Converting models to 'EM' gauge isn't really difficult, the worst part is plucking up the courage to dismantle your latest pride and joy, Items of rolling stock present few problems, as in most cases replacement wheels will drop straight in, at the very worst, the brake shoes might need to be trimmed, or realigned. Sometimes a little material might need removing from the back of the axle boxes, or 'W' irons, but that's about it. Locomotives are obviously more difficult to convert, but there's plenty of help available, online and in the model press. Before I start a conversion I test the model on my rolling road, and on a length of track. I'm looking for any faults before I strip things down, if the model was working fine before I got my hands on it, but runs terribly afterwards then I know who to blame. There are three ways to convert a model to 'EM', and I'll do my best to cover each in turn. To begin with, in some cases you can pull the wheels out, not that I recommend that particular method, but it can be useful as a temporary means of getting something running, or if the correct wheels are not currently available.
When Dapol launched their Class 22, it was widely expected that Ultrascale would soon produce a replacement 'EM / P4' drop in wheel conversion set. However on examining the model they felt unable to proceed, due to the costs involved in producing a suitable new wheel. Some finescale modellers decided to use existing wheels from Ultrascales range, albeit with shorting wires between the metal rim and the axles, and the wrong number of spokes. Whilst others with lathes, and the skills to use them modified the original Dapol wheels. In 'EM' it is possible to pull the wheels out to a wider gauge, and as long as you can accept the coarser wheel profile, its a simple enough job. However care needs to be taken when setting the wheels to gauge, because the Dapol wheel is not machined to the recommended 'EM' profile, or standards. This means that the usual back to back gauge will not set the wheels up accurately, the way to get around this problem is to use a check gauge.
Its easy enough to make your own from a piece of 40 thou styrene or paxolin. The check gauge for 'EM' is 17.25 mm, which is the measurement required, between the face of one wheel flange, and the back of the other. Once each wheel has been set up correctly, and as long as your points have been built with the appropriate gauges, and laid on a level baseboard, then smooth running, without derailments is guaranteed.
This how things are supposed to work, as the wheel set passes through the crossing, the check rail gently pulls one wheel over, so that the opposite one just misses the crossing nose, its that simple. You often come across complaints of derailments, and the usual response is, have you checked your back to back settings? But the truth is, unless you are using one particular make of wheel, which is machined to a consistent standard, a back to back gauge is as useful as a chocolate teaspoon.
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Anyway, enough, what about the actual conversions, starting with the Dapol Class 22.....
First of all support the model, the foam packaging material from its box is ideal. Then remove one of the bogie side frames, and wheel keeper plates, these are a one piece plastic moulding, and released by gently pressing their retaining clips, there being one at each end.
The whole moulding can now be lifted clear revealing the wheelsets, and drive train. Each axle, and its bearings can now be gently levered out of their retaining slots with a small jewellers screwdriver, taking care, not to damage the pick up strips in the process.
The wheels are a push fit into a plastic muff, which also incorporates a drive gear, simply pull them apart, add a 1 mm spacing washer at either side and reassemble. Set the wheels up on their axles by using the aforementioned check gauge, check that they will pass through your pointwork, and refit them into the bogie. The next job involves modifying the bogie moulding as in the above photo. I used a variety of craft knifes, removing a little material at a time, and then finished the surfaces off with nail file boards. The bogie side frame moulding can then refitted, and the same operation carried out on the second one. There are no pickups to adjust, so now its just a case of putting the model on the track, and testing it.
Personally I don't think the wheels look that bad, but if you can't live with them, then you will have to turn them down, or wait until the correct wheels are produced, but don't hold your breath.
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Ultrascale drop in wheels
The next conversion, which uses an Ultrascale drop in wheelset to convert the Heljan / Hattons Class 14 is even simpler. The wheelsets are available in '00 fine', 'EM' and 'P4', the procedure to fit them being the same, though the wider gauges will need the pickups adjusting to suit
The replacement wheels, and flycranks can be seen at the top of the photo, notice how fine they are when compared with the originals. The amount of wheel side play, has to be seen to be believed, fortunately the replacement wheels, with their spacing bushes will take good care of that.
Using a small jewellers screwdriver, the keeper plate is gently levered out, by working the screwdriver along the length of it. Extra care needs to be taken around the gear cutout, as the plate is weak in that area. Next the old wheels are removed, the ready quartered replacements are dropped in place, and the keeper plate refitted. Then its a case of adjusting the pickups, they just need bending gently outwards with a pair of fine tweezers, until they are in contact with the new wheels. A word of warning, watch those cab footsteps, they are ever so delicate, as you can see I broke one off. I simply filed the broken spigots flat, drilled new locating holes for 0,45 mm wire spigots, and glued them back in place with a touch of cyano.
Finally its time to refit the connecting rods, these come in several sections, and are handed. Remove them one at a time from the original wheels, then open each crankpin hole out to 1.7 mm, as per the instructions, I used a broach myself. Now fit the rods onto the crankpins of the new wheels, and secure them with the nuts provided. A pin vice comes in handy to hold the retaining nuts, and to screw them in place. Finally, once the model has been tested, and you are happy with its performance, cut and file the coupling rod pins down.
The work outlined here is more or less the same for other RTR conversions, which make use of the Ultrascale drop in wheels. Now, I don't mean to be cruel, but if you can't do a simple conversion such as this, then stick to '00', and forget about 'EM' or 'P4'.
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Alan Gibson also produce an ever expanding range of wheel conversion kits, and components for RTR models, they also have a range of 'How To' sheets, to help you on your way. Simply visit their website, to which I've provided a link, and click on 'Downloads', then select the 'How To Sheets' followed by the model of your choice. Unlike the Ultrascale kits, these aren't a simple drop in replacement, as the wheels have to be mounted on their axles, and quartered, that's unless you are converting a diesel bogie. The original drive gear also has to be removed from the old axle, and refitted to the new. I've previously explained how I converted my Bachmann 64XX to 'EM' using Gibson wheels, and components, so rather than repeat what has been published before, click on the link if you want to learn more.
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If you fancy an 08 shunter, in 'EM' or 'P4' then take a look here, where, Paul Marshall-Potter explains the conversion in detail. Or join the EMGS, the Scalefour Society, or both, where you will have access to numerous conversion sheets, and be able to purchase the components that you will need.
So there you are, start with something simple such as a diesel, or an 0-6-0, and take your time, for there's no prize for the quickest conversion.