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.

© 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

© 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.

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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.

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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.

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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.

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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.

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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.

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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.

 

 

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.

A Big Commission – Part 1 – Beginning

I got a new commission via the sign on my garden gate. Maybe if I did not live at the end of a road in the middle of nowhere I would have gotten more business that way, but a little is better than nothing.

The customer initially asked me if I could harden a kukri machete that he has bought and found of insufficient quality. My reply was that it might be possible, but only if the steel is good enough and only the quench is botched, not if the steel is craparooni as well. After a bit of back-and-forth, he brought me the bad kukri together with one that belongs to his friend and that he initially intended to buy.

Both machetes are from the same company. I won’t tell you their proper name, but it could be paraphrased as “Low-Temperature Carbon-Iron Alloy”.

The bad one was manufactured allegedly in Africa (the country was not specified) and it is really bad – it has no primary bevel, so it is essentially just a sharpened flat bar. The hardness is about 50-51 HRC, so it is hardened. But this is the lowest point where it might be useful as a cutting tool – with very frequent sharpening. Which would be difficult with steel this thick and this type of grind.

The good one was manufactured in the USA and it is in my opinion still bad, although not as bad as the first one. It does at least have primary and secondary bevels, so there is no need to remove excessive amounts of material when sharpening.

I took a picture of the good one, proposed a few design modifications, and made an outline and a price offer.

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Since this is supposed to be a working tool, we agreed that there is no need for high polish or any excessive fancifulness. On the other hand, there should be some fancifulness since a handmade product is going to be expensive regardless. So there will be a jatoba handle with hidden pins and a dyed leather sheath with a pocket and natural sharpening stone. The offered price is about ten times higher than what the manufacturer of the original has charged, but I do hope that I can deliver a product worthy of that expense.

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I have already cut the outline from 4 mm spring steel and then I got distracted. I could grind the bevels freehand, I do have the skill to do so. But I thought to myself – I might need to make a second one if the first one cracks in quench, I might get more requests for big blades, so it probably is worth to spend some time making a jig. And today, I started to make that jig.

More about that when it is finished.

Big Gay Sword

I have featured michaelcthulhu several times already, and he keeps proving that he is a wholesome and good person.

The summary quote from this video:
“I don’t pretend to understand God or being gay. But only one side is sending death threats to a 22-year old so I’m pretty sure how I feel in this situation.”

Mike is trying to mad science how to make various patina colors on his sword in this one. I feel like I could have saved him a lot of trouble with that.

How to Sharpen a Scythe

The clicking and whispering of whetstone on a scythe blade is a sound that still evokes memories of early childhood in me. My father used to breed rabbits and he made hay twice a year. That, of course, clashed horribly with my allergies, so later on he moved to ducks, turkeys, and geese who kept the grass in our rather big garden in check during the summer on their own, and hay was not needed. Nowadays my allergies are much better than they used to be, we no longer keep any animals that eat the grass so we have to keep it in check by mowing. And the lawnmower does not reach all nooks and crannies, nor is it suitable for mowing grass that has overgrown a bit. And thus a scythe has to be used again.

My father has one and I have my own. We were both using one, but I got terrible back ache from it because the handle was just a tiny bit shorter than I need. For a long time, I could not find a suitably long scythe handle anywhere, so I even started to season ash wood to make my own. Luckily my parents saw a TV advert for a company that sells adjustable scythes so I bought one, adjusted it accordingly and I use it for two years by now and my back no longer aches (apart from normal tiredness that is). And I get to make my own clink-whoosh sounds with whetstone on the blade.

But there comes a time when the whetstone actually destroys the blade – when the cutting edge becomes as sharp as that of a knife. Yus, that is correct, a scythe blade that is as sharp as a knife is of no use. Here is a picture of my scythe this morning, when work with it became finally too difficult and it was bending the grass a lot without cutting it. It would cut yer leg off in a blink, but it was no longer good at cutting grass.

