TNET 40: The Power of the Pentatonic Scale

I find this video absolutely fascinating. I have no idea what a pentatonic scale is and how it differs from the other scales that are there out there. I tried to read up on it and, as it is usual with music, I comprehended none of it. And no, do not try and explain this to me, it is a waste of time (despite rq’s and consciousness razor’s best efforts in the past, I still have no clue what bar and meter are).

But even so, I was able to hum this melody along, I understood what the next tone in the scale should be on an instinctive level and that simple melody has proven to be a real earworm, I could not get rid of it for days.

Open thread, talk whatevers, just don’t be an a*hole about it.

Previous thread.

Project Badgermascus – Part 6 – Trials and Tribulations

I have spent both Monday and Tuesday finishing flattening, drilling, and fitting the handle scales and the brass fittings.

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First I have sieved some bone dust that I have collected through a fine nylon mesh (from pantyhose – I do not wear them, but they can be quite useful in the workshop, so I have indeed several in a drawer). I mixed then the bone dust with five-minute epoxy, filled the hollow back of the bones with it and heated it with a heat gun to about 70°C (not so hot you cannot touch it, but hot enough you cannot press your hand against it for a longer time, a hairdryer would suffice too for this particular task) for quicker curing and stronger bond.

After it completely hardened I ground the back flat again and proceeded to drill the holes for pins.

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Drilling the holes was relatively uneventful. Double-sided tape was very useful in holding the scale on the tang and the whole assembly on a flat piece of wood for drilling to avoid chipping of the bone on exit. Also, I have used blunted and overheated drill bits to hold the scales in place for a good fit and I did not mess up the job terribly. I did make minor mistakes on the left handle scale, but those should be correctable when fixing everything together.

With the scales drilled and fitted against the bolster, I proceeded to make the brass pommel fittings. That went really well, and everything went smoothly. Too smoothly you might say. I glued the brass fittings in place, peened the pins and ground, and polished them over.

That is where the problems started, and I must say – they are not all my fault.

The first problem was that the round stock I have used for pins apparently has different chemical composition than the flat profile used for fittings. Had I known this, I would not file them flush and I would leave them slightly proud of the surface (“admitted” instead of “hidden”). However, there was no way back once I ground them flush, so I was hoping they will get hidden under the patina.

But the patining did not go well too, in three ways.

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The first  – I have made a mistake – I have not masked the steel properly. I thought I did, but I just did not. And as one Czech rather rude but astute saying goes – ” myslet znamená hovno vědět” – “to think (assume/mean/guess) means to know shit-all”. So when I was giving the brass a nice hot bath to copper plate it, some of that bath leaked under the masking and copper-plated and etched the blade in some places too.

The second – the different brasses did not take copper plating identically, it was a lot more difficult to copper plate the pins than the rest. It took over an hour to do on the pins what took mere minutes on the rest (which exacerbated the problem with poor masking later on).

The third – when blackening, I have made the solution probably way too concentrated. It has covered the parts in a nice jet-black matt color almost instantly. But that color has completely rubbed off when I washed it with water and brush. I did not realize the true cause of this so I tried it two more times, but it just did not take, especially not on the pins, After the third attempt I thought I am done on the pommel at least, but it flaked off the next day again.

These mistakes are not catastrophic, but they are a major setback. I had to re-polish everything (done), re-etch with ferric chloride (done), give the steel new tannic-acid patina (in progress), and only after that is done to my satisfaction, can I again try to patina the brass.

However, I have to deal somehow with the pins now. They are ground flush already, but since they will not take the patina the same way the rest does, I must leave them visible. And that means probably leaving them polished and not applying patina to them at all. I will do that and then I will decide whether I like it or not. If not, then I will have to drill them out and either replace them or, if I bungle that job (which is very likely) to make completely new fittings. Either way, it is at least one day, and possibly several days, of work before I can progress further.

However, there did come one good thing out of this – I found two new recipes for black that do not require copper-plating the brass first. One requires hot-bath with ammonia (CuSO4+Na2CO3 – precipitates basic copper carbonate which after filtering and washing with water can be dissolved in hot water by adding ammonia), so it is a major stink and not exactly easy or quick. The second one works at room temperature but is rather caustic and dangerous to handle (HCl + potassium polysulfide). I will probably try the second one now, although I do not like very much working with caustic solutions, since my equipment, as you have seen, is not exactly suited for that kind of job.

