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WW1 Thornycroft restoration

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Indeed interesting. I have a 80A double rcd consumer unit to wire in, the two 32A feed cables are on breakers not protected by rcd, my welder does not like them. I have a old cable that uses 4 strands of 35A cable, but used the neutral bonded to earth in the meter box. I hope i can wire things myself then certification by a qualified electrician to be safe, if it is not a bodge job type like the one that rewired the house 10 years back as he kindly forgot the earth cable between the meter and consumer unit. 

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I don't hold with this electrickery. Gas lights are good enough for me!   ;)

The last couple of days, I have been fooling with the foot brake linkage. Rather unusually, it is all connected with ball joints rather than clevises. I am not convinced that this was a good idea but I shall continue with it until proven otherwise. We are fortunate to have one original joint.

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After stripping down and cleaning, I found that the internal thread is 11/16" x 26. Stupid size! I haven't got one of course so I had to order two taps and a die.

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Three blanks of 1" bar cut by hand. Oh, for Father's bandsaw!

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Then on to the plugs. These were a simple turning job before threading 11/16" and then cutting the split pin slots with a slitting saw. After parting off, I started on the balls whilst I decided what to do about the spherical sockets.

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Then onto the ball sections

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An Arrand spherical turning attachment. I have only used this once, to make the track rod ends so I had to puzzle a bit over how to set it up. All went well in the end and it was quite a satisfying turning exercise.

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Cutting the hexes.

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Now we come onto the spherical sockets.

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Generating these was a puzzle so I made up a D-bit in silver steel.

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I could not get it to cut properly until I got it so hot that I softened it at which point I lost patience and went and ordered a ball-ended slot drill.

Can anyone offer tips for this sort of D-bit please? there must be a trick to it!

More brake linkage tomorrow.

Steve  :)

 

 

Edited by Old Bill
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    You are all doing fantastic work. I look forward to your updates with anticipation and admiration.

     I was taught to relieve all but the last .0005 - .001 below the cutting edge. Also the split needs to be exactly half of the diameter. The closer you can measure this the better. This is fairly easy to achieve on a single lip grinder (Deckel) but I imagine someone with your skills could relieve one by hand successfully the first time. Patience, good light and a magnifier/microscope help a lot.  

       You can buy pre-split blanks in the common sizes up to 1/2 inch in High Speed Steel and Carbide. They are great if you need to match an odd radius or angle and they don't cost much.

 

Edited by wrward
added info.

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5 hours ago, wrward said:

  

     I was taught to relieve all but the last .0005 - .001 below the cutting edge.

       You can buy pre-split blanks in the common sizes up to 1/2 inch in High Speed Steel and Carbide.

 

Many thanks for that. I hadn't even thought of looking for a pre-cut blank.. I should have put more effort into generating a relief but it would have all been done with the dremel or a whetstone. I'm afraid I have taken the easy way out and ordered a professionally cut tool. I wonder if I will ever use it again?

Cheers!

Steve :)

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11 hours ago, Old Bill said:

Cabn anyone offer tips for this sort of D-bit please? there must be a trick to it!

 

Can't the ball turner make concave spheres? I imagine that some ingenuity might be needed with respect to tool shape and cutting geometry but I think it should be possible. 

 

 

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Great as always.  I am impressed by the brass spinning on the Myford.

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3 hours ago, andypugh said:

Can't the ball turner make concave spheres? I imagine that some ingenuity might be needed with respect to tool shape and cutting geometry but I think it should be possible.

I'm sure it could but it would need some fancy tooling to get in there and we are pushed for time now. I'm taking the path of least resistance!

Steve

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6 minutes ago, Old Bill said:

I'm sure it could but it would need some fancy tooling to get in there and we are pushed for time now. I'm taking the path of least resistance!

I have a CNC lathe....

You could have forged them. (probably hammering a red-hot bar onto a ball at the bottom of a tube) then machined the other features as a second-op. 

But a ball-nose milling cutter is quickest (as in, it consumes none of your time, even if it takes a while for the tool to arrive)

 

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Work still going on apace. Wings are on the critical path and Father has been working on them. I have had the front wings in the loft for 25 years and we dug them out the other day. I orignally painted them before putting them up but it wasn't Bondaprime and the rust has started to come through. Father had top spend a lot of time cleaning them back before painting.

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David took on the rear wings  and degreased them and primed them. Thanks for that David.

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I need to start thinking about the brackets as they are going to need some significant work in big lumps of steel. They are very heavy bits of ironwork and will need grinding to a curved section to represent the original forgings.

In the meantime, I have completed the footbrake bell crank. I started on this some time ago by having a blank cut out by water jet machine.

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After the centre holes were drilled, it was then machined to thickness in several steps.DSCN7413.JPG.b9b4250c4ef6c6e8d209eac1bd375e95.JPG

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Then the graft started. This item would have been a forging so the edges would all have been curved. Only way to create that feature was with a file!

