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It is just so Super (Sentinel).


JimH

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On 1/31/2020 at 12:41 PM, JimH said:

Long story. Oil firing was tried a few times in period but was always abandoned because it was just trouble - I suspect you also ran up against the problem was that coal was dirt cheap and oil wasn't. However, when we rebuilt the S we decided that oil firing was the way to go.

Experiment 1. A Laidlaw-Drew burner

We copied this burner from the ones they use at Ffffestiniog. It sat at the bottom of the boiler in a refactory lined support which took the place of the grates. We then took a steam feed from the boiler through a control valve and fuel through a fancy pants needle valve which was supposed to give us decent fine control over fuel flow. To start it we had compressed air. This was OK in the workshop because we have a 115cfm compressor which was more than butch enough. We would fret about want to do away from home later on. There was a propane pilot light  to keep things lit.

Results: Absolutely fucking useless. the main problems were that it would light and burn but trying to balance the burner was nigh on impossible even at a stand still. Had we been bouncing along the road it just wasn't going to happen. The other problem we could foresee was that on the road steam is on and off almost all the time so the draught you were having to deal with was constantly changing. We hummed and hawwed about steam bleeds up the chimney to keep draw on it when the throttle was closed but it became very obvious, very quickly that this project was going nowhere.

I think they could make the LD burners work at BF because they knew what was coming up so they could adjust the burner accordingly. There were no surprises so you got good at knowing how to control it. The other thing was that on a given bit of track the conditions were constant for a reasonable period of time. We are climbing this hill for some minutes so set the burners and off we go. You don't really have that luxury on the road.

Ultimately the problem was that the boiler was not designed to be oil fired. It was simply not possible to get the burner head low enough to get the gas temperature at the tubes high enough to make sufficient steam. Superheater temperature was sky high but the tubes weren't getting enough heat to make enough steam. The other issue was that with the new Super starting to look like it was going to get finished the S's days here are numbered. 

As I understand it, you had no blower to provide artificial draught? On the FfurCo we couldn’t have operated on oil without one. Partly because of the risk of hot gas explosions if the fire went out (standard procedure being to wang the blower open quick sharpish to exhaust any combustible gases before attempting to relight), partly because having artificial draw on the fire made lighting and keeping it lit far more controllable.  Initially the LD system wasn’t a great success, the burners weren’t really designed for railway use, they were more intended for stationary applications with very predictable usage. However once modified to suit they were great at what they did, especially once the railway stopped burning a mix of fuel oil & waste oil and went over to pure heavy fuel oil. 

With regards to usage, whilst it’s true that the railway is a more predictable environment than the road there was still a fair element of variability in each trip - railhead conditions and late running can change the firing requirements on a trip by trip basis. If the loco lost its feet and slipped (a regular occurence especially through the woods) the driver would have to shut the regulator instantly losing the draught. 

Interesting that the boiler couldn’t make sufficient steam, I would have thought that a burner throwing a horizontal flame out would be pretty good at distributing heat evenly across the bottom of the boiler and getting good combustion before it reached the tubes. It sounds almost like you couldn’t burn enough oil quick enough, the superheater would be ok because it’s probably thinner wall pipe and high up where the heat converges before disappearing up the chimney.

I suppose another difference between your boiler and locomotive boilers is that in a normal loco firebox there is also the brick arch to force the fire around, ensuring good heat distribution. 

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45 minutes ago, 83C said:

As I understand it, you had no blower to provide artificial draught? On the FfurCo we couldn’t have operated on oil without one. Partly because of the risk of hot gas explosions if the fire went out (standard procedure being to wang the blower open quick sharpish to exhaust any combustible gases before attempting to relight), partly because having artificial draw on the fire made lighting and keeping it lit far more controllable.  Initially the LD system wasn’t a great success, the burners weren’t really designed for railway use, they were more intended for stationary applications with very predictable usage. However once modified to suit they were great at what they did, especially once the railway stopped burning a mix of fuel oil & waste oil and went over to pure heavy fuel oil. 

