Work on the Mechanical Horse tractor unit has progressed well with Steve completing the wiring. He has tested the circuits and it was a pleasure to see the lights working for the first time. The side lights now have wartime blackout shields fitted to reduce the lens size to ¾" and seem to produce little more than a pinpoint of light. The shielded headlight is particularly pathetic and I cannot imagine the dim glow on the road being any use to a driver at all. No wonder the blackout caused so many road accidents. Apart from a spot of paint under the cab the single remaining job is to sort the engine. To this end we have removed the cylinder head and found the valves and seats corroded which would account for the lack of compression. A few days work has got them about as good as we can get with grinding paste and we hope it will be good enough. We have fitted the head back on (using the old gasket) for trial purposes and the compression is better but not as good as it was way back in the seventies. We have fitted the replacement magneto and I removed the copper fuel pipe and annealed it and re-bent it without all the wiggles and kinks. It won't work any better but at least it now looks tidy. We have fitted new spark plugs and fan belt and once new period plug leads and caps are fitted we should be ready for an oil change, setting the timing and who knows - with a drop of petrol we may be able to get it to start - but I have a feeling more work on the valves is required.
Work on the Pole Carrying Trailer has progressed well also. At first we intended just to fit mudguards to protect the tyres from sun and rain, and maybe de-rust and paint some steelwork that can be saved, but as we had angle iron to hand to repair the supporting frame for the backbone we did that. Then, as we had the jockey wheels for the stand we ordered some steel angle and built that. We also replaced a fabricated box cross piece on the rear carriage, and thought, 'Why stop here?'
The next job was to replace the rear bolster which had rusted to holes. (It was illustrated in the last Newsletter.) We sent drawings to Dero Fabrication in Worcester who quoted a good price for the supply of laser cut and folded pieces to fabricate a totally new bolster. It had to be supplied in pieces because it needed to be built up in situ and welded into place.
At this stage we gave the situation of the front bolster some considerable thought. It appears that the trailer had been extensively modified by the steelworks who previously owned it, by making a completely new front bolster and fitting a spare undercarriage and turntable seemingly from a flat bed trailer. Presumably the original bolster had been damaged. With reference to the four photographs of this type of trailer in our possession, it was clear that by fabricating a totally new front bolster and fitting the existing undercarriage we could exactly recreate the original arrangement. So finally we decided to go ahead and fabricate a new front bolster rather than leave the rusted lash-up in place. A big job, but we decided well worth the effort.
I took all the necessary measurements, some carefully scaled from our photographs, and I prepared another set of drawings.
Bob Brown and I removed the undercarriage ready for servicing and painting. We found that the asbestos rubbing ring in the turntable had disintegrated because the bearing had remained full of rainwater for the last thirty years or more. This was due to the lash-up narrow design of the steelworks bolster offering no protection from the elements. Despite this the bearing surface was not too severely rusted and I was able to clean up the thrust face with a grinder and a file to produce an acceptable bearing surface with just a few hours work. The cast housing in which the rubbing ring fitted was very heavily corroded so we have decided to replace the ring in steel which will be Araldited and screwed to its casting. Clearly the characteristics of steel on steel will produce a different bearing to that of steel running on asbestos fibre but the trailer will have very little (if any) serious use and if well greased should not present any problems.
In readiness for fitting to the new front bolster the undercarriage has been fully overhauled, freeing up all seized joints and bearings and painted grey to match the rest of the trailer.
The laser cut parts for the front bolster were also obtained from Dero and at the time of writing are being assembled and painted ready for fitting. This will complete the structural work on the trailer.
Besides being a visual transformation, the front and rear bolsters will now be free to move along the spine to increase or decrease the effective length of the trailer to any one of five different settings, suiting the length of the load being carried. Previously they were rusted absolutely solid!
I had thought that ours must be the last Scammell pole carrying trailer in existence but a discussion with John Giles of the Mechanical Horse Club has revealed that another, still in original British Railways yellow livery, is in the hands of a collector near Aberdeen. I should very much like to see it, and hope it gets restored one day as well.
This project has been at a standstill for a considerable time. But with progress on the Scammell where the unit and both trailers are nearing completion, we are once again thinking about what is next for the Thornycroft Nippy. One item annoying me was the spare wheel leaning against the wall inside the storage shed. There was a perfectly good wheel rack for it at the back of the lorry - trouble is that the wheel didn't fit.
This was down to my mistake when I fitted the 'U' bolts that secure the body to the chassis. The rear set had been positioned in a logical place but fouled the tyre of the spare wheel. So I repositioned them further forward and the wheel slipped in to its rack just as it should. The next job was to make the clamp, 'J' bolt and wing nut to secure the wheel in position. These items had been lost during the lorry's sojourn in the scrap yard. Fortunately we have photos and dimensions of the missing parts obtained during a visit to The Milestones Museum in Basingstoke. The parts were forged, threaded and welded out of various bits of material in our stores and after two days work the job was complete.
This leaves the lorry complete from the cab backwards except for final painting and fitting the rear lights. So the next logical move is to complete the cab which only needs the roof vent fitting and the mirrors too. The bracket for one of the mirrors is fitted far too high and needs altering, the second is not fitted at all. We have original Great Western mirror brackets and knuckles but the mirrors are unobtainable, although we do have a pair of very similar mirrors which we will have to do. The one remaining big job is the wiring and instruments, also the headlights need major attention including re-chroming of the bezels and we still cannot find the correct side lights. A fair bit more to do yet...