Building a London Road models 50' turntable
The need for a decent UK outline turntable at Thurso was eventually solved by using the kit from LR Models and I thought I would add a few words about it here about it here, not really a blow by blow account but some observations, as it is something that most would build once, I would have thought, and thus have no fall back experience to draw on.
The kit is a nickel silver etch, and obviously well designed and thought through - I encountered no real problems with it, but it does need a good deal of precision and care in assembly in order to function properly, so I approached it with more care than I often apply to stock builds, reading ,and mostly following, the instructions to the letter. They are well written, but need going over a few times to get an overall picture, and might have benefited from a few images for clarity; at least I would have found this useful. However, a bit of searching threw up this topic, which was most helpful in my build.
This is what you get in the box, along with sufficient bits and pieces of brass and plasticard to finish it off.
The sides are two layers sweated together, and holes are provided to put brass rods through to keep everything aligned. I put everything with Carrs 188 degree solder paste which gave a solid easy join with little extra overrun and was easily cleaned up.
The table deck and sides are removeable with electrical contact for the rails coming through the pit rail and carrier wheels, so these need to be isolated from the main decking with layers of Plasticard and are attached by screws to allow some degree of adjustment. I had to open out the holes in the carriers slightly to get everything aligned, but this was because I managed to get the holding nuts slightly off position when soldering them in place. Not a big problem, but indicative of the care needed all the way through.
The carriers and the T shaped drive shaft holder and bar that the deck sits on.
The carrier wheels as assembled off the etch- layered and soldered together. They then need to be filed down to a finished diameter, and as smooth contact with the rail is critical, I realised that hand finishing was not going to give a consistent surface. Also in view is the box that drops over the brass rod and which the table sides and deck is soldered to.
Being no engineer, I cobbled this assembly together, and fixing the wheels into the mini drill, I reduced them to the required diameter. Homespun, but it did the job.
I managed to forget to photo the deck assembly, but it all went together without hitches and the wheels were jiggled to keep in contact with the rails by trial and error. The whole table is held in place on the rod by two bushes that are located at the end of the slot in the box - I was a bit unclear about this from the instructions, but got advice from LRM and LNWRmodeller, which cleared things up. They can be placed either inside or outside the box, with a tiny clearance, as sen in the second photo.
There is a plastic pit available, which I used. It's fairly flimsy, and I did think of reinforcing the base, but in the event it proved unnecessary A brass bush is placed at the centre and care is needed to get this exact, although the base is marked as a guidance. Then it is a case of fixing the guide rails in place, again to precise placing. I made use of a Metalsmiths jig supplied with his T/T kits - I don't know if LRM supply one, but it would be easy enough to make ones own. Once the first couple of chairs were fixed it was a case of setting and gluing around the circumference two or three chairs at a time, letting them set before the next set glued.I would advise a strong solvent for this - I used one that did not have enough grab - some came away when I cut isolation gaps in the rail later, so Plastiweld was run round them with the jig in place which did the job properly if adding a few days delay to it all.
Eventually it was tested, fettled and fitted on the layout, and the drive motor fitted to the shaft. this is a motor /gearbox combination and gives a slow rotation speed ,but without any indexing. As the table is right in front of me I can align by eye, and is not really proving a drawback. The motor is attached to a strip of brass and screwed to the baseboard as shown.
This set up took some work to get a smooth rotation, thanks to crossbeams being in exactly the wrong place, resulting in the whole length of the strip being used. I would far rather had the fixing holes much closer together as the strip has too much flex in it, and might need work done to it yet, although it is working well just now. Finally, a couple of shots of it in place, looking quite at home on a branch line.
All in all, a pleasure to build, and supplies something that is essential for UK modellers - a pregrouping turntable suitable for secondary services.
Edit
Reinstatement of what images I could find, in no particular order, but better than nothing. Hope this is of help to someone...
Edited by Ben Alder
Update
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