There and Back Again: Towing a caravan with an EV

View over the marshland towards the sea

©Giliell, all rights reserved

Some of you will remember that last year, our old diesel died several times on our way home from the holidays, until we had to have car and caravan shipped to us and get home by train. Fortunately we had already been looking into a suitable EV to replace it and were lucky to get a Kia EV6 with all the trimmings on short notice. In our daily lives, the car is just the best one I’ve ever had: I can charge at home, with my own energy in summer, but there is pretty little data on towing a caravan over long distances. There were two major issues: reach and charging and we were a bit anxious about the whole thing.

First of all we, made the most important change beforehand: we changed our expectations. If you keep comparing it an measure it by the old diesel experience, you’ll end up unhappy. The EV will not have the same reach, you will be slower, you need to plan accordingly. Since this was the trial holiday, we were happy to go along when friends proposed to go to the North Sea together. It was only 600km and within Germany and we planned to go there in 2 days, since we had zero experience. Beforehand I said that I would be OK with a reach of 150km, I would be absolutely happy with 200, but less than 100 would mean looking into alternatives.

Normally we only charge the battery up to 80% to go gentle on its life cycle, for the first part we charged a full 100%. Generally, the last 20% charge slowly as fuck, again for the sake of the battery, but that’s no problem when you charge over night. Anyway, we started our journey at home and soon got a feeling for the energy consumption. I usually drive the car around 15 kw/h per 100 km  in summer, my beloved at around 18, but I’m sure there’s lots of people who regularly need 25kw/h. Towing the caravan got us between 30 and 40 kw/h. Energy consumption is much more direct with an EV, because it’s much more energy efficient. A combustion engine uses a hell lot of energy just standing there, so the increase is less steep. An EV doesn’t do that. The first leg of our journey took us through the medium mountain ranges of the Hochwald and the Eifel (Charly will know those) with lots of ups and downs. Once we were past Dortmund, everything became flat. We were pretty careful and always charged the car when we still had at least 30% left, so we made 4 stops in total each way, which gives you that 150km range. If we had very carefully planned the stops, we could have made it with three, but that would have left no margin for a non functioning charger or things like that.

We could have made it to our destination the first day, but since we only had booked for the next day, we called it a day early near Osnarbrück and enjoyed an evening of bathing in a lake and getting a good dinner. we arrived without any problems the next day and had some fun holidays. We made the way back in one day, again, with 4 charging stops and plan to make a longer voyage next year. On the way back we also planned our stops better, looking for fast chargers so charging actually didn’t take that much time. Two breaks for breakfast and lunch, and two for peeing and stretching your legs. A fast charger will go from 30% to 80% in 10 minutes, which is very reasonable.

But….

Nothing is that easy. The issue is that while there’s more and more charging stations and more fast chargers (though a Danish guy we chatted with assured us it was nowhere as bad as in Germany), they’re all made for cars only, so what about our caravan? We always had to detach it, move it somewhere we could park, sometimes do not quite legal driving manoeuvres and later hitch it again. It was annoying, but ok. The big disadvantage of all of this is that I got mostly banned from the driving seat. Not because I cannot drive, but because my beloved is really bad when it comes to all things digital, gets sick when he has to look at his phone to check out charging stations while driving and I am also really good at getting an overview quick, see where the chargers are and where we can put the caravan. This will have to change because if we really go to Spain it would be too much for him to drive alone.

Oh, and a final word on energy consumption: We needed about 180kw/h energy in total. Since one litre super fuel has 8.9 kw/h energy, this equals a bit more than 20l super or 19l diesel fuel for 600 km with car and caravan. No combustion engine is ever going to beat that.

Sciencing Sharpness – Part 5 – My Sharpening Kit

I have found a blunt-ish knife, one that I use in the cellar to open wooden briquette packages. It was not exactly blunt but it was slightly blunt and I have run it over a quartz stone to make it blunt. It is a knife from high-quality stainless steel but it has been sharpened so much that it has lost about 30% of its width. I have tested with it my traveling sharpening kit. I have done completely freehand sharpening, holding the stone in my left hand and knife in the right hand, no angle measuring, not even angle estimating, just putting the blade to the stone in a way that “feels right” and going on from there like I used to before I got the machinery to be precise. I tried to look up on the internet the grits of the stones that I use but it ain’t easy because one of them is a no-name generic grey carborundum whetstone and as you will see, it does not appear like I found the right ones. I have also used all of the orange thread that I have reinforced with PVA glue and from now on I will use the nylon thread since I have already bought it.

