MikeOxon

with the gold price currently above £50 per gram, even 9ct gold is not to be sneezed at! Weight for weight, gold is more than 80 times the value of silver.

I see trouble ahead in Traeth Mawr! The slaters, or slate masons as they prefer to be called will be looking for you, with their 12 inch hammers and zax! - and it won't be slates that they're thinking of splitting. 'Tilers' indeed - we''l show 'im 😠

Another photo in the link you referred to intrigued me - an engine with Mansell driving wheels! I tracked it down as 'Gazelle' on the Shropshire & Montgomery Railway. It was later converted from 2-2-2 to 0-4-2WT and passed into Colonel Stevens' hands. Amazingly it is now preserved - see https://preservedbritishsteamlocomotives.com/1-0-4-2wt-shropshire-montgomery/

It looks to me as though the safety valve cover is bolted to a flanged cylinder, like a short length of pipe.

That was how Josef Prusa started as part of the RepRap project. All the plastic parts of Prusa printers are available as downloadable files

As I mentioned in the original post, all the moving and heated parts are completely exposed and there is no back to the display unit, nor is its ribbon cable enclosed. I did feel that the lack of a back to the display unit seemed an odd omission. On exploring further on the website where i found the calibration tool, I found a 3D-printable back!. It took about 2 hours to print on the Mini+ and does the job very well. I used my usual brown filament which I think blends well with the orange front of the case. I do feel, however, that this cover should have been provided in the first place.

To be fair, I think they had tried hard to provide a decent manual but the photographic illustrations let it down for me. I suppose that there is a problem when preparing something that has to be translated into many languages. My use of captions is probably not possible but numbered call-outs could be used, while line drawings are usually clearer.

Sine I wrote the above post, I have found, from reading on the web, that many people have difficulties with the first layer calibration. There is a 3D-printable tool to set the SPINDA sensor at the correct height, so I download this gauge and re-set my printer. It was now possible to trim the vertical (Z) axis to an appropriate setting for my PLA filament.

