An Experimentental Knife Set

A friend gave me in the spring some cherry wood from a tree that died and dried standing up in their garden. That means the wood has many cracks, some fungus damage, and discolorations. And she asked for a kitchen knife for herself as her primary cooking knife. The type of blade that she requested would be more of a fish-gutting knife for me, but she has her own cutting style and I am not a knife snob to sneer at someone’s cutting technique. If one is not cutting their fingers off, the main thing is that they get the ingredients down to size and to each their own I say.

I got to work but I got distracted several times. Firstly, when I was cutting the steel, I got a small offcut that just lent itself to be made into a small peeling knife matching the one ordered. Secondly, when I was selecting the wood for the handles, I found one piece that was big enough for both handles and a bloc. And thirdly, when I was pondering making legs for the bloc I got an idea to try to make a foldable leg, so I tested it. Having a lot of problems to deal with makes me extremely prone to such distractions. It is a bad habit.

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© Charly, all rights reserved. Click for full size

The knives have very simple rectangular handles that are nevertheless comfortable to hold. The blades are N690 steel,  without ricasso, tumbled. The numbering on the smaller knife is a bit unreadable, but such is life. Bolsters and end caps are from buffalo horn. I made them thin because she expressed a wish for the wood to be the dominant design feature.

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© Charly, all rights reserved. Click for full size

© Charly, all rights reserved. Click for full size

© Charly, all rights reserved. Click for full size

The wood grain and cracks in the handles match that in the bloc. This is exactly why I have used this particular piece of wood, it had just the right size for this. The wood has fairly small pores and is not overly decomposed so trying to infuse it with resin would be an exercise in futility, thus I only coated it with three layers of resin, sanded it with 800 grit, and then I buffed it with home-made silica-based buffing compound.

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© Charly, all rights reserved. Click for full size

The foldable leg is bent from an old knitting needle. The holes in the sides of the bloc are offset so the leg has two stable-ish positions. It is just a gimmick that won’t probably see much use but it would make packing the knives for travel easier if one were inclined or in need of to take their cooking knives with them on travels. But mainly I wanted to try to make it.

If she accepts these, I will actually only charge for the bigger knife since that is all that was agreed upon. The small knife and the bloc she will get together with her husband as a belated wedding gift.

Another Overabladeance

I was spending way too little time actually making knives this year since I spend two-three days a week carting my parents to and from various doctor appointments. And when finishing this batch, my new tumbling receptacles did not work with this particular type of blades and I had to modify them significantly. However, I do have now thirteen finished blades, eleven tumbled from N690, and two from spring steel, mirror-polished with hamon.

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Four kitchen knife sets three three-piece and one two-piece. You might notice that this time I went for blades without ricasso. The reasons are several but the main one is that such blades are significantly easier to make. Really significantly easier. They turned out well and I must say there is something satisfying about getting two chef-knife blades so flat that they stick together when wet. They are probably flat to within a few hundredths of a mm.

The two-piece set in the lower left corner is actually a half-commission. A friend of mine has ordered the bigger blade and I have decided to make the smaller one from an offcut to accompany it. I will also make a bloc as a belated wedding gift. To be fair, I could not give them a proper wedding gift on time since they kept the wedding secret, so it is not that I was inconsiderate, just ignorant.

From now on, I will for several months only dress blades. I still did not finish all of last year’s Overabladeance. The two Puuko I made still have no sheaths. I only started to make these blades because of the commissioned machete in the summer and the commissioned kitchen knife from my friend – I needed a sufficient amount of blades to fill the tumbler and not waste the forge heat. For both things, ten blades is a minimum. So actually I might make some blades again – if I get a commission.

A Commision With a Point

I hope the customer will accept this, I am not completely happy with the result. An acquaintance of mine has given me some deer antlers for crafting and she also commissioned a knife made out of one of them. The antlers are from her father, who is a gamekeeper and she wants to have something to remember him by. She requested a small letter opener with a stand that can also work as a paperweight. Lenticular grind and not fully sharpened edges. Oak wood for the stand because her office has oaken furniture.

