Our Amarylis has blossomed again this year, and I learned that it is not Amarylis but Hippeastrum.
Skull base is really more interesting than the shell that covers our bulbous brain lobes. This is where our brain stem resides, the evolutionarily oldest structures in our central nervous system that could be called “brain”. That means that here are the exits of most of the brain nerves and, of course, the spinal cord. Here also enter and exit all the blood vessels supplying the brain with oxygen.
Profesor Kos has put a great emphasis on the fact that here is the position of the brain stem, because any damage to the brainstem is most likely to be lethal. And what he constantly warned about was the danger of hemorrhaging in this region, which can occur after even superficially mild concussion. He mentioned the absurdity of movies and media in general portraying hitting someone in the head as a routine way to knock someone out. But it is extremely dangerous, especially hits delivered on the top of the head. A hit on the top of the head transfers most of the force right down to the base of the skull and if it causes there a damage to even a small blood vessel, it can mean game ever.
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.
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.
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.
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.
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.
Rathaus has of course nothing to do with rats, unless you mean politicians. Which would be insulting to rats, I guess. Rathaus is from german words for a counsel (Rat) and a house (Haus) and means town hall.
The building is nothing extraordinary in the context of the town, but to the right side of it is a beautiful gate to the castle. Unfortunately you can only imagine the gate, because it was being repaired at the time of our visit so I could not take good pictures of it . And I did not have time to spend with the various plaques around the staircase either.
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.
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.
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.
These are my recollections of a life behind the iron curtain. I do not aim to give 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.
Content warning, graphical description of illness.
Ever since childhood my health was not great. I was allergic to almost anything one can be allergic to, I got sunburned in an instant and to add insult to injury I was wearing glasses. Twice I got blind due to allergy – once when mosquitoes bit my face and it has swollen so much that I could not open my eyes, and once when we were outside with school class and the teacher has allowed us to go into a field of rye. Where a piece of awn got stuck under my eye and again caused my lids to swell to the point I could not see. I had to be led out of the forest by my classmates, and we had to keep in shade because light has made my eyes hurt like hell.
That was not the worst of it. At early age I have developed chronic tonsilitis. It could be treated with antibiotics, but it did not work in the long run. The illnesses came more and more often and a pattern has developed – two to maybe three weeks of relatively normal life, then suddenly my neck tonsils got swollen and I vomited pus and congealed blood during the night wishing I die. Then I developed fever and I could barely eat for a week during which I was on the antibiotics. After the antibiotics (penicillin mostly) have done what they could I was weakly for another week and I had to abstain from any physically challenging tasks and I was excused from gym classes.
Thus about two years have passed in this rhythm. My growth was stunted and I was not behind in school only thanks to my high intelligence and a help from our neighbour’s sister, who was a teacher and tutored me one year during my illnesses.
The problem was of course that I should have been sent for tonsilectomy after the second or third bout of antibiotics at the most. The children’s physician for our district insisted on not doing this because it might, in her words, cause asthma later on. So when the antibiotics did not seem to work in the long-term after years of torturing me, she tried to prescribe a “preventional” course of penicillin, where I was taking half a pill each day. Needles to say this did not work at all, quite the opposite. I developed an allergy to penicillin and another antibiotic had to be used from then on.
She also tried to send me for a month on a recuperation vacation stay in the mountains. Something that was intended for children living in smog-covered cities. Needless to say it was useless for a country kid and I was sick during that vacation too.
My parents have only vocational education and they lacked the knowledge to challenge the physician’s authority. They did the right thing – they delegated the problem to the expert. Unfortunately the expert was an idiot. I do not blame my parents in the least, but I refuse to greet the physician on the rare occasion I meet her although she seems to think I should like her. She should have known better.
I had a stroke of luck in that I almost died and when my parents had to call an ambulance, the arriving doctor was the general practitioner for our district. And he was competent so he explained to them that the antibiotics are now doing nothing for me and are only de-facto poisoning me. And that tonsilectomy is the only viable long-term option. After I got tonsilectomy, the last in a long string of tortures, I could not eat properly for a few weeks, and I had to avoid some foods for a few years, but the wounds healed, one tonsil even grew back, and I only had tonsilitis once or twice ever since and never as serious as it once was.
