There doesn't appear to have been a lot a visible progress but there are some reasons for that. First up, here is one of the front hubs.
All very shiny and somewhere near done. Those with memories longer than a goldfish will note that since the last photo of a hub it's grown some studs. The idea was that we would get the local machine shop to make them because we need 40 of them and making things like that in our workshop is very, very dull. However, the best price that came back was that it was going to be not too far short of a grand so someone, namely not me, got to stand in fron tof the lathe for a very long time making them. Nice eh? You should be able to make out in this picture that the threads are left handed which complicates things a little more.
So 20 studs later it now has a pair of useable front hubs - the rears can wait for now. The next thing that has taken up a fair bit of time is the S which has had one or two issues impairing its ability to work properly. Sentinel uses poppet valves (like what yer car has got) which work well in a car but are not the brightest idea in a steam engine. It is absolutely critical (in bold and double underlined) that the valve clearances are absolutely spot on. By critical I mean that it is very, very important. The problem is that Sentinel designed a valve adjuster which is, to put it mildly, cack. The Sentinel adjuster is the one on the right.
It's not super clear from this picture but the end of the valve stem is threaded and your adjuster screws onto that. The hole in the end at the bottom of the picture is where the ball ended push rod fits. What you will also see is the tapered thread on the outside of the adjuster with a matching nut and slots milled into that thread. The idea is that you set that valve clearance by winding the adjuster up and down the valve stem then once it is in the right place you tighted up the big nut and it clamps the adjuster down on the valve stem. All well and good.
Not really, it is shit. You pull the lock nut up stupid tight and it still barely hangs onto the valve stem. This means that once things get hot the clearances go off and it doesn't like that very much at all. So we went back to the old drawing board and made up another adjuster with a proper lock nut. The prototype one is the one on the left. This works in just the same way except the lock nut goes face to face with the adjuster over a nice big area so you nip it up and it clamps the valve stem as tight as a <insert your own metaphor here>. Check that the prototype fits in and then make four of them out of a proper steel and pop them on the exhaust valves which were the most problematic ones . The way the adjusters are designed make it easy to set the valves with the springs unloaded which means that you can feel when the clearances are right. By the way, the pushrods are ball ended at both ends so you can't set them with feeler gauges - you have to do it by feel which is even harder with the weight of the valve spring on them.
It went for a 40 mile run on Sunday to test them and the results were startling. Being set absolutely spot on meant that the engine runs perfectly balanced (if an exhaust valve on one cylinder starts not opening enough then it can't exhaust the steam fast enough which starts to throw things out of balance) and the adjusters stayed where they were put so it ran just as dandy when it got back as it did when we left.
In short I have completely forgiven the S for being rubbish. It will sit at 25mph all day long and will cheerfull average 23 in the hour without breaking sweat. Its spritely acceleration and well pucker brakes make it a piece of piss to drive in heavy traffic and the steering makes it a doddle to thread your way through towns. It will also canter up hills much faster that the previous Super ever would. It is a very, very powerful engine. On top of that all the work mentioned above to get the crankcase syphon to work properly were all worth it and it just sits there dripping just water from the bottom of the sump. In summary, it's the dogs'.
Anyhoo, back to the next one.
Here is the water pump valve block being machined. The water pump runs all the time and it is this device that directs water to the boiler or if it is not needed to spill it back to the water tank. It is a bit fiddly.
Cutting threads in a tight space. Good test of nerve.
It's sitting on its side here. The funny shaped bit hanging down is the bit that carries the control arm that opens the by-pass valve. Actually, it opens the byepass valve because for some reason the parts book retains some archaic spellings.
And the mechanical lubricator got dug out to start things about what patterns were needed to make the missing bits. This injects steam oil into the inlet manifolds to keep the cyliders lubricated.
And the same got done for the brake valve. Steam brakes are ace. I love them.
And talking of steam brakes the Supers didn't have them originally but a lot were converted to them in period. The reason for this is that the mechanical footbrake was not very good at all so you needed to rely on reverse thrust all the time which was OK when you were bimbling around at 12mph in very little traffic. These days you need something a little more modern so we need some steam brakes.
Here is a very detailed drawing of what is needed made about 25 years ago by someone with some Tippex. Not quite as handy as first appears. It is a representation of the modification carried out by the Sentinel service agent in Liverpool, apparently.
And here is the start of my interpretation of their interpretation
The cylinder sits in the middle and the pushrod (not in yet) pushes forwards. The pushrod is connected to a cross bar which sits in two guides the top part of which are those two bits of channel which are pointing front/back. The brake rods are connected to that cross bar. The thing sits at an angle so everything pulls in a straight line and nothing gets bent. Sitting it at an angle also helps keep the cylinder drained. Ignore the long bolts at the moment because it's just getting fitted up.
Once it is in the right place it will get messed around with to make things look a bit more period. The fact it sticks above the chassis isn't an issue because the bearers for the floor of the body are 4" high. Almost none of this will be visible once the body is on.
Finally, I got a budget cost for lettering the finished item up in gold leaf in Boots' livery (see the picture of the Standards somewhere near the start). Yelp.