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Great War truck

WW1 Thornycroft restoration

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7 hours ago, Minesweeper said:

Just heard that we have been accepted for the "Brighton" and that there are nine WW1 Lorries entered.

Tony

We wanted to go with the Daimler but were told we had to be a member before December 2017 to enter which is a shame, so there are a couple of us entering the Ipswich Felixstowe run instead if anybody else is interested which falls on the same day.

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Right angle drill attachments often allow you to use power drills in confined places where space dictates that it would be otherwise only possible to use a hand drill.

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I'll have to look out for them as we don't have either. So much of this job is 'how are we going to do this with what we have'? Jobs are always easier with the right tools though.

Steve

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Another weekend spent in Devon with the aim of finishing off the body so that Dad can get on with painting. It only wanted one side putting up so we thought it would be up by lunchtime. Best laid plans however!

Dad has been busy on the LHS shortening bolts and tidying up. He masked it off and has given the bare wood two coats of primer. Similarly, he has also done the headboard. He had previously finish painted the outside face as once installed, it would be too close to the seat to paint.

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On to the RHS. The planks were put up with the seperate tongues inserted in between them.

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A couple of odd bolts were fitted and then the top rail was attached. This has a bolt at each end with woodscrews in the back in the middle.

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Getting nice slotted wood screws is becoming a pain. Dad found these but at 23p each we are being careful with them!

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The uprights were held in place and two bolts drilled through We then drilled the rest of the holes and put over-length bolts in place.

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The last job on the body was to fit the corner protector plates. This was a juggle as the seat had to be moved eachway in order to get at the screw heads. All successful in the end.

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Dad is trimming bolts at the moment ready for painting. I am making up the tailboard hinges ready for us to make the tailboard at our next get-together. There are other things going on too  and I shall put them up very shortly.

Steve :)

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We had an interesting parcel arrive yesterday.DSCN5227.JPG.4c2a0b62d7bd82e031a88f9a184572e6.JPG

Rear wings!

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More work for the paint shop!

Steve     :)

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Father has also been to the foundry this week and picked up the pivot mount for the footbrake and the spider for the differential which was made using Barry's printed pattern.

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Father is now in the process of machining it as we cannot assemble the prop shaft until this is fitted as we won't know the required length. The majority of the machining is quite straightforward but the problems start with the spline. This is the old, lashed-up spider which we removed from the shaft.

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As you can see, the bore has very heavy tool marks and the slots are 0.025" wider than the splines so it is not a very good basis for measuring them up.

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Trying to work out exactly what we want and then how to get it machined has been puzzling us for a while. However, Barry has once again come to our rescue and very kindly offered to wire-erode a gauge for me using my best guess at the dimensions.

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This is an amazing process where the job is spark-eroded using a moving wire electrode which is guided under CNC control to cut the required profile. Not ideal for mass production but very cost-effective for one-offs and specials.

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I have had a couple of goes at fitting it now, easing it here and there with a file until it just went on by its own thickness when knocked witha mallet.

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It is still a bit tight but I have revised my drawings and Barry is making me another. Once I have finalised the dimensions, we will use the process to cut the new spider.

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There is always a way out if you know the right people!

Steve

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Something else done now and that's the bonnet boards. We hung fire asking for them as I wanted to see where the bonnet came but Mark has now prepared the timber and I have made rebates and cut-outs to fit.DSCN5213.JPG.7f86dcd2b4780c69c35e80d76b30b314.JPG

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Some more for the paint shop!

Steve     :)

Edited by Old Bill

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Spline Gauge Mark II !

The 1/4" slots for the splines are now 5 thou. wider and there is a 15 thou radius on the inner corners of the spline.The wire diameter is 0.25mm so there is a natural 7 thou radius on the outer, inner corners of the actual wire cut part, which isn't shown on the drawing.

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I thought you made the differential spider blank in cast iron?  I'm not sure that will spark-erode anything like a steel casting -  I might be wrong though.

Worst case you'd just cast the pattern again, in steel this time.

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Gordon, you do have to compensate  by machine adjustment for the type of material you are eroding. However I don’t think the Thorny would really notice as we are only talking about a thou or two. Wire erosion is incredibly accurate. The party piece trick is to make two parts size for size and slot them together. Here is Steve’s spline gauge with the matching inner part.  Only if you look closely by the arrow can you tell that there are two separate splined components.

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I think it is a structural thing.  Cast steel is a fine crystalline structure, cast iron is a coarse granular structure - it might not work at all.

Check with your spark erosion chap it may be fine - or not. You do have the pattern and the spark erosion mask so just casting again in steel might be the thing, but do check.

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I wonder what the Thornycroft engineers would think about the new equipment and techniques being discussed on this thread. Achivable tollerances are amazing. Metal technology, Machine tools and Welding equipment have moved forward a long way since their day. But riveting is still the same.

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9 hours ago, Asciidv said:

Spline Gauge Mark II !

Thanks Barry. That looks most promising. Measuring the spline sufficiently accurately and working out what shape it was before being put into use has proved most tricky and I have spent quite a lot of tie sitting under the lorry with the torch behind the gauge trying to decide where it needed adjustment. I am hoping that this will get it!

The two parts fitted together really caught us out. Dad didn't see it and I only knew to look because or that photo! It knocked out easily enough but I don't think I could put it back together.

Just going back in the shed for the next installment.

Steve.   :)

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It is amazing what can be achieved using modern techniques! That spider will fit better than new I am sure. I have used my old Halifax slotter and horizontal milling machine a couple of times to make internal and external splines, not quite as precise as wire eroding but it does the job for what I need it.

Wonderful job on the Thorny, not long now before it will move under its own power!

Regards

Marcel

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Marcel,

I like the way how you achieved parallel sided splines accurately. I assume that you just milled away the smaller 'leftover' spline. Although I gain satisfaction from making parts with the 3D printer and the Wire EDM machine, I know it would not be anything like the pleasure that you get from making parts like this on machines from the same period as your vehicle. Andy posted a link to a video of a man setting up to cut some splines. There were 6 or 7 edited videos showing the whole process. I think I was set up and cutting splines in the time it took for half the first video to play, so there are some compensations.

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We have had a good weekend. Barry's new spline gauge has arrived and is absolutely perfect! It pushed on easily by hand as a nice firm fit with no rattle. Wonderful and thank you Barry!DSCN5324.JPG.4c8bfbbc5940df7702dedfd5e6dc3522.JPG

We also pushed the lorry outside for a trial fit of the cab. We are pleased with the result!

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More later.

Steve

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Steve 

I think we briefly mentioned this once before, but you really do need a serious shed upgrade.

Up being the priority, but I do see a nice amount of vacant space to the left in the photo. .... Being in England, I take it that there are all sorts of legalities that prohibit additional shed-age?  

I have just doubled my shed and am still reveling in the luxury of no longer having to imitate the maze runner just in order to get from the front of the shed to the back.- which I can see is your problem. 

----

I wonder if mechanics used to modern vehicles dream about the accessibility and simplicity of the engine bay on that Thorny?

Regards

Doug

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I have just been comparing the latest photos with the "as found" photos from the first post in this thread. Very impressive indeed, especially for an "entry level" restoration!

I can't wait to see a video of it running.

Edited by mtskull

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