Building a 3D Printer

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A while ago I got the idea of making my own 3D printer. After a lot of research I eventually embarked on my own build. Due to the severe lack of availability of parts during 2020, many of the structural parts were made from scrap wood I had around the house. While this makes it look very home made, the print quality is surprisingly good. Currently I am in the process of designing new 3D printed parts to replace the wooden ones, and each time I do, the print quality gets slightly better. This is in fact a concept developed first at the University of Bath which developed into the Rep-Rap project. The concept takes inspiration from nature whereby organisms are self replicating, and capable of improving their own design over time. Under the Rep-Rap project, printers are manufactured and then used to print new printers, so becoming self replicating.

The printer frame is based on extruded aluminium which is reasonably cheap, although I had intended to use scarp carbon fibre, I had no access to this at the time of building. The movement is enabled by 5 stepper motors, which move each axis along guide rails. Lubrication free polymer bearings keep the motion smooth and have the added bonus of being essentially maintenance free. Experience with the C-Scan ultrasound machine at work convinced me that greasy bearings and dust are not a pleasant combination for smooth linear motion! The brains of the printer is an Arduino mega micro-controller, paired with RAMPS 1.4 board that helps manage the electrical connections. Both boards are open source, and the RAMPS board was actually designed as part of the Rep-Rap project. The firmware controlling all of this is Marlin, another opensource community based project. This software takes information sent from a computer in the form of G-Code (long established for CNC control). Marlin interprets the G-Code and sends the appropriate signals to the required pins of the RAMPS board. While any computer can by used to send the G-Code to the Arduino, I use my Raspberry-pi. This is largely because it is very reliable, but it can also be permanently tethered to the printer as I have a few Pis.

As time goes on I will upgrade the wooden parts to improve precision and build an enclosure for it to minimise temperature variations during printing which causes warping. For now I am enjoying printing many useless, and sometime slightly useful parts for around the house! I have no doubt that this will become useful for my work, I have lost count of how many times I wanted a little jig but could not justify the expense of having one made!

Sailing Tily Mint

Several years ago in around 2021 my brother and I stumbled on a great idea. We have been sailing dinghies for years, and did do one long passage on the Alba Ventura, from Scotland to the Artic circle. But we have never owned our own boat. The opportunity arose, just after the COVID pandemic, a nice little Hurley 22 for an outrageously low price was available in Edinburgh. So, we did what all sensible engineers would do – we did a cost benefit analysis! It turns out to be one of the best decisions we ever made. The boat was in surprisingly good condition, and we were able to sail it the week we bought it. Its an interesting boat in many ways, and quite good as a first boat. It is small, but since everything from mooring fees to insurance is based on boat length, that also means its cheap to own. It is, even within the context of Hurley 22s quite unique in having a long fin keel and an inboard motor. The long fin keel means the keel is fully encased in the hull, making for a very seaworthy and stable vessel. The inboard is a nice feature in that it makes marina manoeuvring a much more pleasant experience when compared to the more common outboard configuration. What you win in manoeuvrability you lose in maintainability. The Hurley 22 is a tiny boat for an inboard, so there really is not much room to do any work on the engine.

We also got somewhat lucky with our marina. We did select it intentionally, but could not have known how up our street it was until we became members. The club is called Forth Corinthians, and it bills itself as ‘Affordable Sailing For All’ and is very much a do it yourself sort of place. Almost without exception, the club members are people who do not shy away from a challenge and there is no shortage of audacious plans and ideas. A quick walk around the marina and you will find people of all ages, tackling maintenance, repair and upgrade jobs of all levels of difficulty. As a nice example, our neighbouring club, the Royal Forth Yacht Club had one of their boats sink in the marina. This did not deter the Corinthians, one of the club members bought this boat, that was sitting on the sea floor, and set about re-floating it. The wonderful thing is that he was not alone, other members rallied around him and within a few short months the boat was afloat and restored beyond its former condition. This community spirit, and optimistic outlook is what I love about this club.