My story highlights both the strengths and the weaknesses of the system.
First strength was accessibility. Each district had a general practitioner, gynaecologist, dentist and children’s physician that rarely were more than two bus-stops or half an hour walking distance away. Hospitals were relatively regularly dispersed, so the travel to one was not too long either. Getting to a doctor was usually not a problem. The same for apothecaries. Whenever I was sick, we could mostly just walk to the doctor and pick the medicaments on the way back.
Second strength was availability. My parents did never need to worry about the costs of any of this. Everything was paid for in taxes, and everybody had available all the care they needed (even the dentist). And they got paid leave to take care for me whenever needed. That does not mean there were no economical decisions made – some rare illnesses might not be treated because the costs were too high for the state to afford. But nobody had to worry about slightly complicated flu bankrupting them, or having their teeth pulled out because they cannot afford the repair.
But the weakness was that people had their assigned physicians and there was no real choice. There was no “second opinion” really available and people did not even know that such thing exists. So if your physician was an idiot, you were foobared.
But I still think that this is one of the things the regime actually got mostly, even though not completely, right.
I avoid business travel like the plague, but it is unavoidable sometimes. This week thursday I have spent in the beautiful town Idstein. Most of the day was of course spent with traveling to the location and then spending a few hours with the actual business, but we managed to finish at about 4 p.m. so we had still plenty of time to have a look around the town.
I knew I have to expect some splendid medieval architecture, but I did not take my camera with me because… reasons. So I had to do with my phone which luckily is up to the task of making passable pictures in good light. And the light was splendid. The spring did not come this year, winter morphed directly into summer. Only shadows were a little long because of the time of day, but I think you will all enjoy the architecture nevertheless.
For starters here is the town square near the hotel at which we resided.
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.
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.
The blue tits seem not to mind that I fell the cherry tree and hung the nesting box on the plum. I see them daily there and they sing in the tree, so I think they are nesting there even though I have not seen them entering the box. What was my surprise then when I looked at this picture and I saw one blue tit and one field sparrow with a bunch of feathers in his beak. A few moments later I heard some squabbling and the fluff floated down from the tree. Maybe the sparrow was stealing bedding from the tits? These tiny birds are pretty mean to each other so that would not be surprising.
And a first daisies came out.
Today I planted new cherry tree but there was not much that I could otherwise meaningfully do, so I have spent about 40 minutes testing my belt grinder. It has worked reasonably well, but the supporting table needs improvement.
I chose this particular file for this project because it is thick at the base – almost 6 mm – and it already had a distal taper. That means I do not need to grind of as much material, but it is actually more challenging to work with, and therefore better exercise.
First problem was scribing the center line for where the edge shall be. Due to the taper I could not use my scribing tool because it scribes line at a constant distance from an edge. Luckily the curvature is very mild, so I could do with a steel ruler for most of the way and steady(ish) hand for the rest. I am not fond of measuring, I prefer to eyball the work, but for blade symmetry is important. The more asymmetrical the roughed out blade, the more it warps in quench. Very slight warp can be ground off, but big warp not. And of course grinding off a warp on hardened blade is tougher on the abrasive belts, and those do not grow on trees.
After scribing the center line, I also scribed two lines for where the bevels shall go. This dagger will have only one cutting edge, and in order to make it more useful as an ordinary knife, the bevel should go almost all the way to the spine at first grind, and wander de-facto all the way to it during polishing. On the other hand shallower bevel is easier to make and makes for stiffer blade. At this point I have not decided on the way I will do it. I scribed two bevel lines and decided to grind to the first one and reconsider.
With these preparations done, which took only about five minutes, I have spanned a 60 grit belt on my grinder and started. First time I was grinding with the use of supporting table and it was a great help at first and slight hindrance later on. For me it might be good to use the table for first facing and then go back to free-hand. I am slowly finding my personal way of doing these things. After slightly over half an hour I ground both sides to the first bevel line and had to call it quits for the day. Now I am considering my next step. Grind or not to grind, that is the question.