More details of the gingerbread eggs from yesterday – the backsides.
The eggshells are baked on a special form. Before we had that, we baked them on impromptu shapes made from alluminium foil with the help of a spoon. but the results were mixed.
More details of the gingerbread eggs from yesterday – the backsides.
The eggshells are baked on a special form. Before we had that, we baked them on impromptu shapes made from alluminium foil with the help of a spoon. but the results were mixed.
I have realized that I did not post any of my mother’s gingerbread creations last year. At easter I simply forgot, and on Christmas, I did not use PC at all. So I am going to rectify it over the next few weeks, a few pictures at a time.
Let us start with those from easter.
These are my recollections of a life behind the iron curtain. I do not aim to give a perfect and objective evaluation of anything but to share my personal experiences and memories. It will explain why I just cannot get misty-eyed over some ideas on the political left and why I loathe many ideas on the right.
“Zlaté české ručičky” (Golden Czech Hands) – a self-flattering saying that Czechs like to say about themselves for fairly long time. I was not able to google-fu the origin of the phrase, but one of the speculations I believe the most is that it originated during the times of the Iron Curtain.
I have already mentioned the centrally planned economy and the many negatives it has lead to. But I did not mention one of the at least somewhat positive things – the widespread ability to get the most out of whatever little there was available.
For example one of my uncles wanted to have a gramophone, but those were hard to get by. So he scraped and scrounged parts from defunct gramophones and has built a functioning one out of them. He also has built two high-quality loudspeakers for it – and they worked and sounded good for a long time. Previously he also has built a simple radio. And a bicycle from parts.
This uncle, a Ph.D. mathematician, has emigrated to USA when I was only about six years old and he took this mindset with him. He married a Korean-American woman, whom I have met in 1999 during my only visit there. One of her complaints about her husband was that she rarely gets to buy new stuff, because whenever something breaks – be it TV, vacuum, microwave or a kitchen robot – he repairs it. And indeed all these items around the house were visibly repaired.
I have this mindset too. I wanted a nice sturdy knife to take with me on forest walks, but they were expensive and hard to get by, so I have made one. I am not as handy with electronic as my uncle is, but have repurposed parts from his old radio project and used the speakers for building myself high-quality horn-speakers. And many other things.
But around here, this was not exceptional. Every man had to be a handyman, knowing a bit about electronics, plumbing, carpentry, masonry and, if you were lucky, car repair and maintenance. Because when something broke in the household, buying replacement was often not an option and getting a professional to do the job for you was not easy or fast enough. Of course, some were better at somethings than others, and a thriving black market of skills has emerged. Indeed the only way to thrive was to have a network of skilled friends or you were screwed.
Towards the end of the regime, in 1987, there emerged a TV show dedicated to this kind of “DIY” thing, named “Receptář nejen na neděli” (Recipe book not only for Sundays), whose spinoffs and follow-ups run until today under different names. There was also a periodical of the same name as the TV show, another periodical “Udělej si sám” (Do It Yourself :-)) and even one of the periodicals for children that I have previously mentioned (ABC) had sections dedicated to small crafts.
Today there is a lot of moaning about how this aspect of our culture is slowly disappearing. The availability of cheap goods on demand did lead to a decreased need to be inventive and frugal. Some of the moaning is just that – the regular moaning about the corruption of youth and the good old times – but some of it is to my mind justified. Indeed when working in Germany, I was often able to come up with creative solutions to some problems with the things I found in a drawer, exactly because that is what I was used to doing, whilst some of my colleagues were content with listing through a catalog.
I think that being poor is not a virtue, but being frugal and inventive is. The only problem that remains is how to raise inventive and frugal people when being lazy and wasteful is easier.
First I must say that my writing will continue to be very, very sparse for about two weeks (again). I think I finally found out what is wrong with my hands. I had a pain in my metacarpal bones and joints ever since I worked a bit too much in a too short time. Sometimes it almost went away, but then it came back with a vengeance whenever I did some work. The orthopedist has made an x-ray and has ruled out arthritis, and I have not visited a doctor since because it got multiple times better to the point I thought I am OK.