With regards to usage, whilst it’s true that the railway is a more predictable environment than the road there was still a fair element of variability in each trip - railhead conditions and late running can change the firing requirements on a trip by trip basis. If the loco lost its feet and slipped (a regular occurence especially through the woods) the driver would have to shut the regulator instantly losing the draught. 

Interesting that the boiler couldn’t make sufficient steam, I would have thought that a burner throwing a horizontal flame out would be pretty good at distributing heat evenly across the bottom of the boiler and getting good combustion before it reached the tubes. It sounds almost like you couldn’t burn enough oil quick enough, the superheater would be ok because it’s probably thinner wall pipe and high up where the heat converges before disappearing up the chimney.

I suppose another difference between your boiler and locomotive boilers is that in a normal loco firebox there is also the brick arch to force the fire around, ensuring good heat distribution. 

Starting was not easy because we were using compressed air to provide atomisation and something to run the blower. We have a 114cfm compressor which was up to the job and that made it possible to get steam on the boiler and swap over to using steam for the blower and atomising. What we were finding that it was just so very delicate trying to balance draught and firing rate that it was never going to be a lot of fun on the road. We discussed ditching the engine exhaust draught and going for induced draught with the blower. We sketched out an arrangement using FD fan or ID fan which could be controlled more easily. In the end it just felt like it was always going to be a dead end so went over to the pressure atomising burner.

As for not making enough steam with the pressure atomising burnerremember that this boiler is a vertical one so the burner head was at the bottom of the box pointing up at the tube nest. Even with a ball nozzle on the burner it was not possible to get the flame low enough. If the box had been a couple of feet longer we'd have been in business but unfortunately the road was in the way so that wasn't an option. The bottom line was that the boiler was designed in the later 19th century to run with a fire at the bottom of it and what we were trying was going to be tricky to make work.

The Foden O Type had a pretty woeful boiler but it was mounted horizontally which gave much more room to get a burner in. We have a Foden drawing for the O Type converted to run with an LD burner which made quite a tempting project but we decided to build a new Super instead.

 

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Just a few quickie pics because most of the stuff that has been worked on lately isn't terribly exciting or photogenic...

The superheater set up and ready for prepping and welding. Welding is more pressure-tight than Jubilee clips but more expensive and takes time to learn. For those interested in that sort of thing, you see the piece of pipe in the middle? That represents the position and size of the stoking chute so you'll appreciate that your view of the fire is limited. It is worth bearing in mind that the Sentinel design may be rubbish but it is still better than a lot of others. If you can find a coppy of The Undertype Steam Wagon by Kelly there are lots of pictures and diagrams of other designs which are complete shit. IIRC it was Clayton who designed one with a floor mounted chute that sat to the side of the boiler. You just tipped coal in and hoped.

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Moar superheater. Incidentally, we don't do this sort of welding. All our boilers are what you might call "well documented". None of that "Oh, it's a repair" business around here.

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Can you tell what it is yet? Whatever it is it took two bloody weekends to make it.

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That's right. It's a chunk of eigth plate with D beading rivetted to it. Sentinel called it "a door". The first rule of Door Club is that the more crude the design of the door the more of a nightmare it is to make them fit properly. There are countersunk set screws holding the D beading on at this point. These have been replaced with rivets so it all looks right.

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Get's a wee bit more Sentinelly.

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And this is rather exciting. There han't been a pair of these cast for a while now. It's the rear hubs. One flange carries the wheels and the other takes the brake drum/drive sprokets. The little one at the end takes the hub cap. Originally these had plain bushes which are a right pain so they will have roller bearings in them like the later ones did. Much better if you actually want to drive them on the road.

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Other things that have been going on include having the duck canvas stitched up for the roof, grinding away on getting the brakes somewhere near, designing/making the exhaust pipe, getting the levers finished and thinking about exactly how much copper pipe was needed.

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1 hour ago, JimH said:

Starting was not easy because we were using compressed air to provide atomisation and something to run the blower. We have a 114cfm compressor which was up to the job and that made it possible to get steam on the boiler and swap over to using steam for the blower and atomising. What we were finding that it was just so very delicate trying to balance draught and firing rate that it was never going to be a lot of fun on the road. We discussed ditching the engine exhaust draught and going for induced draught with the blower. We sketched out an arrangement using FD fan or ID fan which could be controlled more easily. In the end it just felt like it was always going to be a dead end so went over to the pressure atomising burner.

