WW1 Thornycroft restoration

[Old Bill]

The weather has been OK here although a bit foggy. I'm glad I haven't been on the road.

 

Yes, there will be a canvas covered cushion although it may have had a leather covering originally. I am not sure either way about that and Tim hasn't turned up any firm evidence yet. We have canvas on the Dennis and it doesn't look wrong. No doubt Tim will find something the day after we fit it!

 

We are on the home straight now so I started by fitting the two corner planks of the seat surface.

 

 

Then the other two and the rearmost piece.

 

 

 

The lid was eased very slightly before it dropped in. Another nice piece of Mark's work as it has 'breadboard' ends to keep it flat.

 

 

And then the hinges. I would not have chosen 'Tee' hinges but they are as the prototype.

 

 

This little strip runs along the bottom edge of the side panels on each side. I don't know what it does but it is there!

 

 

Finally, I planed a radius along each inner edge and sanded all of the sharp edges ready for painting.

 

 

 

 

Tomorrow, we shall fit the hinged gearbox access flap which goes in the hole in the front and then the whole lot can be turned over to the painting department. You are right. It is blinking heavy and I don't know quite how Father will handle it!

 

Steve :-)

[Old Bill]

Last day of the holiday and we have finished the seat box. The only part left to fit was the flap for gearbox access. The hinges were soon rebated in and screwed down.

 

 

Complete at last!

 

 

 

It remained only to try it out.

 

 

As I was clearing up, I had a closer look at my drawings and realised that I had done them twenty two years ago! This project is turning into a long one!

 

 

 

The two aging desk-jockeys somehow managed to wangle the thing up onto the chassis as there is simply nowhere else to leave it! Dad plans to paint it up there.

 

 

Next task was to assemble the hand brake mechanism. This started with the handle at the front, now nicely painted by Dad. It is fitted on a key with a locking bolt to secure. However, there is no split in the bottom of the lever so the bolt only sits in a slot to prevent the handle from coming off and cannot make it a tight fit. I don't think this is a good arrangement and it was remedied shortly after the war.

 

 

 

 

 

 

All very satisfactory.

[Old Bill]

Now we move to the rear end.

 

 

There is a compensating mechanism which pulls the RH brake lever directly and the LH via a cross-tube.

 

 

 

The compensating link has three pins, previously made by Father. They are ridiculously complicated in that they are cross drilled for oil, have a feather to stop them rotating, a screw thread for a nut and a split pin hole in the end. A simple clevis and split pin would have done the job so I wonder what the reason behind them is. We shall never know.

 

 

Note installation of the famous Thackery washers!

 

 

We spent some considerable time getting the lengths right and picking the right pin hole in the clevis. All was well in the end and we have a second functioning control.

 

 

The final task for the holiday was to drill out a split pin. This stud is pinned into the inlet manifold and has a split pin through the end to secure a bell-crank in the throttle linkage. Unfortunately, we didn't spot the sheared-off pin until the manifold had been fitted making it tricky to remove.

 

 

I therefore turned up a drilling jig in the shape of a piece of threaded bar with a number of cross holes drilled using my dividing head. I screwed it on until a hole lined up with the pin and then locked it by screwing a bolt in the end.

 

 

Two minutes with the Dremel and a new drill and the job was done. No drama at all which was very nice.

 

 

 

Here we have everything done this week. Two functioning controls, a new seat box and the inlet manifold ready to accept a bell crank.

 

 

All very satisfying. Sadly, reality is going to bite again very shortly.

 

Happy New Year everyone!

 

Steve:-)

[rampant rivet]

Wonderful craftsmanship I always enjoy following your progress ☺

[gritineye]

Well done and thanks for all those enjoyable updates, happy new year to you all.

[andypugh]

It is fitted on a key with a locking bolt to secure. However, there is no split in the bottom of the lever so the bolt only sits in a slot to prevent the handle from coming off and cannot make it a tight fit.

 

Our JCB (3CX) had an interesting arrangement. It had the normal split and bolt, but in the split was a fat washer round the bolt that fitted into a Woodruff slot. Rather neat, really.

[nz2]

Is the seat design the same as used on the Dennis or are there changes?

Doug

[Old Bill]

Our JCB (3CX) had an interesting arrangement. It had the normal split and bolt, but in the split was a fat washer round the bolt that fitted into a Woodruff slot. Rather neat, really.

 

The wheels are held onto the Autocars in a similar fashion. The split collar is screwed onto the end of the axle until the correct end float is attained in the taper roller bearings. The key is then put into the gap in line with a slot in the axle end. On tightening the bolt, the collar grips the axle end and is secured from rotating by the key.