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You can see the edge is laid on a tiny peening anvil fixed to a small wooden horse so when one sits on it, the blade can lay on the anvil and be supported by knees on either side to stabilize it. The left hand holds the blade to move the edge across the anvil, and the right hand beats the crap out of the edge with a hammer.

Scythes are hardened, but they are tempered back to springiness, so the material is somewhat ductile – up to a point. The hammering has thus several effects. It draws out the material a bit, so the scythe becomes a mm or so wider and thinner at the edge.  The second effect is the so-called work hardening of the steel, the thinned drawn-out edge becomes harder. And the third effect, completely undesirable in a knife blade but essential in a scythe, is that the edge becomes all wavy and even cracked in places. Look at a hammered blade.

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For a knife, that looks absolutely terrible. But for a scythe, this is a must. Grass is a mixture of soft and hard fibers, yielding and tough. The jagged edge is much better at cutting it than a smooth knife-like one. My father even tells an anecdote about a former colleague of his who never hammered his scythe and has sharpened it as a knife – and as a result, he had difficulty cutting grass with it.

After the blade is hammered out, a few passes with whetstone are sufficient to straighten it a bit and break off some wire edge and thin it just a tiny bit more than the hammering has done. And that maintenance with whetstone should now suffice for a few months, then it will be hammer time again. A properly sharpened scythe should be able to cut grass that is just a few cm high with a light pass.

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Yes, I am wearing socks in sandals. I think not doing so is just stupid and fashion be damned, especially in my garden.

Don’t Test Blade Sharpness With the Ball of Your Thumb!

Recently I was on a short trip with my friends from the university. I have shown you my traveling sharpening kit and said a bit about its evolution. I did not mention any details about what has happened on the trip.

In addition to a gratis sharpening of one blade per person, I have also offered a gratis lesson in sharpening and knife maintenance to anyone intersted. I did not expect that several parents will herd their children in (mostly, but not exclusively, boys) and that I shall have a complete class to teach. That caught me a bit unprepared, to be honest.

I have therefore included basic knife terminology and knife safety – do not carry a knife with the point upwards or forwards, do not cut towards yourself, that kind of stuff. One mother was afterward worried a bit that the children will try all that stuff I told them not to do just to test it. It was the same lesson I got when I was a kid and it never occurred to me to test whether a knife buries itself in my stomach or my hand if I do not heed my father’s advice (I cut myself plenty of times even so). There is one exception, however, and that is testing the knife sharpness with the ball of one’s thumb. That one thing is, to my bafflement, widespread and some of the boys already got into the habit of doing it before my lesson, and one of them did it on the just freshly sharpened knife after the lesson. For which I reprimanded him immediately.

“But I have never cut myself that way!” he replied indignantly, with his father watching in the background.

“That does not mean you will not cut yourself in the future if you keep doing it. I have just shown you that this knife is as sharp as a razor, it takes just a slight wrong move and you won’t even know you cut yourself until you have bled all over the floor!” was my reply, in a pretty pissed off tone of voice.

His father thanked me later, saying that the boy has picked up this habit somewhere and needed the reprimand from someone whom he recognizes as an authority when it comes to knives. Not the first time that I have ticked off an unruly child in the presence of their parent, and probably not the last time either (so far I have gotten away with it since all instances were about safety).

I do not know where people pick up this bad habit and why they keep doing it. It is completely useless for assessing the blade’s sharpness. Moving the ball of the thumb across the blade is kinda safe – it is the same movement used to shave hair, another method of testing – but with a sharp knife, a slight twitch of a muscle that flexes the thumb is all that is needed for things go wrong. A thing that I have seen happen. This can also easily result in non-bleeding cuts, those you do not know about until you wash your hands with soap – that is how my father got “cured” of this bad habit when he was young.