Here is the picture that’s worth a thousand words:

© Charly, all rights reserved. Click for full size

And here are less than a thousand words explaining what’s in the picture:

It is a bit strange that the fine grey layer of the cheap whetstone does not perform much better than the coarse layer and even performs worse than the beige layer on the colored stone which should have slightly coarser grit. There are several possible explanations or a combination thereof – I got the grey stone grits wrong, I done did do a bad job with this layer, or the fact that this stone uses a weak binder and sheds grains very easily plays a role, or I messed up the measurements. Nevertheless, the knife was capable of cutting freely hanging printing paper at this point, although not very easily, and it did bite into a fingernail.

Anyhoo, the second stone is much harder and I actually know the exact grits from the manufacturer. And once I got to the red layer with “just” 500 grit, the knife was shaving-sharp. The leather strops might have burnished the edge a bit but there is no statistically significant difference anymore from the 500 grit stone. It looks like there might be one, a very minor one if I had performed more measurements or had a more precise method.

I would say that it is pretty convincing for my argument that a two-layer whetstone and a strop are all that is needed to get and keep knives sharp.

It also appears like 500 grit stone is sufficient to maintain a knife edge shaving sharp without any further ado. But I would say that shaving hair with the stropped knife feels slightly “smoother” on the arm than with one that went just over the stone and I feel inclined to trust my skin sensors (they are much more sensitive than the kitchen scale after all) on this issue so I’m not convinced that the strop is completely useless. Measuring as fine differences as these might be is not a task that can be done with a rigged-up kitchen scale.

Sciencing Sharpness – Part 3 – Angle vs. Sharpness

It is not good for my ego to have the predictions mostly correct again, but this time there were things that surprised me a bit.

I have included a sharpening angle of 10° which I never use in praxis because it is not recommended for the N690 steel due to reduced edge retention at that angle (tendency to chipping), but that would not be a problem in this test and it is a data point of knowledge in case I make some carbon-steel sushi knives or razors in the future.

Now the boxplot:

© Charly, all rights reserved. Click for full size

So I got the prediction about how the cutting force will rise mostly correct. Mostly, not completely.

ANOVA test has found no significant difference between the first four angles but I am sure there would be one if I had performed more measurements and/or refined the testing method. The Lookandsee test does indicate a slow rise in cutting force from around 25 gf to around 50 gf.

The jump at 30° is a bit more sudden than I expected. I suspect that it is a fluke. And then the rise at 40-45° was a lot less than I expected.  It seems that the 90° cutting edge is still significantly better than no cutting edge, which would be somewhere around 3-4 times worse with a cutting force of around 1000 gf. I did not expect that. The best-fit function is quadratic. This is less drastic than the predicted exponential growth, although still significantly faster than simple linear growth.

So in conclusion, it does appear that my opinion that whilst there is a difference at angles 10-25°, it is not big enough to matter for casual knife users is substantiated. The angle 30° performed slightly worse than I expected, and the angle 45° performed significantly better than I expected.

I am going to think about all this some more and then I decide how to proceed from now on.

Sciencing Sharpness – Part 2 – Grit vs Sharpness

Notwithstanding dangerousbeans’s comment at the last article, I did find in my steel offcuts pile a blade that broke after it was nearly completely finished, with etched logo and all. That means learning about the sharpening properties of exactly the steel that I use in exactly the state it is in a finished product. In different steel, the results might come out a bit differently, which means I am mightily glad that I could do my tests on this – an absolutely ideal testing specimen.

© Charly, all rights reserved. Click for full size

I have sharpened the blade stub at a 15° angle which is the angle at which I usually sharpen kitchen knives, and always those that I make from N690 steel. (When tasked with sharpening store-bought knives from unknown steel I occasionally sharpen them at 20°, especially if it is clear from the state of the knives that the customer is not particularly careful about their use.)

