WW1 Thornycroft restoration

[Redherring]

 

Here is an alternative home made tool for getting a fine polish on a bore, it can also be used as a glaze buster in cylinders.

 

John

 

I like it. I'm going to make one this weekend. Robert

[mattinker]

Just a word to say how much I enjoy this thread. Thank you for taking the time and trouble to keep us informed of your progress by recording this interesting restoration!

 

Regards, Matthew.

[Hoseman]

We really do NEED a "LIKE" button on here I think!!!

[Great War truck]

We had a very productive day today, pressing tyres on and off Thornycroft wheels. This is a great deal easier if you have the correct equipment and luckily we have a good friend with a tyre press. The press operates by hydraulically pushing a heavy metal plate upwards. You put the tyre on the plate and rest the wheel on top of that. By carefully positioning metal blocks against the edge of the wheel the tyre is slowly pressed on to the wheel. The water pressure is maintained by a hand pump, and for this you need plenty of athletic friends. Today was a big gathering as we had 20 people present. All the more hands to operate the pump.

The recently sand blasted and painted wheels:

The new tyres ready to go on (this had been removed from an Eagle trailer:

The old tyres removed previously:

The first tyre on the press:

The wheel is located on top:

The ram begins to rise out of the ground. The press goes into the ground about the same distance that it rises above it:

The ram has risen further and the metal blocks which the wheel will be pushed against can be seen:

The tyre begins to slide onto the wheel:

The pump:

 

The first completed wheel:

[Hoseman]

LIKE button pressed!!!

[cosrec]

That's unbelievable I have lots of mates that have unusual items lurking around in their yards and gardens but a hydraulic press that size ??? Fantastic

[andypugh]

I think I recognise that press, and have spent some time cranking it myself.

 

It is probably actually a good deal bigger than it needs to be.

[Redherring]

That is an interesting point... i.e. how big does it need to be... Suppose I was desperate and had to make one. What pressure do you think is required?

[Old Bill]

That is an interesting point... i.e. how big does it need to be... Suppose I was desperate and had to make one. What pressure do you think is required?

 

The ram is 14" diameter and the pressure gauge is dual calibrated in cwt/in² and Ton/in² up to 2 tons! We used all of it to get the rear tyres started as Tim will tell you shortly.

 

Steve

[Great War truck]

The next step was to press the old tyres off the rear wheels. The process was similar to pressing on the new ones. However, the rears are a great deal heavier than the front requiring a chain block to lift them into position:

This time the wheel is placed up on blocks the tyre is to be forced down. Here you can see the blocks being slid into position:

The wheel is manoeuvred into position:

The pressing begins:

The suspended blocks are slid out until they just sit on the rim of the tyre:

After a great deal of pumping and effort the tyre begins to move:

Until the first of the two tyres dropped off:

The first tyre is lifted out and the pressing commences on the second tyre:

It must be remembered that the pressure on the wheel is enormous and H&S is not something to be ignored. Unfortunately, just after this photo was taken something very unfortunate happened. Despite being careful it is very easy in your enthusiasm in watching the tyre slide off the rim to miss something very important.

 

Right. Time to get the Sunday roast ready.

[cordenj]

It must be remembered that the pressure on the wheel is enormous and H&S is not something to be ignored. Unfortunately, just after this photo was taken something very unfortunate happened. Despite being careful it is very easy in your enthusiasm in watching the tyre slide off the rim to miss something very important.

 

Such as keeping hands well clear of the suspended tyre rim? (last photo)

[Great War truck]

That was very observant of you. Yes, that would have been very nasty resulting in trimmed finger nails (or trimmed fingers), but that is not what happened (although it could quite easily have done).

I feel like I should be making one of those Health and safety videos. "What happened next"?

There is something not right in our set up which resulted in the incident. If you study the photos carefully you might notice it. The shape of the Thornycroft wheel exacerbated the situation. Think about what forces are being applied. Free mince pie to the first to notice. Don't worry if you have no idea. There were 20 of us watching the pressing and we didn't notice what was about to happen until it was too late.

[andypugh]

The ram is 14" diameter and the pressure gauge is dual calibrated in cwt/in² and Ton/in² up to 2 tons! We used all of it to get the rear tyres started as Tim will tell you shortly.

 

So, 2 tons per square inch on a 14" ram sounds like 300 tons. That's a fair bit more than I would have guessed.

