Chuffer Davies

How on earth did I not know that? I’ve only ever known the station as Bath Green Park, and I’ve never heard of a Queen Square in Bath, only the one in Bristol I cycled through every week day on my way home from school in Brislington. And now I understand the origin of the queensquare handle. Thanks for the explanation. Frank

Surely we are talking about Bath Green Park? My childhood recollection is that Queen Square is in Bristol and being square faces the 4 points of the compass. Frank

Looking remarkable Jerry… The layout that is, although I suppose Glastonbury is remarkable for completely different reasons. Frank

Oops, how embarrassing…..,,, checking my order I didn’t actually put the J50 chassis in the basket which is probably why Chris hasn’t sent it….. Expect a new order Chris…. Frank

No one can be sure without someone trying it and reporting back, but the earlier slide bars are a single casting with the piston rod gland and is a friction fit into the plastic cylinder end plate. I would expect the new and old castings are interchangeable. Frank

Hi Chris, firstly many thanks for the amazingly fast (48hour) turn around on my order. Outstanding service as always. I assume the J50 chassis is on back order which is fine because I wont need it for ages yet but the motor and gears will be test installed tomorrow? Secondly I just wanted to say that, now that the penny has dropped around its design, how I enjoy using your CSB jig. It’s a brilliant piece of kit making the drilling out for the CSB supports near (if not completely) idiot proof. Finally, I’d like to offer my support with regards to your proposal to provide kits without stock wire, tube, etc. Having designed a few kits myself I know how time consuming it is not only to source the materials in the first place, but also to prepare and include all the bits of wire in a kit. The (time) cost to you must be significant and yet most of us kit/scratch builders will already have suitable wire and tube in stock. Regards, Frank

Looking at the samples I’m pleased to see that they have re-designed the slidebars and have removed the flared ends which had been a major bone of contention when the earlier model was released. I think I’ve also read that this model has the revised higher gear ratio which delivers better control at low speed (especially on analogue layouts), and a more prototypical top speed. The earlier model was good but with these improvements the new model has the potential to be very good. Frank

Hi Jerry, Tie bars for double slips are a challenge in my scale of 4mm so I can’t start to imagine how much harder they are in 2mm. Looking at the double slip in the photo I notice that all four blades are fixed solidly at the ‘k’ crossing end. This is problematic and creates significant forces at the tie bar. When I build double slips I cut the rail of the inner blades and install them using fishplates so that they can slide laterally. The outer blades are therefore equivalent to those on a standard point controlling the position of the tie bar between the sleepers, and the inner blades move for and aft eliminating any stresses that would otherwise be created on the tie bar.

Hi Tony, the 28xx chassis is completely different to the 47xx series. The 47xx is an extended design of the 43xx Mogul. Brassmasters sell the Finney 47xx kit and might be a able/willing to provide you with a chassis kit… Regards, Frank

As previously reported, I have been assisting Paul Craig with the development of a new LRM kit for the J52/53. My role has been to test assemble the model using the etches and castings supplied by Paul. A few months ago I showed the completed first test build of the model in bare metal on WW. I have now received this back from Ian Rathbone (many thanks Ian) who has kindly painted and weathered the model for me, and thought it would be of interest to followers of Wright Writes. The model is based upon a loco that was based at Bradford in 1930 which retained its condensing gear despite it being unnecessary for working around West Yorkshire. The model has been built with High Level CSB suspension, Gibson Wheels and a High Level 1219 coreless motor mounted vertically in the firebox. In this instance I didn't want to deviate from Paul's primary design principals and so the model has conventional (back scratcher) pickups to the offside wheels with the chassis live to the nearside wheels. We still have some minor corrections/enhancements to make to the CAD work and I will then test assemble the corrected components before this can go into production. It will still be a while before this becomes generally available but I think it will be well worth the wait. Frank

I concur, it does seem a somewhat extreme decision to have a flat plate across the whole of the coal space looking nothing like the prototype as a result. It would have been more appropriate, perhaps, to provide an alternate moulding with a more accurate representation of the coal space that could be removed/replaced for those minority (?) of modellers wishing to fill the whole of the tender with loudspeakers for DCC sound. Frank

Hi, thanks for the suggestion but I’m thinking High viscosity would not be drawn into the wheel/axle interface whereas a low viscosity glue might be better drawn into the joint by capillary action. What would be your take on this? Frank

