Great War truck Posted January 9, 2014 Author Share Posted January 9, 2014 As an aside from putting the engine back together, we have also been looking at the Hand Brake Linkage – this was amazingly still mainly all there under the Shepherds Hut body but was heavily rusted. Some of the parts will live to fight again, but the two large clevis’ in the linkage with additional holes in them for adjustment purposes were very badly corroded and must be replaced. Replacements have been made in the home workshop and machined from steel bar measuring 1 1/2” x 1 1/4” in section although the originals appear to be forgings. They come out at about 7” long, overall. The sequence of machining these with modest facilities may be of interest. The bar was cut to length and first of all, the four holes for the Clevis Pins were marked out in the Milling Machine, using calibrated dials on the machine to find their exact locations. They were drilled out to 9/16” and then opened up their finished diameter of 5/8”. http://s30.photobucket.com/user/Greatwartruck/media/Thorny%20restoration%201/DSCN9796_zps28ee833f.jpg.html Further along the manufacturing sequence, a long 7/8” slot has to be milled in the clevis but at this stage a 7/8” hole was just machined in the bar where the inner end of the slot will be. We do not have the capacity to use a 7/8” slot drill in our equipment, and to get the end of the slot nicely rounded, we have drilled and then bored out to 7/8” diameter. Milling the full 7/8” slot in the bar later on with smaller end mills will meet the 7/8” hole, giving us the correct diameter curve at the inner end of the slot. The end of the Clevis must be threaded 1/2” BSF to take the rod so the bar was set up in the 4 Jaw Chuck, centred and drilled right through 7/16” to the large hole previously put in for the end of the slot, ready for tapping. The cross slide was then set over 5 degrees so that this part of the bar could be machined into a cone. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 10, 2014 Author Share Posted January 10, 2014 When the coning was completed, the 7/16” hole was then tapped 1/2” – the tap was supported with a centre in the tail stock to ensure that the thread went in squarely. The bar was then set up in the milling machine again so that the slot could be milled out. Although the slot has finally got to go right to the end of the bar, leaving the slot open, it would not have been sensible at this stage to cut right through as the stresses locked into the bar would be released, causing the two sides of the slot to spring apart. So a temporary “bridge” was left in at that end to hold the two sides of the slot together whilst it was being milled. When the still- closed slot was completed, the bar was placed in the vice and the temporary bridge was cut through with a hack saw – and the picture shows how the two sides have sprung apart! It was just a case then of cleaning the two ends separately with the end mill. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 10, 2014 Author Share Posted January 10, 2014 This then leaves with a pair of clevis’ – but with still more work to do on them. The open ends of the clevis’ then had to rounded off and this was done with the aid of filing buttons – placed through the end holes in the clevis’ and the surplus cut off with a hack saw and then finished off with a file and a flap wheel. Getting near the end – the sharp edges were rounded off and the shoulders faired in. And the last job, mill 1/8” slots in the clevis pin holes to take feathers. [ Quote Link to comment Share on other sites More sharing options...
gritineye Posted January 10, 2014 Share Posted January 10, 2014 Nice job and thanks for going into such detail, it's odd how little things add up when restoring old machinery, I wouldn't have had a clue what a feather was before yesterday when I found my WW2 American lathe lead screw didn't have the standard woodruff key, researched it and it's a European type feather key, so must be a replacement. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 19, 2014 Author Share Posted January 19, 2014 Steve was in Devon this weekend and had some time free today to join Tony to do some work on the Thorny. With only just one day free, they decided to get on with another job that has been outstanding and awaiting completion. The two rear chassis cross members were very badly corroded in the corners and we had previously decided that the wasted sections had to be cut out and new steel welded in. These three pictures clearly show the condition of the steel! The rotten steel was removed with cutting disc on the Angle Grinder. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 19, 2014 Author Share Posted January 19, 2014 The original steel was 1/4” thick and the replacements are 6mm. They were cut and folded by a local Sheet Metal Worker for us, but left slightly oversize for us to fit.. The edges are bevelled ready for welding. The other corroded cross member is situated just inside the rear one and consists of flat strip, bent in a “V” shape to meet another cross member of similar shape, where the two points of the “V” meet and are bolted together, thus making an “X” shape. Only one of these “V’s”is in need of some work. It is only the two ends that require attention and they were cut out. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 19, 2014 Author Share Posted January 19, 2014 Because of the shape of this cross member, the bolting face to the chassis rail is at about 45 degrees to the main part of the cross member. Each piece of steel needed to be about 7” long. For our convenience, the sheet metal firm were asked to provide one piece about 14” long with a right angle pressed in at 1” from each end. We then had to adjust this right angle to about 45 degrees to suit the the cross member. This was done by getting it red hot and bending it back in the vice until we were satisfied that the angle was right. The whole thing was then cut into two halves – one for each end of the cross member. The two ends to be joined were chamfered up, ready for welding. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 20, 2014 Author Share Posted January 20, 2014 With the clevis’ on the Brake Linkage out of the way, we thought that we would finish off that job by making new Clevis Pins. The original ones were beyond redemption, not only showing heavy wear, but the nutted ends had rusted away. There was sufficient of them left and together with the picture in the Parts Book, we could see what they should be like. They have a 1 1/8” diameter head, 1/4” thick, the shank is 5/8” diameter with the end part threaded 5/8” BSF for a standard nut. We would have expected to have seen a Slot Nut used on the end, but the Parts Book and the picture of the clevis on the original Carlton Colville Thorny confirm that an ordinary nut was used with a split pin place through the end of the clevis to stop the nut working loose and coming off. There is a hole through the centre of the head into the shank for lubrication purposes, about 9/8” long. About one inch in, a hole is drilled in the shank to meet the hole in the centre of the pin through which grease can go. There is a “feather” under the head of the pin to mate with the slot in the clevis, to prevent the pin from rotating when the nut is tightened. The new pins are made of EN8 – fortunately, we had a piece of 1 1/4” diameter in stock. We need seven pins but for ease of machining in our set up, four pieces were cut off the bar, each sufficient to make two pins when machined back to back. This means that we always have one to get hold of in the lathe when working on its mate. The 5/8” BSF thread was mainly screw cut in the lathe but finished off with a die, supported by the tail stock to ensure accuracy. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 20, 2014 Author Share Posted January 20, 2014 (edited) When the first side had been done, they were then turned around and held in a 5/8” collett in the lathe so that the other side could be similarly machined and threaded. Although we only need seven, we decided to machine up the last one, number eight as the set up was in place for it – so we have a spare! Then just a case of putting the four “doubles” in the Band Saw and split them into eight pins. The eight were then put back in the lathe so that the heads could be taken back to the finished thickness of 1/4”, the edges chamfered and the Grease Holes drilled through the centre. Final jobs – drill the grease holes in the pins to meet the long holes drilled through the heads, drill holes in the end shoulders for split pins and drill and fit the “feathers”. “The feathers” are just bits of 1/8” silver steel, pressed into holes drilled just under the heads of the clevis pins. Edited January 20, 2014 by Great War truck Quote Link to comment Share on other sites More sharing options...
Asciidv Posted January 21, 2014 Share Posted January 21, 2014 Tony, is it time for castellated nuts next?!Barry. Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted January 21, 2014 Share Posted January 21, 2014 Tony, is it time for castellated nuts next?!Barry. Plain nuts were fitted so plain nuts go back on! We try to restore, not to modify - unless critical! Tony Quote Link to comment Share on other sites More sharing options...
Asciidv Posted January 21, 2014 Share Posted January 21, 2014 I always thought the Thorny wasn't quite the standard of a Dennis! Quote Link to comment Share on other sites More sharing options...
David Herbert Posted January 21, 2014 Share Posted January 21, 2014 Actually the nuts, plain or slotted, serve very little purpose as there is no force making the pins slide out. All they need is a washer and bigger split pin as was discovered a few years later... If they need greasing it is also easier to drill the non force side of the lever that they pull on than to drill and cross drill the pin, then you can let the pin rotate in the hole and equalise the wear on it and don't need the feather. But it does make them so much more interesting than the purely functional design that gradually evolved. Nice job by the way ! David Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 26, 2014 Author Share Posted January 26, 2014 Regular readers may remember that when Steve started to reassemble the engine over Christmas, he broke two of the spring clips which retain the gudgeon pins. This prevented the second block from being fitted. Fortunately, he was able to rescue the clips from the second set of pistons and has recently shortened them for the smaller bore, closed them up a bit and hardened and tempered them again. This morning, he fitted the two remaining pistons to the rods and then fitted the rings to the pistons. This was not without incident as one groove was about 0.0005” too tight and the ring kept hanging up. Steve took the ring out and carefully dressed the groove with a needle file. It was not too difficult a process but quite time consuming Then he fitted the rod to the crank and did up the nuts. All was well until he tried to get the split pins in. This meant tightening further until the holes came in line by which time, the bearing had tightened up as well. Our normal approach to tightening nuts like this is FT (Feels Tight...) followed by more until the split pins go through. In this case, it didn’t work and an afternoon of bluing and scraping ensued. Eventually, an acceptable fit was achieved and the pins were secured. Finally, the last rod was fitted and this was fine. Unfortunately, they had run out of time so the block must wait for another day. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 26, 2014 Author Share Posted January 26, 2014 While Steve was playing with the engine, Father Started to fit the repaired rear cross-member. The rear corners had rusted away so Father had some pieces bent up and these were cut into the ends of the cross-member and welded in by a friend. The Cross-member was knocked into position the remaining original holes were used to bolt it in place. The diagonal cross brace was also fitted and the whole lot clamped up ready to drill the bolts holes in the new metal before cleaning and painting. Quote Link to comment Share on other sites More sharing options...
andypugh Posted January 30, 2014 Share Posted January 30, 2014 The cracking in the chassis rail is due to `work hardening`...cracking like that is a typical sign of `cold forging`....iron is particularly susceptible to this.... iron (unlike steel) is fibreous... Marvellous, pre-war metallurgy to explain a pre-war truck crack :-) You could have blamed "anomalous crystallisation" too. You do not get any work-hardening effect unless there is plastic deformation, which seems very unlikely in that position. The only cracks I know of that grow like that are the ones due to the hydraulic action of rainwater in railway tracks, and I am pretty sure we can exclude railway wheels rolling up and down the chassis :-) I feel that a flaw in the steel is more likely. (and I used to study cracks for a living) Quote Link to comment Share on other sites More sharing options...
