Making a Rondel Dagger – Part 10 – A Bolster and a Guard

Whilst the blade was the most time-consuming part, in a project like this there is still a lot of metalwork to be done. Once the handle is turned, next step is to make a bolster and a guard, and fit all these four parts together. Precision is important here. Not precision as in adhering to measurements from a drawing, but precision of how the parts fit together. I have made myself a set of measurement from the game 3D model that I aim to get near to, but I will not fuss about getting them exactly.

The bolster I have made from a piece of pipe of unknown origin that has almost the exact diameter that I actually want to have. It is also completely free of rust, which has made me suspicious whether it is not stainless steel. No matter, I have simply cut off a piece and polished it.

I did not polish it on the belt grinder all the way through the finest belts, but I stopped at around Trizact A16 and I went straight tot he buffer after that. Only I did not use the felt wheel straightaway, but a coarse sisal one with coarse polishing paste, then a felt wheel with medium polishing paste, then felt with fine polishing paste and finally felt wheel with jeweler’s rouge.

In order to be able to work with the piece on the buffer safely I have hammered it on a round dowel. During the polishing I took care to turn it in different angles against the wheel in order to get slightly satin surface – buffing in one direction only makes mirror polish and I did not want that.

The bolster is not completely round, but very slightly oval. I wanted to be able to feel the edge alignment of the dagger when held in bare hand. To further help with this I have also filed a fine grid of grooves on each side of the bolster. With that done, I could affix it to the handle. For that I have coated the relevant part with hot hide glue, stuck the bolster on there and hammered a few wooden splinters between the bolster and the handle to center it properly and to hold it in place.

With that done I had to shape the tang on the belt grinder so it was continuously ever so slightly smaller than the blade and square the shoulders (those were round prior to hardening because a sharp edge could lead to the tang breaking of in quench). To protect it from scratches I have covered the whole blade with masking tape. When the tang was shaped, I have affixed the blade in the vice with additional protection of a wet rug, and I shaped the hole in the handle to fit by the previously shown burning technique. I had to be careful for the heat to not overheat the blade base, but to be hot far enough to get a fit where the bolster was mere 3 mm from it.

Next piece in this jigsaw was the guard. I wanted that to be between 3 to 3,5 mm thick, but I had no suitable piece of steel that was not pitted too much. In the end I had to cut a piece of a structural steel V profile that was way too thick. I have spent rather more time on truing it and grinding it down to desired thickness than I wished to. Unlike for the bolster, I had no good and comfortable way to hold on that small flat piece of steel safely, so I nearly ground my finger tips off. Luckily only fingernails got slightly chewed and I have learned how to do this safely later on, when I was polishing it. I have to finish the supporting table for my belt grinder in order to do these finicky things.

When ground to slightly above the desired thickness, I have punched the centre and drawn the design of the guard. I like to make my own tools, and I have indeed made my drawing needle, but I wimped out and bought the compass. The work required to make it might be fun, but it would be way too much time that would definitively be spent better elsewhere.

Next step I have just drilled a 4 mm hole in the center, 0,5 mm smaller than the maximum width of the tang at the blade base. In order to transfer the outline of the blade base onto the steel I have poked a hole with the tang into a piece of paper – Lipton tea box was the right thickness and firmness.

Cutting the hole for the tang I have done with a fret saw. In the past I broke a lot of blades whilst doing this, but it seems I have finally learned how to do it properly this time. I broke none and it was done in lickety-split. Note the aluminium covers for the vice jaws. These are important, because I need the piece to be held firmly and safely, but I do not wish the hardened jaws of the vice damage the soft steel of the worked piece.

After cutting the rough outline of the hole came of course the most difficult part – fitting and shaping the hole to fit the tang precisely. This took the better part of an hour with fine and diamond files, and another hour or so the final shaping and polishing of the piece to the same finish as the bolster.

Here you can see the face of the guard. The other side, facing the hand, has rounded edges. I was thinking about doing that, then I was thinking about doing both sides flat and in the end I had no choice because before I figured out how to polish it properly, my hand slipped and I chamfered an edge that I did not want to chamfer. I was lucky – the result is comfortable even against bare hand and it looks good. I might however take some more time for polishing this piece. A few hand courses with coarse hematite might be needed, right now it shines a bit like a bare arse among the bushes.

Here you can see the parts assembled. Of course there is a lot of masking tape covering all the bits that I do not want to get dirty or scratched, and most of the focus is on the mess that is my workbench. But you would not expect me to show you pretty pictures at this stage, would you?