I think I know what is wrong – I think I have started to develop stress fractures. Those are not visible on x-ray until they develop in a full-blown fracture.
And whenever they almost healed, I did something to aggravate them again. There is only one cure for that – several weeks of no-strain. And due to the nature of the injury, that also means no-excessive writing on PC, no grinding knives, no cutting or splitting wood, etc. I have tried consistently this last week to do that and today and yesterday I was again almost pain-free. But I think I need to keep it up for at least two more weeks for the bones to recover completely. If that does not help, then I am going to the doctor again to try and find out what the hell it is.
What I could safely do was to coat the knife handle with boat lacquer. And this weekend I started, carefully, working on the sheath.
First I have cut the two slabs for the sides and then two strips for the belly and the back. To get the strips to conform with the blade geometry I did not cut them curved but I formed them from a wet leather strip. When it dries, it holds form nicely and it saves material.
The next step was to glue everything together with wood glue. In case you ever do this, beware. Wood glue on dry tanned leather works really, really fast. Not superglue-fast, but fast enough for you to want to be sure that when you press the parts together, they are in the correct position straight away. Wetting the leather beforehand might give me some time, but I did not want to do that because the clamps would leave impressions in it.
I have let it dry for a few minutes, then I took off the clamps and I inscribed a line with a knife-tip for stitching and cut the opening for a belt. In case you are wondering why there are round punched holes at the end of the cuts – those are there to avoid stress concentration and thus to prevent the leather from tearing further when used.
Now I leave it to completely dry until tomorrow evening. In the meantime, I am trying to figure out a way for making my maker’s mark on the leather. I could cut it, but that seems a bit inelegant.
The HDD magnet proved to be very useful when polishing the bolster/handguard. It proved to be strong enough to hold it when grinding on the belt grinder, but also when polishing with the angle grinder. I did not intend to use the magnet in this way, but now I will because it has proven itself to be extremely useful for holding these tiny things steady. Shame that other metals that I am going to use for these things – aluminium and brass – are not magnetic.
The next thing I have done after the bolster was fitted was to make the handle. That did not go too well as you may remember. The first piece of wood had cracks, on the second piece of wood I messed up the drilling and the third time was the charm. It is a nice piece of wood and looks great when the grip is fully shaped, but I do wish that I have managed to get the grain alignment a bit better. But grain alignment is not something that anyone else fusses about that much, so I should not fuss about it either. Here you can see the grip roughly cut and shaped on the belt sander.
After the grip was shaped, I have also glued to ti the end cap/pommel thingie and I have decided to sign the blade before assembly. For that, I have tried a new thing, which unfortunately completely and utterly failed.
I have bought photosensitive lack that is used for etching PCB boards. The idea is, you spray-paint your metal surface, you print your design, you put your design on the surface and use UV light to quickly deteriorate the paint on illuminated areas. Then you wash out the deteriorated paint with a 1% solution of NaOH and voila – you can etch.
The paint did not deteriorate under UV lamp as advertised and the NaOH solution did not wash it out of the illuminated areas. I have followed every step of the instructions, multiple times, and it just did not work. So I tried to increase the NaOH solution concentration – and it washed off all of the paint. So until and unless someone shows this particular product to me to work, I am considering it an unfortunate waste of money.
I do not want to make my signatures too big, and I want to number the blades from now on, and the wax is not very conducive to tiny fine details. So I had to revert back to how I did things in the past, with slight improvements. I have covered the blade with plastic adhesive tape. But this time I have used double-sided tape on the parts where the signature and numbering were due to go, and then I glued to it one print of the now useless stencils for the failed photo etching. Then I cut out the letters with shaving razor and a pointy scalpel blade.
Because I did not want to damage this blade, I have first tested this new technique on the failed machete (that fail has proven quite useful, I have hardened piece of steel for experimenting).