Caddy Posted January 31, 2014 Share Posted January 31, 2014 Marvellous, pre-war metallurgy to explain a pre-war truck crack :-) You could have blamed "anomalous crystallisation" too. You do not get any work-hardening effect unless there is plastic deformation, which seems very unlikely in that position. The only cracks I know of that grow like that are the ones due to the hydraulic action of rainwater in railway tracks, and I am pretty sure we can exclude railway wheels rolling up and down the chassis :-) I feel that a flaw in the steel is more likely. (and I used to study cracks for a living) I think that this might be a litmus test of some sort....... Quote Link to comment Share on other sites More sharing options...
fesm_ndt Posted January 31, 2014 Share Posted January 31, 2014 I think that this might be a litmus test of some sort....... nah we only do the litmus test for prevention of chloride stress corrosion cracking but I thought the same thing i.e. it most likely resulted from an inherent manufacturing process defect when the steel was first rolled. Anyway it's the weekend in the UK so we should be getting another WW1 Thornycroft restoration instalment soon Quote Link to comment Share on other sites More sharing options...
David Herbert Posted January 31, 2014 Share Posted January 31, 2014 Yes, come on, back to work, your fans need you ! David Quote Link to comment Share on other sites More sharing options...
Old Bill Posted February 1, 2014 Share Posted February 1, 2014 Hi there! Yes, progress has been a bit slow recently. This having to earn a living really gets in the way! For the last twenty years or so, I have managed around 360 hours per year working on my various projects ( I have a chart in my workshop; sad git!). Last year, it dropped off to only 220 for a variety of reasons and this has slowed things down. I am also giving a few hours to the Maudslay project at the moment to get the thing ready for the Brighton run this year. That is going to be another last minute dash but we should do it, even if not complete in every detail. I will post a few pics of that later too. How many hours do you chaps devote to your projects? More later! Steve Quote Link to comment Share on other sites More sharing options...
42 chevy Posted February 1, 2014 Share Posted February 1, 2014 I average around 200 hours per year. Where I live, the weather (cold currently) can really slow things down. John G Quote Link to comment Share on other sites More sharing options...
fesm_ndt Posted February 1, 2014 Share Posted February 1, 2014 Time, that would be an interesting thread on its own......... I am a weekend warrior with my projects and with my real job starting to be long hours it is hard to drag myself out of bed on a weekend to go play. I don't have to worry about the cold but the heat sucks the life out of you. But this is all the hands on work, how much time is spent on the other bits, finding manuals, chasing parts, chasing suppliers. I wonder how many restoration people are workaholics. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted February 3, 2014 Author Share Posted February 3, 2014 We have not posted very much these last few days but work has continued nevertheless! Steve has been making bits for the Coventry Museum Maudslay to help them out and to ensure that it will be finished in time for the London to Brighton Run in May. If you have not looked at the Maudslay thread, then do so and you will see what Steve has produced for them. Meanwhile, back in Devon, painting has continued on the chassis and on various already made and other prepared “bits” so that they will be ready for installation when they are wanted. Today, we have started to make new Shackle Pins – 12 are required of 4 different patterns and we have “kicked off” with the front ones. The two very front ones also accommodate the front hooks as well as the spring so are quite long. The method of manufacture is exactly the same as the recently made Clevis Pins – two are made back to back so that there is always plenty of material to hold on to when machining! The thread on this first one is 3/4” BSW and was mainly screw cut in the lathe and finished off with a Die. We could not resist holding it up with the Hook, even though there is still a lot of work to do to it for the Grease Passages. The other 11 will be made to this same stage and all 12 will be finished off together at the end. Quote Link to comment Share on other sites More sharing options...
.303fan Posted February 4, 2014 Share Posted February 4, 2014 how many hours do you guys spend on your projects per day.... 3 to 4, sometimes up to 9 depending on rain and pain. shopping for parts count, building a dryish shed from a wood rot box, needing to drive to liverpool region from mablethorpe to pick up a petrol engine :-) Bill, can you do custom projects on the side that is about milling and machining with a lathe? if i can get precise drawings for a winch drive line , can you make some bits? cheers, Arjan Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted February 4, 2014 Share Posted February 4, 2014 Well, I can't speak for "Bill" but we don't do any outside work - commercial or otherwise as we are only amateurs playing at it. Steve's work on the Maudslay was done as an unpaid volunteer to help out where our knowledge of working to a deadline on a WW1 Truck could obviously be helpful. The "Brighton" is now looming up so quickly and there is still so much to be done to complete the project in time for it. There are a whole number of small firms around who will take one-off commissions with the sort of work that you are talking about and perhaps you could make some enquiries for such a firm near to you? Tony Quote Link to comment Share on other sites More sharing options...
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