WW1 Thornycroft restoration

[Great War truck]

The final part was to add the finger grips. A trial was carried out done by cutting a 3/4” length of 3/16” half-round brass and filing the ends spherical before bending it into a curve and trying it on the rim.

From the photos, it appears that there should be forty of them so Steve made the remainder by rather tediously filing them all individually and then attached them to the rim with Araldite.

(65, . Finally the whole assembly was treated with our usual two coats of Bondaprimer, with the first heavily rubbed down to create a surface and the second gently polished with wire wool. The pattern is now ready for a trip to the foundry for casting in aluminium.

[andym]

Very nicely done. A random thought, but you could probably have used acrylic false nail tips for those finger grips!

 

Andy

[Hoseman]

The final part was to add the finger grips. A trial was carried out done by cutting a 3/4” length of 3/16” half-round brass and filing the ends spherical before bending it into a curve and trying it on the rim.

From the photos, it appears that there should be forty of them so Steve made the remainder by rather tediously filing them all individually and then attached them to the rim with Araldite.

(65, . Finally the whole assembly was treated with our usual two coats of Bondaprimer, with the first heavily rubbed down to create a surface and the second gently polished with wire wool. The pattern is now ready for a trip to the foundry for casting in aluminium.

bloody hell gents, excellent work there AS USUAL I may add!!!

That wheel looks good enough to use as is...!! LOL

One of my favourite threads and try not to miss an episode! ............Shes got Corrie....I got Thornie!!!

[Old Bill]

Very nicely done. A random thought, but you could probably have used acrylic false nail tips for those finger grips!

 

Hi Andy.

 

I hadn't thought of those. Rather outside of my usual shopping experience! I did spend some time trying to find something that might do the job but the brass was the only solution that I could make work. It doesn't Araldite very well though so I may lose some in the moulding process. We shall see.

 

Steve

[ajmac]

New years honours required all around! For services to the preservation and restoration of First World War British transport vehicles. A joy to read, as always.

[flandersflyer]

well....i`m generally very busy with my work (electrical contractor)...but i just have to come in here at least twice a week to get my thornycroft fix!!

 

well done fellas....keep it up.

[Asciidv]

Steve,

How exactly do they cast this? I was puzzled by the Dennis wheel and the recent pictures have raised the same question. There must be a simple trick but what is it?

 

Barry.

[mtskull]

I never cease to be amazed at the quality of workmanship, depth of knowledge and sheer ingenuity that goes into this project; I am looking forward to watching it all go back together.

 

Re. the steering wheel, isn't the wheel fitted to the Taunton scrapyard example different to the others which you have used for reference? -It appears to be have been made out of steel, with a separate rim, rather than cast in one piece in aluminium. Perhaps the need to protect steel spokes from rust might explain why they are coated as well as the rim in this case?

It is difficult to be 100% certain but the spokes of the wheel in the old photo of the tipper look as if they are bare aluminium. Also, if the aluminium spokes were once coated, then in the case of the bus in the museum, somebody has gone to a lot of trouble to remove every trace of the coating from the spokes, before wrapping the rim.

[8_10 Brass Cleaner]

I never cease to be amazed at the quality of workmanship, depth of knowledge and sheer ingenuity that goes into this project; I am looking forward to watching it all go back together.

 

Re. the steering wheel, isn't the wheel fitted to the Taunton scrapyard example different to the others which you have used for reference? -It appears to be have been made out of steel, with a separate rim, rather than cast in one piece in aluminium. Perhaps the need to protect steel spokes from rust might explain why they are coated as well as the rim in this case?

It is difficult to be 100% certain but the spokes of the wheel in the old photo of the tipper look as if they are bare aluminium. Also, if the aluminium spokes were once coated, then in the case of the bus in the museum, somebody has gone to a lot of trouble to remove every trace of the coating from the spokes, before wrapping the rim.

 

The common make up of a steering wheel of this age is a cast spider, usually in Ali, with a hollow tubular steel rim. Usually formed in two pressed halfs, usually a plain top and a bottom incorporating the hand grips. Quite often there is a mechanical connection between the rim and the spider (screw or rivet).

 

Sometimes the rim only is coated, often the rim and the spider is coated, but usually leaving the centre boss free.

 

The scrap yard picture is missing its steel rim because it is likely rusted out.