From the manufacturing point of view, there were not very many interesting things – I ground and polished the blade and blackened it with oak bark, then I fixed it to half of the antler with the burr at the pommel end. Because the antler is old, scratched, and irregular – as antlers are – I have hammered the pakfong pommel into an irregular shape. I also hammered the bolster and I only wire-brushed and polished them over the hammer marks. A bit interesting was the making of the stand.

To weigh it down, I chiseled holes in the bigger piece of wood before gluing it together and I poured molten solder into it.

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I learned this technique from my maternal grandfather. I have never met him – he died long before my parents even met – but he made for my grandmother a top for winding the thread on bobbins and the top has been weighed this way on its circumference. Molten solder cools in wood quite quickly and it does not char the wood on the edges all that much, especially if it is hard and dense wood. I was itching to try this out for years.

The pakfong throat on the stand for the blade was a bit difficult to make and there I had to use a creative solution to make it hopefully solid enough so it does not become undone in a breeze. I did not want to rely only on epoxy, so I soldered two pieces of copper wire onto the pakfong piece, and I glued those into tight-fitting holes. This way it should hopefully withstand even some mild abuse like falling on the ground.

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© Charly, all rights reserved. Click for full size

The full finished set weighs about 860 g, I have possibly overdone the weighing a bit. The stand is slightly decorated with pokerwork and the underside is covered with brown natural felt so it does not click when put on a table. The finish is tung oil and beeswax, which are more pleasant to the touch than lacquer or epoxy.

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© Charly, all rights reserved. Click for full size

© Charly, all rights reserved. Click for full size

© Charly, all rights reserved. Click for full size

© Charly, all rights reserved. Click for full size

© Charly, all rights reserved. Click for full size

Crafting Perk Unlocked – Hamon

When making the commissioned machete in the summer, I had enuff steel left for one additional blade and two more blanks lying around made from the same steel, thus I decided to try my hand at making a blade with hamon again. So far, I have succeeded only once, with a “mystery” stainless steel, and I had to cheat by carbonitriding it for several hours at ca 500°C. The 54SiCr6 is 0,5% carbon steel, which is not ideal for hamon. 1-1,5% carbon would be better. But I decided to try it nevertheless because if I fail, I can (usually) always harden the whole thing.

Well, I did fail in multiple ways – from three quenched blades, one had to be tossed completely, one I damaged because of unforeseen circumstances, and one turned out OK. This is better than my previous attempts and I think I have a working process now for making blades with hamon. Here is how I did it.

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First the used materials – three blade blanks ground with 40 grit. I went for three different geometries to see what happens. A sample size of 1 per geometry is of course not very indicative of anything, but it is better than nothing. On the left is a bottle of liquid glass, a water solution of sodium silicate, a chemical that is sold cheaply in CZ and is used to waterproof cement, make cement go harden faster, and as a binder for heat-resistant cement. Then there is a receptacle with perlite, which I have bought in huge amounts for use both in my gardening and knife-making endeavors. And the last ingredient is fine-sieved dirt from my garden taken from deep below the topsoil – I have a heap of this too from the building of my sewage cleaning facility.

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The first step was to cover the blades with a thin layer of just the liquid glass mixed with some clay and sprinkle some more clay on top of that to soak up excess liquid glass and prevent cracking of the layer when drying it with a heat gun (a torch and charcoal fire work both too as I found out later).

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Here you see the various phases of the second step, which consisted of adding several layers of perlite. For this, I have used the mixture of liquid glass and dirt again, but I have sprinkled it with perlite. The liquid glass serves as a binder, the clay as a filler to prevent cracking, and the perlite as an insulator. I dried the added layer with a heat gun again and I continued to add these layers until I had about 1 cm thick insulating layer on each blade. To finish it off I have added one more layer of liquid glass and dirt only to make a hard shell that holds it all together.