We have over the last few years had our fair share of challenges to deal with. Having never previously owned a yacht we had much to learn. Some simple jobs turned into big jobs, like changing the impellor on our inboard motor. The small space and limited access we had to work in on the 22 foot yacht meant it took us several days to remove the necessary bolts. Some jobs we never expected also came our way, for example when we set out to sail one day, started our engine. A fatigue crack in the engine mounts propagated at that moment in time far enough that the mount catastrophically failed, taking the battery starter cable with it. Thankfully there was no additional damage, we removed the engine mount, had it repaired professionally and rewired the starter motor. We were back in business, just in time for the weather to turn and ruin all our remaining days before lift out!

Lift out is itself a huge operation. Again, the club rallies together and makes sure the day is a success for all club members. I was on site for the full day, and around midmorning it was time for Tily Mint to make her way over to the crane. I had three club members assisting me on my first lift out, and thankfully since the boat has been moored at the club for years, there were experienced hand on deck to help me. All in all, the lift out was a success and I look forward to many more days spent at the marina, whether we make it out sailing or not!

Merida Ride 77 Tiagra Upgrade

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This old work horse has been running for well over a decade. It originally belonged to my brother, but when he bought a new bike this fell into my hands. I have done some subtle upgrades here and there over the time I have had the bike but for the most part this is stock. It came from the factory with a very nice frames, tripled butt welded aluminium frame with a CFRP fork. By today’s standards its perhaps somewhat old fashioned in design, its made primarily as a compromise between stiffness and weight reduction, whereas a lot of new bikes have areas designed to flex for comfort. So they will have a reasonable amount of flex in the vertical axis, and a lot of rigidity in the horizontal axis to enable efficient power delivery.

That said, the rest of the bike is where Merida cut their costs. This is very common on mid range bikes, they will either give you a good frame and cheap parts, or they will give you a set level of parts, and make some short cuts on the frame. The former is definitely the preferred option, you can always upgrade parts in your own time, but there is not much you can do to upgrade the frame. The most common area to really save money on parts for manufacturers is the wheels. Therefore the wheels were the first thing I replaced. I did initially service the bearings, and found all sorts of treasures in there including quite a lot of hair from my brother’s cat Jack! That got me a few extra years of life out of the stock wheels. But after I fitted the new wheels I really wish I had done it sooner. The difference is incredible, they are more comfortable, more efficent at deliving power and most importantly, they look beautiful!

The ones I went for are Campagnolo asymetric wheels, so the front has fewer spokes than the rear. With this done, and several more years of enjoying this setup I started thinking about the rest of the bike. The next more important investment is contact points, so anywhere you are touching the bike. My brother had already put a really nice saddle on the bike that I was happy with. So I set about changing the tape, I went for a blue foam tape from sram. This fits well into my colour scheme which comes from both the original frame colours, and my new livery, the Icelandic crest.

I also added some road pedals that interface with the bottom of my cycling shoes. Now, with contact points sorted, I set about changing some of the other components. This really started with the crank falling off my bike once on the way to work. This was a shame because as it came off, it rounded the square tapered fitting on the spindle that runs through the bottom bracket of the bike. I did replace the bottom bracket, but it always seemed to me to be a mistake. I would always rather upgrade than replace where possible. So I saved up and bought a full Tiagra groupset with shifters, deraileurs, gears, chainset, brakes and bottom bracket all included. This was effectivly major open heart surgery for the poor old Merida. But the final result was amazing.

For those who do not know, Shimano offer a range of components that are grouped into a hiarachy, starting with Claris, Sora, Tiagra, 105, Ultergra, and Dura Ace. Claris being entry level, Tiagra and 105 are mid range, and Dura Ace is for real pros. What was on the bike originally was Sunrace, which is a fairly solid, but low cost Tiawanese manufacturer of bike parts. They had held up nicely, but what you get with a midrange setup is much more precise and smooth shifting. The process was not without some difficultly. The most troubling issue was that the diameter of the bolt for the front brake was slightly too large for the hole on the bike. So I unfortunatly had to drill out the hole a bit, which was not a comfortable experience, there is no going back from something like that. The other issue was the nut/bolt was too short for the front brake. To fix this, I bought a new nut that fits better, and I now have more than 4 threads of engagement, with a bit of locktite that seems to be rock solid. The final version of this bike is now a very capable road bike, comfortable, nice to use and as always, most importantly, it looks brilliant!