andypugh

if you can't find a bearing to suit exactly it might be possible to machine a modern bearing to size. I haven't tried machining a bearing race, but I have had good results machining ballscrews (similarly hard) with CBN tips and a very high cutting speed. (hard turning is more like single-point grinding)

Possibly just for general utility. Pulling down trees and walls, shifting things too heavy to lift, that sort of thing. Fire engines of the same vintage have similar hooks, and they were unlikely to be wanting help from a horse. http://farm4.staticflickr.com/3716/9433449987_c939ffbd44_b.jpg For example.

I know of a 1920s Morris Truck with "Dynastart" (Google brings up many links)

Compared to high explosives and mustard gas? As another caver (not quite ex-caver yet) I can say that acetylene light is fairly easy to live with, and some of the large old vehicle lights are extremely bright. The smell of acetylene is strong enough that you pretty quickly realise when you have a leak. In some ways that thing that makes acetylene good for caving (that you can easily carry a lot of extra light) would be good for long-distance motoring, but for a fire engine that probably only ever needs to drive 5 miles then one less thing to have to fettle before being able to set off.

I hadn't previously considered the possibility that they might have used primary cells rather than accumulators. I suppose it is possible that originally the lights ran from readily-available radio batteries. However the fire station would almost certainly have had mains electricity and have been capable of charging accumulators. Interestingly, what is claimed to be the longest-burning light bulb in the world is in a fire station. http://www.centennialbulb.org

As a first step, I would try ignoring it. Perhaps is won't leak. If it does leak then the normal repair is metal-stitching, but there are also specialists who can weld engine blocks. http://www.castironweldingrepairs.co.uk

Indeed, LP8389 our 1916 Dennis fire engine was supplied with electrical lighting. We believe it was originally a 4V system, but is currently 12V. There is no evidence that a dynamo was ever fitted, she has always run a total-loss system.

Ooh! Yes please, that would be fascinating.

At that price, I am not so surprised. It's a marvellous looking device, but isn't that about the same price as a running Dennis N-type?

What do you need? I have a CNC lathe and Mill and I am reasonably happy as long as I make a profit on materials and/or tooling.

I should probably have asked this before rewiring the vehicle, but... Does anyone have any original WWI vehicle wiring on their vehicles? I am curious as to how it was done. I realise that electrical lighting was very much in it infancy at the time. I recently rewired a 1916 Fire Engine, supplied from the factory with electrical lighting. However all trace of the original wiring has disappeared, so I don't know what style of wiring terminal block was used. I can even imagine that they strung bare copper on porcelain insulators. I ended up making a specifically-designed wiring board that _could_ have been made in 1916, though they would have had to use Vulcanite rather than Delrin.

Marvellous, pre-war metallurgy to explain a pre-war truck crack :-) You could have blamed "anomalous crystallisation" too. You do not get any work-hardening effect unless there is plastic deformation, which seems very unlikely in that position. The only cracks I know of that grow like that are the ones due to the hydraulic action of rainwater in railway tracks, and I am pretty sure we can exclude railway wheels rolling up and down the chassis :-) I feel that a flaw in the steel is more likely. (and I used to study cracks for a living)

I think that the "rule of thumb" is somewhere between 0.5 and 1 thou per inch diameter clearance (as measured by Plastigage) In practice this seems to end up as "slight nudge" when new, and rather free-er after a few minutes of running. We made the breakthrough of pouring and boring our own big-end bearings on LP8389 a couple of years ago, and the one we did is still going strong. The kit and materials are all there at IC if you need to do one.

Practically speaking this is nowadays a job that might be passed on to a wire spark eroder. I recall back before the turn of the century that David Brown's of Huddersfield (still probably the premier gear maker in the world) offered to make a set of gears for the 1916 Fire Engine operated by Imperial College. It is pure coincidence, of course, that at the time I was a student there and my dad was a manager there :-). Anyway, they made an "at cost" quote of £400 then found that the gears had a 5-spline hole in the middle. (in 1916 5 splines was seen as "almost metric". 10 was in, 6 was out, 5 was more like 10. (I am not kidding)). They ended up paying £600 for the spline broach. Anyway, I am not at all sure that you can index a broach. You can definitely index a slotter (as the tool is self-guiding) and you can press a shaper and rotary table in to service as an indexing slotter (I have, Dennis "Box Joints")) but I can't see the typical keyway broaching machine indexing very well at all. <thinks> Actually, with a guide bush that indexes to the first slot for slots 1+ then it would probably work fine.

There is some danger of asphyxiation if using it in a confined space, but other than that it is actually significantly less dangerous than boiling water. It always used to amuse me that we put on a load of equipment to handle LN2 then took it all off again to boil a kettle. Now, the mixture of LN2, Bromine and Methanol, that wasn't at all nice.

Nice work Ben, as always. I am still looking for a 6DP 14.5 PA HOB, just so you have no excuse not to use the ratchets. Actually, I am happy to extend this, I will make gears for anyone if they can provide the hob and the blank, and if it is for a vehicle that interests me. View this is a fisherman talking to fish-pie makers.. "Oh, very well, I will go try to catch you one of those, if you insist"

Just a thought, but what happens if you freeze cork? (replumbing the coolant pump for liquid nitrogen might take more time than the machining)

It is possible to buy Ebonite as bulk material, but I have no idea how they coated it onto steel or aluminium for steering wheel use. http://www.nikkoebonite.com/english_site/manufacturing_processes_of_ebonite.html Suggests that you would probably wrap the rim in the material and then vulcanise in-situ.

It seems that Thornycroft were a bit less mad than White and Poppe then, the spring retainer seems relatively sensible. I would like to point out as a general observation that heat-treating spring steel doesn't get you back to a spring temper. That is typically the result of cold-rolling or wire-drawing. But it is typically eutectic steel (0.8% carbon) so will harden well too. Having said that, I am pretty sure that leaf-springs are typically heat-treated rather than cold-rolled. I probably should have introduced myself, though you have probably guessed by now that I am one of the IC motor club folk. I was at college at the same time as Steve (I think) then went on to do some postdoc research on spring steels. I don't actually play with old vehicles very much any more. (Other than Jez, the 1916 Dennis N type). I do own a 1922 Ner-a-car kit, but haven't touched it since I bought it. I mainly experiment with machine tools for a hobby. My Youtube channel gives a flavour of what interests me (finding ways to make things, though not necessarily doing so) http://www.youtube.com/user/blyndpew/videos

To put things in some perspective, the White and Poppe 4 cylinder in LP8389 ran for decades with one piston weighing 2lbs more than the others. It didn't seem to cause any real problems. When we nibbled away as much excess metal as we could (using a boring bar made from a road-breaker chisel) we got the imbalance down to a few hundred grams. And some people managed to persuade themselves that the engine ran more smoothly. I thought that White and Poppe were the only ones crazy enough to run piston rings through the gudgeon pins, but clearly not. On LP8389 the gudgeon pins were a (very) tight shrink fit, with assembly requiring the use of heat and liquid nitrogen. Not a great combination as getting the pins in to just the right depth and with the ring-grooves properly aligned was extremely difficult. On one piston the gudgeon pin lost its fit for some reason. The effect of this was to twist out a chunk of ring (which caused some bore damage). I would be very nervous of your arrangement of rings through the pins + free-floating pins. On LP8389 we gave up on the original arrangement, and now simply omit the middle piston ring, and have floating pins with bronze buttons in the end. This makes life a little less interesting, but the white-metalling guys smash fewer of our pistons when pressing pins out.