Etching in a cup with solution works, but it takes a lot of space and a lot of solution to immerse the whole blade. So I have built myself a new thingie that allows me to perform etches with very little solution.
I took a piece of graphite and ground it flat to about 20x30x5 mm. On top, I glued a piece of wood and covered it all with excess epoxy glue to protect it against moisture. The next day I drilled a 6,5 mm hole into the wood down to the graphite. Lastly, I took a piece of 8 mm brass pipe, cut M8 thread in the hole and on the pipe, and I screwed the pipe into the hole so far that it has a solid connection with the graphite.
For the etching itself, I have simply put a piece of felt soaked in diluted FeCl3 solution on top of the design, between the blade and the new graphite electrode. Anode (+) on the tang, cathode (-) on the brass pipe and after five minutes the job was done. The etchings are clean and nice looking.
Just like last time, I have no pictures of the assembly. Imagine me slathering epoxy mixed with wood dust all over the tang, hammering the handle onto it and then peening the end of the tang whilst being in a constant state of panic that something goes wrong. Nothing went wrong, although I am not happy with how the peen turned out. But the customer did accept in advance that peened tangs can be a bit unseemly. Even unhardened stainless steel does not like to be peened and tends to crack around the edges. And I did not dare to try and weld soft steel stud at the end of the tang, this steel allegedly does not weld well. But maybe I will try something different for the second blade. This one is unfortunately stuck with this, although it might get a bit better with some more polishing.
So the knife is now more or less finished and functional. The last thing to do is to clean and polish the wood to about 300 grit and then impregnate it with boat lack.
What I find the most interesting about his video is the realization that our modern perceptions of what is and is not beautiful are heavily skewed towards unreasonable and sometimes unachievable perfection. Sometimes perfection that you can only evaluate up so close, that you need a magnifying glass and calipers.
I blame the industrial revolution and mass-produced machined goods.
I have decided to buy some new thingies for the ole workshope, and they arrived this week.
The thing that I was most looking forward to was a new respirator. The one I use these last few years has some serious issues – the strap that goes around the head is just one strip of elastic and it really hurts when worn for a longer time. I also have problems with sealing – but not around the beard as the manufacturers of these things like to warn, but around the nose, where it is too wide and soft. The new one seems to fit well, but I did not get around to test it in action yet. The load on the head is spread on two solid strips so that should be better too. Here you can see my staring into the void wearing that thing. It does feel quite comfortable, today I shall see how it feels when worn longer and doing actual work.
Another safety-related thingie that I bought is a stand for my angle grinder. I have been mulling this over for about a year but decided finally to buy it because by coincidence I have seen it at my friends’ garage and he confirmed that it does in fact work as advertised and is compatible with my tool. It is assembled now, but it probably won’t get into any real action before the next batch of knives.
When at it, I also bought a mini-vice with a swivel ball joint at the base. I hope it makes manufacturing and finishing of fiddly little things easier. It came right with plastic soft jaws and at a glance seems to be exactly the thing I have needed for a long time by now.
There were other small things in the packet not worth extra mention, but one other thing is. Unexpectedly I have also received a nice big package from Marcus, who was so very kind and has sent me two pieces of steel rope damascus and a piece of stabilized maple to play with. That is simply grand, because it will take some time before I can make my own damascus (if ever) and stabilized wood (on that one I am more confident). So big thanks to Marcus, after my currently running projects are done, I already know what will come next.
I am realizing that instead of pretty pictures I am serving you mostly things from my workshop but as you can imagine that is where I concentrate most of my effort these days and I did not have time to play ft with my camera for quite a long time by now.
Hell isn’t forever after all. Today I have finished both blades and for the second one, I opted for a satin finish. Not because it is easier – it is not – but because I wanted to see the difference and decide what I like more for the future. Well, I am still undecided, but I can see the difference. And so can you, although it was not easy to think of a way to photograph this.
The satin finish was made by me not going to the finest buffing compound. Instead of that, I went for a fine abrasive pad right after the medium buffing compound and I dragged it along the blade a few (hundred) times. And I probably will do some more.