As for not making enough steam with the pressure atomising burnerremember that this boiler is a vertical one so the burner head was at the bottom of the box pointing up at the tube nest. Even with a ball nozzle on the burner it was not possible to get the flame low enough. If the box had been a couple of feet longer we'd have been in business but unfortunately the road was in the way so that wasn't an option. The bottom line was that the boiler was designed in the later 19th century to run with a fire at the bottom of it and what we were trying was going to be tricky to make work.

The Foden O Type had a pretty woeful boiler but it was mounted horizontally which gave much more room to get a burner in. We have a Foden drawing for the O Type converted to run with an LD burner which made quite a tempting project but we decided to build a new Super instead.

 

Similar start to what we were doing then. 

From cold it was something like connect air, clean oil filter, turn oil tap on, close oil drain. Then set a lit rag ready in the firebox door inspection tube, crack blower valve to provide draught, oil to around the 2nd mark (of 9) on the valve, atomiser to 20psi. Shove the rag down the tube, listen for the whistle as the oil made its way into the burner, then whoomph. Stabilise the fire, keep the chimney clear and then switch over to steam for the atomiser and blower once the boiler was showing 20-25psi. Obviously we didn’t use pilot flames or anything.

With regards to using a fan for draught, is there no blower ring or jet at the base of the chimney? 

You could always build the O after the Super is done.... 

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There is a blower ring around the blast pipe. The reason for the fan was it might have made it easier to control it automatically rather than using steam. You need to remember that the boiler in the S sits behind you and viewing the fire is far from easy. What we were looking at was the poor sod who was fireman permanently facing backwards trying to juggle the burner.

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7 hours ago, JimH said:

There is a blower ring around the blast pipe. The reason for the fan was it might have made it easier to control it automatically rather than using steam. You need to remember that the boiler in the S sits behind you and viewing the fire is far from easy. What we were looking at was the poor sod who was fireman permanently facing backwards trying to juggle the burner.

I would have thought some sort of spring loaded valve would be a simpler solution for that? Held closed by steamchest pressure and opens when the blower pressure exceeds steamchest pressure. 

Fair point about the boiler location, every day is a school day! For us on the footplate our only visual references were the chimney, water level and boiler pressure. The only time we would open the inspection tube on the run was to pour a bean tin of sand down it to clean the tubes. 

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  • 1 month later...

There doesn't seem to be much going on in the world so we'd best have an update. Lots of new bits have arrived which is good but lots of things have needed finished off which have taken forever so at times it looks like little hs changed despite many man days disappearing into the thing. One thing we did get was the rear hubs. These are cast in steel and are vast. However, to cast them you first need a pattern and that wasn't what you would call cheap.

This is a pile of patterns that went into making the hubs. There are a lot of fiddly bits in the wooden box below.

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And here is one of the fiddly bits that goes into making the hub. Ignore the saw - that isn't for pattern making. In fact we have very little for making patterns including talent so that is why someone who is extrememly talented made them.

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And after a significant sum of money has changed hands they give you the patterns and two very big lumps of cast steel.

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This one has already begun the machining process. There are two flanges - one takes the wheel and the second takes the brake drum and sprocket. This has been bored out in the boring machine prior to going in the biggest lathe for finishing. When the conversion to pneumatics was designed by Sentinel the Super hubs used plain bronze bushes. Because we drive them a lot this is a no no so we took the slightly later DG design which uses roller bearings. Much more trouble free. This also lets us use later DG style drums and sprockets which you can't see once the wheels are on so there.

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The bit at the end is where the hub cap bolts on.

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And here is the other one being bored out.

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You should start to get a feel for how big they are. And also get an idea of how fiddly the pattern making process was. Middle flange take the wheel and the flange on the left takes the sprocket.

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What was also cast was a pair of front hub nut caps. These just cover up the 2" whit nut that holds the front hub onto the axle. The bit that stops your foot from slipping off will be milled in.