Project Badgermascus – Part 5 – Handle Scales

Tomorrow you will get a break from this project, I promise. But today, the Great Flattening from yesterday has continued.

After some deliberations I have decided to try and go for fully blackened brass fittings. That means that the blade will be dark grey, and the fittings really, really dark gray. What kind of handle material should I use? Marcus has sent me a nice piece of stabilized spalted maple, but I do not think it is the right material for this project. Ditto, any of the dark woods that I have. I think the blade deserves the poshest material I have available – bone. I think it will provide a nice contrast to the dark metal.

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

Which meant I first had to rough-cut the scales with a hacksaw, which is one hell of a job, let me tell you. Bandsaw or any electrical saw is a big no-no for cutting bone, this has to be done manually. Including pre-cutting he flat sides, before grinding them truly flat.

Thus I had to spend the whole working day with a respirator and my fingers are all sore now. Because the grinding had to be done manually too. Belt sander does work on bone, but it destroys belts way too quickly for my liking and as I learned in the past, these thin flat pieces would have a tendency to be dragged out of my grasp, increasing the risk of injury or bungled work. So flatstone+glue+sandpaper it was. Maybe after I build myself a disk-grinding attachment this work will be easier, but now it is not.

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The scales are ever so slightly bigger than the tang and thicker than the bolster now, and they will remain so. I do not intend for a flush fit, but for a proud one ( I have seen English-speaking knife-makers refer to it as “heirloom fit” although I was not able to find anything specific about it, so I am not sure that is the correct term).

The principle is the same in carpentry – whenever two surfaces join, you can make the joint either hidden or visible, but it should not be visible because you failed to hide it. So if you make it visible, it should be apparent that it was intentional. Like gluing in spacers, making the surfaces meet in a groove and not on a flat, etc.

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Today’s work ended in the kitchen, where the two rough-ground scales ended in a pot at 60°C for an hour or so with circa a teaspoon of washing soda and one spoon of washing powder in 1 l of water to dissolve and wash out as much of remaining fat as possible. In the end I have added a teaspoon of hydrogen peroxide to whiten the bones a bit, although complete whitening is not possible on these.

Tomorrow when they are dry I shall fill the hollows on the inside (where marrow used to be) with epoxy to make them flat. After that, I can start the remaining works, i.e. fit and polish the pommel, drill all the holes, and finally, the glue-up. We will see how that goes.

Project Badgermascus – Part 4 – The Great Flattening

Today I have started the work on the handle, starting with brass fittings. First I have cut four pieces of brass, two for the bolster, two for the pommel, and I drilled 2,5 mm holes in the bolster pieces. On the left piece, I have then cut M3 thread and on the right piece, I have widened the holes to 3 mm.

For pins, I am going to be using a 3 mm brass rod. I cut 4 small pieces and on each, I have made a bit of M3 thread to go into the left side of the bolster (and later on the pommel). The M3 threads are, strictly speaking, unnecessary, but I find they help with two things. First, they help to keep track of which part is left and which is right, so I do not confuse them at some point and make a false cut with a file. Second, fiting the two halves together is easier, because the pins hold fast in place and do not fall off when manhandling the assembly.

I guess these preparations should not take me too long. They took me over five hours. The drilling, cutting etc was not the biggest issue. The biggest issue was the tang. During polishing of the blade it became noticeably thinner, and because the polished area bleeds over to the tang, the tang was not flat anymore – it was a few tenths of a mm thinner at the bolster. So I went and flattened it on a stone.

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As you can see, the tang has relatively deep gashes cut into it with the edge of the grinding wheel. Those are there for three purposes – they reduce the weight, they provide a good grip for the epoxy later on, and they reduce the area that needs to be manually ground off when making the tang flat.

Even so it took me a lot longer than it should have because I did not have the correct sandpaper readily available. What you see here is green corundum, which should be used only dry and only for wood. I have to buy very coarse wet & dry sandpaper, but I keep forgetting and the coarsest I have in stock is 120 grit, which is not nearly enough for this.

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

And this is where I am now. Next, I will polish and finish the front side of the bolster but not assemble it. Then I will make the handle scales, fit and drill those, and only after that is done I will drill and fit the pommel part. I have not decided yet whether or not the pommel needs a hole for a lanyard.

