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WW1 Thornycroft restoration

Great War truck

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It could have been made in two pieces but I am pretty sure that it wasn't. Malleable iron sounds more likely as it is a good thin section all over making it easy to produce the white iron stage. Was it a common process at the time? I have never asked the foundry whether they do it and it would be a useful process to keep up my sleeve. They didn't teach us about it at college!

Not much visible achieved today although I have primed all of the outstanding parts. I have been laying out the lettering for the signwriter but I need Tim's expertise to pick a suitable number for it. I have also been laying out the petrol tin carriers but there won't be time to get them done before Brighton.

Steve   :)

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They taught me about it in college ( Chesterfield ) though that might be giving my age away.

Malleable Iron is Spheroidal Graphitic, or SG Iron.  The graphite is heat-treated into nodules rather than flakes, and that moves the physical properties of the material closer to a mild steel - when stressed it will deform to a degree before it will fracture.

It was certainly in existence long before WW1, but in those days it has the added production cost of  extensive heat-treatment, so wrought iron or an early version of what we now call mild steel would be much more likely as much cheaper and faster.

Edited by Gordon_M
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I have an almost identical (but smaller) lamp bracket in my 1923 Leyland. The flat portion has a sand cast finish on the back while the rest clearly bears marks consistent with a forge power hammer with a rectangular tool of, say, 3/4" on the narrow edge. The ears have been bent up during the forge process. Also noted are the marks of a heavy handed grinding wheel.

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On ‎04‎/‎04‎/‎2018 at 10:30 PM, Old Bill said:

Many thanks for all of your thoughts. I am pretty sure that I don't need the hot air inlet as modern fuels are so much more volatile. However, I will keep that one up my sleeve for the time being. I have been doing other things today whilst I mull it over but I have investigated the timing and this is what I have found. Taking 'valve opening' or 'closing' as the point at which the tappets contact or part then, at the moment:

Inlet opens at TDC

Inlet closes 34° after BDC

Exhaust opens 32° before BDC

Exhaust closes 5° after TDC

Steve   :) 

I know I am a bit late with this but I found this timing diagram in a 1920 Thornycroft Q Type instruction book (and believe it had the same engine).


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11 hours ago, mammoth said:

I have an almost identical (but smaller) lamp bracket in my 1923 Leyland. The flat portion has a sand cast finish on the back while the rest clearly bears marks consistent with a forge power hammer with a rectangular tool of, say, 3/4" on the narrow edge. The ears have been bent up during the forge process. Also noted are the marks of a heavy handed grinding wheel.

After reading through these posts on the lamp brackets  I had a look  through some of the lamp brackets that we have  collected up and one becomes aware and notices the various styles of manufacture as described above. Thornycroft and Leyland have a common shaped lamp mount aside from the T section where it is bolted to the scuttle. The Thornycroft T is flat as per the scuttle while the Leyland T is curved to fit the scuttle radius.  A common supplier for these parts? 

 Doug W


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43 minutes ago, BenHawkins said:

I know I am a bit late with this but I found this timing diagram in a 1920 Thornycroft Q Type instruction book (and believe it had the same engine).

Thanks Ben , that is wonderful! Yes, the earlier Q-types had the M4 engine. I think the later ones had the AB4 inlet-over-exhaust type. The chart seems to match what we have so I am pleased that we didn't change it. I don't have any time for messing now and everything has to be right first time. Our test run, which is planned for 29th, won't be more than a mile at most! Thanks or the confirmation!

Dad has decided that we must have the signwriting done so he has rung the signwriter. He is coming on Monday so I am now panicking trying to produce some artwork for him including choosing a number. This is what I have laid out this evening:


Computers make this a lot easier but I need to be careful to pick a font which doesn't look 'new'. There are a couple of very nice vehicles out there spoiled by the style of the lettering which is a great shame.

Steve     :)

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14 hours ago, Old Bill said:

Computers make this a lot easier but I need to be careful to pick a font which doesn't look 'new'. There are a couple of very nice vehicles out there spoiled by the style of the lettering which is a great shame.

I quite agree, a particular bugbear of mine. Modern style lettering and numerals or even worse sticky back vinyl letters....

This is how it was done in the wild. Check out the Lyle's golden syrup tin and 'paint stirrer' Don't be afraid pick up the oversize brush with five bristles and have a go. It's more authentic!

The original caption to this photo in an album I have is ' 'Razor' Gilette paints up his armoured car' It's a Daimler AC.


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When you look at the pictures, you realise that there was very little standardisation with the numbering. They are roughly the same size and in similar positions but a lot were applied by anyone nearby who could hold a brush!  Some are really classy with beautiful shaded script but others are not even horizontal. Our signwriter commented that the font on the Dennis was not of any standard and the shapes were slightly wrong to the eye. He couldn't resist tidying it up a bit! I have just picked a plain font which, to my eye, doesn't look wrong. I hope Tomo approves as this is one of his specialist areas.

Steve   :)

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Well, it is painting, painting and painting. Dad is pressing on with it and now has the first top coat on the inside and outside of the bonnet.



He has also painted some steel for the nuimber plates and primed the 'pyramid nosing' so kindly provided for us by Mark and delivered by David. Many thanks for that chaps. It is exactly what I wanted!


I wasn't expecting to be able to get that on but we should now, with a bit of luck. The next kill-or-cure obstacle is to braze up the propshaft, the project for this weekend. Everything is crossed for this one!

Steve    :)

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Well, we are still at it but getting tired now. Only two weeks to go now though so we will keep at it. I am down in Devon again and, as the traffic was reasonable yesterday, I managed to put in another couple of hours and fit the bonnet boards.



Never as quick or easy as one would expect but satisfactory in the end including a P-clip to stop the fuel line vibrating.