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About four hours of filing later.

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Then the end holes were drilled out to accept the ball joints currently in work and the main pivot hole was bored and reamed.

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An additional feature is that both ends are cranked in opposite direction, This was done hot using the vice and an adjustable spanner for leverage.

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A good wire brushing and another one off the list.

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Steve   :)

Edited by Old Bill
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8 hours ago, ajmac said:

Great as always.  I am impressed by the brass spinning on the Myford.

The spinning is a bit hard on the Myford as the forces on the bearings are rather high. I had no option in this case. Even the disc was 7" diameter which is the limit. It got bigger during the process and I had to dress it back with a file to stop it clipping the bed!

Have a go at spinning. It is a very useful skill to have up your sleeve.

Steve   :)

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1 hour ago, Old Bill said:

Then the graft started. This item would have been a forging so the edges would all have been curved. Only way to create that feature was with a file!

In the interests of saving some time, you might want to consider buying something like this:

https://www.amazon.co.uk/Black-Decker-KA900E-power-sander/dp/B000XG3ORW

I have a different (cheaper) one and it has proved invaluable. It is probably the only tool I have that it permanently plugged in and to-hand in the bench. 

It might even be worth you spending the money on a good quality one. 

https://www.amazon.co.uk/MAKITA-9032-Filing-Sander-Inch/dp/B0000614UT

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Andy, if you remember from the Dennis thread Tony bought a Black and Decker 'Power File' on my recommendation to clean up the steering wheel casting. He managed to blow it up in less than a day!

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The offset crank is a beautiful piece of work, with lovely fillets into the bosses. Almost too good to go onto the Thorny!

 

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Thanks Andy. Dad has one of these but, as Barry said, it failed within a day! He now has another which he uses regularly. I still do it the hard way but the results are very pleasing. Actually, they laugh at me at work as I often say that I can stand by a vice all day with a file quite happily but five minutes with a piece of software which won't do what I want and I lose it completely!

The magneto advance control has two levers on the ends of the shaft so I have made these up this afternoon as well.IMG_3785.JPG.3f02318c0af98218ae1df828d728d536.JPG

More silver soldered fabrications of course.

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This one goes on the end near the bulkhead. I will drill through and pin it in situe.

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The one on the magneto end had the extra challenge of a bend. Rather brutally, I put it in the vice and hit it until it looked about right. Then drilled it and milled the slot before filing the ends.

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The slot engages with a pin in the contact breaker and the control shaft is secured by a tube between the two bearings in the bronze casting so I made these as well.

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I just need another crank on the bottom of the advance control rod and I will be able to put that together. A job for tomorrow.

Steve   :)

Edited by Old Bill

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2 hours ago, Asciidv said:

Andy, if you remember from the Dennis thread Tony bought a Black and Decker 'Power File' on my recommendation to clean up the steering wheel casting. He managed to blow it up in less than a day!

Oh, OK. Well my £27 one from Screwfix (which I don't think they sell any more) has lasted years. 

So I still recommend them, just not the B&D one, it seems. 

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20 hours ago, Asciidv said:

Andy, if you remember from the Dennis thread Tony bought a Black and Decker 'Power File' on my recommendation to clean up the steering wheel casting. He managed to blow it up in less than a day!

Well, I did subsequently buy another similar B and D one and it has been fine! Lightning did not strike again in the same place!

 

Tony

 

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The postman was a welcome visitor this morning as he delivered my ball-ended slot drill.DSCN7532.JPG.29dc9371bb2d9315b9a5d3d5abc3b6d9.JPG

It soon made short work of the buttons and plugs,

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I have now closed that job down which is great.

Steve

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Something I started on a long time ago was the ignition advance lever. We are fortunate in having an original example, albeit broken across the detent.DSCN3679.JPG.f1b041f4e8591a42ea0bc59eaef5cc07.JPG

It is actually a gunmetal casting so a fortnight in the pickle brightened it up a bit

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The original control tube was still in it but rusted off.

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This was removed by boring it out.

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The knob was then silver soldered back on and a steel detent made and fitted.

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The lever has been sitting on the bench for ages and so the time has come to make the actualting arm for the other end. As usual, this started witha silver soldered fabrication (can you see a theme developing here?)

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Filed to shape using a button for guidance around the ends.

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Centre hole bored out. This is quite big as the advance mechanism is controlled via tube fitted around the hand throttle rod.

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Ready to fit.

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I will cut the tube to length on the job and solder them both on. Another half-done job off my bench!

Steve

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Throttle and advance linkage is the current focus and this is what I am trying to replicate.

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This is the best picture I have and it is causing me a bit of head scratching. That is the bottom of the steering column to the right and just above the spring is the advance lever I have just made. The ball joint at the bottom is attached to the end of the throttle pedal. Whilst I ponder on what I am going to do about this, I decided to make a throttle linkage bell crank.

