Asciidv

...and it is now Sunday night and I keep wondering if Steve has been down to Devon this weekend to spin the brass cover. I just can't wait to see what he makes of it! Barry.

Andy's lamp parts look fantastic! Although I am surprised that he hasn't progreammed up his little CNC lathe to spin them automatically? I think the shape of the lamp parts have an advantage over Steve's task as they are are an expanding bell shape whithout any large change of contour. Steve has to spin his material through 90 degrees with quite a small radius and then spin a long parallel tube. This has always defeated me with my spinning attempts. The brass part in the picture has a parallel section of only an inch and when I have tried for more the brass has torn or wrinkled up. As Andy said, this is a great sport for producing scrap. I also have a feeling although I cannot be sure that the disk which you start with should be perfectly round. I have been cutting my disks just with a treadle guillotine so that they look like octagons (maybe 16 'o' gons ) rather than perfect circles. Can anyone confirm that this is important? Barry.

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.

How are you going to turn the ball end? Do you have one of the many little 'gizmos' for such a task or are you going to put it out to a friend with a CNC lathe? Barry.

Steve, Thank you for the explanation. This video shows the moulding of a very similar part. although a slightly different technique is used. Rather than cutting away the sand down to the split line, sand is built up to the split line. There is a whole series of videos by this person showing home foundry exploits. Barry.

Steve, where was the split line on this part and did the moulder have to do any fettling to make it work? Barry.

They do look very nice! Perhaps a little big for Steve's Myford :-(. Even the bolt hole pattern might be stretching you milling machine too? Barry.

As Doug has pointed out the tyre band is not a basic hoop. This extract from the Dunlop solid tyre catalogue illustrates the variations. The American style tyre has a flat band but with raised edges to keep the tyre in place. The Dunlop style tyre has dove-tail grooves to keep the rubber in place. How do you roll dove-tails into a band? Barry.

Well I am an electrical engineer so I can talk nonsense on this subject if I want to! I did think Andy's statement that the hoop was at yield point was a little far fetched purely from a practical point of view. In most cases the hoop is just a rolled steel band welded together. For a 720 wheel, the band pre-rolling, has to be 2.262 metres long. As a rule of thumb it is said that the you reduce the length of the band by 1mm so that when it is welded up and pressed onto the wheel, it will be a 'good tight fit'. I would have thought that the ability to achieve sub millimetre precision for this kind of work would have been very difficult to so that the hoop strain was very variable or 'all over the place' for the want of a better description. (But is this just an argument in Andy's favour saying that you always size your band to be at the yield point or beyond so precision isn't required?). A question for those who know better. Were the bands ever bored on a big lathe after rolling to achieve the tolerances needed? All the bands that I have seen have not been machined. ....A quick calculation shows that the tyre band only has to be 24 thou (0.6mm) smaller on the diameter for the yeild point of the band to be reached. Not much margin of error to play with. Barry.

This is a section taken from the "The correct ordering and Fitting of Dunlop Solid Rubber Tyres". It relates ram pressure to tyre diameter. It is well worth noting that if you are going to purchase solid rubber tyres from Dunlop and have them delivered to you by the Great Western Railway that; I am grateful to Ben Hawkins ( A Dennis Restorer ) for sending me a copy of this wonderfully informative manual. Whilst we are talking about old solid rubber tyres can I ask again if anyone has knowledge of surviving 'Air Cushion' tyres which competed with solid rubber tyres in the early 1900's. The air cushions look like octopus tentacle suckers. I now have this Dennis and would just love to return it to it's original specification with this type of tyre! Barry.

Steve, is the split line going to be down the central rib? If so how does the foundry resolve the cut away for the clevis end? Would it have been easier for them if it had been kept solid and you milled the slot in afterwards? How many hours did this pattern take for you to produce? I do like your pictures mainly to see what you have lying around your work bench. I see that you are loyal to your employer with your Dennis Eagle mug. (I always have to look twice to see the Eagle in the reverse pattern) and the other day the plastic container labelled 'ACID' caught my eye. What acid is it and what do you use it for? Best wishes, Barry.

I know it must be just me (because nobody else has said anything) but I am unsure as to what is meant by 'chassis wracking'. I can guess, but it would be nice to have a definition from the 'Gosling English Dictionary of Automotive Terminolgy'! Barry.

I don't have a picture to hand of the point on my engine, but the extract from the manual is almost as good. At the top of the oil filter there is an oil gallery which runs the length of the engine to the front. There is a point half way along with a tapping for the oil pressure gauge. I do think a gauge is far better than an warning light! Best wishes, Barry.

Leo is a pure bred Belgian Shepherd dog, which is a lighter build of German Shepherd. He still has problems telling a 1/4" Whit. spanner from a 1/2" AF but he is getting there :-D !

Today, I bolted everything back together again. I was still a little doubtful whether it was correct to be starting on full fuel delivery, but as you will see from the video it is absolutely correct. The governor acts instantaneously pushing the rack to the left to reduce fuel delivery to give the tickover speed. The engine stop lever pushes the rack even further to the left to shut off fuel delivery altogether. So back on the road again! Thanks to all who have been so helpful with their advice and comments. [video=youtube;TFlPGu0L-qg] Best wishes, Barry. (P.S. The heavy breathing you can hear between the first engine start and the second isn't me, but 'Leo' my dog who keeps me company and passes the spanners when I am down at the shed).

