TangoOscarMike

With new slots cut in the chassis the body now fits, as shown in this hideously lit picture. In fact the body is offset towards one end by (I estimate) about half a millimetre, so this gives further grounds for printing a revised version. While trying to smooth the join, I realised that I don't actually have suitable tools for this job. So I made a very thin chisel/gouge/scraper out of a nail set into a piece of dowel, hardened (I hope!) with heating and quenching, then filed to shape and sharpened. And for smoothing in those tiny gaps, I'm supergluing little pads of sandpaper onto the ends of wooden skewers, after first cutting off the point at an angle. We'll see.

I'm fairly happy with the 3D printed chassis: The dimensions are correct It looks a lot like an elongated version of the Hornby original I don't mind the rough surface, since it's all flat black The NEM pocket is at the right height The springs and axle boxes look fine to me, and so does the detail underneath The weight from the original fits where it's supposed to But I made a couple of mistakes The buffers are too far apart The rectangular holes are meant to accommodate the clips on the bottom of the body, and I intended this to work with a coach made either of 2 x 2-compartments, or one made of 1-compartment plus 3-compartments. But the inner holes aren't in the right place So I'll try to cut new holes to make this one workable, but I'll probably also fix the design and get another print.

I tinkered with the chassis, and found that after a bit of backwards and forwards running, and a bit of oil, it started to move much more freely. It's still rather unreliable on track, and the pickups do not make contact with the back wheels. But when it does move it is rather brisk. So I've ordered another motor, with a higher gear ratio, and I'm crossing my fingers.

Still looks good, even though exploded!

Thus far, I have designed four conversions (side-tank, saddle-tank and two tender engines) for the outside-cylinder version of the chassis, and one tender engine for the inside-cylinder version. These are here and here (I haven't got around to making the streamliner available for sale yet). The outside cylinder tank engines simply use the existing cylinders, whereas the tender engines have wrappers around the cylinders. The tank engines are my earliest and least satisfactory designs. I'm hoping to replace them (hence the saddle tank above). Indeed. I could certainly violate my ban on chassis modification for these purposes (provided it did not alter the outside shape of the cylinders). The slot in the cylinder is quite large, so I think there is room in there for a 3D printed part, which could be the basis and anchor for the rest of the mechanism. I have produced a few sketches, but so far nothing more.

What you're showing here requires more skill, boldness and better resourcing than my reference pre-teen can muster. I know that some people (of all ages) can step straight into the hobby at this level and achieve a success, a failure and two successes in short order. But I regard this as fairly advanced modelling. My 12-year-old is, frankly, a bit gormless (I don't mind insulting him, because he's me!). Such people need a little bit more help dipping their toes in the water. And if everything (except glue and paint) comes in a single box, then their chances of success are much higher.

I should have said - "... the only R-T-R chassis that fits this description and is currently manufactured...". My target 12-year-old doesn't have the knowledge/experience/money/driving-license for scouring flea markets and Ebay for the right chassis, and maybe making a working chassis out of three non-runners. There are certainly some enterprising 12-year-olds who can do these things (and the Internet helps these days). But I'm aiming for the lowest common denominator: an un-enterprising 12-year-old living miles from the nearest shop (myself, in other words). From this perspective, a working chassis is a precious, scarce resource. Let us suppose that exactly one working chassis is available, and the number is permanent and fixed. The project must not require the modification of the chassis because: It must be possible to get back to the original working state with the original locomotive body. We must minimise the risk of turning the chassis into a non-runner. It is the combination of these factors and the price that make the Hornby 0-4-0 chassis the only option, from my perspective. But you're absolutely right - a (normal/traditional) chassis, with the motor completely between the wheels, would be far better. The basic form of this chassis is perfect. The Hornby Peckett chassis would be better, a low-end Hornby 0-6-0 chassis would be fine, a Bachmann Percy chassis would be fine. But all of these things are a step up in price (certainly when new) from the Holden and its cousins. If my hypothetical kit maker also supplied a chassis (sold separately) then all these problems would evaporate. One cheap-ish chassis, plus 4 cheap-ish modular superstructure kits (covering a few different locomotive types) could produce a couple of failures and a couple of nice working models. This would bring the whole activity back into model Spitfire territory "I made a mess of the paint job, but it doesn't really matter" versus "I took the wheels off, and now I can't get it working again".