If you need to test a knife’s sharpness and you do not have a piece of paper or string to do so, you can put the blade on the fingernail of your thumb at an angle of approximately 45° and try to scrape it without exerting extra pressure. If the blade tends to dig into the fingernail with its own weight and resists movement, the knife is sharp. If it glides over the surface, the knife is blunt. It is completely safe and sufficient.

End of rant.

Evolution of My Sharpening Kit

When going on a get-together with my friends from university, I occasionally offer to sharpen their knives for free or gratis. For that purpose, I used to take with me my sharpening stone, which initially was all that I had to sharpen knives. With time this has evolved into a kind of traveling sharpening kit and in this post, I will describe its evolution a bit. Let’s start with a picture, followed by less than a thousand words.

©Charly, all rights reserved

I have started with the grey, two-layer silicon carbide whetstone on the left. It has to be soaked in water before use and it is the exact type of cheapo basic coarse/fine stone that my father has used to sharpen knives all his life and with which he taught me how to sharpen knives when I was ten years old. With care, it is possible to sharpen a knife with this stone alone, although not to shaving sharp, for that, stropping is necessary. As an impromptu strop, I have used on my travels either folded paper or a dishcloth with a bit of toothpaste on. It was possible to get knives to shaving sharp that way, but it was a bit laborious and time-consuming.

Thus came the second addition to the set, the beige-red stone. The red layer is of a significantly finer grit than the fine carbide layer on the grey stone, which is better for a touch-up on a knife that is not overly blunted. It is a very hard and not overly porous stone that can be used with either water or oil. I do not know its composition, but it does not behave like carbide and does not soak up water much. I only use it with water, it is more practical on travels.

However, stropping was still a major pita. Luckily, I found my grandfather’s old leather strop for razors when rummaging around in the attic (I found the razors too). It consists of a leather belt sewn into a loop that is spanned with a screw. The leather was rotten, but it was not a lot of work to replace it. I improved the design a bit with a bottle cork cut in half to not span the leather over a sharp edge, which would lead to faster deterioration. I am thinking about making several of these for my shoppe too. This has made stropping a lot easier, although it is not ideal for big knives. It works reasonably well even without abrasive paste – this strop is not primed and I am still pondering whether or not I should prime one side or leave it as it is.

One of my friends has a small folding knife that has a kukri-like blade gomtry. That unfortunately means that it is not possible to sharpen with a flat whetstone that cannot reach inside the tight concave curve of a small blade. A stone with a curved surface is needed. And I found a few exactly such stones when I was visiting my aunt – she lives near a river in an area where quartz cobbles are easy to come by in all kinds of shapes, sizes, and surface smoothness. A quartz cobble does not remove the material as well as a carbide stone does but it does work well for maintaining an edge that is not overly deteriorated. And no, I am not joking – it really is perfectly possible to sharpen a knife properly with a stone found in nature, with a bit of skill and care in selecting the right stone.

The last edition to the hand sharpening kit was a hard-backed strop and a hematite-based stropping compound. The strop is simply a black-locust board with leather glued on both sides and a handle screwed on one end. The leather is with the skin-side out on one side and flesh-side out on the other. The rougher flesh-side out was subsequently primed with the stropping compound. It is hard and big, and thus suitable for stropping even really big knives. It is very efficient too, a few strokes on the primed side and a few more on the clean side, and any knife is as sharp as a razor.

For traveling the stones get packed into a plastic food container with a silicone pad and a few other things like the two wooden wedges with winkles (those were an afterthought this time because I knew I will be teaching someone to sharpen knives and I wanted to have some easy way to demonstrate the right angle) a smaller bowl and a silicone pad.

I think this is the final stage for me, I cannot think of anything else that I could need.

I do wonder whether it would make sense to make all of this into some kind of snazzy “traveling sharpening kit” and offer it in the shoppe. It is not a sharpening gizmo, it does require some skill to use properly.

And if you are wondering what you need to sharpen knives to a truly wicked edge, here is all you really need to achieve that goal and none of it is overly expensive or difficult to make. You can buy fancier or more expensive equipment but you do not need to.