I then set to to fit the differential spider. Again, this was quite time consuming making sure that everything was just right. The spider needed a good clean-up so that Barry's gauge would fit all the way down. Access underneath a lorry isn't too bad but I did end up  bit closer to it than I wanted. I also don't bend that well any more when crawling in!


Dad had machined the end cover casting some time ago so all it needed was a gasket and felt seal and it was ready to go on.



It pushed most of the way on but the threads were a bit gummed with paint and the nuts had to be wound the whole way down with the spanner.


Then the centre nut went on. This should have tightened hard against the spider but I was concerned when it didn't but continued to push the spider along the shaft along with the bearing inside. At this point and all morning in fact, the shaft had been lumpy when being turned. However, I kept winding the nut and after another complete turn it tightened up as I would expect and  the worm went silky smooth, much to my relief.


I jammed a piece of wood under the spider to allow me to put some torque on the spanner and all was well.



For that job, I must thank Barry very much for printing the pattern for us and for arranging for the spline to be cut.

The next job was to put the handles on the bonnet. Dad has been painting like mad and the signwriter is coming on Monday so the bonnet needs to be on! We bolted the handles on temporarily.


Then laid the whole assembly on its back on the floor on an old blanket donated by a friend. It is actually better than those on my bed!


The rivet snap was mounted in a vice and used to support the rivets from underneath whilst I knocked them down.



Fitted at last! Dad is now in the process of touching up.


Many years ago, I saw a set of bonnet catches for sale at a rally so I bought them ready for this day. They are genuine military standard but 1957 rather than 1917. Don't you just love NoS parts?



I must make the fittings to hold them to the boards now, a project for this week.

Then, the main reason for my visit, the propshaft. I started off by setting up a hearth and cutting a piece of tube to go underneath to stop the main tub falling through when hot, a not-unlikely scenario, I can say from the voice of experience!


Steel end polished and fluxed up. I similarly fluxed the inside of the casting.


Then propped it on the firebricks with a stepladder behind to which was clamped a piece of timber to keep it in place. I really didn't want a six foot length of red hot steel tube falling on me.



Heated all round with the big propane torch and all went well. I could have used a bit more solder but it ran in beautifully and I am sure will be fine.


The other end will be tomorrow's first task.

Finally, some springs had turned up so I installed them on the footbrake shoes ready for when I get around to setting that system up. That is going to have to be soon if we are to manage our test run next Sunday!


Steve    :)

Edited by Old Bill
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On 22/04/2018 at 1:02 PM, flandersflyer said:

I think you'll make it...just...

Not sure yet but we haven't hit a show-stopper!

After brazing up the first end and giving it a clean, it looked OK. A stick and a half went into the joint and didn't come out anywhere so I think it is fine. I didn't get the clean fillet I wanted around the bottom but it will be OK.


On to the second joint. First job was to cut it to length after some very careful measuring. I was aiming to make it between size and 1/4" short so that I could add shims if necessary. Too long would be a disaster!


Father's trusty bandsaw soon made short work of it. That doesn't half save some graft!


Then flux both parts and brick up as before.



I found myself a nice stool and, using Father's biggest burner, off we went.


Flux just coming up to temperature.


Run some 455 grade silver solder.


Move the torch around the back to make sure it runs properly.


And bingo, a nice sound joint.


I did a much better job this time and the solder ran right through. Underneath the ring of flux was a nice fillet. I was very pleased and quite relieved! Each joint used a stick and a half which at £14- a stick means that each joint cost £21- to make. It isn't a cheap process but for one-offs it is very effective. I love the process, as you can tell!


Then it was the moment of truth and time to try to install the thing. First job was to insert the leathers and partially insert the bolts.


Then it was a two-man lift to get it roughly into position and knock the bolts in to take the weight. Amazingly, it was exactly the right length with no shims required. Access isn't bad but I can't sit like that for very long any more...


Dad machined the heads off the bolts and drilled them for split pins ready for me to install. There are only six bolts at each end but it is surprisingly time consuming to fit them properly.


Back end done.


And on to the front where access was more awkward.



All went well, however and we have a prop shaft.


When you turn the handle at the front, the differential turns. All we need now are some half-shafts and it will drive. Sadly, I am back at work so that will have to wait for Saturday,

One more tick in the box!

Steve   :)

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Steve, did I miss the bit where you dynamically balanced the prop shaft up to 1000rpm before fitting?  My local Fire Brigade workshops were fixated on prop shaft balancing  but to me it always seemed unnecessary compared with the other rotating masses which could be out of balance.

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We haven't balanced the shaft. The rotation depends on how well I drilled the leather so there will be some variability in it. Hopefully, there won't be a problem but if there is, then I will have to get it done. No time left at this stage!

Dad is still pressing on and has sent this report:

Our old friend and  great old lorry enthusiast, John Corah arrived to do the Sign Writing for us. Previously he completed similar work on our FWD and then on our Dennis and we have always been full of admiration of his wonderful skills. Steve had made life quicker and easier for him by completing all of the Art Work full size, before hand so that when he arrived, John could go directly into his procedure of covering Steve’s writing showing through to the back of Steve’s paper with a white chalk crayon so that when the paper was impressed against the position to be signed , all John had to do was to go over the drawing on the outside with a pen to leave a chalk impression on the surface to be sign written for the chalked shape to come off..
The following sequence of pictures will show what happened.
Incidentally, John has written book entitled “The writing’s on the the Truck” which demonstrates his skills and procedures and contains dozens of photographs of old vehicles which will be enjoyed by any old lorry enthusiast.






And then it was exactly the same procedure again for the remainder of the writing on the side of the lorry.







And then the Number Plates and lastly, painting the Thornycroft Name Badge!




Thanks John. Now it looks the part!


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