Hi Bill, I’m confused…. Can you restate for clarity please? After your earlier comment, I’m going to do some investigation around Loctite products and superglues. My concern with superglue is that I’m not sure it would provide enough time for tweaking the quartering (I do it by eye) before it goes off. Frank

Hi Mike, that is useful information about the Gibson tyres. I have occasionally had a problem even recently but it’ll be because I abuse the wheels by soldering shorting tags to them. The heat no doubt causing the tyre to expand and break away from the wheel. No matter, as I have said previously, a quick dab of Epoxy sorts it as it would for tyres on the early wheels before Colin took over. My experience of less grippy Gibson wheels has definitely supported my observation that grip degrades as the wheel diameter increases but I defer to your greater experience on this matter. I must say that some of his smaller wheels are so friction tight on their axles that I have to put my Marigolds on to get enough finger grip to shift them. Frank

Hi Tony, you have indeed illustrated on many occasions that Markit wheels can readily be used in EM and often without modification to the kit/commercial model being built. None of the contributors to WW have ever said anything to the contrary. What we have said is that this is not universally the case and SOME models need adjustment to allow for the extra width of the Markit wheel that is not necessary when using plastic centred wheels in EM. However: several equally experienced modellers have said that plastic centred wheels can be used just as successfully if certain precautions are taken. These are: - ensure that any sharp edges are removed from the axle end before attempting to press a wheel onto its axle. This prevents any risk of plastic being shaved away from the hole in the wheel which will introduce an incurable wobble. - in the case of Gibson wheels, if the wheel’s date of manufacture pre-dates Colin taking over the business from Alan Gibson, check the tyre is firmly attached to the wheel. If it is loose it can be refitted with Epoxy glue. (Not an issue for wheels purchased today) - keep to a minimum the number of times wheels are fitted and removed from the axle during the build process - with (perhaps) the exception of the smaller Gibson wheels you should never rely on friction alone to hold a wheel permanently on its axle. Wheels can be reliably locked onto their axles using Loctite 601 or by methods such as knurling with a file, or pinning. Plastic centred wheels require a back to back gauge to ensure correct spacing. Quartering can readily be achieved by eye but some modellers prefer to use a jig. There are commercial b2b gauges and quartering jigs available. Be aware that (unfortunately) some Gibson wheels run eccentrically to a lesser or greater extent. In summary Markit wheels are by far the easiest to use but their width is sometimes a problem. Plastic wheels require care when fitting but are often visually closer to the prototype and the axle ends look better than the nuts on a Markit’s axle. Their thinner width as compared to Markit wheels in general avoids the need to reposition slide bars or splasher fronts. Modellers currently modelling in OO but with aspirations to model in P4 might benefit from experimenting with plastic centred wheels because Markit do not sell P4 wheel sets. Frank

The wheel centres on Markit’s wheels are approx 0.5mm thicker than those of Ultrascale and Gibson. In EM this causes the crankpin on the leading wheel to hit the rear of the cross head/slide bar. Modellers either have to find a way to move the cylinders out or re-drill the positions of the piston rods and slide bars off centre to adjust for the extra width. Ultrascale provide a special crankpin nut for leading wheels to help overcome this issue. I use this Ultrascale crankpin nut even when fitting Gibson wheels for this very reason. The other problems in EM with the thicker Markit wheels are that the splasher fronts on some kits and proprietary models are set at the prototype distance and Markit wheels are too wide to sit between them. This can also be an issue for locos with narrow cab sides. In the case of the Bachmann Atlantic (above) it would have meant removing the cast footsteps on the side of the footplate to get clearance for the connecting rod. Regards, Frank

Whilst Markit wheels are excellent for the inexperienced modeller, plastic centred wheels are not the disaster that is often portrayed here on WW, and Markit’s wheels cannot be used if modelling in P4. Several of the regular contributors on WW have reported considerable success with plastic centred wheels because they have taken the time to understand the pre-requisite actions needed for success, as well as being willing to take the small amount of additional time and care required to fit them. The positives with plastic centred wheels are that the modeller can more often obtain the correct one for the prototype being modelled and it also more often avoids the need to reposition slidebars and splasher fronts when modelling in EM due to the narrower wheel profile. As to the suggested simplicity of using a nut to attach a wheel to its axle, I can only see a minor distinction between using a nut or applying Loctite to fix a wheel firmly. With practice quartering without a jig, and setting the back to back accurately, are easily acquired skills. I think it is unreasonable to suggest that all plastic centred wheels share the same issues. Ultrascale wheels are flawless, tyres cannot come off, and they always run true if fitted correctly. I acknowledge that the delivery time for Ultrascale products is 8 months but if you plan ahead this is rarely an issue. Gibson’s wheels occasionally have problems but are much cheaper than Ultrascale’s as well as being considerably cheaper than Markit’s. Their quality reflects their lower price and they sometimes suffer from loose tyres but these are easily cured with an Epoxy glue. Some Gibson wheels wobble slightly but under normal running conditions the loco doesn’t ride any more roughly than the prototype tends to do. In summary plastic centred wheels can, with a bit of care, be used successfully as long as the modeller has taken the time to learn how to fit them properly. Markit wheels are the best wheels for an inexperienced modeller but are expensive and be prepared for other problems if modelling in EM. Frank

