1917 Foden Steam Wagon

[Old Bill]

Nice to see it coming on again. Just how did you bend the pipe? Did you just pull it around a piece of bar or was there some trick to it? It really is very difficult to get such a tight coil without it collapsing and I should like to know!

Steve   🙂!

[Foden7536]

Thanks Steve,

Work on the Foden hadn’t stopped - just my reporting had! I shall Endeavour to do better with keeping it updated 

 

The copper came out so much better than I was expecting I was amazed myself to be honest! 
 

At a friends farm we have a huge radial arm drill, I borrowed the table (a stonking great lump of cast steel weighing god knows how much but several hundredweight) as I know this would give me a stable bench to work from, and plonked it in the middle of the shed as I would be walking round it all day bending the pipe.

To the bench I clamped (using the T slots in the base) a piece of plate to which I had welded a piece of steel pipe of the right outer diameter to suit the internal diameter of the coil (this was sticking upwards) This plate had a hole in for the end of the pipe to stick down through and a second piece of pipe welded at 90 degrees to the vertical piece of pipe to pull the first bend over (where the feed water pipe comes into the heater straight and then turns to start to form the first coil.

 

Is this making sense so far, I appreciate my description isn’t the clearest?   
 

Using a large propane / oxygen heating gun I got a section of pipe about 18” long cherry red and then immediately dunked it in a barrel of cold water to anneal that section of pipe, then placed it in my jig and with the amount of leverage I had in the three meter length of pipe it bent really easily, but I also used a hide mallet to GENTLY tap the pipe around the former,  You could feel it getting harder to bend so it was then a case of removing the pipe from the jig, heat and quench (overlapping the previously annealed bit) Place back onto the jig and bend the next bit. 

Once I had done all the coils I welded about piece of pipe to the vertical one to pull the “exit bend” to get things straight again. This was the most fiddly part as I had to weld it strongly enough as not to break off when forming the copper around it, whilst at the same time only having small welds to access and grind off before I could slide the copper coil up and off the former. 
 

The whole operation took a day (not forgetting mandatory tea breaks!) I had done some trials before, and had been advised to fill it with sand etc first, but I found this unnecessary. I was really pleased (and surprised to be honest) with how well and easily it all went, so much so that I was too busy doing it to think about taking any photos. 
 

Did you manage to make head or tail of my description?

 

David

 

[Old Bill]

Hi David.

Many thanks for that. I can see exactly what you have done. The thick wall pipe makes all of the difference but I am still surprised that you didn't get a flat on it! Working copper is very satisfying and it is fascinating to feel it harden up. The trick is to stop when it does!

Thank you for your description. I shall look forward to further installments!

Steve 🙂

[andypugh]

I don't think that you _need_ to quench when annealing copper. It is just that you _can_ as it does not have any hardening effect, it can remove some of the scale, and it saves waiting for it to be comfortable to handle again. 

 

[7VHU]

Great job David!

How thick was the wall thickness?

I’m sure that there used to be an extra heavy tube that was thick enough to take an external thread (screwing copper?)

Physically harder to bend but easier to make tight bends as much more resistant to flattening. Slip a bigger pipe over the copper for extra leverage.

just might need to mortgage your house to buy some.

the refrigeration grade copper tubing is good for lighter work and also still comes in proper sizes (imperial)…

Peter

[Foden7536]

Good morning Peter, 

Happy new year too! The copper tube i used was the same OD as 1/2” steel tube (.0825”) so could take a BSP thread, I had one length of this, but now I’ve only been able to find thick wall copper tube which is 1/8” wall, so the OD is 0.75” so sadly not large enough to take a thread.

 

Your comment on refrigeration grade copper is interesting, do you know what wall thickness this is? 

I've attached two photos, the first shows an original Foden feed water heater coil from a albeit slightly later wagon removed from a corroded casing during restoration of a friends Foden, and my newly manufactured version...

David

[Doc]

Wellington Tube Supplies in Hayes (02082305708) have 7/8" od x 0.128" wall C106 copper tube in stock. 

My 12th edition Machinery Handbook (1945) gives the major diameter and depth of 1/2" BSP parallel thread as 0.825" and 0.0457" respectively. 

This should leave a minimum wall thickness of 0.0573" at the root of the threads. Is that enough?

regards

Doc

[7VHU]

Hi David,

bes.co.uk is handy for plumbing.

BS EN 12735-1 copper tubing (under section on air con).

7/8” x 18 swg

3/4” x 19 swg

5/8” x 20 swg

1/2” x 21 swg

3/8” x 21 swg

Edited January 3, 2022 by 7VHU

[Clive Stone]

Hi David

DCC Foden  wagons

l have several photos of DCC wagons which l am happy to share with you

My grandfather was RM Stone who purchased them while he was the County Surveyor based in Barnstaple 

l would also be pleased to see photos of other DCC plant 

thanks

clive

[Foden7536]

Good evening Clive, and May I say what a thrilling message to get! 
 