‘Bout the Whole Sharp, Pointy, Stabby Things Issue and Guns

I am not feeling particularly well these last few days. In addition to the usual depression that is  just an everlasting companion these last years, and the hay fever due to my neighbour not having harvested the hay yet, several joints have decided to act up so I cannot work properly. And I do not feel like discussing partisan politics this week except to say fuck all politicians and political ideologies across the spectrum left right and center – sideways.

However this is my hundredth post on Affinity and despite the number being completely arbitrary, I thought it should be about something more substantial than about strawberries misbehaving.

The whole issue of sharp and pointy objects has got me thinking more than one time throughout my life. When I was a kid I was being told that I will be allowed to handle sharp things from the age of ten years. I looked forward to it. For my tenth birthday I got a small pocket knife and my father has taught me how to sharpen it and how to properly care for it. In our household a sharp knife is really sharp and a blunted knife is what usually gets called sharp by many people I know. I had a knife somewhere around my person ever since.

I really like knives, daggers, machetes, axes and swords. I also like bows and crossbows. I am not collecting either, but I would like to make some of each and when I do make them, I will take care to make them not only functional, but beautiful too.

However there is no denying that all these objects are potential murder weapons. Some of them are indeed optimised for being a weapon, whilst others can have as a primary function being a tool.

I would like to know where this fascination with dangerous things comes from. My take on the issue is that it si far more common than people might realize at first thought. For example many of the most aesthetically appreciated animals are very finely tuned killing machines. Many people like cats and a person who does not appreciate the beauty of a tiger or a leopard would be a rare specimen indeed. Dragons and dinosaurs are very popular among kids and they are not known for being fluffy and cuddly.

This has brought me in a roundabout way to thinking how is liking knives different from liking guns and how is that in turn different from liking squids? And my take on the thing is, that not too much, if at all.

The important thing is not what one does like, but what one does about it. A gun collector or skeet shooter is just as normal as a sword collector or a fencer, and they all are just as normal as a stamp collector. The difference is in how people are conditioned by culture about dealing with the specific issue – both from the point of the enthusiast, and from the point of of the general populace. Some hobbies are frowned on, some are viewed as harmless oddities, some are reviled, some admired. And accordingly some people are reclusive about their hobbies, whilst others engage in them publicly and proudly.

And this is what makes the american gun nuts such a big problem. The difference between a gun nut and me is not that they are someone “other”.

It is not that they like guns and like to collect them and/or tinker with them. Gun/weapons collectors and enthusiasts are in every country around the world and nowhere, regardless of how strict/lax the laws are, are they a problem of the magnitude one sees in the US.

It is not that they think about their weapons in terms of how dangerous they are and how optimised for doing harm they are. I do that too and I do not believe that anyone who has ever held a sharp knife in their hand has never thought about it.

It is not that they think about how they could use their weapons in self-defense should the need arise. Whoever has ever been on the receiving end of violence will think about what they will do next to minimise the harm to themselves and their loved ones.

It is the culture that has elevated owning murder instruments onto a right in itself, sanctifying it and worshiping it, that pushes otherwise normal people over the border of normality into the land of the dangerous. It is the culture that makes people actually wishing to use the weapons against other people, instead of dreading that it might come to that.

In a culture where carrying a sword  was similarly held in high esteem, and where dueling for the slightest offence would be considered not only normal, but positively desired a different problem might arise – instead of an epidemic of mass shootings an epidemic of dueling, where the young and hopeful would waste their lives pointlessly at the end of a sharp piece of steel.

And you know what? That scenario ain’t fictional. And it took both legislative change and a shift in culture to deal with the problem.

Making a Rondel Dagger – Interlude

The now finished blade came out really nicely, so I will not be ashamed to be associated with it. So I will definitively sign it. However I mentioned already that I do not currently have my own maker’s mark, since the one I used from 10 years age is now used as bluetooth logo. I am not sure whether continuing to use it could lead to legal trouble, but I guess it would lead to confusion. “That knife has a bluetooth? What does it do?”.

I tried to design a new logo, but all designs I came up with either do not appeal to me, or they require quite precise etching process to be made on a blade. And that would definitively not fit this blade, where I aim for as authentic medieval look as I can achieve.