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Initially, I went for three different hamon lines, but unfortunately, this did not work out. After I quenched the machete and one of these blades (I forgot which one) without problems, I had trouble reaching the required temperature again because the coals got smaller and the blown air did not reach under the uppermost layer anymore. So first quench was unsuccessful on two blades, I had to cover them again and try to quench them again. This time I was using the charcoal fire to quickly dry the successive layers and it worked well. Next time I am preparing blades for hardening this way, I will probably combine it with BBQ dinner, combining pleasant and useful.

As I already mentioned, two of these unfortunately failed.

The first fail was the blade with a fuller – it cracked near the ricasso. That is always a risk with hardening steel and it is higher with this method it happens even to masters of this craft because the blades must be quenched in water which is more stressful than oil. So while I am not happy about having to toss the blade, I do not beat myself over the head over it either.

The second fail is the drop-point blade. And I am beating myself over the head about it because this is completely my screw-up. I have read books, internet articles and watched videos about how blades with hamon are made, but I do not remember anyone ever mentioning that a peculiar thing can happen when the hamon line is parallel with the edge – the steel has developed lengthwise stripes that when polished, look under certain light conditions and from certain angles like lengthwise scratches made with low-grit sandpaper. I have ground the blade very thin trying to grind these phantom scratches out, I messed up the grind completely at the end near the ricasso and I had to remove the ricasso and shorten the blade to “save it”.

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Here you can see it finished. It is still a blade suitable for small outdoor/hunting skinner knife. Maybe. I will think about it and maybe try to make a suitable handle for it. But I do not like blades without ricasso, not only for aesthetic reasons but also because that way the tang actually really is way too thin for comfort near the handle. But I have finished polishing it because I needed to find out the best finishing method on it before finishing the only successful blade. Btw. it still has those phantom scratches near the tang where the hamon is close to the cutting edge. They drive me crazy.

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The best polishing process was pretty standard although very laborious. From 320 grit up I have inserted hand-polishing after each belt-grinder step, removing the angled belt-grinder scratches with lengthwise ones. This leads to very smooth and very flat surfaces and crisp lines and ridges. From 2500 grit upwards it was only hand polishing and only lengthwise. Here you can see the result at 5000 grit, which is the phase at which I left the workshop and went indoors. I have tried buffing the failed blade with buffing wheels and commercial buffing compound but this has led to an interesting effect – the hamon went completely invisible although it could be brought out by etching with oak bark for an hour or two. So for this blade, I have forgone the buffing altogether and went to 7000 grit sandpaper with walnut oil (it is runnier than other edible oils, and does not stink like WD40). 7000 grit is the finest abrasive paper that I can easily buy but it still did not bring out the hamon very well. I could just about see it but it was still nearly impossible to make a photograph of. I etched it with oak bark, but I did not like how it looks so I removed the oak patina again with 7000 grit and I tried another buffing method, one that I have used in my rondel dagger project – very fine hematite.

I put some paper towel cuts in a receptacle with finely ground and sieved hematite dust and shook it a bit so some dust gets caught in the paper towels. Then I dusted the paper towels off to remove the coarser particles that still might be there. I smeared some dubbin on the blades and I tried buffing them manually with these hematite-primed paper towels with lengthwise strokes, using the spine of the blade as a guide. And that has resulted in a nice mirror-polished hardened edge and slightly foggy yet still mirror-polished soft spine, making the hamon really pop out. That way it was not only easily visible but I was also finally able to make a picture.

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Hamon is the white line between the darker hardened edge and the lighter soft back.

I am not planning on making very many of these but it is nice to have the knowledge and skill how to do it. I think this blade is deserving of nice fittings so after I etch the logo and serial number, I will start seriously thinking about what kind of handle and sheath to make for it. I am done making blades for a few months however, I still did not dress all of those from last year’s overabladeance and I have eleven kitchen-knife blades in the tumbler now. Unfortunately, I have longer pauses between knife-making days than I like.

Sciencey Thoats About Tangs

Teh almighty YuTub algorithm has recommended this video to me:

Why military gear isn’t always a good idea…

And whilst I do agree with the title and the overall message of the video, I do have some objections to it. It is not an issue that can be distilled down to a universally true video quip.