I’d love to see any photos of the Devon CC wagons, and likewise and other details you may recall from your Grandfather. 
 

I have sent you a private message, if you can’t access it for any reason please let me know. 
 

I look forward to hearing more, any information which can put the history of the wagons 

 

ive attached two photos of Devon wagons I have, the first is a Garrett with the early “Devon County Council Northern Div” lettering (and in small script you can just make out what looks like “...Stone Surveyor” - which you’ve filled in some information on already!) and the second photo is a later Foden 10530 of 1921 painted in the later livery of “Devon County Council” as according to my records Northern and Southern (Barnstable and Tavistock offices) combined in 1921 so vehicles after this date carried this lettering.
 

Hope this is of interest,

David

[Foden7536]

Good evening all, just to confirm I haven’t dropped off the planet, Foden work progresses but everything seams to take such a long time! 

So, back in September 2020 (crikey) I stripped the crank and found it was in need of major work, this is now complete and so I thought it was an opportunity to update this.

As the old main bearings were very worn I needed to ensure the alignment of the crankshaft was correct, I made aluminium blanks to go in the cylinder bores, the neck rings and the trunk guides, all with a 1” hole bored in the middle, so if all three lined up and I could feed a bit of inch bar through the holes it would prove the centre line of the piston / piston rods. The below photos show this set up for the high pressure, I did the same for both bores. 

Once this was done I could put another piece of bar at 90 degrees to these rods, to set the position of the crankshaft, however when this was in place it didn’t look correct, this “crankshaft” was too high in relation to the old main bearings which I had put in place to give me an idea of the set up. I spoke to several people involved in Traction Engine restoration work, and the opinion of them was that the centre line of the crank should be bang on centre line of the pistons. 
 

When measured mine had a difference of 3/8”, being below centre line, again I spoke to several people who all said that this is incorrect, and I started looking into correcting this “mistake”. I am in contact with a chap in Australia with a couple of Fodens and I was explaining this to him, and he kindly did some measuring on one of his Fodens and again found the centre line of the crank to be exactly 3/8” below centre line of the bores, his foden being a lot later than mine suggested that this wasn’t an error after all. After doing more research I found that this is called “desaxe offset” (desaxe meaning “unbalanced” in French) so there isn’t a true “top dead centre” so to cut a long story short(er) I kept the crankshaft 3/8” below centre line of the bores, and more alumnium billets bored to take my “alignment rods” (a snug push fit) to hold everything in position.

Having set and finalised the position of the crankshaft centre position I decided to line bore the newly cast bearings, however I had never done any line boring, and hadn’t a line boring set up, so my next task was to build a line boring machine. I had seen these in use before but I didn’t like the feed method on others, some use a ratchet type feed, which I felt would give an interrupted cut. It was whilst using my mill that I came up with the plan of using a align power feed unit as this is variable speed, does forward and reverse, as well as rapid traverse, so a unit was purchased, I then made myself a lead screw, boring bar etc. To power the cutting tool rotation I used a variable speed drill. 
 

The actual boring bar was initially run in two bearing blocks, each held on plates attached to the boiler hornplates, however I found that I was getting too much “whip” on the bar and a poor surface finish so I ended up having to put a third bearing in the middle to keep everything rigid. 

I experimented with speeds and feeds until I was happy with the finish, and considering this is all home made I was very pleased with how it was progressing….

…. so well in fact that one Tuesday having a day off from work I was on the final cuts on the second bearing, it was a slow process with lots of measuring, boring, measuring, boring etc but I was aware that I was getting nearer and nearer to size. My final measuring revealed that I had 0.015” to come out, so I moved the tool but in my haste and excitement to finish the job I forgot that I had measured the diameter and I needed to move the tool by half the amount…. I realised my mistake when it was about half way through the bearing, and sure enough to my horror when I measured the bore I had taken too much material out, so I had no option but to go back to the foundry, get another bearing cast (and big lumps of bronze cost!) and start that bearing all over again! I’ve kept the scrap bearing on the wall in the shed to remind myself to double check !!!

Once these were finished I could drop the crank in with more aluminium pieces to ensure the “left / right” position of the crank was correct, spacers made, and the sides of the bearings faced to give clearance.

With the main bearings eventually finished my attention turned to the bearing caps. These are cast iron, but one has been replaced with a fabricated one, so I decided to replace them both with new cast iron ones. Once again my friend Roger made me a pattern and I undertook the machiningA quick coat of “service colour” and finally this evening the crank was dropped into the crank pit hopefully for the final time! It was very encouraging to be able to turn the crank and everything rotate nice and freely, so hopefully it’s not too far off being somewhere near correct. 

