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WW1 Thornycroft restoration


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Thank you David for the description of railway tyre making,. As you say it would be a logical step to use the same process for vehicle requirements.

 

It was even the subject of a "How it's made"

http://youtu.be/85qpD15BPac

 

There are still companies in the UK that makes them (Doncasters for example) though you have to be careful not to get them confused with "Ring Mills" which were different.

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The castings for the new brake rings have been received from the foundry and are ready for machining.

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Very nice. How will you ensure that the brake rings are concentic with the hubs? Have you access to a lathe big enough to machine them while bolted to the wheels, or is there a means of centring them after they are fitted?

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Very nice. How will you ensure that the brake rings are concentic with the hubs? Have you access to a lathe big enough to machine them while bolted to the wheels, or is there a means of centring them after they are fitted?

 

Have a look at the pictures on Posting No. 1402 dated the 12th August - you will see that there are 4 small plates each fastened by two rivets to the back of the wheel designed to hold the rings exactly on the centre for the rings to butt against. So provided that the new brake rim is turned to the precise diameter, it will be self centring against those small plates in the centre of the wheel! Easy!

 

We are very fortunate to have a friend with a lathe large enough to hold the brake rings and he has very kindly said that Steve may use it! The new rings are on their way today with Steve, to Leicester for that purpose!

 

Tony

Edited by Minesweeper
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You have already seen the results of this pattern! However, there is some interest. A little while back, we were talking about how we were going to make the pattern for the rear brake drums as it is quite a size. Our joiner friend, Mark, offered to do the donkey work for us by using a laser cut ply ring with several layers of flexible ply for the drum itself. We didn't know you could laser cut plywood without burning it and the flexible ply was a revelation too. I gave him some dimensions and this is what he came up with, complete with draft.

 

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It was a lovely job, made exactly to my measurements and perfectly round which is something I couldn't achieve. I then set about finishing it off, firstly by adding leather fillets.

 

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At this point I realised that I had been very mean with the iron and if it did not come out perfectly round and true, I would not have enough to machine it back. I therefore set about thickening it up using an additional layer of this miraculous plywood.

 

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It bent around remarkably easily and I secured it with PVA glue and all of my toolmaker's clamps. This was insufficient so I also added a further 34 woodscrews to hold it! This worked well and I simply planed the edges back and then removed the screws and filled the holes.

 

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Two coats of Bondaprime and off to the foundry with the results you have seen.

 

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They are remarkably heavy and the foundryman surprised Dad by carrying both at once to the car. Neither of us could do that!

 

Father has been to the foundry again today with the transmission brake shoe patterns so we should see those before Christmas too. We are going to have plenty to keep us amused over the break!

 

Steve

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Another bit that had to be fabricated – we never had it – was the tie bar that goes between the fulcrum pins of the Transmission Brake. Its general shape and dimensions were sketched from information obtained from photographs and from looking at other still complete Thornys. The original was probably a forging but we have used a piece of 2” x 3/8” steel bar with some 1/16” steel plate silver soldered to the ends to give it the same shape as the original. The four pieces of steel plate were drilled 3/8” through their centres, bolted together and turned to 2” diameter to match the dimension of the main steel bar. One disc to be held each side of the 3/8” bar at each end which has had matching 3/8” holes drilled in it 13” apart to match the distance between the fulcrum pins on the gearbox. The steel bar and discs were held together with a 3/8” nut and bolt to hold them in place during silver soldering.

 

The bits were thoroughly cleaned before fluxing and silver soldering and the nut and bolt were not be done up too tightly as otherwise the silver solder would not penetrate.

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Not sure is the stuff in this advert is of any interest. but if you dont see, you never know

 

http://www.tractiontalkforum.com/showthread.php?t=33429

 

The seller has neglected to add contact details other than PM for registered forum users, which strikes me as short sighted. but there you go. I can send messages if necessary.

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Not sure is the stuff in this advert is of any interest. but if you dont see, you never know

 

Thanks Hedd - would like to have a look - I don't know if you have my Email but will send a PM to you when I work out how to do it! May come from the boys!

 

Tony

 

Tony,

These solid tyres were advertised on this forum yesterday, with photos;

http://hmvf.co.uk/forumvb/showthread.php?47389-Continental-800-x-94-new-old-stock-solid-tyres

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Tony,

These solid tyres were advertised on this forum yesterday, with photos;

http://hmvf.co.uk/forumvb/showthread.php?47389-Continental-800-x-94-new-old-stock-solid-tyres

 

Thanks Richard - but it appears that in addition to the solid tyres advertised here on HMVF, there are also 4 Thorny wheels which were not mentioned on "our" Forum! Have a look at the one that "Brass Cleaner" mentioned in his posting - tell me that I have it wrong - which has been heard of before!

 

Tony

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Thanks Richard - but it appears that in addition to the solid tyres advertised here on HMVF, there are also 4 Thorny wheels which were not mentioned on "our" Forum! Have a look at the one that "Brass Cleaner" mentioned in his posting - tell me that I have it wrong - which has been heard of before!

 

Tony

 

Hi Tony,

Yes I thought afterwards that those Thornycroft wheels might be of interest to you. What about the rubbers, no chance that they are for the Thorny' ?

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Over the Thanksgiving weekend, we decided to fit the newly machined and painted transmission brake drum in order check that the brake shoe pattern was correct and get the drum out of the way! After a scrape and polish of the spline, it went on with a few good thumps and a block of wood.

 

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It is secured with a single nut which is itself locked with a spring clip which wraps around the outside and engages in a cross hole in the shaft and nut.

 

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I marked the hole positions using a marker and, ignoring the drip of paint which seemed to have found its way into almost the right position, tightened the nut with a socket.

 

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The pin was inserted successfully after switching the nut with the one from the other end of the shaft to get the holes to align....

 

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Finally, the brake shoe pattern was held against the pivot shaft and the drum just to check that it was the correct length before sending it off to the foundry.

 

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All was well, fortunately!

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We are trying to get the bits together now in some form of sequence and with the Transmission Brake Drum recently fitted, it was time to move on to the Brake Shoes. This again involved more pattern making as we never had the original Brake Shoes and two had to be cast – so it was back to Steve again for him to make the pattern for those. This was probably one of the more elaborate patterns attempted so far and our friends at the Foundry took one look at the end result and said “Looks good”! – all very reassuring!

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