I established the bevel with 120 grit and then I progressed from 180 and 240 grit Zirkorund and then Trizact belts (in the evaluation translated into grit equivalents) from A 65 all the way to Trizact A6. I only differed from my usual sharpening procedure in one way – I used fresh belts, instead of old ones. Normally for sharpening, I am using old belts because sharpening is extremely rough on the belt and destroys it very quickly.

The measuring method is wildly imprecise – the testing thread is not homogenous, the angle at which I put the blade on it is not always precise, I do not always hit the center, I am not pushing with constant speed, the kitchen scales do not renew the measured value with sufficient frequency and probably several other variables. I have experience with such measurements from my previous job though and there are ways to get relatively reliable, reproducible, and usable results even so. One of those ways is to make lots of measurements – that is why I took 12 measurements, discarding two of the most egregious outliers and making the evaluation with the remaining 10. There are mathematical methods for discarding outliers but for my personal purposes, the Lookandsee method suffices. (Thirty or fifty measurements would be better, but I am not going for exact values for individual grits, I am going for a comparative assessment between those grits. Anyway, not going to write a boring lesson about measuring).

Here is the boxplot of those ten measurements per each grit:

© Charly, all rights reserved. Click for full size

And it looks like my prediction from yesterday was bang-on. Which is satisfying to my ego, but also boring in a way. It would be much more exciting if it were different.

What you see here is the cutting force going rapidly down from ~270 g at 180 grit to ~ 75 at 400 grit. At this point, the blade is capable of cutting freely hanging paper. Then it falls some more to ~40g  at 800 grit and more or less stays there till the end (the knife is shaving-sharp at these stages). The slight increase at 1200 is a fluke that would most probably go away if I have made more measurements and/or invested time and resources in refining the method. I made ANOVA test and there is no statistically significant difference between the last three fine grits.

So in conclusion, sharpening knives beyond 1000 grit indeed appears to have very little practical value. At 800 grit the blade is already shaving-sharp and polishing the edge further only costs more time without noticeably improving its cutting capabilities. With more precise measuring method there might be a difference, but it would be very, very tiny. I think that I can replace the last two belts with a leather belt infused with stropping compound and get the same result. And since time is money, I will do exactly that.

Sciencing Sharpness – Part 1 – Predictions

I hope to use my new sharpmeter to get some knowledge about, well, sharpness. And since I am going to be playing at science whilst doing so, I have decided that I will write down the predictions for my tests. The tests will not be blind, because I will be doing both the sharpening and testing and there will still be some subjectivity to these tests, but nothing is perfect. I am doing these tests to gain some knowledge and I will share that knowledge for free but there will inevitably be bias.

The first test that I intend to perform is the influence of grit on edge sharpness. I think that after establishing the bevel with 180 grit the cutting force will go down significantly with the next steps, but it stops changing significantly above 400 grit. My reasoning for this is the fact that it is possible to get a knife shaving-sharp with ca 320 grit stone and at 320-400 grit usually the wire edge/burr falls off. I think that I have mentioned in the past in comments somewhere – either in Marcus’s place or here – that going above 1000 grit in sharpening makes little sense function-wise, although I cannot find the comment now. I will go up all the way to trizact A6 belt (the equivalent of 2000-2500 grit) in the experiment.

The second test that I intend to take is the influence of the sharpening angle. There was a heated debate between me and Marcus on this issue a while back -click-  and I really want to test it (caveat from the first paragraph applies doubly). I expect the force needed to cut the thread to rise exponentially, i.e. slowly from 10-25°, then some more for 30° and even more for 40° and again even more for 45°. I won’t test sharpening angles steeper than 45° because it makes no sense IMO since a 45° sharpening angle means a 90° edge. I know from praxis that knives sharpened at 15°, 20°, and 25° can be shaving-sharp. I do not know much about the 30° angle, since that is extreme and I only sharpen hatchets and axes at that angle and I never even tried to get those to shaving-sharp. They do cut paper though.

So, sometime this week I shall heat the workshop again, sharpen some steel offcuts (probably pieces of old hacksaws) and go measuring.