Hi Mike, Just for clarification, do you knurl the axle ends as well as using, or instead of using, Loctite. Frank

Guy Williams definitely wrote about drilling and pinning friction fit drivers onto the axles of some of the models he built. I am not convinced that mechanically this would prevent any slip from occurring because of the malleability of the plastic; surely the wheels would still twist slightly before the pin finally locked the wheel from moving further? As someone who has used friction fit drivers extensively running heavy trains around the Hungerford exhibition layout, I do not pin my drivers but always Loctite them onto their axles during final assembly. The join can be broken if necessary at a later date but it needs considerable finger force to do so, and far more than a model motor could excerpt. The one failure I have had with this approach was when the centre hub of a Gibson wheel developed a fine crack down to the axle reducing the pressure gripping the wheel against the axle. In my opinion the activity, if anything, that is going to crack the joint is when the power is removed from the loco suddenly (i.e.a sudden short) and the whole weight of the train is then pushing against the motor driven axle. This sudden force might be sufficient to do it. This is unlikely to happen with Portescap motors (used extensively by Guy) because the gearbox can work in reverse and the wheels can then drive the motor avoiding the lock up that will occur with a worm driven gearbox. Frank

Hi Iain, that’s just what I needed to know so thank you for going to the trouble of describing it so completely. Just one further question please: is the scriber a generic scriber or one specifically for glass cutting? Once I know, I can get on and order one along with some slip covers and have a practice. The thought of building brass coaches itself doesn’t intimidate me but it’s the non-brass bits that make me nervous. Many thanks, Frank

Hi Iain, as someone who has yet to start building any coaches, but I have an articulated pair of D&S coaches to build in due course, can I ask you where you source the glass for the windows and how do you then cut it? How then do you attach the glass to the carriage sides? TIA, Frank

As I said Tony, it is quite evident the model runs well. You would not tolerate anything different. It’s just that if you were able to examine it close up under operation the middle wheels will be constantly climbing up and dropping down in their slots albeit by a minute amount. Had you used a floating bearing of some type the spring would maintain the contact between wheels and track as you intended. Frank

I feel your pain. It took me a couple of goes to get my head around it but I’ve not looked back since. Frank

Hi Tony, Your J3 chassis may not actually mechanically operate as you believe. It obviously still operates sufficiently well to meet your needs, but I suspect your centre axle may actually be climbing up the grove you’ve created in the top hat bearing and lifting a wheel off the track when it does. I say this because of a school boy error I made when making my very first compensated chassis. It was for a GW 2-8-0 tank engine. I made the frames out of 1/16” thick brass strip. The axle holes were drilled out 1/8” and then elongated vertically with a file to create slots for the axles to rotate in. I built beams resting on the tops of the axles to provide the compensation mechanism. The model ran perfectly light engine but as soon as it had to do any work it rocked and rolled its way along the track because the resistance created by the train caused the axles to climb up their slots. I’m pretty sure the same thing will be happening with your J3 chassis but because you’ve made the slots very short it won’t be noticeable. Certainly not enough to cause the kind of problems I had, but neither will you be getting the outcome you think you are getting. The mechanics of this kind of solution needs some sort of hornblock even if this is just a top hat bearing held by some means to prevent it turning but still able to move vertically in its slot. Steve’s solution includes such a mechanism and will work as expected. Frank

Hi Steve, sounds like a nice compromise way of gaining much of the benefit of springing without going the whole hog. As I see it, the downside of raising the position of the centre axle to avoid rocking also results in the centre wheels no longer being in contact with the track which in turn results in their no longer effectively providing traction or current collection. In contrast your approach results in the centre wheels constantly contributing to both traction and current collection. I also applaud your experimenting with the American pickup system, an approach I have long adopted myself so as to remove any need for the installation of physical pickups. Frank