An idea came to me to use my initials, but not in Latin script, but in Glagolitic. At least for this particular dagger. It has the advantage that not only is it a very simple design, it is also thematic – Glagolitic script is the official script of the Witcher 3 game from which the inspiration for the dagger originated. And I am not appropriating other people’s culture.

So today I set out to try how it looks and also to refine/remember my etching process, since I did not do it for quite a long time. For that I yesterday polished a piece of steel from my failed broken machete.

In the past I tried different materials as masking for etching and the best results I have got with material that does not look appealing in the least. But do not worry, it does not smell like what it looks like. It smells actually very nice when worked, because it has been made from equal parts of beeswax, bitumen and spruce resin, all boiled together and poured into water to solidify. I formed it in sticks and for last ten years it collected dust. But it does not spoil and it is just as usable as it was when new.

When heated with heat gun or even with hair dryer or a candle it quickly gets very sticky and adheres to the de-greased steel quite well. So I heat gently both the steel and the stick and rub them together to transfer some of the sticky material onto the blade. Then I use the air flow from the hot air gun to make an even thin layer. It is important for the layer not to be too thick, because it would be difficult to draw the design in it, but also not too thin because then it could delaminate during etching around the edges (delamination was a huge problem when I was trying to use paraffine btw.).

Next step is to draw the design. The layer remains fairly soft and plastic for long time and can be easily scratched through. For this I am using an old compass needle, but for finer design a razor blade or very sharp wood carving knife tip can also be used. It is important to keep the needle clean after every scratch, since the stuff adheres to it too. It is also necessary not only to scratch through, but more like scratch/chisel away. Minor mistakes can be repaired by pressing a piece of the mass on desired place and pressing it gently against the spot until it connects again. After just a few minutes of work under a magnifying glass I was ready to try etching.

For just a small logo I did not want to prepare whole big etching bath, so I used the masking mass to glue a bottle cap with cut-out top as a barrier for the etching fluid to remain in place. As a source of electrical current I have used a DC power supply from an external hard drive that has died on me a few years ago – it has an on/off switch which comes in handy. Anode (+) is connected on the steel and cathode (-) on a piece of graphite (a pencil core works too and I used it for very fine etchings in the past). As etching fluid I have used ordinary kitchen salt solution in the past, but today I have tried ferric chloride because I reasoned (correctly) that it will work better. It is solution for etching printed circuit boards diluted approximately 1:10.

It is important to not use too concentrated solution for two main reasons:

  1. The current that can go through the solution depends on concentration. Too high concentration can mean too high current and that can burn the DC power supply (lesson learned in the past).
  2. Too concentrated solution also etches too quickly and that is not desirable because it makes uneven “burned” looking and spotty etch.

After that I turned the switch on and waited for ten minutes. It was not complete success because towards the end the bath evaporated too much, it got warm and the masking layer delaminated around the whole logo. So I repeated the process once more with only five minutes etching time. I am satisfied with the result, the etching is clear and has nice black color that I know I would not get with table salt. Now I will play with the letters a bit in Photoshop to get the proportions right.

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Knifesharpenophobia

When working in US some twenty years ago I borrowed from the local library in Ketchum (ID) the Ed Fowler’s book Knife Talk: The Art & Science Of Knifemaking. Unfortunately I did not have time to read the whole book so I basically just skimmed most of it and therefore I do not remember all. I can recommend the book with good conscience though, because I did read one chapter in full and remember its title and contents well – “Knifesharpenophobia”. I consider that a sign of good and persuasive writing.

I have remembered about this book and this particular chapter recently when I was obsessing over properly hardening a blade for a knife that in all likelihood will never be used to cut anything harder than a mushroom or perhaps some soft wood during a walk in the forests. And maybe not even that.

In the past I have made knives from improperly hardened steel. Not that I wanted to, I did not have much choice. I did not have high-quality knife steel available just a few mouse clicks away, and even if I had I was so poor I could not afford it. And I lacked a lot of the knowledge I have now so I could not improve the steel I had.

Two of those knives are occasionally still in use (by me) whenever I go to the forest.

A knife

©Charly, all rights reserved. Click for full size

A knife

©Charly, all rights reserved. Click for full size

I let you in on a little secret: They cut perfectly well. With the second one, made from low-carbon structural steel, I was able to do even quite a lot of wood carvings and heavy cutting/chopping when I was camping in the past.The first one is made from some unknown martensitic stainless steel that I was not able to harden for unknown reasons.