I hope this update has been of some interest.

 

 

 

 

Edited June 9, 2023 by Foden7536

[rog8811]

Thanks for such a detailed update, hat off to you for the amazing way that you went about the job, I look forward to seeing more progress.

[john1950]

Wow, a man in his shed. Such attention to detail.

[mammoth]

Are you able to talk about the machining for the four drive keys and what stops them flogging out. Does a pimion slide along them?

[Foden7536]

Good evening, thank you for your kind remarks. 
 

I am only a hobby machinist with a workshop in the garage, for “real work” I am a central heating engineer, I have friends who offer me advice and guidance but I basically make it up as I go, and as the scrap bin would testify things rarely go right first time!!!

The keyways and keys are outside my machine, and personal capabilities. They are dovetailed into the crank, these were very worn and working within the dovetails, a local(ish) firm (Inca Geometric in Charing - near Canterbury) recut the keyways for me on their massive CNC mill, the keys were then made by a friend (Paul Smith Engineering at Gaza, Sevenoaks Weald) they are ground - and I don’t have a surface grinder - nor the experience of using one!

There is a gear cluster carrying the two crankshaft gears which slide along these keys for high and low speed, as well as “out of gear” this needs replacing as now the crank has been ground it’s too loose on the shaft (the old was beyond saving as it was very worn in the keyways too) I am going to have new gears cut, but before I can get these I need to sort the second shaft so I can measure the gear centres etc (I also need to save some more money as they’re not going to be cheap!) 

I hope these photos illustrate the key arrangement

David

[john1950]

It is many since I have seen a dovetail key. This kind of work in saving the countries heritage.

[Rootes75]

Absolutely superb work.

[mammoth]

The reason I asked about the keys is that I have the same repair issue ahead of me with my Ruston Proctor traction. For sliding gears manufacturers generally used either square shafts or with up to eight keys machined from the solid. The dovetailed keys is an interesting take, obviously in an attempt to stop the loose keys from rocking in the keyway.

[andypugh]

9 hours ago, mammoth said:

The reason I asked about the keys is that I have the same repair issue ahead of me with my Ruston Proctor traction. For sliding gears manufacturers generally used either square shafts or with up to eight keys machined from the solid.

I have been thinking about how to machine this from solid, and can think of at least two ways. 

1) Use a form cutter on a horizontal milling machine. This is probably how it would have been done in the day, but making the tool for a one-off would be a lot of effort.

2) CNC with a rotary axis, much like I used here: The key to making it work is a coordinated movement of the tool at right-angles to the shaft axis as the work rotates so that the shoulder of the tool is in the right place when it gets to the key flank. 
I suspect that my machine is too short to make one, I can only machine parts up to 356mm long. 

3) Amongst the ways that I can think of are....
The shaft could be wire-eroded in sections (I doubt that any wire eroders can do the whole shaft in one)  and joined by Hirth couplings and a draw-bolt down the middle. As the torsional strength of a shaft is almost all in the outside, the presence of a drawbolt would have little effect. 

I don't know off-hand how strong a Hirth joint is relative to a solid shaft (I would guess at about half as strong) but they work well enough to be used in racing crankshafts

 

[Foden7536]

Thank you for those thoughts Andy, 

The correct dovetail cutter was available off the shelf from MSC, so tooling wise this wasn’t an issue. The original keyways weren’t at exactly 90 degrees to each other, the advantage of getting it done at Inca was the crank sits easily within there machines capabilities and with the modern electronic dividing head the keyways could be cut more accurately, not a second out from 90 degrees, this has meant that the gear blank (the keyway slots in which I had wire eroded) can be accurately made and fits in any of the four possible positions. Working on a friends Burrell Traction Engine we found that the keyways aren’t very accurate and the gear only fitted in one position, each keyway having been scraped and blued to fit - I guess this was when being “a fitter” as a skilled job.

[andypugh]

50 minutes ago, Foden7536 said:

The correct dovetail cutter was available off the shelf from MSC, so tooling wise this wasn’t an issue. 

Sorry, I was going a bit off piste and hijacking your thread to reply to mammoth's requirement for a similar shaft machined from solid. 
I have since concluded that making a suitable cutter isn't as hard as I thought. You could CNC wire-erode replaceable blades from HSS or carbide, and fit them into a holder. Like this: 

https://a360.co/3ClcKKi

 

 

[Foden7536]

You’re not hijacking it at all, it’s all interesting and relevant stuff, thank you for the information 

 

David

[Runflat]

Just spotted another picture of the Wilkins moving floor here: 

 

Edited August 3, 2023 by Runflat

[Citroman]

Looks like  Ypres.

[Great War truck]

A great picture. Yes Ypres for sure.