Sharpmeter

It is freezing here and I still do not have the slightest inclination to do something useful. But I need to heat the workshop occasionally to prevent it from completely freezing. Not that it would be super bad, except that maybe ice forming in the cooling receptacle near the grinder could damage it. Anyhoo, yesterday was a workshop heating day. I could not do anything super useful – it took me hours to raise the temperature to a bearable level and soon after I stopped feeding the stove, the temperature got down quickly again. But I could use the time to do something small and simple so I have made a device for measuring knife sharpness (I did not invent the concept, I saw the principle somewhere on the interwebs sometime ago).

© Charly, all rights reserved. Click for full size

It is simple and consists of two main parts. One part is a board with four legs and a 35 mm hole in the middle. A tiny table that can be put over my kitchen scales.

© Charly, all rights reserved. Click for full size

The second part is a small wooden cylinder with a cutout and two screws on each side of it.

© Charly, all rights reserved. Click for full size

I can span a thin thread between the two screws and when the cylinder is put on the scale through the hole in the middle of the tiny table, I can cut the thread safely for me, the scale, and the furniture.

The main downside is that my kitchen scale does not have a “Hold” or “Max” function so the measured values are not super precise. Another problem is the used thread – a very thin fishing line would be probably better since this one has a tendency to get damaged during spanning. Or perhaps a very thin copper wire – I might try to extract some strands from leftovers from speaker or ethernet cables. But when being very careful with spanning the thread and doing the cut slowly and carefully, the setup gives useable results and I did learn some things.

Here is a boxplot of 10 measurements with the three cutting implements in the photos – a fresh razor blade, a paper-cutting-but-not-shaving-sharp sharp knife, and a blunt table knife (I used the non-serrated part which is about 1 mm thick),

© Charly, all rights reserved. Click for full size

The razor had an average cutting force of ~6 g, the sharp-ish knife ~60 g, and the blunt knife ~ 1000 g. The less sharp the blade the bigger the spread but even with sometimes ridiculous outliers, there is a definitive and statistically significant difference between these three and it does give me some information and opens future opportunities. I would like for example to examine the relationship between sharpness and sharpening angle, to get some hard data to back up my opinion that anything between 10-30° works just fine. My prediction is that the relationship is not linear and as the angle gets steeper, the cutting ability gets exponentially worse.

I did learn one thing – my “Not a Masterpiece” was sharpened at a 20° angle and the only knife that actually scares me – the bigger knife from the two-knife applewood set – was sharpened at 15°, yet both measured within the same range as the razor. Although the applewood knife completely failed to register on the scale one time, thus my suspicion that it is the sharpest knife I made so far might be true.

Of course this only tests edge geometry, not blade geometry. I could use a similar setup to test the influence of blade geometry on cutting force too, but I do not have a reliable medium to do so yet. All things that I have thought of so far are either expensive (cork, rubber, silicone) or have highly inconsistent properties (fruit & veggies). But maybe I will think of something to test blade gomtry too.

I Wanted to Write an Article Today But…

…quite coincidentally Adam Conover has made a much better job at delivering the message that I wanted to say.

I have seen with my own eyes how high-up and extremely well-paid managers and CEOs think and work and I experienced first-hand three corporate takeovers (which successively stripped the venue of assets and know-how and slowly turned a profitable and respected business into a hollow shell). For about fifteen years now I had no illusions that rich people actually really work harder, are smarter, or both than your ordinary Otto Normal. Quite the opposite in fact, and the word “manager” gained an extremely derogative meaning in my private vocabulary as a result.

And the only good managers were not those who took a hands-on approach with the sole goal of making as much money as possible as quickly as possible, but those who just chose teams of experts in their field and let them do their jobs. Profitability usually followed if the market was there. Those who thought they know better than people who have been doing a particular job for years or even decades inevitably ended up screwing things over, as well as those who preferred short-term solutions over long-term ones. And because big companies have some inertia, it often took a long time for the negative effects of said bad management to be really visible – which is an answer to those silly people out there who insist that Musk is not doing a shitty job just because Twitter has not completely collapsed – yet. Oftentimes it happens that a bad manager is screwing people over at some other company by the time the fallout of his (mostly his) bad decisions really starts to show.