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These are the start of the brake drums. We had the plate already so that got cut into strips but it was waaaaay beyond (22mm) what our rolls can do (3mm). A few emails were sent and to say the least we were slightly disappointed in the replies. One outfit wanted £1250 plus VAT to roll them with no guarantee that they would be able to work to the requested tolerance. In the end Watson Tower in Coatbridge did the job perfectly for something daft like £85 plus yer dreaded each. Result. So, Watson Tower for all your heavy steel fabrication needs - really, they were lovely people. These have been welded up and we are waiting now for the rear hubs to go on so we can start setting things up. The last job will be to set the drive sprocket on these drums. After that they will be welded up and machined to size.

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Talking of brakes I've been trying to get the rest of them finished off. Here is the brake cylinder somewhere near finished in its frame. This has taken a very long time to get this far.

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Taken from the side you should have a better idea of how it works. The cylinder pushes forward on the balance bar which sits between two guides. There will then be a joint at either end of the balance bar which take the rods that go back to the brake arms. The bit poking out the front  takes a rod forward for the handbrake mechanism. The balance bar took forever to fabricate and machine. What also doesn't help is that there is nothing to copy - steam brake conversions were made up as people went along - so you are trying to design and make it at the same time.

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And from the front you should see how the balance bar is fitted. It swings around a pivot so hopefully pulls the brakes on evenly. Note Bimota style milling marks on the front of the balance bar.

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And at the other end the levers look exactly as they did before. Two weekends have gone into finishing these off. Everything is now almost (there is no detent spring in the reversing lever yet) fitted and feeling just fine. The 4th generation spent a long time learning to use files and die grinders to fettle these and make them look pretty.

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From the front you may notice that things are bolted on place, there is an arm for the hand brake poking through the floor and there are thrust washers keeping everything in the right place.

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And here is an exhaust pipe.

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Someone who isn't me has been practicing their TIG welding...

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Things like this are a nightmare because they take forever to set up and then weld and if anything is wrong it is blindingly obvious. Closer to the engine is the exhaust drain valve to let you dump water that has gathered in the exhaust while you were stopped. Without this you blow it out the chimney and people get cross. It is operated by wire from a lever in the cab.

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From the engine it passes through the cab floor straight into the feed heater (economiser). This has a copper coil in it to heat the feed water before it goes into the boiler and makes things mre efficient. Copper coil not shown. Or made yet.

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And from the feedheater it is sent up the lum through a blast nozzle which induces draft on the fire. Note the not exactly shabby welds. This pipe will be lagged in ladder tape that may or may not look exactly like asbestos.

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And finally here is a dead (ish) Saab.

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You can probably spot the new bellows on the floor which is why it is sitting on the lift. They arrived a couple of weeks ago but there has been no need to go anywhere so its just been left there. At least being confined to barracks means that the house will get finished a bit faster. I dare say there is going to be a fair bit more progress before the current mayhem is over.

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  • 2 months later...

It's been a while. I've not done a huge amount since the lurgey got out because I've been working/home schooling/trying to finish houses/trying to be Capability Sodding Brown. However, someone else has been working largely interupted by having to do any proper work so progress has been brisk.

We left the hubs somewhere near machined. However, there is a lot of things to get inthe right place around these so here is a hub sitting on a dummy axle trying to work out what will go where. It should be pretty clear now what goes where. The straight edge is giving the line of the chain. The brake drum/sprocket bolts to the inside flange and the wheel to the out flange.

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And if the wheel is to be bolted on then you need some wheel studs. So someone had to stand in front of the lathe making 20 of the buggers.

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And you also need a brake drum. These were cast originally but mainly because machining the sprocket on would be expensive we have fabricated our ones. You won't be able to see them when they are on. Here is the rolled drum with the flame cut mounting flange.

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Then I missed a load of photos as the drum was bored out, the mounting flange machined and fitted then a mountain of weld piled in joining the two together. So here is a big jump to a welded up and partially machined drum being fitted to the hub.

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But the drum also needs some spikey bits for the chain to snag on. These were water jet cut a couple of years back but they needed popped in the big lathe to bore them out to size.