First the agreements:

Military gear that is issued to grunts en masse needs to be essentially consumable. The grunts will lose it, steal it and/or destroy it with gross abuse and negligence on a regular basis. I read about conscripts in the Austrian army in WWI breaking their bayonets by opening cans. Stealing was a problem even in former Czechoslovakia, with the UTON  even though that was not issued to every grunt but mainly to paratroopers. The knives disappeared regularly as the soldiers reported them “lost during exercise” even though they had to subsequently pay for them and everyone knew they took them home. Those knives are good, but they are not as excellent as some people think they are “military grade” is definitively not always a synonym for “high quality”.

Now the disagreements:

A good bushcraft knife needs not to have a full tang to be reliable. It is more complicated than that – rattail tangs were and are used in even swords and machetes to this very day and they are not useless. Puuko is a survival knife with hundreds of years long tradition for example. The above-mentioned UTON also has rattail tang, and one that does not go all the way through the handle at that, and still it is a knife that can withstand serious abuse. I have put some of my knives with similarly thin tangs through their paces, both full-length and half-length hidden tang and they withstood serious abuse just OK (although I was only using them as knives, see further). Hidden tang alone is not an issue, the overall construction and heat treatment are.

My biggest beef is with the presented “knife gets stuck and you try to wiggle it out”. Sorry, but if your knife gets stuck in something hard right up to the hilt, then you are probably an idiot for using the knife wrong. A knife is not, and should not be used as a pry bar. But let us say one were to use a knife for making firewood splinters from a log by batoning. That is a legitimate use for a bushcraft knife and it can get stuck that way. It happened to me with my working knife and I had to use serious force to get it out. However, if you try to “wiggle it out” by holding it solidly against the ground and pushing at the handle sideways, you are definitively an idiot for trying to remove it in the least effective and most dangerous way imaginable. Simply put, abuse like that shown in the video does not represent even remotely reasonable and appropriate use of a knife, not even a bushcraft knife that should be sturdy.

Another thing I would like to address is the handle material. It is shown to be natural leather rings and apparently, not overly compressed and not glued together or hardened. That is a problem because it is a soft material that can easily be compressed and give way for the tang to bend. A wooden handle – like on European medieval swords and daggers – significantly improves the resistance of the tang against bending. If the rings were glued together and hardened by hot wax or boiling or epoxy, it would improve the durability and resistance of the handle significantly too.

The thickness of the tang and the blade at the weakest point plays a far greater role than the width. The force needed to bend/break a flat profile rises linearly with width but exponentially with thickness. If you double the width of the tang, you double the force to bend/break it. But if you double the thickness of the tang, the force needed to bend/break it can rise approx ten times (I do not know exactly how much, the calculations are complicated and I cannot pretend to understand them). So a knife with a thickness of 3 mm and full width (~15 mm) tang will be about as strong as a knife with a thickness of 4 mm and 6 mm wide hidden tang.

A role also plays the heat treatment of the tang. A fully hardened tang will be stronger and more resistant to bending and will spring back when bent. But when bent beyond the plastic deformation, it will be more prone to permanent damage and/or catastrophic failure when straightened again as shown in the video. Unhardened tang – that is used throughout history for swords from Europe across Asia all the way to Japan I might add – is easier to bend but can subsequently be straightened again.

And lastly – anything will break if used wrongly or excessively abused. A knife is not bad because it cannot be used as a pry bar and a pry bar is not bad because you cannot cut cutlets with it. When I made the custom machete, I tested it by hitting a brick with it – but I still advised the customer not to do that.

Not a Masterpiece Sheathed

I have realized that I did not show this on Affinity, only on Instagram. With all that is going on, I haven’t done any actual work in my workshop for weeks now, but this one was finished months ago. In the end, I have decided to make a simple, unadorned sheath for my Not a Masterpiece knife. I decided to do that because I felt in the end that an overly decorated sheath would needlessly distract from the beautiful woodgrain in the handle. The striker and ferrocerium rod have simple stainless steel handles. The bronze caught patina, which was to be expected. It does require some maintenance to remain shiny.