 

The coating has a nasty habit of cracking and debonding, and when it does so the best thing to do it to take it off, you can peel it off like pealing an orange. Its basically an early form of plastic. The standard 'repair' was to wrap in tape, a bare metal steering wheel gets proper cold with no windscreen (and I hazard a guess probably why earlier vehicles have wooden rims to the wheel).

 

Guys, how are you going to coat the rim and spokes?, I have an Austin 7 steering wheel needing the same treatment.

Edited November 5, 2013 by 8_10 Brass Cleaner

[Richard Farrant]

Guys, how are you going to coat the rim and spokes?, I have an Austin 7 steering wheel needing the same treatment.

Powder coating works well. I am restoring a 70 year old vehicle with steering wheel made of alloy and steel. The plastic coating was lifting off so stripped it and the powder coaters blasted and primed it and coated black, as good as new and not expensive at all.

[Old Bill]

Steve,

How exactly do they cast this? I was puzzled by the Dennis wheel and the recent pictures have raised the same question. There must be a simple trick but what is it?

 

Hi Barry.

 

I haven't actually seen it done but I think that the wheel is placed face down on a board with the drag around it. It is then packed with sand completely including under the spokes. When the drag is turned over and the board removed, the moulder cuts the sand away down to the centre line of the pattern using various spatula like tools. The cope is placed on top and a sprinkle of parting sand is applied before filling up with more sand. When that is lifted off, the pattern can be removed.

 

This approach is fine for the one-offs that we do but I think he would probably want a backing piece made up to go underneath if he was doing very many.

 

I remain to be corrected!

 

Steve :-)

[Old Bill]

Guys, how are you going to coat the rim and spokes?, I have an Austin 7 steering wheel needing the same treatment.

 

As Richard says, we plan to use glossy powder coating again, just like we did with the Dennis. That worked well at very reasonable cost. This picture shows it on its return but before cleaning and tidying the finish at the ends of the spokes.

 

Steve

[Old Bill]

-It appears to be have been made out of steel, with a separate rim, rather than cast in one piece in aluminium. Perhaps the need to protect steel spokes from rust might explain why they are coated as well as the rim in this case?

 

I'm afraid we are rather taking some liberties with this wheel. It was originally a steel tube rim surrounding a cast steel centre, not aluminium, and coated with celluloid or similar all over including the hub. We are using aluminium just because it is the easy way out and it will be disguised by the powder coat. Of the ones we have seen, all are in poor condition except the gun lorry of course. Unfortunately, when I last saw that, I didn't think to take any pictures of the wheel!

 

Steve

[Asciidv]

 

I haven't actually seen it done but I think that the wheel is placed face down on a board with the drag around it. It is then packed with sand completely including under the spokes. When the drag is turned over and the board removed, the moulder cuts the sand away down to the centre line of the pattern using various spatula like tools. The cope is placed on top and a sprinkle of parting sand is applied before filling up with more sand. When that is lifted off, the pattern can be removed.

 

 

 

Steve,

 

I had thought that there must be some 'trick' to this. For the moulder to produce his own centre lines (especially on the thin features like the angled spokes) must take a great deal of skill and experience. When this wheel pattern goes off to the foundry it would be wonderful if they gould take some pictures to show how it is done.

 

 

Barry.

[andypugh]

As Richard says, we plan to use glossy powder coating again, just like we did with the Dennis.

 

It is possible to buy Ebonite as bulk material, but I have no idea how they coated it onto steel or aluminium for steering wheel use.

http://www.nikkoebonite.com/english_site/manufacturing_processes_of_ebonite.html

 

Suggests that you would probably wrap the rim in the material and then vulcanise in-situ.

[Minesweeper]

Expense is a factor, too! The last steering wheel that we had powder-coated only cost £30 plus VAT! Quick and easy with quite acceptable results! Tony

[Gordon_M]

The technique of moulding something like that is called an odd side or odd side, and is described quite well above, in that you make up a dummy section under the wheel, ram up a top half, invert it, remove the odd side, tart it up a bit, then make the proper 'other' half ( could be either top or bottom )

 

Bigger production quantities would get a false pattern plate under the wheel, and do away with the need for the odd side, but that is a lot of extra pattern work if you are only doing a few.