The ‘gear’ I’m referring to in the title is my 3D-printer, which I have just replaced. As I mentioned in my previous post, my Geeetech E180 is no longer supported, with essential items like replacement print-heads not available. I have therefore bought a Prusa Mini+ as its replacement. The E180 was cheap and took me some time to optimise, following a rather shaky start, but eventually performed very well, until key components started wearing out. My choice of the Prusa machine was a deliberate move to choose a European product and one that has gained a good reputation amongst the 3D printing community. Unlike the E180, which was smartly styled, the design of the Prusa is strictly functional, with most of its working parts fully exposed. I have stayed with a ‘fused deposition’ type of printer (FDP), because it does not not use liquid resins and other materials that require careful handling and disposal. I recognise that FDP cannot provide as good a surface finish as some other methods but I have found it adequate for my interests in historical modelling. The Prusa Mini+ is supplied either as a kit or partly assembled; I chose the latter course, since my eyesight and general dexterity are no longer what they once were. The packaging and overall presentation of the machine as delivered was excellent, with all the parts firmly secured within the cardboard packaging and all the small parts in individual, labelled, re-sealable plastic bags. There is also a substantial printed manual, covering both the assembly instructions and operation of the printer. Prusa Mini+ Components after Unpacking from Box Assembly Unfortunately, the photographic illustrations in the manual are small and, because most of the printer parts are coloured black, it is difficult to make out many of the details. My troubles started with fixing the soft feet (foam pads). These do not fix onto the obvious flat areas under the plastic end-pieces of the base section but under the aluminium channel sections. The illustrations are far from clear and caused me some hesitation. Fortunately, I found a helpful video on YouTube at https://www.youtube.com/watch?v=xYGaWYKzvsM This video presentation is rather too rapid to follow on its own, but is very useful to check on any points of doubt. N.B. There are also some, to my mind, dreadful American ‘live’ videos about assembling this printer, where the facts are submerged in peripheral chat. The same problem of poor illustrations applied to many other parts of the assembly task. I still don’t understand the statement from the instructions: "try fitting the “clamp” (XZ assembly) directly on the M3nE nut which you have moved to the centre of the extrusion.”. It took some time for me to work out that the long screw passed through a ‘tunnel’ within the electronics module to reach the nut in the base unit. A diagram like that I made below might have helped a lot! Screws connecting main units It’s actually quite simple, once one has interpreted the instructions, with three screws connecting to nuts that slide along aluminium channels in the base unit. These screws hold the two major components together. There are then several cables to be connected between the two major components. The ‘electronics module’ is very compact, with a high density of sockets and wiring. If you are familiar with the small connectors that are widely used within computers, then it is not too difficult but, once again, the instructions are minimal and more guidance would be very helpful to many people. The first cable to be connected is the ribbon cable that will eventually attach to the display unit. This has to be orientated correctly in its socket. The most obvious guide to alignment is that one side of the ribbon is coloured red but this fact is not mentioned in the instructions, which are therefore hard to follow. The circuit board is referred to as the ‘Buddy Board’. There is no diagram that shows the various sockets on this ‘Buddy Board’ in the electronics box, nor is there any very clear indication as to which connector goes where. Again, I suggest that a diagram like that I made below would help a lot: Electrical connectors on circuit board Finally the lid has to be re-fitted to the electronics box, which is quite tricky, since all the cables have to be squeezed inside. There is a dire warning that ‘The nut must not fall out’. I never saw this nut, so sincerely hope it is safe! That completes the main assembly. There is also a spool holder. The instructions start by stating “Take the two BASE parts”. Actually there are four parts in two pairs, which confused me at first. Note that there is just one hexagonal recess in each part to take a nut. In my experience, it is essential to use one of the screws to draw the nut down to the bottom of its recess, otherwise the screw will not reach the nut when attempting to join the paired parts together. As I stated at the outset, the design of this printer is strictly functional. All the moving and heated parts are completely exposed and there is no back to the display unit, nor is its ribbon cable enclosed. Unlike my previous E180 printer, this machine has a heated print bed and the ‘hot end’ is also completely exposed, so any children need close supervision, if allowed nearby when it is operating. Prusa Mini+ after assembly First Start Now it was time to switch ‘on’. The LCD screen lit up and the ‘Calibration Wizard’ started to run; the first stage being a series of ‘self tests’, which were all cleared successfully. Switched ‘on’ and Ready to Print After this, it’s time to load some filament. I pushed it into the PTFE tube and the system recognised it as ‘loaded’. It then carries out ‘Mesh Bed Levelling’, and finally ‘First Layer Calibration’. For this process, the printer is supposed to lay down a zig-zag course of filament across the printer bed, so that the user can make any necessary fine adjustments to the vertical (Z)-axis to optimise first layer adhesion. The calibration proved to be so far out that I could see the filament extruding from the nozzle while it was at least 2mm above the print bed. There is a knob on the controller to adjust the height but the range was insufficient to close the gap. The manual claims that “the ‘SuperPINDA’ sensor height is set from the factory, no need to adjust it now”. Disappointingly, this did not seem to be the case, so I turned to the ‘Help’ pages on the Prusa website, which included instructions for setting the sensor height. I followed the procedure given on the website and did manage to achieve reasonable adhesion within the range of the control knob – just. I suppose one should always expect some teething problems but because this was a relatively expensive machine, compared to the many ‘clones’ that are available, I was not feeling very happy about these irritations. Printing The real proof, however, lies with the performance, so I had prepared a 3D model of a GWR Tilt Wagon in ‘Fusion 360’, to see how it would go. I used the Prusa slicer software, in my 'Windows 10' computer, to prepare the ‘gcode’ file for printing and copied it onto the USB memory stick supplied with the printer. My 3D model of GWR Broad Gauge Tilt Wagon in 'Fusion 360' As soon as the memory stick was plugged in to the socket on the side of the printer, the LCD screen on the printer helpfully showed a colour image of the job to be printed, which I think is a good feature. The printer then set itself up automatically, first checking the printer bed height at several points across the entire surface. Completed ‘First Test’ on Printer bed For this ‘first test’, I printed the central section of the wagon, comprising the floor and side walls. First impressions were good: the rivet detail is clear and the sides have printed very smoothly. There is a little ‘over-print’ in a few places and some fine gossamer-like excess that I had not seen with the old printer. What was most impressive was the quietness and smoothness of the printer, as it carried out its task. When I left it for a while, I thought it must have stopped, because I couldn’t hear it all from outside my work-room, but the job was progressing well and somewhat quicker, I thought, than when using the E180 printer. This job took just 43 minutes to complete, as recorded on the display screen. My impression was of a well-engineered machine that performed its task with a minimum of fuss. This was a considerably better ‘first test’ than when I first started with the E180, just over four years ago, and I have made no attempt to optimise any of the settings as yet. It will probably take me a while to familiarise myself with this machine and its associated software but, apart from the teething problems referred to above, it’s smoothness of operation indicates a good quality product. Mike

I agree and I was most put out when this site suddenly refused to let me load it until I by-passed 'AdBlock'. I nearly quit in irritation, since I naively believed I was contributing quite a lot,through my various 'how to' posts. Nowadays, though, everything has to be 'monetised' What did I say? - the lingerie is getting raunchier - I think they've noticed that I noticed 🙂 It says 'next day delivery' but I bet you won't get that in NZ!