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© Charly, all rights reserved. Click for full size

The full set is for sale in the Knife Shoppe.

A Big Commission – Part 9 – Da Pictures

Today the customer has picked up his brand new machete. He was apparently delighted, at least he said so. His exact words were “This is much better quality than I have expected, especially the leatherwork.” So today I did not feel like a total waste of space. Here are some nice pictures for you to look at. I did not have to do too much post-processing after all.

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© Charly, all rights reserved. Click for full size

© Charly, all rights reserved. Click for full size

© Charly, all rights reserved. Click for full size

© Charly, all rights reserved. Click for full size

© Charly, all rights reserved. Click for full size

A Big Commission – Part 8 – Photographing

I do not need to make nice pictures for the webshop for this one – unless the customer rejects it, which I hope he does not – but I do want to have nice pictures for myself, for Instagram and, of course, for Affinity. And since it was a nice sunny day today, I took my photography session outdoors. One advantage of that is the sunlight, one disadvantage of that is way too focused light. Shade has, of course, diffuse light, and whilst it is very bright on a cloudless sunny day, it is alas also of the wrong color for this thing and I did not want to spend too much time with corrections in either the camera or on the PC.

So I have rigged up a small thingamajig to make pictures in diffuse light whilst getting the benefit of direct sunlight’s color whilst getting it a bit diffuse. I will have to edit out an occasional ant or piece of debris though, so I am not entirely sure I have saved time in the post-production at all. Well…

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A slightly overcast sky would be best but despite my valiant efforts, the weather still refuses to obey my commands. Mind you, if I could command the weather, I would not command a slight overcast right now, I would command a week of slow, drizzling rains and make the pictures indoors.

Pictures will be posted here and on Instagram after the customer picks up the item. I hope it will be tomorrow, but it might take a few weeks too, depending on circumstances.

A Big Commission – Part 7 – Missed Opportunity

AAAARGHHH! Amidiotextrordinaarggh!

Today I have sharpened the machete, thus de-facto finishing the commission. I have decided to test it in a way that poses minimal risks to the nice surface finish and still tests its cutting capabilities. By cutting milk boxes filled with water standing on a pole. That is a good way of testing an edge because a blunt blade just bats the box away from the pole, a sharp-ish one cuts partly through, tears the rest, and throws both pieces away, and a really sharp one sails through the box, the top falls off and the bottoms stays on the pole. A bad cutting technique may lead to a bad cut, but not even a perfect technique can lead to a good cut with a blunt blade. It does not test an edge’s durability – a well-sharpened bronze sword would perform well too.

I considered filming it and then I thought to myself “Nah, nothing interesting ever happens, waste of time”. Then I cut the first box and I immediately cursed my laziness and stupidity.

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I cut the top of the box cleanly off, and it stayed on! I have cut dozens of these boxes when I was testing my own machete and this has never happened. And since there was enough of the box left for a second cut, I went on and cut it a second time.

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And the blade sailed through like there was nothing there and both cut pieces stayed atop the bottom part. If my hair was long enough to grab and tear out, that is what I would be doing. A rare thing happens and I did not film it because I was lazy to go upstairs and set up my tripod.

Of course, I went upstairs for the tripod in a hope that I will be able to replicate it or at least get some interesting footage from the remaining three boxes that I had at hand. On two I got useless footage because I messed up my cutting technique. Probably nerves. Definitively nerves. On the third attempt, I did manage to get three clean cuts through the box, but the first two stayed on only because they remained connected on a minuscule (~1 mm) strip of paper – I was standing a tiny bit too far from it. After the third cut the top fell off but the bottom stayed on the pole so at least there’s that.

It is a wicked sharp blade, it cuts like a lightsaber. It will be a good tool. But I missed an opportunity for getting good advertising footage. Bigly.

