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WW1 Thornycroft restoration

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We collected the new rear tyres for the Thorny today –these are of polyurethane being a much cheaper option rather than going for rubber which really would be preferable. We did this for the Dennis and they have been absolutely fine. No skidding or slipping. They are a little shiny before they are run on the road but they quickly become dull after just a little use.

 

The “poly” has been bonded to the original steel bands – the old rubber on the bands was removed by the “poly” manufacturer so we did not have to do that on this occasion – they are “tooled up” to do this sort of thing and they tell me that this something that they do every day! The bands have to be sand blasted and be very clean for the new “poly” to bond.

 

Next step, take the tyres from Devon to Bedford to get them pressed on to the wheels again!

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The tyres look really good! We're considering the same path for our Garrett steam wagon - a little worried about the higher loads and speeds though!

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The tyres look really good! We're considering the same path for our Garrett steam wagon - a little worried about the higher loads and speeds though!

 

Ed.

 

Tom Varleys Foster wagon ended up with PU tyres. Martin Fagg gave it plenty of stick untill the recent fire. One issue is they are not as tolerant of being kerbed.

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I have just had a quick Google looking for fork truck tyre ratings. Haven't turned anything up yet and will look some more but generally, they have a load/speed/distance index. Fork truck tyres are often very heavily loaded but only go short distances and not that fast. Our wheels are about twice as big so we can go twice as fast for the same rating. Also, we are not loading them quite as heavily as all of our vehicles run around unladen. The Dennis is four tons unladen so I expect the fronts are carrying up to a ton each. Your Garrett must be about two tons on each tyre but they are twice as wide. I expect you would be running at the top end of the rating but will get away with it.

 

I'll see what else I can find.

 

Good luck!

 

Steve

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In my experience with PU tyres used industrially (fork lift tyres, handling equipment, and machinery roller coatings and suchlike) there's a wide variety of formulations and hardnesses available for different uses. If you talk to the PU people they should be able to tell you whether the tyres are up to it and make recommendations.

 

If you think about it, in industrial use PU is subjected to very high loadings without issue. For example, pallet trucks are typically rated at 2 tons capacity on a tyre contact patch which is probably well under a quarter of that of a truck or locomotive tyre and last for several years in everyday use.

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Thanks gentlemen! I think we're tending towards thinking it is worth a try. Steve - you're absolutely on the mark with the weights.

 

The worry we have is that we also go somewhat faster than many of the other users of these tyres (mid twenties is comfortable, which if I have calculated correctly, would be 4 revolutions per second), and can do about 30-40 miles without stops, other than for traffic and there is a historic concern about heat build up in the core of the tyre due to hysteresis. Having seen the results of a solid rubber tyre exploding (as has happened on the front of several steam wagons), it's a concern about any tyre in this service.

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Thanks gentlemen! I think we're tending towards thinking it is worth a try. Steve - you're absolutely on the mark with the weights.

 

The worry we have is that we also go somewhat faster than many of the other users of these tyres (mid twenties is comfortable, which if I have calculated correctly, would be 4 revolutions per second), and can do about 30-40 miles without stops, other than for traffic and there is a historic concern about heat build up in the core of the tyre due to hysteresis. Having seen the results of a solid rubber tyre exploding (as has happened on the front of several steam wagons), it's a concern about any tyre in this service.[/quote

 

My Fiat will only do 15mph and I can buy five sets of poly tyres for the cost of rubber ones.

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The worry we have is that we also go somewhat faster than many of the other users of these tyres (mid twenties is comfortable, which if I have calculated correctly, would be 4 revolutions per second), and can do about 30-40 miles without stops.

 

Of course, there is a blanket legal speed limit for solid tyres of 12mph anyway!

 

Steve

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Mine too. While the Garrett is marked with 12mph, later wagons were marked at 20mph.

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Mine too. While the Garrett is marked with 12mph, later wagons were marked at 20mph.

