Valentin

This works so well, it made me get another three coils of code 30 plain rail. I use a cork instead of the eraser.

Not on my workbench, but new "housing" for my workbench (work in progress):

I get 9% phosphoric acid from stands at railway modelling exhibitions. Around £3.00 for a 100 ml bottle.

Thank you, Jim. After a bit of work I came up with this, which gives me an overall reduction ratio of 52:1. I could go with a 40 teeth secondary gear (instead of 38) which would give a 55:1 but I would really struggle to fit the motor and the clearance between the gear and the side frames would be very tight. Not sure if, and when, this is going to materialize; for the moment, on my "workbench" are ten lengths of 45 x 145 x 3000 mm timbers for the next stage of the garage conversion. Hopefully I will finish it in time to be able to do more work on my GJLC entry...

The end elevation shows that I can increase the overall reduction ratio.

I wouldn't hold my breath, Keith. I remember you emailed me that photo a while back; it's a shame the engine didn't meet the line's expectations. They're still in production, hauling logs from the forests in Romania. And also on some heritage railways.

Encouraged by Julia's 4mm-gauge diesel engine, I am planing to build a 5mm-gauge steam engine (see the drawing below). The current overall reduction ratio is about 26:1 but, I would like to increase it as there is space for a larger than 30 teeth (O/D 6.4) idler and a smaller than 16 teeth (O/D 3.6mm) driving gears. Could anyone advise on how far I can go? There is enough room in the boiler to fit a 12 teeth driving gear and a 40 teeth idler to achieve a 47:1 overall reduction ratio. I am not sure if this would be practically possible though. Another question is about the gear material; I am thinking of brass but Mikroantriebe can supply then in black polyacetal or white polyacetal. Apart from being less noisier than brass, is there any other advantage in using polyacetal (black or white)?

I will do an end elevation anyway, but this may also work. I am thinking of a 7x15mm Tramfabriek motor with shafts at both ends so I can fit a flywheel.

Thanks for the feedback, Jim. It's narrow gauge (2'6"):

That, Jim, was my first thought when trying to change the overall reduction. Here we are: And I tried even this: Or this, with pulleys, although a have to increase the spacing to about 6 mm as the smallest belt is about 4.5 mm inner diameter.

I forgot to mention that this is not a "split-chassis" design, so no muffs - the brass gears are soldered directly to the steel axles. All axles are 1.5 mm in diameter apart from the one supporting the worm gear which is 2 mm. The reduction is 16.5:1 and the wheels are 5 mm in diameter. I came up with another arrangement, which gives an overall reduction of just over 26:1. I'm not sure if this is a better design though. Another option to further increase the overall reduction would be to use pulleys.

Your work gave me confidence that I may be able to achieve something similar with my little engine although in a slightly bigger track gauge (5 mm). The rear two axles will drive the front two by coupling rods. I wonder if this is feasible.

Hi Max, Please don't get me wrong but I think you keep asking these questions in the wrong section of the RMWeb forum. I am sure there are some finescale modellers here who may be able to help, but you could get much more feedback to your enquiries if you post them elsewhere. For instance, RMWeb hosts a Collectable/Vintage section, or maybe the Modelling Questions, Help and Tips one? Best regards,

Hi Max, Please don't get me wrong but I think you keep asking these questions in the wrong section of the RMWeb forum. I am sure there are some finescale modellers here who may be able to help you, but you could get much more feedback to your enquiries if you post them elsewhere. For instance, RMWeb hosts a Collectable/Vintage section, or maybe the Modelling Questions, Help and Tips one? Best regards,

I'm following this with interest as I try to make sense of a slightly larger, 2ft 6in gauge, outside frame engine...

The paper clips are far too stiff to reliably rub against the tyres. You should really use phosphor-bronze (P/B) wire or very narrow strips - much better elasticity and less prone to collect dirt from the tracks. You won't find many chassis using pickups in 2mm finescale as these are made redundant by the split-chassis design; you should probably look for help with this issue in the "Modelling Questions, Help and Tips" forum.

Two SG90 servomotors controlled by an Arduino UNO board. The actuator wire will be installed horizontally, in line with the wire / omega loop connected to the tie-bar. Together with the 'straight' and 'divergent' angles, the speed can be also adjusted. The four push-buttons have integrated green LEDs. Link to the video clip (approx. 35 seconds)

I doubt it. I needed it just for an accurate drawing. In real life I would use the gear meshing tool.

The Gear Data Tables in the Yearbook state that 0.1 mm running clearance should be added to the theoretical M0.3 gear centres and 0.15 mm for the M0.4 gears. Is it correct to assume that 0.05 mm should be added for M0.2 gears?

The wheels are Märklin and, together with the gear, are fitted to 1.2mm dia axles (pictured below). The project involves narrowing the gauge, from 6.5mm to 5mm, which leaves the axles protruding around 0.5mm at each end (the P/B outside frames alone are 0.7mm thick). The plan is to use a "gear puller" tool, and remove the wheels and the gears from the axles, replacing them with longer ones so they can pass through the frames and allow enough length to solder the cranks. I could also rim the wheels and the gears and fit them to 1.5mm dia steel rod ("Eileen's" don't sell 1.2mm dia steel rod.

Would be possible to use the Brass Straight Wire 1.2mm dia (Eileen's Emporium) as wheel axles? they will spin in P/B frames. Is this wire tough enough to not easily bend? I could go for steel rod but I would like to solder the N/S cranks at the ends of the axles; I am not sure I can do a sound join between N/S and steel.

What sort of baseboard is that?...

In the August 1984 edition of "The 2mm Magazine", @Phil Copleston wrote the "Narrowing it down" article, describing what might be the 2mm Narrow Gauge standards with normalised gauges, a potential benefit being the batch production of precise building aids, such as roller gauges and back to back gauges. I know that these are now ready available for the prototype metre gauge (normalised 2mm gauge of 6.5mm) but what about for the other prototype narrow gauges? I am interested in 2'6" prototype (or 5mm scale equivalent).

Hello Max, I am a fan of the American couplings; I use the Micro-Trains Line Z coupling for my Nn3 models. If I was you I would try to keep the existing ones on your model as they are representing better the real knuckle couplers. I'm afraid I couldn't advise you on any "Toy Like" couplings but please note that you may be asking the questions in the wrong section of the forum. This is the 2mm Fine Scale area of the forum - although near to the commercial N scale there are big differences. I'd say the best place to get answers would be the "Modifying & Detailing RTR stock" section of RMweb. Good luck,

Thank you all for your feedback. I will leave it for longer than a day as we're going on holiday for a couple of weeks. Once we're back home I will start the "troubleshooting" with your suggestions.