However the softer than normal blade did not impede work in the slightest. All that was needed to do was to sharpen the blade a bit more often than is perhaps usual and it was much quicker to sharpen than other blades. Just like Ed Fowler says in his book:

…Granted, edge holding is a fine attribute for a knife. The problem is, knives that seldom need sharpening generally are usually too hard to sharpen when the time comes to sharpen them…

I could not agree more.

I think that for anyone who starts to learn the knife making trade it is vitally important to keep in mind the fact that for thousands of years people were perfectly capable of hunting, cooking and fighting with blades made from soft metals like copper, bronze and wrought iron. Sure, steel was the ideal material of choice once discovered, but untill the invention of blast furnaces it was hard to come by in larger amounts and it rarely had consistent properties.

I hate it when I come across some smug knife maker who berates some young beginner for forging or making knives out of the steel they can get their hands on. Some people even feel the need to hurl derogatory epithets at knives made from rail spikes or structural steel. I wish they stopped doing that, because it accomplishes nothing except maybe discouraging a future master from pursuing further the hobby they enjoy. Obsessing about the frequency of sharpening and edge retention is not necessary for a beginner, I would even argue the opposite. And why the aversion to knives that need sharpening? Well, I let Ed Fowler have a say again:

…What is knifesharpenophobia? …I define it as an irrational, excessive and unnecessary fear of sharpening knives. This is a malady that strikes fear in the hearts of all too many knife lovers and users.

And to make the point even finer you can watch this video where it is demonstrated that properly sharpened flat bar from 5,-€ low-carbon structural steel can cut just as well as 100,-€ katana:

 

Youtube Video: FightCamp 2015 Federschwert longsword tournament – HEMA

I normally do not like to watch sports, but I liked this very much. Somehow these fencing matches look interesting and much more real than modern fencing or over-choreographed Star Wars jumping matches.

In the very first minute is a moment of two opponents sizing each other up, both deciding to wait for the other to strike. The tension in there is very intense, palpable even through the screen.

Very interesting is also the match that starts at 12:47 between a very diminutive woman and a huge bulky man. Lesson to be learned here is unfortunately that in these competitions size does matter – to my amateurish eyes she does not seem any less skilled than he does, but she just does not get within striking distance before he does. Longer hands mean longer reach and longer reach means huge advantage. So everything else being equal, the bigger guy wins. I certainly hope she did not feel discouraged. I am not fan of competitions for this very reason – it is not only a test of skill, there is always a lot of variables outside of anyone’s control that can affect the outcome.

And the most memorable point is that in the last match a sword breaks (32:39). What is interesting about this is that it does not break at the striking point, but just near the handle, at the strongest part. Given that this sword was made from modern steel with modern technology one has to wonder how often did swords break in the past?

Making a Rondel Dagger – Part 5 – Bounce

I lied to myself when I said that I will continue even though the blade might not be hardened properly. I just could not do it. Even though the knife will in the end be just ornamental thing, a wall hanger that will never be used, I could not bring myself to making a knife with improperly hardened blade. So I had another go at it. Fail again, the steel was still soft and it was not only surface – I tried to break of the tip and it bent and straightened as if it were copper. So I had another go at it, using water as quenchant – a big risk because in high carbon steel this can lead to the blade cracking or even exploding into bits. Fail again, it remained soft.

At this point I had to reconsider. I was convinced that I did everything correctly, testing with magnet for the austenite transformation etc. and I am already relatively good at assessing the temperature by the glow color, so I did not think the failed quench was due to wrong temperature. The quenchant also could not be the problem, since I hardened three blades in it without problems and one at the same time as this one failed.

So I surmised the problem lies in the steel. Perhaps it was surface hardened file and when I did the test with ferric chloride I had all the hardened steel ground off already, so it could not show in color. Or perhaps I burned off the carbon due to the not-so-well functioning protective coating. I consider the first option to be more likely. Anyway, I could throw this blade away and start anew, or I could do what I mentioned before – surface harden it.

Theoretically this makes for a very good dagger, because under the hard and brittle surface remains soft and tough steel, which means the dagger would not break easily when hitting something hard – like an armor. But it is a long process that burns through a lot of charcoal with results unsure. And the layer might be too thin and get ground off during polishing.

