Great War truck Posted July 10, 2013 Author Share Posted July 10, 2013 The Gearbox ended up its commercial working life as part of a drive mechanism to a Water Pump in North Wales. All of the Transmission Brake gear – apart from the Brake Drum was stripped off the Gearbox as that would have been surplus to those requirements, all that time ago. It appears that the Drum was not wide enough to take what we assume must have been a flat belt drive to the Pump, and a further ring was welded on to the Drum, just to make it wider and to suit that purpose. You will see from the photographs that it was a neat welding job. In due course, that ring will have to come off again – it will have to come off before we can put the Drum in the “gap” in the Colchester Student to skim the circumference and clean up the edge as the Drum as it is too wide for the “gap” as it is. So we have turned our attention first of all to machining up the fulcrum pins for the brake shoes. Some years ago, Steve was working in the Portsmouth area, and with the blessing of the Garage Foreman, he spent some evenings in the Bus Garage there, where the Portsmouth Thorny J Double Decker was kept at that time, just measuring up and sketching bits for our future use and reference. It is now, after all that time that the drawings and measurements are coming into their own! These two pins are simply machined from 32mm Hex Steel Bar – reduced to 1” in diameter at each end with one end threaded 1” whit to take a securing nut. And these two pictures show the pins in their position. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted August 11, 2013 Author Share Posted August 11, 2013 I am sorry that there have been no new posts for a Month now. Things will start again very soon. Tim Quote Link to comment Share on other sites More sharing options...
42 chevy Posted August 11, 2013 Share Posted August 11, 2013 That's great news, I was hoping for an update soon. John G Quote Link to comment Share on other sites More sharing options...
Great War truck Posted August 12, 2013 Author Share Posted August 12, 2013 We were at last able to collect the piston castings back from our friend Andy W who has now bored them for the Gudgeon Pins. We also wanted him to shorten the old Gudgeon Pins by 3/16” to fit the now smaller pistons to suit the reduced bore of the engine as they will be used again. The Gudgeon pins are extremely hard and again, Andy was tooled up to deal with them where it would have been difficult in our Home Workshop. Andy has made a nice job of it and he has left the pins to a wringing fit in the castings. The castings will now be fitted to a truly running mandrel on the lathe to be reduced to their final outside diameter and have grooves cut for the rings as shown in an original piston in the final picture in this sequence Quote Link to comment Share on other sites More sharing options...
FW200 Posted August 12, 2013 Share Posted August 12, 2013 Best thread on the forum Quote Link to comment Share on other sites More sharing options...
mattinker Posted August 13, 2013 Share Posted August 13, 2013 Nice to see you back at it! I've never seen cast Iron pistons before, all that mass flying backwards and forwards, the mind boggles! Enjoying the progress as always, Regards, Matthew Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted August 13, 2013 Share Posted August 13, 2013 Nice to see you back at it! I've never seen cast Iron pistons before, all that mass flying backwards and forwards, the mind boggles! Enjoying the progress as always, Regards, Matthew Hi Matthew, Cast iron pistons were quite common up until around 1950. I rebuilt a few 1940's Austin 6 cyl engines recently, all with cast iron pistons, they run very quietly. Quote Link to comment Share on other sites More sharing options...
ajmac Posted August 13, 2013 Share Posted August 13, 2013 Some 1940s Ford Flathead V8s had Ferrous pistons too, I have a set in the workshop. With all the attention on WW1 over the next four years are you chaps going to be in any particular high profile events? There must be a place for wartime lorries driving down the Mall! Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted August 13, 2013 Share Posted August 13, 2013 With all the attention on WW1 over the next four years are you chaps going to be in any particular high profile events? There must be a place for wartime lorries driving down the Mall! Yes, we have thought about that but really do not know what is on at the moment - so we are keeping our powder dry to see what happens. We would very much want to support anything that is arranged - two lorries would be appropriate for any British event - the Dennis and the British Army (WD) Autocar. Tony. Quote Link to comment Share on other sites More sharing options...
lowfat Posted August 13, 2013 Share Posted August 13, 2013 I have to join all the others here in saluting your achievements so far truly outstanding. Quote Link to comment Share on other sites More sharing options...