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This was done just as the others. Mind you, I think a better photographic background is in order for the future!

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At least that is one more ticked off. Throttle lever first tomorrow. Then I need to work out how all the bits go at the bottom.

Steve.    :)

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I have been watching this thread for a very long time and I am in total awe of your abilities! I cannot wait for the first start-up, which surely must be just around the corner?

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After doing some more painting, Father started on the footbrake bell-crank mount casting.

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There isn't actually too much work involved which is the point of a casting. However, the thing is big and very awkward to hold. After a good cleaning up all over, he machined the top face and then drilled it through ready for tapping 5/8" BSW.

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Next part will be the mounting holes inthe rear face.

Meanwhile, I have been working on the hand throttle lever. All my usual approach with a steel profile, silver solderd fabrication and lots of filing.

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This one has the added interest of a brass knob on the end. The ball turner came into its own again and soon made short work of the job.

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A bit of Autosol brought it up nicely.

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Secured with a screw from underneath.

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I am now part way through the throttle lever at the bottom of the column. Only one day left before reality strikes again!

Steve   :)

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Dad started the day by tapping the pivot pin hole in the brake pivot casting. Rather sensibly, he used the mill to align the tap and keep it upright. Slightly off-line tapped holes can be intensely annoying!DSCN5411.JPG.d0ef2d3f1df67c581616b339b9065471.JPG

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There just remain the four holes in the rear face to attach it to the chassis rail.

I went back to the throttle linkage. After puzzling over the picture above, I realised that there is a floating link on the hand throttle shaft. This has three holes and is free to rotate on the shaft. The centre hole is pushed by a ball joint from the throttle pedal whilst the outer hole is connected to the carburettor. The link is pushed around by the hand throttle by a peg attached to the shaft. The last photo should make it all clear. In the mean time, I made the floating link in the usual manner.

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The peg drops from a boss which is pinned to the throttle shaft. It started out as a turning but was then cut and dressed back with a hack saw and files.

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The peg comes around and pushes it. I hope I have made it thick enough!

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I have started on the sidelamp bracket too but that's the end of my holiday. Back to reality tomorrow!

Steve     :)

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On 19/03/2018 at 9:05 PM, Old Bill said:

A week off work, Hurrah! I could get used to this. An opportunity to really get things done!

I think the reason they all lost the oil filler is that it is copper and brass. Should anyone need Thornycroft information to aid their rebuilds then we are always only too delighted to help. I don't have full engineering drawings of everything we have done but I have an enormous folder of notes an dimensions. That is what comes of nearly 30 years of collecting data!

Back to the oil filler. This is what it looks like.DSCN0474.thumb.JPG.7aecba04d7a247aeedf218984e33686c.JPG

As you know, I have been struggling to bend the tube so, for the sake of expediency, I have put together an assembly using commercial fittings. This will be replaced when I find time to make a special pipe bender and can do it properly with no time pressure. 

I made the base flange a long time ago when I was getting bored with pattern making and desperately needed to cut some metal.

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The fittings were a gift from a pal in Exeter.

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Fluxed up for silver soldering.

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A good clean and job done!

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Then onto the cup. The only way I could think of producing it was by spinning from a sheet of brass. The first job, therefore, was to turn up a 'chuck'. I found some pieces of old school workbench which I laminated. These were beautiful pieces of beech.

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Then off we go. A disc of 20swg brass annealed and then rubbed with soap as a lubricant.

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I am not yet skilled enough to do it without creating ripples or to spin the ripples out. My most successful solution to this problem has been to remove the job and beat the ripples out with a mallet on a piece of wood before having another go.

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And again!

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This cup has a beaded top edge which is something I have not done before. Unfortunately, I got a bit carried away and broke the top flange right off. There was just enough metal left to turn over but it is rough and cracked so I will make another when I get around to bending the pipe.

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It will do.

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Then spin the lid in the same manner. This time I managed to bead the edge without breaking anything.

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The lid needed a knob which has a projection underneath to secure a spring. This was a nice turning job.

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Then the moment of truth, solder the tube to the cup. This actually went surprisingly well but I did treat it with solder paint first, hence the runs which soon cleaned off.

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The original has a gauze inside to prevent anything from entering the sump. Whilst poking around the workshop this afternoon, I found a shield from the back of an old fan oven, rescued for some reason. It was perfect!

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A rummage in the spring box found something suitable.

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Job done!

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This is only temporary until I can make a better one but it will allow us to run the engine. Start up is going to be the Easter weekend.

Back in the shed tomorrow. Foot brake bits next.

Steve    :)

 

That's worked out OK Steve... 

I've not done any metal spinning myself...but I've heard its an acquired skill... 

From what I've seen of it being done is that you've got to steadily persuade it over the form... 

I think a lot of metal spinners push it beyond the edge of the form...then part off to length...

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