A Big Commission – Part 6 – The Sharpenstone

Today I have made the last piece of the puzzle – a small whetstone for edge maintenance in the field. I expected it to take me two to three hours, it took me twice as much. Partly because it was the first time I was doing it so I did not really have a clear plan on how to properly proceed and what will work best, partly because I screwed up and I had to start all over with one part. But I think that if I were to make another, it would indeed be those two hours that I used for price calculation.

I started with a piece of native, strongly metamorphized phyllite. It has visible big garnet grains and it is very hard.

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I cut a strip off with a diamond stone cutting wheel in my angle grinder. I have used that wheel also to roughly shape it and thin it.

For the second, fine layer,  I have used a piece of old roofing shale. Those can sometimes be found around here on building sites and even in my garden.

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Those are not native stones, they are the remnants of long demolished houses from before WW2. Initially, I wanted to use a different piece of local phyllite, less metamorphized, softer, and with finer grain, but I screwed up and it delaminated down the middle, becoming too thin. So I went for the shale for my second try because it is stronger and I wanted to be definitively done today.

Using five-minute epoxy, I glued both roughly shaped flat stones on a thin jatoba board, making a small stone popsicle.

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© Charly, all rights reserved. Click for full size

© Charly, all rights reserved. Click for full size

After the epoxy cured, I shaped the outline, covered both outward faces with adhesive tape, and submerged it whole into linseed oil for a minute or so to soak the wood.

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After that, I had to grind down the faces a bit again, it was just a bit too thick to fit into the pocket. I ground them down with the diamond wheel and then flatterooned them on granite stone with wet&dry carborundum abrasive paper on it.

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Both phyllite and shale are soft enough so they can be shaped with abrasive cloth or paper, but hard enough themselves to abrade steel.

This is not a stone for serious sharpening work and I have told the customer so. Its abrasive action will be relatively mild compared to modern carborundum-based whetstones, even on the rougher phyllite side. But it should be excellent at maintaining an already sharpened blade and giving it an occasional touch-up during work. I have used pieces of phyllite or shale for exactly that, although those were stones found by the wayside, impromptu flattened and used out of necessity, not nicely crafted like this one.

Thus almost all work is finished – tomorrow I will sharpen the blade and make nice pictures to present here and on Instagram.

 

A Big Commission – Part 5 – The Stitchening

The original sheath the customer provided as a template has the tip reinforced with plastic. I cannot do that of course. Making a metal cape would be an option, but an expensive one since I would have to make multiple metal templates to press it and then solder it, polish it and all that jazz. So I have convinced the customer that reinforcing the tip with 4 mm thick leather should suffice. Which I think it should.  But I did make an extra step to make that thick leather just a bit harder – I heated it to 70-80°C in water and kept the heat until it shrank to about 80% of its original size.

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This makes the leather inflexible and somewhat brittle in bending, but very hard. Hard as plastics in fact. Caskets or boxes can be made that way. It has several caveats that need to be taken into account, however.

  1. After it is taken from the hot bath, it remains pliable for some time but not very long and it keeps shrinking for a while. If it needs to be formed in a specific shape, it needs to be pressed into the form quickly and left to cool down and dry in form.
  2. Because it shrinks, any decorative carving that is done can only consist of outlines. Any fancy pressing or stamping simply won’t work. And the shrinkage has to be taken into account – as well as the fact that the shrinkage is not completely regular in all directions and predictable.
  3. As it shrinks, it gets also significantly darker, dark brown. So it reduces the possible dyes that can be used to change the color to any shade you wish, as long as it is black.
  4. It needs to be heated up carefully. If overheated, it curls up and becomes way too brittle.
  5. If there is a risk of any bending stress, it should be reinforced with fabric or untreated leather. It is hard and scratch resistant but breaks when bent.

For my purposes, I needed two flat plates, so I left them to cool down and dry under two flat pavement bricks.

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On the top, you can see the already dry pocket taken out of the form. On the right is a glimpse of my impromptu cardboard template for the sheath.

Working on a complicamaticated thingamajig like this the ooo is very important – order of operations. If one glues and sews together some parts it can make some other parts impossible to add or modify, so I had to think carefully about how to progress. For example, on the outside, I had to first sew on the pocket flap, and only after that I could sew on the pocket itself.