The way things are going, I have still quite a few days of work ahead of me.

Project Badgermascus – Interlude 3 – Blackness Achieved!

Kestrel mentioned some commercial blackening compounds containing Tellurium and that train of thought sent me down a path of thinking whether I do or do not have some chemical compound containing sulfur anions, which too react with copper to make a black color. And I realized that I do because a solution of polysulfide is sold as a common fungicide. It does not work on brass directly, but if that brass is first coated with copper, then it does work. So I did exactly that, and voila! It takes a long time, but it works.

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

It is not pitch-black, it has a bit of bluish-grey tint to it, but under a coat of wax or lacquer, it would be a lot darker. I consider it a definitive success.

I am wondering whether it would be possible to make pictures on brass with different patinas. As a kind of colored etching process. I do not see a reason why that should not work.

Project Badgermascus – Interlude 2 – Practice Makes Perfect (Allegedly)

I want this knife to be special because the blade deserves it. That means not only patined fittings but also decorations. So I have decided to do some filework – definitively on the tang spine and possibly the belly too.

However, I did not do a lot of filework yet. I did some, but that was twenty years ago and not only was it rubbish, but I have also already forgotten everything I learned back then.

So I am in this conundrum – I really want to make something I know I am not good at making. So I have decided to do today a practice day. I took a piece of mild steel, ground it to roughly the thickness of the tang, straightened it and I went on to figure out the hows and whats.

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

What you can see here from top to bottom is a progression both in time and (I hope it can be also seen) in quality. The top one took me over two hours, the last one under one hour. Whilst the photo magnifies all the little imperfections to an unreasonable degree, there is still definitively a lot of space for improvement, some issues are still visible even at arms-length viewing distance.

I am bloody nervous about doing this because if a file slips, there is no way back. It was a huge problem for the first three patterns actually – establishing the first cut was the biggest issue I had. Files have angled teeth and they cut best when drawn perpendicularly to the edge. When you run a file at an angle, not only has it a tendency to slip and wander off, it also behaves differently when used left-handed as opposed to right-handed. Once the cut is established, all these problems are a lot less pronounced, but establishing that first cut precisely where you need it to be and at the right angle is a major PITA.

For the fourth pattern, I have finally found out how to best establish that initial cut. I have a beat-up knife made from an old saw blade in my workshop, that gets used for all those jobs a knife is good for but simultaneously not advised for. Like putting the edge on a piece of steel and hitting the spine with a hammer, to establish a cut line in the metal surface. Which is what I did here. Essentially like a center-punch for drilling. And just like center-punching prevents drill bits from wandering, line-punching prevents files from doing the same.

Now to beat my anxiety and to convince myself that I can do this…

Project Badgermascus – Interlude 1 – Sciencing How to Patina on Brass

So, the blade came out of the etch just spiffing, and giving it dark bluish-grey patina with tannic acid made it look really cool and mean, almost tacticool. But it is, of course, no longer shiny. Which made me think a lot about how to proceed from now on.

As you know, this is my first time working with damascus. Up until now, I have worked either with carbon mono steel or stainless mono steel, either with mirror or satin finish. Making the fittings on such steels from new brass, aluminium or steel is perfectly OK and does not detract from the blade. But making fittings shiny on this blade would feel, as we say in Czech, “jako pěst na oko” (like a fist punch in the eye). I do not have any spare damascus or mokume gane to go with it, nor the means and knowledge to make them, so what can I do? And the title, of course, gives away what I have decided to try – to make the fittings out of brass and make a patina on them.

So I went to my personal library, took out my favorite book “Chemistry for everybody” (published in CZ in 1990) and looked up the recipes in there. Then I looked a bit around the internet too. And then I went and bought a lot of pre-made commercial solutions for the job… NOT.

I looked up which chemicals that I already have could kinda-sorta emulate what the book says should be used for copper, brass and bronze and then I have of course performed a series of experiments to try whether I can make my own solutions. And the results are pleasing. And because there are a lot of pictures in this, the rest is below the fold.

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I Wish I Were This Strong

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

She was carrying the dead beetle for several meters already when I caught up with her, and she still had several meters to go. And it was by no means easy to get a sharp picture, but she took a breather for a moment here.

If you have ever wondered where end all those insects and little critters that you step on in your garden – now you have an answer.