Barney Posted August 14, 2013 Share Posted August 14, 2013 Yes, for the Gosling family to be heading a National WW1 Parade up The Mall, in sight of Queen and Country, would be a fitting accolade for your magnificent dedication and achievements in returning these lorries to running order. John Quote Link to comment Share on other sites More sharing options...
N.O.S. Posted August 14, 2013 Share Posted August 14, 2013 Just another anecdote on cast iron pistons: The Perkins P6 is worth a mention - the tractor engines had cast iron pistons, but the automotive (truck) engines had aluminium pistons and a significantly higher top speed. Not sure about the industrial spec engines. Efforts to increase the speed of cast iron pistoned engines to that of the automotive engine invariably met with disaster! Quote Link to comment Share on other sites More sharing options...
Great War truck Posted August 15, 2013 Author Share Posted August 15, 2013 Steve is very much in contact with the team at the Coventry Transport Museum who are restoring a Maudslay WW1 Army Lorry – they are pushing on very well with it and hope to get it finished for next year. They visited us here in Devon earlier this year and took the Dennis on the road so that they could sample the delights of WW1 Army motoring and so that they could see what was in store for them when they have completed their project. Like us with the Thorny, they are short of a steering wheel and one of the pictures shows the state of our original Thorny one that we have which we think everybody would agree has passed its “sell-by” date! The Maudslay steering wheel is very similar to that of the Thorny and Steve has offered to make the pattern for our steering wheel now, which is really very much a long way down the road for our project, so that they can have a casting taken off the pattern for the Maudslay. The second picture shows the original Carlton Colville Thorny steering wheel – though we imagine that it was not originally bound with plastic tape! We made a steering wheel for the Dennis – that one was a five spoke wheel whilst the Thorny and the Maudslay both have four spoke wheels – so a fresh pattern has to be made, So far only the metal frame for the pattern has been made – again laser cut with the spokes cut where they join the hub so that they can be “dished”. The pattern will again be completed with MDF with that steel frame and the process was explained on page 104 of the Dennis thread. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted August 18, 2013 Author Share Posted August 18, 2013 Like many early engines, this one should have a priming cock mounted over each cylinder in order to be able to add fuel directly to the bores to ease starting. Ours were all missing or broken off. However, we were fortunate that one had been used as a drain tap in the bottom of the sump. Although leaving the engine on the ground had knocked it around a bit, it was still usable and provided a pattern for the replacements. A good hunt at Beaulieu Autojumble turned up another, with a smaller thread and the remains of the knob. Father tracked down some knobs on Ebay and Steve proceeded to make up two replacements. The main thread was cut first on two blanks. Then a piece of hex was drilled and tapped and left in the chuck. The blanks were screwed in and the profiles machined and filed by eye. The cup was cut using a ball-ended end mill and then the chuck was unscrewed from the lathe and mounted on the dividing head in the mill for the flat to be cut. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted August 18, 2013 Author Share Posted August 18, 2013 Steve then wanted to drill the cross-hole for the tap which he was keen to get in the middle. To do this, he used an ‘edge finder’. This is a marvellous device in the shape of a small cylinder of known diameter, held on the end of a spindle with an internal spring. The cylinder can float sideways slightly. The spindle is placed in the drill chuck and, with the chuck turning, slowly brought into contact with the job. When rotating, the cylinder will be seen to be off centre but as it comes into contact with the job, it will come more closely into line until it suddenly jumps sideways. At this point, the outside diameter of the cylinder is exactly touching the job. It remains only to remove the edge finder and wind the job across by half of the diameter of the cylinder and half of the diameter of the job to leave the chuck exactly over the centre. In the photo, you can see that the cylinder has just jumped across. This is a wonderful gadget and I don’t know how we ever managed without it. Steve drilled the hole through and then used a home-made reamer to cut the taper. This was repeated for both before he turned up the actual plugs themselves. Again, the square and cross-holes were cut in the dividing head and the hole for the handle was held in the machine vice. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted August 18, 2013 Author Share Posted August 18, 2013 The ball ends were dressed with a file before cutting off and silver soldering in the handles. Washers and spring cups were turned and the square holes were broached before final assembly. The four taps are now safely stored pending final assembly of the engine. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted August 18, 2013 Author Share Posted August 18, 2013 We are getting to a very exciting time with the Thornycroft restoration. In a few weeks time the plan is to have a reshuffle and make room in the central bay for the J chassis to be fully dismantled. We thought it would be a good idea to get the chassis ready for the move. We put it in to its current location nearly 20 years ago and since then things have been stacked on it, under it and in front of it, so getting it out is going to be a right old job. The first thing to do was to find it: In here somewhere: After half a day of ripping out the weeds and brambles we uncovered the spare parts pile: Another half a day and we uncovered the chassis and had a massive pile of plant life to dispose of. How many axles can you see: Springs have spread more: I had forgotten about the crack. Nothing that cant be fixed though. Quote Link to comment Share on other sites More sharing options...