I succumbed, knowingly, to the sunk cost fallacy and decided to go for it in an attempt to save the blade. This is what I have done:

Cleaned dagger blade

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First I have cleaned the whole blade thoroughly with angle grinder and a twisted knot wire brush wheel. After that I also scrubbed the whole blade with abrasive pad (similar to Scotch-Brite, only different manufacturer). Whilst doing this I noticed that the blade got slightly blotchy and pitted, so there was definitively more material burned off than I am happy with. Inevitable after three failed quenches. Theoretically quench could be attempted infinite amount of times – but practically the blade would burn away pretty soon.

 

 

Blade packed in charcoal

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Secondly I took my limited supply of stainless steel foil and wrapped it around the blade forming a little trough. Not wanting to perform more than one experiment in one project I did not experiment with the hardening material and I used powdered charcoal. Any organic material would do, really (sugar works extremely well I might add, and in the future I intend to experiment with bone dust and various mixtures from easy to get chemicals), but they give blotchy, coloured surfaces, and with charcoal I had a best shot to get evenly hardened and evenly coloured surface.

 

Package enclosed

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After filling the trough about halfway with the powder I crimped very tightly the edges, folding them twice and pressing the folds together in a vice. It is important to get the package as air tight as possible. But the tang was not packed in, because that was supposed to remain soft. Thus prepared package was now ready for heating. For this I have used my improvised setup build from fireclay bricks, but without forced air supply (a fancy way of saying I left the vacuum cleaner in the workshop). I filled the fireplace with charcoal, buried the package in it, lit it and left it to its own devices over night. Under an impromptu cover because it was raining.

 

The next day the package was burned through near the tip, a bad sign. But the charcoal dust was still all in there and it did cling to the blade very nicely – I had to scrape it off. A good sign. But I decided to repeat the process once more just to be sure.

Today, after I returned from work, the weather was again good so I could have another shot at quenching this cursed thing.

And it is a success. The blade is hard as glass on the surface and there are no cracks that I see after cleaning it with wire brush. I hope no hair thin cracks shows later on.

Tomorrow the blade goes into the baking oven for heat treatment 150°C half an hour. Maybe two courses.

Poor Man’s Belt Grinder – Mark 2

As I was saying last time, I have given my belt grinder a complete overhaul.

Since now I knew that I can do it and it will work, I was not so stingy about spending money so I bought for about 50€ a few beech wood profiles 50×50 and 50×30 mm, some new ball bearings and a few other thing.

First thing I have done after that was to remove the belt support and compeltely dismantle the idler wheels. I have rebuild them. Instead of using threaded rods throughout I used about 100 mm length of a 10 mm rod on which I cut thread on the ends – on one side just about 1 cm each side . This has provided better fit with the inner opening of the ball bearings. I also shortened the inner spacer between the  ball bearings so that I can sink in the nuts inside so it and the rod are flush with the wheel edge.

This has allowed me to to fix the wheels on the future idler on only one side, so I fixed them perpendicular to 50×30 profile and after that I got distracted.

Latch

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The distraction was the spanning wheel, which I did not intend to rebuild. But changing belts was a bit awkward – I had to pull on the lever with left hand and change the belt with the right hand. And I got an idea on how to improve that. So I have built out of plywood a gravity latch that falls into position when the lever is pulled beyond certain point. That frees both hands to put on the belt comfortably and without hassle. When the belt is on I lift the latch, the spring spans the arm and after I let go the latch end lays on the top of the spanning arm without restraining it.

Idler

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With that done I returned to the idler. Whilst I did spend some money on good materials, I did not spend too much time with planning except in my head. So I was still working by mostly piling stuff on other stuff making it up as I go along. I did not bother with precision too much and relied heavily on epoxy to fill any gaps and I added dovels and sometimes screws for strength

The only thing that I actually have spent some time to make precise was the parallelity of the wheels.

On the idler I prepared two screws with wing nuts for fixing the platen, and on the other side are two screws for fixing the support table (not seen here, but the positions are the pale circles in the lower half).

With that done I have cut two platens out of an old U profile that was rusting in my garden for years. Here is the final setup with all threee options visible. Left is setting for 20 cm hardbelt, middle 12 cm hardbelt, 10 cm slackbelt and right is 24 cm slackbelt.

Belt support options

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After this was done and tested – which I have done by truing the platens by alternating them as support/workpiece against each other on the grinder – I gave the whole thing a new coat of paint. The machine blue and the detacheable idler arm pale grey.

Belt grinder

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

Belt grinder

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

It is Amazing how a simple paint can improve the looks of things, isn’t it? I am glad to say that it all works as intended.

Next step is to make second detacheable arm with changeable wheels of different diameters, for hollow grind an fullers.