 

( If we get to the point where I have to start explaining the drawback technique we will really be getting down to it )

[Barney]

Hi Steve,

You say of the Thorny steering wheel that “It was originally a steel tube rim surrounding a cast steel centre”

Which poses a question; will your new aluminum wheel have the same strength as the original?

John

[mattinker]

Hi Steve,

 

You say of the Thorny steering wheel that “It was originally a steel tube rim surrounding a cast steel centre”

 

Which poses a question; will your new aluminum wheel have the same strength as the original?

 

John

 

I don't think there would be a strength problem, the Denis one seems to work. How about a crash test to see! ;-}

 

Regards, Matthew

[Great War truck]

The whole team assembled in Axminster this weekend with the aim of completing the strip down of the Thorny chassis so that just the frame would be left and that then would be ready to go for sand blasting. All of the smaller bits had already been removed from it and it really was just the heavy and more difficult bits that were left to come off. The three of us were joined by our friends Andy C from Taunton and John P from nearby Dalwood who came to help. Most of the nuts had already been removed from the chassis and in theory, we were left with a simple task to complete! We were very conscious that the springs would have to be treated with some caution as they were very badly decayed but that there was still a lot of energy left in them which could be hazardous if taken apart without safety planning.

 

Fortunately the weather was kind as we really needed to get the chassis outside to have sufficient room to work on it. The front wheels came off quite easily and revealed bearing surfaces which were not in too bad a condition.

 

 

 

 

 

This is the second of the two front wheels being taken off – you will see the method that is used to secure it to the axle quite clearly. The front wheel is quite heavy and can be managed – but not lifted by one person.

 

 

 

 

 

[Great War truck]

When we recovered this chassis many years ago, the bolts and the top retaining plate for one of the front springs to the axle had already rotted away so that side of the front axle was “floating”. This was the make-shift arrangement that was used to keep the axle attached to the chassis whilst the chassis was being moved.

The nuts on this temporary arrangement were released gradually so that the spring leaves could be separated under close control and be removed separately as they became free.

[Great War truck]

The other front spring was still bolted firmly to the axle but all of the leaves had spread considerably and we were very conscious of the amount of stored energy that must still be there. Ropes were placed around the leaves so that should they suddenly decide to go, then they would be captured. The bolts holding the leaves together were cut with an angle grinder, and the spring was released from the chassis, but the spring would not come away from the axle so axle and spring were lifted away together to be dealt with separately.

Once the axle and spring were away from the chassis, it was easy to knock the spring off the axle and then work carefully on the spring until the leaves began to separate.

[Great War truck]

We then turned to the back wheels – fortunately, the retaining nuts had been well greased and came undone easily. The back wheels are very heavy and had to be slid off the axle with the weight of them taken by the engine hoist – revealing the bronze bushes as they came off.

 

The Brake Drums are very rusty and will have to be skimmed. The Bronze Bush looks to be in reasonable condition, too

[Great War truck]

The Back Springs were once again treated with caution with the nuts on the retaining bolts to the leaf springs slowly undone – after being released by heating them first of all.

 

When the retaining nuts were nearing the ends of the bolts, we could see that there was still a lot of energy remaining in the springs so a temporary “corset” was put around the spring which could also be undone gradually so that the spring leaves could be controlled until any remaining pressure had gone. The springs were released from the chassis and the whole back axle assembly with the springs still sitting in situ on it were pulled out.

 

By this time, it was Saturday evening and it had become dark – so we gave up for the day – with the job to be completed on Sunday – which it was, with more pictures to follow!

 

[Great War truck]

Sunday and another day. The objective that day was to remove the remaining shackle pins that were either still retained in the chassis – or lodged in the spring parts already removed from the chassis. They were rusted in solidly and were tackled with heat – and a big hammer. None of the shackle pins were fit to be used again so harsh treatment with the hammer would not matter as replacements must be made.

 

Something that we had suspected became a fact –unlike the Dennis, we thought that the spring ends were not fitted with bronze bushes and as soon as the first pin was removed from a spring “eye” we could see that there was no bush there. Thornycroft were obviously content to run steel shackle pins in the steel eyes of the springs.

 

 

 

 

 

Despite considerable heat and firm attention from the big hammer, some of the shackle pins would not come out and they had to be cut, either with a hacksaw or a thin cutting disc in the angle grinder – where there was room to insert the blades without damaging the castings or forgings.