After the blades were finished, I have decided to sharpen them. I probably will sharpen blades before assembly for several reasons. Firstly I like making apple seed (convex) edges, that give the blade look as if it does not have a secondary bevel at all. For that, I might need to re-buff the blade a bit, and that can only be done before the handle gets in the way. Secondly, should I scratch the blade by accident during the sharpening, it is easier to re-polish it before assembly. So whilst I do not necessarily sharpen the knives to shaving sharp at this stage, I do sharpen them to some 90%.
This steel (N690) should not be sharpened at an angle steeper than 15°, steeper than that and the fine edge allegedly tends to break off. I have no reason to doubt this since the blades are hard as hell. This time I have a way to get a really nice and consistent angle – I could use my magnetic jig. So I did. The N690 is steel with so-called “secondary hardening”, so it is basically nearly impossible to overheat and destroy the edge during sharpening. Nevertheless, I took care to take my time and not overheat it, it does not pay to get into bad habits.
You may see that there is no platen behind the belt, so I am using a slack-belt setup here. That means the secondary bevel will be concave and the cutting edge itself will be sharpened in fact at an angle a bit higher than 15°, which is ideal for a hunting/camping knife of this type. Convex grinds are very durable – the knife that I have made for my mother needs sharpening only about two-three times a year despite being used and abused daily.
Speaking of that, when I was at it I also sharpened all her kitchen knives. Those took just one-two very quick passes on the slackbelt and then a few passes on my stropping wheel (made according to Walter Sorrell’s video)
Your eyes do not deceive you, that grinder with the stropping wheel is back-to-front. For stropping, the wheel must rotate in the direction of the edge, not against it, because it is softer than the blade and if you try stropping against the edge, the blade will bite into the fast-spinning wheel and dire consequences will follow. Having the grinder backward allows me to work on the upper side of the wheel, so should it grab the knife and throw it, it will hit the wall and not my leg or the concrete ground. I find it also a lot easier to strop the blades that way.
The stropping wheel gets the knives to scary-sharp in mere seconds. I am using the coarse stropping compound, in my opinion, it makes a better edge than the fine ones.
Now the blades are polished, nearly completely sharp and wrapped in masking tape. It took me three times more time than I think it should and about 30% more than I thought it will. But now the most time-consuming and nerve-wracking part is hopefully behind me and next steps will be free of trials and tribulations. Or at least with significantly shorter ones.
This weekend I only could work for about 4 hours on this project, but I have finally managed to finish one blade.
I am not happy with it. Like, at all. I could have done a better job, and I have done a better job in the past. I just could not get into the thing at all. I kept making mistakes, and whilst to make a mistake on belt grinder takes a split of a second, correcting it can take hours. After 400 grit I went to hand-sanding. It is more strain on the fingers than the belt grinder, but a lot less space for a mess-up. And therefore I was, paradoxically, suddenly a lot faster. I might switch to hand sanding on the other blade sooner.
After 1000 grit I went for buffing wheels. Buffing a blade like this is not optimal and if I did not mess up the grind on belt grinder so often as I did, I would not go for it and I would polish it up to 7000 grit sandpaper. However buffing has one advantage, besides being fast – it hides and smoothens slight imperfections on the bevels by ever so slightly rounding up the ridges. Which is also the reason why I normally would not go for buffing for a blade like this.
This is the blade that goes to the customer. Next weekend I will hopefully finish the second one and then I can start on the accessories.
But after I am done with currently started projects, I will definitively make a batch of these. It is a complicated shape, and thus an excellent exercise.
Last time this part of the process gave me some grief and I also have expressed some skepticism with regard to how much time it takes me. Yesterday I have calculated that unless I get this time under 12 Minutes per blade, it is not worth doing from a financial point of view. So, how did I fare today?