I've been rummaging on google and found this. https://cults3d.com/en/3d-model/various/oo-ivor-the-engine

The problem, as I see it, is that there are plenty of resources for older (or more experienced) people, but nothing for a young (or inexperienced) modellers who want to dip a toe in the water. There are numerous inexpensive tank and aeroplane kits, but no railway model equivalents. The remaining Kitmaster/Airfix/Dapol kits are fine for producing static models, but motorising them is not for beginners. My stipulations for a beginner-friendly locomotive model kit are: It has to work on a proprietary motorised chassis (alternatively, a kit could include a working chassis). If a borrowed chassis is used, then as far as possible, it must be unmodified, so that the original body can be restored. People with reasonable incomes can buy plenty of second hand Smokey Joes, but people with only pocket money might not want to risk their one-and-only tank engine. If a borrowed chassis is used, then it must be as cheap as possible. Assembly must be straightforward - this suggests injection moulded polystyrene (and NOT whitemetal or etched brass!), but maybe other materials would be suitable. Painting must be manageable - ideally the kit would include waterslide transfers or similar, just like a 1/72 aeroplane kit. Unfortunately, the only R-T-R chassis that fits this description (somewhat) is the Hornby 0-4-0 Pug/101/etc. I say unfortunately because the motor mount is very wide, which makes it hard to design bodies (apart from side-tank bodies) that will fit. My 3D printed bodies are a step in this direction (and others have taken similar steps, both on Shapeways and elsewhere) but we are still a long way from anything that satisfies my 5 stipulations.

Thanks folks! Another advantage of having separate details is that the main body/structure could be printed at a relatively low quality, and the details printed at a high quality (fine resolution). And yes, I think it would make sense to have a modular kit with a variety of different build options. I think that Shapeways is a bit of a dead-end for my purposes. Removing details wouldn't reduce the cost, and having separate detail parts would of course increase the cost. What I would really like (to give to my 12-year-old self) would be an injection moulded kit along these lines. And maybe one day I will identify and approach a suitable manufacturer. Or approach someone who provides 3D prints of higher quality at a more favourable price. As for the bunker - I justified these dimensions to myself on the grounds that the Hornby Holden 101 (and the prototype, I believe) also had a very skinny bunker. But I agree that it looks a bit weird. Maybe I can enlarge it by a millimetre or two without making the footplate too small. In fact there are many shared elements between all my designs thus far. A lot of things get re-used with small adjustments. Thank you! I wanted it to be generic but with GWR leanings, and whenever I needed guidance I asked google for "GWR saddle tank" images. So if it looked like that to you, then I've succeeded. Failed prints are not much of a risk with Shapeways once the design is known to be printable. And I've made the details chunky to ensure that they can be printed in the low-resolution "Versatile Plastic". And this stuff it extremely strong - damage in transit is not a worry at all. That is the upside of the poor detail. Pilot holes or indentations - yes. As you say, I could easily make two versions, one with and one without. The Versatile Plastic (previously known as Strong and Flexible) has two related drawbacks - the inability to support fine detail, and the rough surface finish. For me (working down here at the "toy trains" end of the spectrum) the rough surface isn't all that bad. The poor detail is the worse problem. I have seen people filling and sanding to get a high quality finish (since this sometimes destroys what detail there is, this also contributes to the case for separate detail parts). But for my tastes a few coats of paint are enough to achieve an acceptable (although not ideal) surface. Good idea. The answer to "why not?" would surely be "but Ivor should be a 009 conversion of an N gauge tank engine". But (again, acting on behalf of my 12-year-old self) I want to bring the carefree fun of freelance 009 to the more beginner-friendly 00. So something Ivor-esque would make perfect sense.

Hello. Here is a saddle tank body to fit on the inside cylinder version of the Hornby 0-4-0 tank engine chassis. I'm planning to (get Shapeways to) 3D print it in 3 pieces, with the cab roof and bunker separate. Before I do, I would be grateful for any suggestions for improvements, but: The large splashers are necessary to conceal the motor mount. I don't plan any finer detail (such as handrails) because I'm already near the limits, detail-wise, of the "Versatile Plastic" printing option. Full disclosure: I will offer this for sale (but my Shapeways shop is not a business in any meaningful sense).

I finished my sanding and joined the sliver to the main body. I stripped some of the paint off to get a better view of the beading. It isn't perfectly aligned, but I don't think I could have done much better. There was also a little gap on one side, in spite of my caution. I have filled it with a sliver of plasticard (sanded down from a thin sheet - you can see where I made holes with my fingernails. I've designed a chassis, trying to follow the general style of the Hornby chassis, but with some vague suggestions of detail added. Hopefully this will help to make the 4-compartment coach look as though it belongs with the 3-compartment coaches. I have ordered a print from Shapeways - I will be able to recoup the cost if I go without food for a month!

Slowly, slowly sanding the two ends back a little bit at a time.

I've cut out the two ends (cutting parallel to the length of the body), and started sanding them back to glue together. They must both be sanded back by the same amount, until the one-window sliver fits into the gap. Hopefully the remaining beading will line up perfectly.

And here: https://plasticsoldierreview.com/Review.aspx?id=239