Musk’s biggest mistake is that he started to believe his own propaganda and he really thinks he is a genius who knows better than everyone else. Which is inevitable with sociopathic narcissistic assholes.

Look at the Grinding Noise!

I have been contacted by my previous employer, which has led me to remember the various works I used to do. One of which was measuring and evaluating noise. That has meant that I was making and interpreting pictures like this.

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

Of course, this was only done with my phone, whereas at the laboratory I had various kinds of fancy equipment and software available. But back then I did in fact check whether this phone app measures reasonably accurately, and it does.

At the very top, you can see that grinding handles is a very noisy work indeed. When the equipment runs idle, it emits over 78 dB, which is very near to a level when the noise becomes truly dangerous (80 dB). And during work, it exceeds 89 dB. So I am indeed diligent about wearing hearing protection since that noise level would damage my hearing pretty damn fast.

Whoever knows how to interpret the above picture, can tell that when the grinder runs idly (those parts with green at the top), most of the noise – and indeed the loudest noise – is below 500 Hz. And whenever the wood touches the belt, another very loud component is added, between 5 and 80 18kHz (those parts with red-magenta stripes at the top). There is nothing I can do about the noise that is emitted during the grinding, but I could if I were inclined to spend my time on it, try and identify the spots where the loudest frequencies are during idling and try to do something about that. For example, I suspect that a significant source of the low-frequency loud noise is the tensioning wheel.

However, as much fun as it might be, I do not think I will spend a lot of time over this anytime soon. It would be fun though. I liked my previous job, the work was not the reason why I quit.

Women Educators on YouTube – Architect – Belinda Carr

This Hempwood product sounds interesting. I actually think that with a bit of tinkering and upscaling of the production, it could become cheap enough to be a viable material for large-scale construction. Definitely, it could replace for example wooden OSB plates for walling. And since the fibers run lengthwise, it could also definitively be used for making load-bearing beams.

Completely independently of this – this spring I was actually really thinking about growing Hemp in my garden for fuel, but although it is legal to grow technical hemp on a patch of land up to 100 sqm, the costs of seeds are prohibitive and there is a risk of cross-pollination with someone’s illegally grown weed so producing my own seeds for future poses risks of accidentally creating hybrids whose THC levels are above the legal limit. It is not worth the potential hassle of discussions with the police. My only hope there is that hemp gets finally legalized for personal use. Until then, I will try and grow hazels, poplars, and willows on my unused land to try and reduce my personal carbon footprint.

Edit: my PC glitched out and the article was initially published with nonsensical title.

Disemboweling a Phone. And Emboweling it again.

For about two weeks I won’t post too much, since being healthy again means I am playing catch-up with my garden. More on that later, perhaps. Lets just say for now that after six weeks spent mostly in bed, two hours of manual work feel like ten and the results are underwhelming.  So this week is it work and next week I am on holiday in a hotel which has, from experience, crappy internet connection.

So today instead of a Slavic Saturday, which always takes a lot of time to write, just a short anecdote.

Whan I was sick, I dropped my phone on concrete floor. It hit it with one edge and a plastic corner component chipped off. I wanted to glue it back as soon as I get well – but I dropped the phone again and it fell on that very same edge second time. And due to the lacking plastic part to soften the blow, the display cracked. Phone dead, Charly sad.

I bought a new phone immediately, but I loathe throwing things just away so I looked into if the old one can be repaired – either to keep it asa  spare, or to use it as camera in workshop so as not to damage my actual camera with dust and humidity. I requested an offer from company specializing in repairing smartphones, but their answer was “sorry, we do not support this type”. Not wanting to waste too much time asking around,  I googled just a bit more and coincidentally and I found that for  60,-€ I can buy a new display and special glue. I also found some videos about how to replace the display. So I decided to try my hand at repairing it myself. 60,-€ is not exactly little money – for perspective, it is about 6-8% of median net income in CZ – but it is little enough for me to be willing to risk it.

Removed back – the bowels of the machine are exposed.

First thing was to remove the glued-up back cover, which was achieved with the use of brute force and an old screwdriver. I have managed it without damaging any of the innards. Which is lucky, because I have done this actually before I decided to try to repair the phone, at a time when I was resigned to toss it – I just wanted to look inside for curiosity’s sake and thus I was not very careful.