 

Seat Box:

This seat box is a copy of the Carlton Colville Thornycroft as close as I can make it. Unfortunately, we didn't have such detailed information for the Dennis so the Dennis one is simply based on it. It is one inch wider (I have that dimension from the coachbuilders' drawing) and the seat hatch is longer to accommodate the fuel tank. The end panel is also a slightly different shape but that was discerned from the photographs. I am sure that the production method would have been very similar to the Thornycroft so this is a pretty good approximation.

 

Steve :-)

[Old Bill]

We haven't been idle in spite of evidence to the contrary! Dad has set us the very tight target of London to Brighton in May 2018 when they are having a special WW1 vehicle class. This really is going to be very hard to achieve but we are going to have a go. To that end, I have done a critical path analysis of the project and have realised that the three items most likely to upset the applecart are the bonnet, the fuel tank and the canvas hood of which the longest lead item is the canvas. Jim Clark at Allied Forces has kindly promised to do the canvas for us but to do it in time, he needs the hood frames very soon. I have, therefore, been concentrating on the steelwork whilst Father and our joiner pal Mark, are doing the timber bows. Fortunately, we have done all of this before as the Dennis has hood frames made to the same pattern. Whilst I understand how they go, they are still a very tedious job however!

 

There are two steel pieces on each side, two uprights and two J-shaped horizontal pieces hinged to them. I started off by bending the J-shape using the forge at my local miniature railway. They bent and joggled quite well but when I got them home, I felt that one could just do with a bit of adjustment in my press with the result you see below:

 

 

It went off with quite bang and just snapped. I was quite surprised about this as it is only mild steel. However, I had heated the parts in a coke fire for an extended period (I am not a good blacksmith!) and then quenched them. The carbon rich environment and quenching had case hardened the steel and caused the breakage. The case hardening is quite evident in the fracture and the edges are razor sharp. I carefully heated and air cooled the second one and then arranged to visit the railway again for another go!

 

In the mean time, I started on the verticals. First task was to turn up some bosses and weld them on.

 

 

My welding hasn't improved! I did stick them in the vice and lean on them and they remained attached so I deemed them adequate.

 

 

 

Then there were two thicker boss areas at the top to carry the pivot point. These were turned and silver soldered on.

 

 

 

Then the filing and angle grinding started. This went on and on for hours.

 

 

 

 

Interestingly, the section changes from elliptical just above the pivot to half-round where the timber bow is attached. Careful filing required but they did work out OK.

 

 

I bent up a second bar and this one went a lot better with fewer hammer marks. It looks a bit odd because of the joggle which is not obvious but which distorts one's perception.

 

 

 

Then again endless filing and angle grinding.

 

 

 

On these, the pivot boss is generated by filing only. I bolted a washer to the surface to give me a guide.

 

 

 

Main pivot point drilled out and the screw holes were countersunk.

 

 

Pivot pins turned up.

 

 

Job complete.

 

 

 

Now we are waiting for the timber to finish the job. Pleased to see the back of that one!

 

Steve :-)

[Great War truck]

Another assembly that we did not have and have had to make from scratch – this is the Tube which carries the “high tension wires” together with the two Brackets which hold and support it. The whole thing is best illustrated for you with the picture of the one on the “Thorny” at Carlton Colville.

Fortunately, Steve measured this up some time ago so we know the dimensions and he has drawn it out. The material used for the Brackets is bronze – the second picture shows the basic “kit” (the blanks) in the early stages. The rods have been machined from 1/2” bronze rod and tapered and left over length at this stage - the big “rings” have been machined from an end of hollow bronze bearing material (because that is what we had!) and the short round pieces have also come from the 1/2” bronze rod.

[Great War truck]

The big rings were “barrelled” In the lathe and then drilled to take the rod. The rods were cut back to length where they went into the big rings – and then silver soldered in.

[Great War truck]

The rods at the short tube end were then cut back to length and the short tubes and the rod were then silver soldered together.

 

All that then remained to do was to prepare some more of the bronze rod to make the two bosses to be silver soldered into the two big Rings to take 1/4” securing screws for holding the wires tube in the brackets. These were again made over length and threaded on the inside so that they could be screwed into the big rings to hold them firmly in the correct position during the silver soldering. These were again initially made over length for ease of handling and were finally machined in situ.

[Great War truck]

With all the silver soldering completed and the little bosses cut back to final length and threaded, that then completes the brackets.

 

The Tube for the wires will want some thought. The original one on the Dennis was made of a Cardboard type of material – it was quite damaged when we got it and Steve repaired it using a Cornflakes box for the material – the cardboard was obviously sealed and painted and has been fine in service. What we do for this one has yet to be decided – It will be beyond using a multitude of Kelloggs boxes!

Edited January 24, 2017 by Great War truck

[Sean N]

The Tube for the wires will want some thought. The original one on the Dennis was made of a Cardboard type of material ... the cardboard was obviously sealed and painted and has been fine in service. What we do for this one has yet to be decided...