Making a Rondel Dagger – Part 4 – Hardening

Today, after finishing with my bonsai trees for now, I got an hour or so to use and get a shot at hardening the blade.

I was so stressed from working almost non-stop the whole weekend and trying to manage to replant all my outdoor bonsai trees that I forgot to take pictures of the process and only could take pictures afterwards. So here is a picture of my setup. I was hardening two blades.

Blade hardening setup

Blade hardening setup.

Slight  contrast with Marcus’s fully equipped workshop I guess :-). On the right is gas mini-forge where a future kitchen knife was heated up most of the time, on the left is a charcoal fire between fireclay bricks for the dagger and in the middle is quenching oil. This is the main reason why I cannot harden blades in bad weather – I have to go outside to do it.

And here are the blades after hardening and before tempering, covered in burned oil and, in the case of the dagger, slag and scale.

Blades after quench.

Blades after quench.

I am not all together sure It was a complete success. I am sure it was a 50% success. I definitively successfully hardened the kitchen knife. Which is slightly strange, because the kitchen knife is made from N690 steel that is allegedly difficult to harden in impromptu settings, whereas the dagger is simple carbon steel that should have been easy-peasy. The kitchen knife is completely without deformation, the dagger got a very slight bend that I was able to correct after tempering the blades in kitchen oven at 150°C for an hour. In fact, it was maybe too easy to correct. File skids on the kitchen blade like on glass, but it is possible to make a shallow bite with it into the dagger.

The problem might be that I tried to coat the dagger with an experimental anti-scaling solution that unfortunately did not work as intended. Back to the drawing board there I guess. So it might be that the blade is hardened, but a few tenths of a mm on the surface have slightly lowered  carbon content due to decarburization. The N690 steel blade was not covered in the solution, but was covered with stainless steel foil that burned through towards the end.

I have no way to measure the hardness of the steel, and I am probably not going and try to re-harden the blade. I will proceed and we will see what comes out of it.

Making a Rondel Dagger – Part 3

All of my garden has woken up, but none of the figs or pomegranates have shown even a budding leaf. I got so disheartened at this that I had to go and do something fun. So I went to work on the dagger to lift my spirits at least slightly.

I have decided to grind the bevel higher up to the spine, but not the same way along the whole blade – I ground less towards the tip so it remains strong. This has meant that the blade has a bit complex geometry which meant I could use hard belt most of the way, but I had to switch to slack belt for the tip. Luckily I have kept the option of half hard/half slack belt setup on my improved grinder.

I also ground the spine at approximately 45° angle to take off some weight. But again not all the way to the tip, so the tip is reinforced.

After I ground this basic shape It took me about an hour to get through four ceramics belts (60, 80, 100, 120) and the final was a zircon 120 grit where I stopped. This is actually a fairly difficult and delicate process and it is still possible (nay – easy) to mess up the lines and irreparably ruin the blade geometry, so easy does it. Because I am not too experienced with the belt grinder yet I had a few heart-stopping moments, but I managed to correct all the blunders in the end. From my previous works I know I have to be extremely careful up to approx 600 grit. After that messing up the lines in hand is not possible. But on my previous dagger I found out that on belt grinder that level moves up to 1000 grit, possibly 1200.

A lot of eyeballing was involved. After certain point I could no longer use the masking blue color and scribing tool, so to check whether my grind is symmetrical I used a folded piece of paper that I cut with shears to two aligning points. When I folded it around the blade  I could see whether the lines are in the same position by putting the point on one side of the blade  on the line and checking the point at the other side. After the final grind I scrubbed the blade lengthwise a bit with coarse abrasive pad to remove the quickly building rust and to scratch through the grind marks.

Ground blade shape.

©Charly, all rights reserved.

The future cutting edge is now approx 1 mm thick. Next step will be hardening the steel. For this I had to check whether this file was carbon steel throughout or case hardened. That I have done before polishing the whole shape by dabbing the spine and one side of the blade approx 5 cm from the tip with  ferric chloride because in this area is preserved steel that was near the surface of the original  file as well as steel that was deep inside. If the file was case hardened, the steel that was originally near surface should turn grey, while the steel that was deeper should be shinier. If the file is carbon steel throughout, it should all turn grey.

It has all turned monotone grey, so it is carbon steel throughout. That is good since it makes the hardening process easier. It is possible to make a cutting blade from case hardened file, but it requires to perform again case hardening, which takes more time and resources.