The left bank of injector pump was removed. The pin has a spiral slot cut into the end of it. A it is pushed up by the injector pump cam it carries diesel into the injector pump pipe. The rotation of the pin determines how much fuel is transferred. The pinion gear shown in the picture which rotates when the longitudinal rack is moved in turns rotates the pin. In my case the pin had stuck in the fully up position which prevented the pin from rotating, which prevented the rack from moving. Gently tapping the pin out and then cleaning it with no more than a few squirts of WD40 made everything move smoothly again. After talking to an old sage on Gardner engines, I learnt that pin sticking is not uncommon and there is a very easy 'fix' without removing the injector bank. Quite simply you can disconnect the injector pipe, remove the pipe coupler and lift out the one way valve. The top of the stuck pin is now visible and this can be tapped back down with a piece of 1/8th diameter rod. HOWEVER I STILL HAVE AN UNKNOWN. All of this began when I started the engine and it began to race away. Now with the pump all assembled again with everything moving freely the rack is in the full throttle position. I would have imagined that the governor should be pushing the rack over to the left to be starting with minimal fuel. Starting on full fuel delivery just doesn't seen right! I had thought that the governor spring might be broken but this is a huge valve spring type spring and when I took it out it was perfect. So the question to ask you all is....with the engine stationary should the rack be sprung in the full fuel delivery position over to the right, which means it starts up like this until the governor acts? Any suggestion would be gratefully received.

....and this weekend some progress. Following advice from Rob on this forum I split the link joining the two racks together. The right side rack was completely free but the left side rack was completely solid. I therefore removed the top section of the left bank of the pump. 2 of the pistons are correctly sprung, but the central piston has no springing at all. I suspect that the spring has broken and has jammed rack, but this has to be explored another day. This video shows all; Barry. [video=youtube_share;5zW8Hha1QoU]

Boat driver indeed! Don't worry it has wheels, but it is in fact a Dennis Fire Engine Control unit. It was built in the cold war years. The idea behind it was that it could head for the hills if the bombs started dropping and command the fire brigades in the North of England from somewhere safe. Although it was (is) fitted with an extensive array of VHF and UHF Storno radio equipment it was pre-mobile phone days, so there is an external panel for connection to your nearest telegraph pole to link in conventional land lines. It was actually built on a Dennis Dominator bus chassis, but no-one better call it a bus. Barry.

Rob,Thanks for this, I will look forward to the relevant pages from the manual (DrBAH999@aol.com). It is a mystery why and how this rod is jammed. I thought a little tap with a hammer might free it, but even with your biggest hammer I don't think it will spring free. There is more to this than meets the eye.

A sad tale..... I started up my Gardner 6LXB and the engine began to race. I thought it was probably due to a sticky air operated accelerator cylinder, so I pressed the engine stop button and nothing happened. So I lifted the engine lid and pushed back on the engine stop lever on the injector pump and after about 10 or 15 seconds the engine slowly came to a halt. The next time I tried to start it, it just wouldn't start. It seemed as if the engine stop mechanism had stuck in the stop position. I am not familiar with the Gardner injector pump so all the rest I did by instinct. Taking off the pump covers reveals the stop lever which pulls on a thin connecting rod which I assume moves a rod through the length of the injector pump. At the other end of this rod is a spring plunger which I assume keeps the rod in the 'open' position until the engine stop lever moves it to the 'closed' position. However this rod appears to be jammed. There is a slight amount of push-pull movement (perhaps about 15 thou) but that is all. Does anyone have any ideas? I have just bought a 6LXB manual on ebay but it will not be here until next week. I would love to have it running again this weekend. Any suggestions would be gratefully received. I hope I do not have to go to a bus forum for my answer!!! Best wishes, Barry.

Andy, but you do play their game! With a plasma cutter you could have fitted the torch head to your CNC mill and profiled out your Ner-a-car footboards. For anyone who finds this Thornycroft restoration essential reading, Andy's restoration of his Ner-a-car is equally as ingenious and deserving of admiration. http://bodgesoc.blogspot.co.uk/search?updated-min=2014-01-01T00:00:00-08:00&updated-max=2015-01-01T00:00:00-08:00&max-results=9 Barry.

Whilst the Thorny restoration is moving at a little slower pace, I wonder if I could ask a period question about something I know very little? How were solid rubber tyres manufactured like those shown in the above photograph? Are the pads hard rubber disks which are screwed into the rubber below? Could they even have been moulded like this!? Do any tyres of this type survive? Has anyone tried to re-create such tyres in recent times? Kind Regards, Barry.

I was a little set back when Richard Bannister said that the pedestal packing pieces were not available for the UNF engine, so I decided to have a two pronged attack. The first approach was to bore out the pedestal and then sleeve the pipe from the strainer. In this way it is possible to make the two parts a good fit to minimise the chance of an air leak. As the pedestal is not square to the base of the oil pump it had to be mounted on a plate first and then angled in the vice. A brass sleeve was then turned to fit and pressed over the strainer pipe. By chance I then spotted this soft rubber bellows which I had put to one side thinking it might come in useful one day. It was removed from one of the slide pins of a disk brake caliper. Here you see the bellows fitted between the pedestal and the flange of the strainer pipe, just as Mike in the previous post suggested. It made a perfect seal and still allowed for rotation (although admittedly not as freely as before). Of course the proof of the pudding was seen when I started up the engine. I had just fitted a new set of N-8 Chanpion plugs and it fired instantly and settled down to a regular steady tickover on all 8, with 18 PSI showing on the gauge. When the engine was revved the oil pressure went up to 30PSI at which point the oil pressure relief valve opens to limit any further increase. Success at last!:-D Barry.

Is it holiday time down in Devon? I am sure I am not the only HMVF reader lookling forward to the next installment? Now that the catalogue has been published for Michael Banfield's sale, I see that there are dozens of WW1 chassis just waiting to be collected for a rust up restoration. Best wishes, Barry. http://www.bonhams.com/auctions/22201

Not the gauge for the vehicle which is mid 50's but the standard type on all early 30's Dennis Fire Engines. Hence the brass bezel to match up with all the other bits of brass on a fire engine. Barry.