 

Papier mache? Would be easy to do, easily mouldable and if made with the right glue and sealed would be just as resistant and mechanically strong. You could make up some bucks out of dowel or tube which you could arrange so they could be pulled apart to get them out of the finished tube. Alternatively, plastic pipe cut and glued - you could use filler to reproduce any curves etc. and might be able to flare it by warming and moulding gently? More difficult to paint though.

[Minesweeper]

[QUOTE=Sean N;483173]Papier mache? Would be easy to do, easily mouldable and if made with the right glue and sealed would be just as resistant and mechanically strong. You could make up some bucks out of dowel or tube which you could arrange so they could be pulled apart to get them out of the finished tube. Alternatively, plastic pipe cut and glued - you could use filler to reproduce any curves etc. and might be able to flare it by warming and moulding gently? More difficult to paint though.

 

 

 

Thanks for that, Sean! Steve tells me this morning that in fact, the Thorny one was made of steel and was not similar to the Dennis one - so we shall have to tackle this one differently!

 

Tony

[Sean N]

I have to say I thought that one in the Carlton Colville photo looked metal.

 

Sounds a lot easier though - thin wall tube and solder?

[Citroman]

My old Citroen has a metal tube for the cables. The cartboard tube can be made by glueing thin paper bands around a metal or plastic tube. If everything is hardened you can slide this of the tube.

[MatchFuzee]

[QUOTE=Sean N;483173]Papier mache? Would be easy to do, easily mouldable and if made with the right glue and sealed would be just as resistant and mechanically strong. You could make up some bucks out of dowel or tube which you could arrange so they could be pulled apart to get them out of the finished tube. Alternatively, plastic pipe cut and glued - you could use filler to reproduce any curves etc. and might be able to flare it by warming and moulding gently? More difficult to paint though.

Thanks for that, Sean! Steve tells me this morning that in fact, the Thorny one was made of steel and was not similar to the Dennis one - so we shall have to tackle this one differently!

 

Tony

 

Could the original tube simply have been a 1 1/8" OD steel tube with the end flared?

[Great War truck]

Steve outlined in his posting no. 2334 of the 22nd January that our ambition now was to get the Thorny finished by the Spring of next year so that we could enter it in the 2018 HCVS London to Brighton Run of that year – a special anniversary – the centenary year of the end of the Great War, but there is still a huge number of jobs to be done. One of the important things to be completed – and one which perhaps we would not have tackled quite this early on – is the Cab Roof. Jim Clark at Allied Forces has very kindly agreed to do the canvas for it but it would be very unfair to ask him to do this at the last moment, bearing in mind his other commitments, so we opted to make the framework for the cab now so that it can be passed to Jim and that he will have about a year to complete it!

 

The two attached pictures illustrate what the Cab Roof looks like – it does have the ability to fold back if required. It consist of three wooden bows with steel attachments to them. Steve has already made this steelwork and a full description of that is covered in posting no. 2334.

 

So we turn to the woodwork now and this where our good friend Mark (Big Mark – we have two good friends named Mark) comes in as he is a very skilled Woodworker. Almost certainly the bows on the original assembly were “one piece” and steamed and bent around but we have opted for an alternative in laminating thinner sections of Ash around a template and gluing them – this was a method introduced to us by Mark’s late father Gordon who made the wooden bows over the load space of our FWD some years ago.

 

[Great War truck]

Two Ash Planks were cut down into 1/8” thickness strips – and planed – so that they could easily be bent around a template and glued together. The template - or jig – was made on a sheet of chip board – to the internal dimensions of the bow – the jig had to be adjusted as each bow came along as they are of different sizes. I guess that this is a “trick of the trade” but the jig was covered in Newspaper so that any surplus glue would stick to the news paper and not the jig during the gluing process.

 

All the Ash strips were firstly glued and put to one side, ready for laying against the jig. Just one side was completed first and clamped up against the jig. Then all the strips on the completed side – about 11 or 12 of them to each bow, were pulled around the jig together for the remaining two sides and clamped up tight as they came into position. The wet glue acted as a kind of lubricant between the strips at this stage as they came into place, bearing in mind that Mark was working on an increasing diameter as he progressed.

[Great War truck]

[Great War truck]

To ensure that all the strips were lying flat against the chip board of the jig, – a thump with a hammer did the job.

[Great War truck]

[Great War truck]

All the surplus glue squeezed out between the joints to be washed and wiped off before it dries.

[Great War truck]

Pictures showing two of the Bows just out of the jig and before being cleaned – with the evidence of the newspaper still attached and three pictures of a finished Bow duly cleaned up with the corners nicely rounded.

 

Next job, get them primed and ready to fit the steelwork to them.