That's no ordinary black, that's Blackberry Black :) I've just noticed, as one of those cheapskates who leaves the ads on, that your post is bordered by an array of shots of young ladies in lingerie! Perhaps there are advantages to not paying £12 per year 🙂

I've always been rather sceptical about the colour in that photo of the model at Swindon. I feel that the whole photo has a blue cast - see the (presumably) white box in the right background. If that is corrected in Photoshop the result looks like this: which I feel is a more plausible blue-green shade. Mike

Thank you @Mikkel. It's strange how 'experience' creeps up on one - I looked back at some cattle wagons I designed a few years ago and some of the methods I used seem laughably clumsy now.. The PLA fillament I use is reasonably bio-friendy, being based on starch.and I am content using it in a domestic environment. 3D printing is not a quick process and dies not lend itself to repetitive manufacture, although it is possible to use it to make the master for lost-wax castings.. I like to use the method in conjunction with stronger materials, such as brass, for the mechanical parts of models. The chassis I show here is fine for a static model but would need more rigidity and suitable bearings for a working model. What I have enjoyed is the opportunity that 3D printing has given me to explore historical aspects that will never attract mainstream suppliers. I have learned a lot about how early vehicles were built by trying to replicate them in model form. The ability to re-create such things has given me a great deal of pleasure and I share Brunel's view that these engines can be seen as 'works of art'. Mike

Superb modelling and your photography has played its part in presenting them in such a good way.

I've restored quite a few photos to my older posts - I usually wait until I want to refer to one for some reason or someone else asks a question. You need to find the box marked 'Entry Actions' at the bottom of your original post then select 'Edit' in the list that appears. You will see your original entry with 'place holders' for the original pictures and a box at the bottom for adding new images. Assuming you still have the originals on your computer, drag and drop them into the box at the bottom, where they will add to the list of missing images. Then you have to click on the place where you want an image to appear in the text and then click 'insert' just below the relevant image. Repeat until all your new images re in their correct places and finally delete all the 'dead' images by clicking the 'X' by each image. You will also have to say which 'group' your post should be in and a reason for editing. If you then click to save the new version, it should replace the original version. I think the bug that caused posts to appear with the current date has gone but it thts is a problem, you will need to re-enter the date when the post was first made before saving..

It's amazing to see what you are doing with the Penzance to Cambourne line. I have the TaNE version and realise it is a complete mish-mash, purporting to be 1930s. I haven't a clue how to modify it but, perhaps one day, when I can no longer drive a 3D printer, I might start looking at 'virtual modelling'. In the meantime, I shall enjoy watching your progress. Mike

I agree entirely with this multi-media approach. Many of my 'hybrid' models have brass boilers with 3D printed cladding that carries surface details. The same applies to frames, which are better made from brass (or nickel silver), with 3D printed overlays to carry rivet detail, etc. In 4mm scale, I have had to make compromises and the splasher tops are over-width. That can be partly 'hidden' by only applying the brass finish to the outer part and leaving the excess width matt black. The best face I can put on it is that the printed plastic is non-conducting, so less likely to cause short circuits to the wheels! I had almost forgotten that a few years ago, i experimented with the idea of using 3D printing to produce templates around which to shape thin brass splashers - see : Perhaps I should explore that idea a bit further. Since then, I have found that I can push the limits of 3D printing a little further to produce thinner sections and overhanging valances. Nevertheless 0.5mm (20thou) is about the limit for panel thickness. A lot of my modelling is done on a whim - I had a career in research and my modelling follows the same vein, so I am usually trying out a new technique or researching a period of history. One of my reasons for wanting to try a Prusa printer is because it can work with a wider range of filament materials and I want to see how this capability might be exploited. Thank you for your interesting comments.

Thank you @Lacathedrale. It's a good question! The first requirement would be metal tyres for the driving wheels. Apparently, the BGS is looking into the possibility of supplying tyres for various large-size broad gauge wheels. After that it's a case of where to install the motor and gearbox. My usual 'cop out' has been to go for a motorised tender and, in the case of single-driver engines, this remains a good option. For a 4-4-0 like this, with a large boiler and firebox, it should be easy to accommodate these components. Before embarking on that road, though, I'd need to build some track to run on!!! Perhaps ... one day 🙂 I'm glad you think the new chassis looks a good deal better - it also cost a lot less in blood (literally), tears, and sweat. Mike