Removed battery and untangled cables.

Second step was to carefully unclip the battery connector (which is surprisingly tiny) and carefully remove the battery. This proved difficult, because it was held in place with double-sided adhesive tape. I have scratched the black paint over the printed circuit behind it a bit, but luckily not too much and without damaging the conductors. After the battery was removed, I had to carefully untangle the intricately folded cables at the bottom near the charing connector, where the display cable connector is clipped onto them. Very, very intricate work, and there were some very tiny screws that did not want to budge – especially since I do not in fact own the right screw driver for those. But I managed it in the end.

Cracked display removed.

After losing about half an hour searching for our hair dryer, which nobody in the family uses much, I managed to find it and I have used it to heat up the edges of the display to soften the glue a bit. More brute force was used to pry it off, damaging it even more in the process. Once it was removed, I have taken one of my sharp tiny flat screw drivers and I cleaned away thoroughly any residual glue on the phone itself.

Glueing up the new display.

I inserted the new display in, connected it and the battery and tried whether it works or not. It did, so I unplugged it again and applied glue on all the places where it previously was applied. The glue had to harden for three hours under slight pressure, so I have put some plastic clamps on it and went bout other business. After three hours, I folded back all the intricate cables, clipped back all the clips, screwed all the screws, connected the battery and glued back the cover. And left it again for a few hours with clamps.

Its alive! Now kill it with fire…. Or not.

And success! It works. There are some funny coloured spots on the display, whether because it is a cheap non original spare or because I applied too much pressure during the repair I do not know, but apart from that it seems to work perfectly well and all funcionalities are there – the camera is cameraing, the speaker is speaking, the telephone is telephoning and the display is displaying.

I actually really felt like I did something worth doing.

YouTube Video: A Super-Material You Can Make In Your Kitchen (Starlite?)

Today a bit of chemistry and engineering that took my fancy. I have read about Starlite before, and I always wondered what it was made of. It would be swell if it could be made to actually work on big scale.

There are other materials that have similarly amazing insulating properties – aerogels – but they are brittle and a pain in the arse to make at home (i tried, and failed).

I am already thinking about how to use this in knifemaking.

Oh and sorry for being so quiet, but I was away for almost a week without internet and I am still catching my breath after getting back to work after.

10 out of 10 for First Impression.

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

My new drill press arrived yesterday evening and I just installed it instead of the old cheapo one in my workshop. I must say that my first impression is absolutely great. I cannot definitively say whether it was a good investment or  not – ask me again in a few years, because new devices tend to have some crucial mechanical parts (like gears etc.) out of plastic that wears out rather quickly and subsequently the whole machine has to be tossed – but on the surface the machine looks really great. Someone has actually thought about the design and, a rare occurrence in today’s world, the design is very functional and sensible. Use is very intuitive and all levers and settings are easily accessible. I worry a bit that the wheel might be too small to provide adequate leverage for drilling steel, but we will see. That is the only worry I have on first sight though.

The drill has a digital display that actually shows the rpm, which is very nifty – I will not have to guess by the sound. It has two main gearing settings and a continuous rpm regulator, so it covers very wide range of rpm on a nearly continuous scale without me having to flip v-belts. That is probably at the cost of some efficiency, but the max power (710 W) is higher than on other drill presses that I could choose from, so that might not be a problem for actual use, although it might be a problem regarding power consumption. But it is not a device that will  run more than a few minutes at a time, so slight inefficiency is not as big of a deal as it woudl be for, say, bench belt sander.

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

As a knife maker I fell instantly in love with the quick-span/release chuck that is standard attachment. The chuck is simply ideal for holding down flat stock, something very obviously crucial for a knife maker.

And the laser cross! A LED light illuminating the worked area was just a final bonus on top of that. It was always a bugger to find and hit the tiny black dot on black piece of steel – now those troubles are, hopefully, over.

And of course it does not wobble in all directions so I hope I need not fear anymore drilling tiny holes and breaking two drill bits per each.

All in all right now I have no regrets for spending the non-trivial amount of money for it. I think it is money sensibly spent and I look forward to trying it out as soon as possible. I might indeed regret a bit not spending that money sooner.