[onthecorner]

When the tyre "let go", the wheel shot upwards at a rate of knots and knocked out a couple of the top blocks from their slots?

[cordenj]

The domed centre of the wheel ended up damaging itself and the chains against the top block?

[Tony B]

One side stuck resulting in the whole thing swinging to an angle and shooting the old tyre out?

[N.O.S.]

As the press pushed the wheel up, the domed centre of the wheel contacted the top of the press before the tyre was released from the wheel.

 

Little bit of straightening to do? :whistle:

 

Our press has only one original curved cast iron block - and thanks to your pictures I now know what that was used for! We have several different length blocks made from RHS with heavy plates top / bottom, but they would be dodgy to use for this application.

 

That's what you needed - a longer set of blocks!

 

Tony

Edited November 16, 2014 by N.O.S.

[Great War truck]

Well done chaps. You have got it.

 

The top blocks are just not quite long enough for this set up. As the wheel was pushed up the chain fouled the top of the press.

We noticed just as the tyre was about to drop off:

Nasty dent and gouges:

Actually, a lot worse than it looks in the photos:

Disappointing to think it is nearly 100 years old, survived two world wars and then we damage a wheel like that:

 

Anyway, it is still in better condition than the tyres:

Edited November 16, 2014 by Great War truck

[N.O.S.]

Looks like you'll need a press to get that out - if only there was one not too far away (wood / trees).

 

I am certainly not going to embarrass myself by telling you how I knew what you'd done either!!!

[gritineye]

That's a shame but don't over do the straightening and repair to the point where it can't be seen, those chain marks are interesting and future generations will need something to puzzle over...

[Great War truck]

Yes, we live and learn. We probably wont make that mistake again..........

 

Due to the design of Thornycroft wheels they are particularly awkward to repair. We would not be able to use a press on it as we would not be able to reach the other side to press against it. I have come across several references to Thornycroft wheels having to be scrapped after a small collision.

Luckily we were in the very fortunate position of having access to a very well equipped workshop and lots of skilled and interested people. While we were still contemplating what to do the wheel had disappeared and was already under repair. The photos are very much self explanatory but having the right tools for the job was a great help as you can see:

Many hands make light work:

Almost as good as new. Another scar to add to its history:

[Asciidv]

This is a section taken from the "The correct ordering and Fitting of Dunlop Solid Rubber Tyres". It relates ram pressure to tyre diameter.

 

 

It is well worth noting that if you are going to purchase solid rubber tyres from Dunlop and have them delivered to you by the Great Western Railway that;

 

 

I am grateful to Ben Hawkins ( A Dennis Restorer ) for sending me a copy of this wonderfully informative manual. Whilst we are talking about old solid rubber tyres can I ask again if anyone has knowledge of surviving 'Air Cushion' tyres which competed with solid rubber tyres in the early 1900's.

 

 

The air cushions look like octopus tentacle suckers.

I now have this Dennis and would just love to return it to it's original specification with this type of tyre!

 

 

Barry.

Edited November 17, 2014 by Asciidv

[Old Bill]

So, 2 tons per square inch on a 14" ram sounds like 300 tons. That's a fair bit more than I would have guessed.

 

We didn't actually get to the limit of the gauge. At least, I don't think we did. It was on the shelf in the workshop! However, there are two pumps of different diameters and each has two pivot positions. To get the first pair of tyres to let go, we were on low ratio of the small pump and it was as much as one man could push on the handle so I think we were well up. Mind you, the lorry was broken up in 1937 and the tyres had been worn out before then so they can't have been moved for at least 80 years. Once they went, it was relatively straightforward to keep pushing.

 

Steve

[N.O.S.]

An electric water pump from a steam cleaner on the press saves a lot of time and effort, especially when setting up. But sometimes the pump would get fried - especially when pressing crawler crane track sprockets off 6" shafts and we'd have to 'man the pump' and finish off by hand :sweat:

[8_10 Brass Cleaner]

An electric water pump from a steam cleaner on the press saves a lot of time and effort, especially when setting up. But sometimes the pump would get fried - especially when pressing crawler crane track sprockets off 6" shafts and we'd have to 'man the pump' and finish off by hand :sweat:

 

The other option is to slit the rings with a disk cutter. They go bang just before you cut through, but with no drama.

 

They fall off then.