Project Badgermascus – Part 3 – Polishing and Etching

Well, now that I am down to only one blade, I can at least concentrate on it. So I did and today I have polished it all the way to 7.000 grit. There is still cable damascus on the very tip, but I have decided against making the knife shorter again and I will go with it as it is. The cable damascus is hardened and in composition similar to the 1095, so it will still cut and hold an edge well.

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

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

Now it will sit in FeCl3 for a while.

Initially, I have used still relatively concentrated solution (~1/10 dillution of solution for printed circuit boards) to see where the 1095 is. Now I am using a very diluted solution (~1/100) for the final etch, because etching this works a bit differently than etching damascus made from two kinds of steel where one has high nickel content. Why is that?

As a former chemist, I know at least a bit about what is going on now so I can show off.

The way etching works on carbon steel like this is an electrochemical process. The impurities gather during the forging process at the boundaries between the various steel layers and those impurities make the steel in those areas more susceptible to chemical attack because they create a sort of microscopic electric cells that attract the ions from the solution to the area. That is why in the etch with the more concentrated solution the cable steel quickly turned all grey and the 1095 remained all silvery – the 1095 is a mono steel with very few impurities uniformly spread throughout, whereas the cable, whilst being similar to the 1095 in chemical composition, has most impurities concentrated at the boundaries between former cable strands and at the boundary with the 1095.

In a concentrated solution, the reaction happens too quickly and can lead to pitting in areas with inclusions or more impurities. And a layer of various oxides builds up, leading to blotchy, uneven etch. That is ideal for revealing where the mono steel in the sandwich is, but not so great for showing the grain boundaries.

A diluted solution gives the reaction more time to attack the steel more evenly, but it of course also takes a lot longer. I probably won’t risk letting it sit in there overnight, but it will take hours. Allegedly the smiths of times bygone have used fruit (citrus, apple) juices, and it took a very long time, but I do not have several pieces to make a scientific study of it. Although, I might just cut the failed pairing knife into several pieces and perform an experiment….. Hm. I will think about it, that would be one way to get some knowledge and some fun out of a failure.

Project Badgermascus – Part 2 – More Failure

I want to stress up front, that none of these failures is Marcus’s fault.

So, what went wrong this time, I don’t hear you ask? Well, a lot, I am down one blade out of three.

I thought the pairing knife goes on really well, until 320 grit when I noticed a little perpendicular line on the spine. And It was not a line in the damascus pattern – those become visible during polishing, and that is very cool – it is a crack. I do not know when it happened. It might be there from the start, it might have happened when I was straightening the blade, it might have cracked due to the stresses involved during polishing – it is a very thin piece of steel after all. There are also some imperfect welds with inclusions in the piece, but this is not one of them, this is a crack.

Cracked spine. There is one more crack on the other side of the blade too. © Charly, all rights reserved. Click for full size.

No matter the cause, this blade is now irredeemable garbage, the only thing it could be reworked to is an awl,

I am going to finish the piece only as a show of what it could have been, but I am definitively not using any fancy materials for the handle. I planned on using stabilized maple burl (also a gift from Marcus), but now it will probably be just some random piece of birch or oak.

Works on the boot knife also did not go well. First I messed up the grind, bigly, but that was not the problem, that was still repairable, there was enough material that needed thinning out anyway. What was not repairable was the position of the cutting edge towards the blade’s tip. It turns out that I did not hit the 1095 at the center of the blank quite well. My grind was straigth, but the the 1095 in the center of the san mai damascus was bending ever so slightly to the left in this area. Had I positioned my grind just about 0.25 mm to the left, this would not have happened.

The darker cable damascus is reaching all the way to the cutting edge near the tip, where only the shiny 1095 should be.
© Charly, all rights reserved. Click for full size.

I have tried to re-grind the blade, but for that, I had to make it about 1 cm shorter and I  do not think it looks as well as it did before, it is too short and stubby. It should become a usable little knife, but I am not happy with it, and I am not finished yet.

Next time I will work with san mai damascus, I will probably first polish and etch the edge to see exactly where the cutting steel is. Too bad I did not think of that before.

All in all, so far this project has made me nearly cry several times and to want to quit knife-making because I am no good at it. When one spends several days with some work only then for all that effort to be for nothing, it has quite an influence on one’s mood.