Six years ago, in June 2017, I embarked on scratch-building a model of the Broad Gauge ‘Waverley class’ engine ‘Rob Roy’. The prototype was involved in an accident near Bullo Pill, where some of my wife’s ancestors were working for the GWR at the time. ‘Rob Roy’ – Accident near Bullo Pill, 1868 I took advantage of the fact that the boiler used for the Waverley-class was the same as that on the Gooch Standard Goods engines, for which the Broad Gauge Society (BGS) provide an etched-brass kit.. My old series of posts described in sometimes graphic detail how I constructed the kit, which involved rolling a boiler from rather thin brass sheet. After completing the boiler from the kit, I was then faced with scratch building the chassis, which I also constructed from brass sheet.. The process was not without its problems, especially when fabricating the bicycle-style splashers over the large driving wheels but, after much trial and error, I ended up with a passable model. One major compromise, however, was that I used wheels supplied by Hornby for their ‘Lord of the Isles’ model. I chose these because they have the required 24 spokes and these exposed driving wheels create a large part of the ‘character’ of the Waverley-class engines. Unfortunately, the wheels are over-size and this not only means they stand a little too tall but also that they had to be more widely spaced than on the prototype. At the time, I felt I had to live with the compromise but now that I have the means to print my own wheels, I felt I should try something better. My first scratch built model of Rob Roy, with Hornby driving wheels Enter my 3D-Printer The advent of 3D printing completely changed my approach to model building and I realise that there’s now no need to undertake the tricky fabrication of splashers from brass sheet and nor do I have to cut out the profiles of the sandwich frames by hand. All I had to do was find a suitable drawing – I chose the one by E.W. Twining – and trace over it in ‘Fusion 360’ before extruding the drawings into 3D structures. My methods have been amply described in earlier blog posts but one of the important lessons I have learned is that it is possible to extrude the valances around the outer rim of the splashers without the need for any additional support during printing. This method worked successfully on my ‘Firefly’ model and I applied it again here. Extruded Frame over Twining 'Canvas' in Fusion 360 I then created a mirror image of this first frame and separated the frames at the appropriate distance, linking them be means of a buffer beam and drag bar, as shown below (rendered in Fusion 360): 3D model of chassis, rendered in Fusion 360 As on my previous model, I filled the open space under the front of the boiler by adding a motion plate and ‘suggesting’ part of the motion. Further back, any underpinnings are hidden by the sandboxes and splashers. 3D model of chassis with motion plate added Printing the Components The next step was to pass the various components to the Cura slicing software and then to my 3D printer, which created the following components: 3D printed chassis components, together with my boiler assembly, constructed from a BGS etched-brass kit Once assembled, the chassis looks as shown below, with the boiler supported by the curved motion plate. An advantage of designing the model in ‘Fusion 360’ is that the ‘fit’ of all the parts can be tested before committing them to print. This was especially valuable for this model, in view of the tight tolerances between the splashers and the driving wheels. Note that, as in the prototype, the hind wheels are flanged but the forward pair of drivers are not. 3D-printed Chassis and Wheels after assembly Although I had felt reasonably content with my original fabricated chassis, mainly because I was unable to improve on the over-size wheels at the time, I realise now how ‘wrong’ it looks, when placed together with the 3D printed version! My original chassis in front of the 3D printed version, carrying my original brass boiler assembly Overall, 3D-printing this chassis was a lot easier than using traditional methods, now that I am reasonably familiar with the ‘Fusion 360’ software. Of course, it is an option that was simply not available to me when I built my first model. Now I have to add the brass finishing to the splashers and valances. End of an era This is probably the last model that I shall print with my ‘Geeetech’ E180 printer. It has given a few problems recently, first with the feed mechanism and now the hot-end temperature has become erratic. This printer uses a modular print-head, specific to this model, and Geeetech have informed me that replacements are no longer available. After some thought, I’ve decided to buy a Prusa Mini+, partly because I prefer to buy a European product (although I have no complaints about the Geeetech company). I shall report my impressions once I receive the new printer. Mike

They put me off attempting a model, too - tricky clearances to fit the coupling rods between wheels and steps!

I checked your links all work for me, too. I recall discussing something along these lines a few years ago: One problem is that some of our 'railway fantasies' may be in conflict with one another! For example, in my parallel universe, a (actually proposed) branch was built to Witney from the OW&W Cotswold Line, via North Leigh, and so the Fairford branch never go built. I suppose we could create a new junction in Witney between the two schemes! Mike

... but the South Wales lines, including the line through Bullo Pill, were all converted to standard gauge in 1872

Thank you for the reference - 'charming' is not an epithet I have seen attached to one of my models before 😀 Mike

I just grabbed the Tri-ang as something familiar, to indicate how rapidly things changed in the second half of the 19th century. Thank you for your comments on frame design.

After posting this entry, I realise that I fitted 10-spoke Losh wheels to my model whereas BGS Data Sheet 102 states that these carriages were fitted with 8-spoke wheels. Fir the sake of 'correctness', here is a photo of my model with 8-spoke wheels. It makes the underframe look even less substantial! Mike