 

I stand corrected. I always understood that 20mph was the limit for two-wheel brakes. One lives and learns!

 

Steve

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I have been doing a bit of work on the oil pipes this week. We are fortunate in that they have, in the main, survived although they are a bit battered.

 

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Father has a die nut which I ran over the threads which came up well. However, the short extension pipes were rather beyond hope and we determined to replace them.

 

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The end one had had an interesting repair in that it had been wire wrapped at some time and then sealed with solder.

 

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I un-soldered the stubs and then annealed the main tube before just straightening it in my fingers and giving it a good clean up.

 

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The tube is half-inch and quite heavy in section. Fortunately, we had a short length which had come with the Dennis so I straightened that and cut some short lengths to replace the originals.

 

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I sweated these in using solder paint. This is wonderful stuff to get the solder right into the joint. Rather expensive but well worth it.

 

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We need two more union nuts so, rather rashly, I bought a set of 5/8" BSP taps and a die.

 

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They will always come again and there is such joy to be gained in using brand new taps in brass!

 

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Finally, there was a rather fancy Tee to be made. The orignals were castings but I just fabricated ours using silver solder.

 

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Finally, a set of parts ready to assemble. I will cut and bend the pipework to fit on the job the next time I am in Devon.

 

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Governor next!

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Interesting about speed limits for resilient tyres but no discussion about tyre wear, so I thought that paragraphs 6.2 and 6.3 in the British Industrial Truck Association's Guidance Note - Tyre Tread Wear are worth reading.

 

www.bita.org.uk/download?code=5237066f73b79

 

Thats because a solid rubber is usable until the rubber comes off the band!

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tee.JPG

 

So you thought you would sneak this photograph through without anybody questioning it! What was the purpose of the pin in the centre of the top segment?

 

Barry.

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Quite right David! Yes, I partially drilled the boss the pipe size but just went through with 1/8". A copper rivet dropped down the hole located in a similar hole in the main body. You can just see it at the top in the centre. After cleaning up, it was simply a case of putting the drill right through.

 

The parts would have balanced but would undoubtably have moved just enough to be annoying!

 

Steve

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We had the full team assemble at Barrys place for a tyre pressing day. Really pleased that Barry put a block and tackle on the press.

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A little disappointingly the first tyres just dropped on to the wheel so we had to take it off and rip up some of Barrys prized canvas to fill the gap. It was all wet so it will help rust everything together.

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Then it was all hands to the pumps:

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Once that was on we put the second tyre on top and broke for tea

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Then back to pumping again:

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With great success and merriment all round:

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We then unloaded it and did the second one:

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With the benefit of hindsight we should have dropped it straight into the trailer. Instead we parked the trailer below an earth bank and rolled the wheels across a plank and dropped them down.

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Now Dad just has to unload them. Another pending big task is to select the best back axle, clean it up, paint and attach to the springs. Soon be on all four wheels again...........

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Looking great, another milestone achieved! I also like the press very much. Is there any freeze protection for it, or is the water just drained after a session?

 

Regards

Marcel

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Good question. Without the pressure the press just drops down and forces the water out of the cylinder in to the tank. Unfortunately, the tank does not have a drain plug so that has to be syphoned out. A real cold freeze would shatter the tank so we have to be careful.

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The main ram in the ground is safe but if it froze, then the table would simply lift. The tank is cast iron so the last job today was to syphon the water out.

 

The press itself is a wonderful piece of equipment of 1915 origin. Exactly the right tool for the job!

 

Steve

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The tyres look great, I will have to decide if I can cope with driving slowly enough for polyurethane on mine.

 

Speed Merchant!

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The tyres look great, I will have to decide if I can cope with driving slowly enough for polyurethane on mine.

 

Since most modern tanks have solid tyres made of polyurethane and can reach speeds of 50 MPH with quite high wheel loadings I think you should be ok. Mind you there are lots of different grades of polyurethane.....

 

David

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