proper table saw for a long time by now. This one seems to be sturdy, the table is nice and flat and it has built-in extension support and various end-stops, as well as grooves for cutting jigs.

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It can cut up to 87 mm depth, which is nearly double what I was able to cut with my previous setup. And of course, setting of cutting depth and angle is much more convenient with no fiddling under the table and cursing the whole time because I cannot get the depth and/or angle right. It is powerful but can still be connected to my shop vacuum (it has 2000 W usage, which is near the maximum), so I do not need to plug it separately and turn on two devices for each cut or have the vacuum run continuously – the vacuum will start automatically with the saw when the saw is plugged into it.

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And the thing that makes me most happy so far – the legs can be folded and it can be stowed away under my workbench in the same place where my previous saw was residing. Hooray! I need not do any big changes to the Shoppe!

Caliper Pin – New Knifemaking Tool

When grinding blades, it is important to have the ridges, fullers, and similar as symmetrical as possible, especially before quench. An asymmetrical blade has a much higher probability of warping or bending in the quench.

On an unhardened blade, one can scribe markings with a scribing needle and/or compass, but once the blade is hardened, that is no longer possible. And I still want my blades to be at least mostly, even though not perfectly, symmetrical too.

I used to measure the symmetry with a help of a folded piece of paper that I have cut with shears so that it has two perfectly aligned points. When folded over the blade, I could easily-ish check if the points align on the ridge on both sides and thus check where I shall grind more during the polishing to keep the symmetry.

But the pieces of paper get wet and manky in the process, and I kept of course losing them so I had to make new ones over and over every day and sometimes several times a day. And today I finally got an idea how to replace them with something much better and hopefully permanent. I took one wooden clothespin and I ground it in about 5 minutes to sort of mini-calipers that can be clipped onto a blade

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This pin is made from softwood so I could not make the point too refined, but I do not need to. I want to make my blades mostly symmetrical, not perfectly symmetrical. And anyhoo, I shall, in the future, probably make a better and more precise one out of brass, this is just a proof of concept.

And it works well, here you can see it in use. It shows that the ridges on both sides are within few tenths of a mm apart, and that is good enuff for me, that is a difference that cannot be seen with the naked eye and is not easy to measure even with calipers.

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Walter Sorrells has recently made a video about a sharpening tool for his belt grinder, which gave me an inspiration for finally making my own. I have been planning to do this for a long time, but watching that video helped me to solve the final piece of the puzzle.

Walter Sorrells is of course not only a much more experienced knifemaker than I am, but he is also much better equipped. So my project has all the hallmarks of my handmade tools – it is crude and made from scraps.

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I have started with a very rough sketch of the jaws and I have also spent some time calculating trying to establish various proportions whilst finding a compromise between stability (shorter arm is better) and consistent angle across the blade (longer arm is better).

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Here you can see it in full when finished. Jaws for holding the blade are mounted on a ca 40 cm long 10 mm stick with a ball on the lower end. The ball goes into a socket at the end of an arm that can slide forward and back with regard to the belt, thus adjusting the angle at which the edge leans on it.

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The 10 mm steel rod is recycled from our old heating oven. The plastic ball at the end is an old furniture handle. All the wood is recycled from an old bed.

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The jaws are made from 4mm mild steel and lined with 0.25 mm bronze held in place by means of double-sided adhesive tape. Near the tip of the jaws are two 5 mm pins that are screwed into the smaller jaw and slide into holes in the bigger jaw. They provide an end-stop to rest the blade against in order to fix it easier into the jaws and they also prevent them from wobbling.  The upper screw tightens the jaws and the lower one sets the distance between them, so I can vary it according to the blade that is being sharpened.

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Originally, I have planned to make the socket from wood and I expected it to take a lot of time. But I got a brilliant idea during the work to use a lid from a fabric softener bottle. It cracked during work, but I still could attach it to the arm with a  screw and a large washer. After that, I have covered the screw head with a piece of PVC flooring and after some consideration, I have also added two hard gaskets to keep the ball centered and to provide ever so slight resistance to movement.

The sliding arm can be fixed in position with a fastening screw salvaged from some defunct kitchen appliance from a long time ago and a galaxy far, far away, from times when things were made to last.

When the weather allows it, I will give the thing a coating of grey paint so it looks slightly less amateurish and also to protect the wood from moisture. And I will mark a scale on the sliding arm so I do not need to bother with measuring the angle.

I do not expect this to save a lot of time. I already sharpen knives on the belt grinder and it does not take me more than about five-ten minutes per blade. But it will make the job a bit easier and the angle should definitively be more consistent, which is a plus. I am not one who is overly concerned with sharpening angle, I think that anything between 15° and 25° works just fine for most knives, but consistency does have an influence on the durability of the edge. For example, the N690 steel that I am using for most of my knives allegedly should not be sharpened at a too steep angle (below 15°) because then it tends to chip and break. With this tool, I can at least be definitively sure that I won’t go any lower than that.

We shall see how it works. I do have a lot of knives that need sharpening.

I Almost Didn’t Fail the Second Time

My first attempt at big blade ended up in a disaster and after several years of procrastinating the issue ended up as a smaller (though not small) knife. I gave it a second shot because 1) I really need a machete 2) I want to learn to make these big blades for I have big plans for the future, that will no doubt never come to fruition.

And as the title says it, I almost didn’t fail this time. At least, I do have a serviceable tool to use in my garden.

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Spring steel, blackened with oak bark. 4-6 mm thick, 51 cm overall length. Fully hardened, spine tempered to spring.

This time things went reasonably well, but I was suspecting that I have ground the fullers too deep. At least they were passably symmetrical – there was no trouble in the quench. The blade came out hardened and mostly straight, and the very slight bent it has developed (circa 1-2 mm over the whole length) was easily corrected with my unbender after heat treatment.

However, when I was trying to polish the blade and smooth out the fullers, it turned out I was right – I made the fullers too deep and near the tip I have thus ground through. But it might not be a functional issue, just an aesthetic one, so I have decided to finish it, albeit with less attention to detail than I would had it been a complete success. I have filed the hole bigger and oval with diamond-coated files (to remove any stress-risers) and I have stopped polishing the blade, especially the insides of the fullers. I just gave it a few buffs with scotch brite discs for angle-grinder and then it went into the oak bark tee for a nice night-long bath.

Handle fittings are from bronze and handle scales are from pickled black locust. I did want the blade to complement the previous one since they will both be used by me in my garden. This handle is specifically fitted to my hands, so nobody with different-shaped hands would probably feel comfortable using it. I have no idea yet how it will work out in the long term, but it did feel perfectly fine when I gave a few whacks to an old wooden board with it.

I might make a scabbard or a sheath for it too. I am currently thinking about whether to make a double-sheath for the pair or a separate sheath for each item. Both options have pros and cons. Not that I do actually need a sheath for wearing them, they are unlikely to ever leave the house further than the 60 or so meters that is my backyard long, but they are both sharp and big and dangerous and could get rusty, so I need an option for safe storage, both protecting them from elements and me from injuries when they are not used.