I had 13 kitchen knives and 2 hunting/camping knives to for hardening. I wanted to harden one half in foil and one half with a new experimental protective coating, but I only got enough foil for five blades, so I used it for both hunting knives (those will be sold, so those were more important to not mess up) and three kitchen knives. The rest got the new experimental protective coating.
I started by properly preparing my workplace in order to not needlessly waste time. On the left, you see a can with oil, a water bucket, several pliers and the blades. On the right is my mini gas-forge on my circular saw table, which is metal and thus non-flammable. I had to work indoors, there was a threat of homeopathic rainfall.
First I let the forge heat for fifteen minutes empty and then I started to put blades in it. In order to give the steel the soak time it needs (30 minutes), I started by putting in one blade every five minutes, always putting the last blade on the left side, pushing all the blades inserted before that to the right towards the burner. After half an hour I could quench the first blade and I continued with 6 blades in the fire at once.
Unfortunately, just like last time, the temperature was a problem. I tried to insulate the forge a tiny bit better, but it just did not help, this burner is too small. I got over 950 °C, but that is still some 70°C short of the minimum for this steel. It got hardened alright, but probably not to the fullest potential. That I will not know until I have cleaned and tested the blades, and that will take a while. So far I only could take each blade and try if it scratches into a piece of unhardened steel – and they all did. (A side note to temperature measurement – I tried to look it up, and oxidized steel at this temperature has an emissivity around 0,9, so my IR thermometer should give accurate enough readings in default settings.)
I knew that my oil container is a bit small, so the oil will heat up way too much in due course, that is why I quenched the blades double – first in oil, then in water. That way I also extinguished any flaming oil clinging to the freshly quenched blade. It is a bit risky, but I did not hear the tell-tale cling of the cracking blade this time, so maybe I got away with it. We will see if some cracks show later on.
Hardening the blades in foil was a bugger. For the kitchen knives, I pulled them out of the foil before hardening, and they all warped in quench something awful. The camping knives got quenched still in the foil, and they surprisingly still got hardened rather well. Maybe the next step has helped? I do not know.
For the next step directly after quenching (after quenching all blades, which took me 2:25 or 145 minutes) I packed all pieces in plastic foil and gave them into our freezer at -20°C. Ideally, I would put them in liquid nitrogen to cryo-freeze them, but I do not have that kind of equipment to play with. So I looked at the internet and I found that in some steels of similar composition simple freezing below 0°C is enough, so I reasoned – it costs me no money and no time either, so on the off-chance that it does something I will do it. I have no way of measuring whether it helped or not, but it did no harm for sure.
After about two hours in the freezer, the blades got out of there and into the kitchen oven at 150°C for 1 hour.
After that, I left them cool down to room temperature and when they cooled off and lay for one hour at RT, I tried to fix the warpage on the three kitchen blades by clamping them between a few pieces of steel before the second tempering, which was again one hour at 150°C.
It did not help, the edges remained warped. So I clamped them again and tomorrow these three blades go into the oven again, this time at 200°C for one hour. That means they will be less hard still, but hopefully they get a bit straighter.
If not, then what I have here is a case of “knifemakers do not make mistakes, they make smaller knives”. The mistake that I did not make this time has, in my opinion, nothing to do with the use of protective foil, it was in my opinion just a coincidence that all foil-wrapped knives warped. I think I have simply ground these blades too thin – remember how I complained about my abysmal skill with the belt grinder?
At least I had no banana-bending to one side, which means that my grinds were symmetrical.
The protective coating actually did dissolve significantly in hot water this time, so I think that I am on the right track there.
And what was the time? All in all, with packing some blades in foil and coating some with badly prepared mixture whilst chatting with my brother and my sister in law, and preparing and cleaning away the whole workplace, it took me about 15 minutes per blade. That is an excellent result. 75% improvement compared to the last time. I think with a few more tweaks I can actually really get this to the 11 minutes per blade that I need. I am not there yet, but I think it is possible.
The next part is the polishing. The biggest time-eater and finger-breaker of them all.