Charawacky Posted August 18, 2013 Share Posted August 18, 2013 Can you tell me the angle of the taper for the priming cups, looks like I may have to make some. Once the spring fails and combustion gases pass the seat wears! Tom Quote Link to comment Share on other sites More sharing options...
nz2 Posted August 20, 2013 Share Posted August 20, 2013 Your images of the vegetation growth and subsequent removal is a problem we also have here in NZ. A trip through the depositary can become like a " voyage of discovery". I've been trying to read the stamped chassis number on dumb iron with no success. Can you advise me of the number. Doug Quote Link to comment Share on other sites More sharing options...
Great War truck Posted August 21, 2013 Author Share Posted August 21, 2013 The chassis number appears to be 1791 – but I think the first number could be anybody’s guess! Could it be a “4”? There was some discussion earlier about the rear hooks on some Thorny’s – ours has the “Pig tail” variety – though one of the hooks has become “uncurled” at some time during its lifetime. Another job to do! Quote Link to comment Share on other sites More sharing options...
David Herbert Posted August 21, 2013 Share Posted August 21, 2013 I don't think that the character before the 791 is a '1' as the top is not sloping as it is on the clearer '1'. However it is not a very convincing '4' either and certainly not a '7'. So could it be something other than a number? Also is that a 'H' after the 791 ? Can you tell anything about what range the chassis number must be in from the build standard? It would be nice to know it's identity, especially when you are this close. David Quote Link to comment Share on other sites More sharing options...
mammoth Posted August 22, 2013 Share Posted August 22, 2013 Jokes aside from being down under, turn it upside down and the '7' is clearly an 'L' and the other figures look like letters as well?? Quote Link to comment Share on other sites More sharing options...
FW200 Posted August 22, 2013 Share Posted August 22, 2013 Jokes aside from being down under, turn it upside down and the '7' is clearly an 'L' and the other figures look like letters as well?? Indeed... Says TCL (definate) and then "F" ? Appears to be some sort of H in front of the T by quite a margin but looks a bit out of place so might not be anything.. Quote Link to comment Share on other sites More sharing options...
David Herbert Posted August 22, 2013 Share Posted August 22, 2013 Before we decide about which way up to look at these characters stamped into the chassis, can someone confirm that this is actually where Thornycroft stamped the chassis number? If it is not the chassis number it could be any sort of a code, part number or inspectors mark and any or indeed both ways up. Was it stamped by someone who was dyslexic ? David Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted August 22, 2013 Share Posted August 22, 2013 We do have the front half only of a second Thorny Chassis here and I have been having a go at that with the wire brush this morning. Sadly, that one is even more corroded - there would appear to be something stamped on that one in an identical position but it is not at all clear. I will try again later to see if I can bring something up. Doug in NZ might be able to help with the numbering and positioning system..................Tony Quote Link to comment Share on other sites More sharing options...
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