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The kukri sheath is wide open on the back and the blade itself is thus held in place with a flap with two snap-fasteners. To avoid rubbing of metal on metal, I have pressed the lower part of the fasteners on an extra piece of leather and glued & sewn that onto the sheath.

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When making the belt strap, I had to form it, glue it and sew it together about 90% of the way, then I had to leave it with the threads hanging, glue the eye shut, and sew the rest. The strap is sewn from two layers for several reasons – I have used relatively thin leather and I was afraid it would not support the weight of the whole assembly, which will be over 600 g, and the way the sheath was cut, on the strap it would be the suede side of the leather facing out, and on this one, it is not particularly pretty.

I have possibly slightly overengineered the whole thing – there is double stitching along the edges as well as stud reinforcements and I have spent several more hours with it than I planned to. I do hope that it bears out in durability, I need satisfied customers to spread the word.

I have now applied some dye to the finished product and it hangs outdoors in the shade to dry. I have also applied linseed oil to the handle and it hangs outdoors in the sun to dry. Tomorrow I will condition the leather, and sharpen the blade and I am nearly finished. All that will be left is to make a small sharpening stone that fits into the pocket. I hope that won’t take too long, a few hours at most. Although I have some funny over-engineering ideas there too…

A Big Commission – Part 4 – Surface Finish & Glue-up

As I said because this blade is supposed to go “only” to 100 grit, that in no way meant that polishing it will be an easy task. I had to polish it on the belt sander to 150 grit in fact, and then remove all perpendicular scratches with 100 grit wet&dry sandpaper manually with scratches that follow the curvature of the blade. It was a bit of work not only due to the steel being hard but also because the surfaces are fairly big and wide when compared to even the biggest knives.

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After it’s been polished, I etched the logo and number and put the whole thing into oak bark extract overnight, then I washed it off, made the handle scales, and put it into the extract overnight again. Today morning it had a nice dark grey color all over.

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You can see the boundary between the hardened blade and soft tang near the sharpening notch. I forgot to tell the customer about that, I hope he won’t mind. In my opinion, the boundary is really neat and it is just another small detail. A good sign is that there are no such sharp boundaries anywhere on the blade. I have tested the whole blade by scratching but this is yet another confirmation that the whole blade is properly hardened and tempered.

Today was glue-up time. You have seen that already, but this time I think I have a nice picture to illustrate the construction of the handle here.

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For kitchen knives, I only use dowels 6 mm in diameter, 2 bamboo ones in the middle, and two metal ones on the front and back. However since this tool will probably encounter a lot of impacts, bends and vibrations, I have decided to use 2 metal pins and 3 beech wooden dowels with 8 mm in diameter (the third pin is there for the lanyard). The wooden pins are there for the glue to have something to really adhere to and the metal pins protect the assembly against shearing forces. And because none of them go all the way through, there are no visible pins on the outside. Except the one for lanyard, which must go through the wood otherwise the end would most likely split sooner or later due to the lanyard.

And so today, after the glue fully cures, the machete is 90% finished. All that remains is apply linseed oil to the handle. But before I do that, I will have to make the sheath otherwise I would have to wait several days before the oil hardens. So tomorrow is leather cutting and maybe leather glueing and stitching day.

A Big Commission – Part 3 – Stuff Got Really Hard

It rained a bit on Wednesday, which was lucky. I did not want to start a charcoal fire when the whole garden was bone dry. And I had to start a charcoal fire because this blade is way too big for my small gas forge. I have managed to quench and harden all that I have set out to (it would not be worth starting the fire for just one blade, so I prepared three more plus a platen for the belt grinder – I will post about those later) but it was extreme pain in the ass. And I finally found out why I have sometimes – but not always – trouble reaching the right temperature with this setup. As the coals burn, they get smaller and smaller and since I am blowing the air in the pile from the sides and from up, the air cannot reach the bottom of the fire anymore and thus I get scorching heat on the surface, but barely any heat just one-two cm below it. It makes perfect sense when one thinks about it. I will probably have to build a bigger gas forge for such big blades or a charcoal forge with air input from below the coal.  If I will go through the trouble, I will probably build a gas forge since it is significantly safer than charcoal. The problem is in getting my hands on proper housing for the forge – I do not have any.