I did not expect to get a commission this early. I am not quite there yet to be able to make a good quality knife in a reasonable time. I am confident I can get the “quality” part right, but time – definitively not. My original plan was to perfect my manufacturing process with the kitchen knives, which, if you remember, I have left this spring at a phase where the outlines of the blades were established, but nothing else.
But I need to work on both projects now because apart from the time I also need to use my resources – electricity, propane gas and charcoal – in a more economically savvy manner. That means hardening multiple blades in one go for example. And that means I have to establish the primary bevel grind on the commissioned knife as well as on the kitchen knives so I can harden and temper all those blades together.
But the whole point of the kitchen knife project was to develop a viable manufacturing process, and establishing the primary bevel was the part where I knew I have to develop and build a fixture first. You have seen my very first attempt. It did work, but not very time-effectively, I wasted about a minute each time I needed to flip or change the blade. That is a lot, considering that for the basic grind I need to go through five belts on both sides. It was clear I need some way to hold the blade steady, but being able to dismount and re-mount it quickly.
The second attempt was this.
The idea was that the hinge and two screws will allow me to set the tilt, and the knife-blank can go into the slot where it will be held by the levered screw. It did and did not work. That is, it worked for one knife and then it broke. The problem was moisture which caused the wood to deform and split. But even without that, fixing and releasing the blade was still not as easy as I would like it to be. I got an idea on how to improve this design, and I already bought the materials to try it out, but then I got sick and everything got put on hold for a few months as you know. All I could do was to think about it.
And then my parent’s hard drive died and I got the idea to use those strong neodymium magnets. But for that, I need first to develop a system on how to switch them on/off, and that needs more time than I can spare right now for fooling around. The customer is not in a hurry to get the knife – they know I still have my day job and that I can only do this in my spare time – but still I think I should not strain their patience. So I needed a fixture, fast.
Luckily I got an idea utilizing things that I already have – the first attempted fixture and a few cheap, weak magnets. There is a way to make weak magnets a lot stronger, at the cost of reach – by concentrating the magnetic field to one side with two slabs of iron/mild steel. It is also possible to make longer arrays with this system.
So I took six of those cheap magnets and cut nine pieces of mild steel exactly as long as the magnets, but a few mm wider. Then I covered a piece of steel with masking tape and glued the magnets and steel together into three blocks, each consisting of two magnets and three pieces of steel, with the magnets facing each other with the same pole. That means the magnets oppose each other in the middle of the array, forcing the magnetic field of each magnet to the side.
The masking tape has stopped the magnets from glueing onto the steel, and the steel was there to get nice alignment on the backside of the arrays. The frontside has the steel pieces overlap a bit, and the spaces were filled with epoxy and sawdust mixture.
Whilst the epoxy was curing, I took the first wooden fixture and attached a long strip of aluminum to it for the spine of the knife to rest against, and I chiseled out three spaces for the magnet arrays to be glued into. After the epoxy has cured I ground the front faces nice and flat and glued the arrays into the wooden block, again with using a piece of steel covered with masking tape to hold all three on one plane. I used a lot of fast curing epoxy that day, all the while completely forgetting to take pictures of the process. So the next picture is the finished fixture with a knife blank attached to it.
To get the tilt the fixture has four screws on the downside (up in the picture, not visible).
And the fixture works. The magnet arrays are strong enough, but not as strong as neodymium magnet arrays, so it is still possible to comfortably detach the blade by hand. It allows me to apply a lot more even pressure on the blank, for a longer time without cooling it because I do not burn my fingers (temperature not being of concern at this stage). There is still room for improvement – the aluminium stop is a bit too fat for kitchen knives, the screws for tilting do not provide stable enough support and they are a bit finicky to get right. But you can see it allows for making nice, flat and even grind.
Added bonus is, that after two hours of grinding not only did I do more work than before, but also my fingers hurt a lot less because the fixture gives my hands more material to hold onto. I am definitively going to use this a lot, and perhaps there will be other uses for this concept as well. I have an idea for sharpening gizmo in my head for about a year by now…