Anyhoo, the quenching was such a pain in the ass that I spent several hours with it after which I was dead-tired. I managed one tempering cycle at 150°C in the oven in the evening that same day, and the next day while the knives were in the oven for a second 150°C cycle, I tempered the kukri manually with a propane burner.

© Charly, all rights reserved. Click for full size.

I put water-soaked paper towels on the edge and heated the spine of the blade until the blue color crept almost all the way to the bevels on both sides. The paper towel near the tang is not there to shield the tang, however, just to shield the plastic clamps. Later on, I tempered that area more than the rest of the blade because that is the area where there will be the least cutting action – thus least need for edge retention – but the most stress during chopping – thus most need for toughness. Here you can see the fully tempered blade shining with some of the colors of the rainbow. You can see that after I took the towels off, I tempered the edge a bit too.

© Charly, all rights reserved. Click for full size.

Here is where things got really hard. 54SiCr6 is very tough spring steel. On the spine here it is tempered at 300-400°C, where it is at its toughest. Which is good.

What was not good however was a slight left-leaning bend towards the tip of the blade and a slight wave near the tang. This is 4 mm spring steel, tempered to springiness. It was difficult enough to straighten the blank before work – It broke my unbender so I have reckoned that straightening this will be hell on earth.

I was 100% correct. I tried a clamp and two steel shims, a method that I used to straighten the blank. It did not budge. Then I tried the old method with two screws in the vise. It did not budge, but I was very close to breaking my vise. After over an hour of completely futile effort, I have decided that I have to repair and reinforce my unbender and if that fails, I will have to ask the customer if they accept the bend.

Therefore I took some steel L-profiles from my scrap pile, some flat mild steel, an M10 threaded bar, and some ball bearings and I got to work.

© Charly, all rights reserved. Click for full size.

As you can see, I have replaced the upper connection with two girders from L-steel profiles. What you cannot see is a similar reinforcement under the two rollers on the base. What you also cannot see in this picture is the upper rolling wheel – that one got totally obliterated.

© Charly, all rights reserved. Click for full size.

The axis of the upper roller was completely bent out of shape. It is bent on one of the lower ones too, but not so drastically. I could not easily make a new roller with a thicker axis from materials available to me straightaway so I have just put 6 ball bearings side-by-side on an M10 threaded rod and that’s it. Next week I am taking my parents to a doctor in a nearby district town where I can buy more ball-bearings to make the lower rollers sturdier too. I have decided that buying and using ball bearings directly will be probably easier than trying to find a pipe in which they fit. Sometimes not having a lathe is really a pain in the nether regions, but one cannot have everything.

Thus reinforced unbender  – bolted to the table – was finally strong enough to actually do something. I did not get a perfectly straight blade, but instead of the tip straying over 2 mm from the center line it has now just a few small wobbles, under 1 mm. One has to look very close to notice them and some of it will come out in the polish too.

I took the now hardened, tempered, and straightened blade outdoors and I bashed a few things with it – a brick, a stone pavement, and a few ash logs in the firewood pile.

© Charly, all rights reserved. Click for full size.

It is not sharpened yet but it did stick in the end grain of the ash logs already. I was not joking when I said that I have bashed a brick with it. I really did, I wanted to make sure that the blade does not shatter. It will be used as a foresting/garden tool and it must be able to withstand some serious abuse. If it did not, it would be very wrong of me to charge the money that I do.

© Charly, all rights reserved. Click for full size.

I took a picture of the blade stuck in the log so you can see the straightness a bit. It was difficult to align the lens of the phone properly, but I think you can see that it is mostly straight.

Now there will be some grinding and gnashing of teeth. Luckily this blade will not need very high polishing, just to 100 grit. Even so, it will be a hard slog since it is hard, tough material.