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Then once it is at the right size it can be slipped onto the drum ready for welding. This amount of welding tends to pull things all over the shop so there is plenty of machining allowance should anything not end up in the right place. The bit of pipe is temporary. It comes out once everything is welded. The reason that the drum overhangs the sprocket is to form a groove to catch the oil off the chain. Without this the oil runs onto the brake drum and doesn't help slow you down.

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Then you need an axle. Here is the second axle. The first bit of bar that was ordered as about 8" to short. You have to laugh, eh? We have to machine it like this because the big Swift is very big but the spindle bore is not big enough to take the axle.

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Another view of a long and heavy bit of bar.

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And once you have it turned down you can put it all together like this. Surprisingly it slipped together very easily so something must have gone right. A brand new Super Sentinel rear axle. Not too many people built one of these.

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In all this progress someone got bored and painted a lathe. They aren't DSG's but these Swifts are really nice to work with.

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And here is a front hub cap all machined and milled so your feet don't slip off them.

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Oh, and while we are at the front axle, what's missing?

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That's right. It's these bloody things which are going back for the second time because they are still not right. However, it was our fault they were wrong this time. I thought the front axle was very close to the ground.

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As well as front hub caps you need some for the rear. We had a pattern made for these because it was going to be too much of a pain to fabricate them.

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And the other cap sitting where it is meant to be. This assembly is very, very heavy.

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A pair of boiler clack valves (non-return valves) machined with their seats, valves and spindles in place. These let water from the feed pump and injector pass into the boiler.

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And this is the bottle that smooths out the flow from the water pump. This had one or two cracks in it from frost damage so it was brazed up and made to look pretty. It will be painted black.

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And Vintage Wings and Radiators made a pair of rear wings for us.

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With the correct swoopy trailing edge so they look all fast and high performance.

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And finally here is the S4 all back together and ready to go again.

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Incidentally I know I tend to rush through these things but I assume that most people don't give much of a toss about the finer points of lining up the drive sprockets. If there is anything you want to know more about just ask. Do understand that the answer might start to get a bit dull.

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The sprockets are just steel with no surface treatment. The chains are of the roller variety so the relative movement between chain and sprocket is not great. We did exactly the same thing on the last one and they’ve lasted for about 20k so far.

You had a choice of 1.75” or 2” pitch chain back in the day and loads of people still make them in those sizes so we went for the smaller ones because they are more than up to the job. We need to order some of Renolds finest soon.

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  • 5 weeks later...

Things start to look a lot more waggoney these days so pictures of bits of cast steel begin to make more sense. Let's start with a first fit of the rear hubs and brake drums. When we last saw these they were in the lathe being turned. This is what they look like when they come out of the lathe. Note lifting strops. You do not lift these by hand.

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And this is what they look like when they are fitted for the first time to make sure all the measurements were somewhere near right. You will also see that there is a bit of chain held in place with some rope. This was to let us count up what chain we needed to buy.

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And from the front. It should now be clear how it works and why the crankshaft needed to have so many gears in it. Also in shot is the alternator which takes a chain drive off the back of the main drive sprocket. This is not original but the original set up looked shit, didn't work  and you couldn't spin the dynamos of the day fast enough to get any meaningful output from them. This set up will let us spin the alternator fast enough to be able to drive round with full beam on at night. 

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This is actually the smaller chain you could specify. If you were knocking seven bells out of the waggon you could opt for 2" pitch chains but these are more than enough for what we are doing. You will also see that everything lines up. Chain is surprisingly cheap these days even for Renold stuff.

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The alternator (it is an alternator in a dynamo looking body) so you can see the chain sprockets. Once the body is on you won't see any of this.

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Now we have some brake drums that just leaves the brake shoes to sort out. First you need a shaft to work the brakes. This is worked fairly hard so we've gone for EN24. Here is the shaft being turned down and having a thread cut on the end.

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And this is the paddle that screws onto the end. The brake arms turn the shaft and the paddle forces the shoes out. Modern wagon drums work in the same way.

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And these springs turned up. These hold the brake shoes about where they are meant to be. In the original set up these were the only return springs but on the steam brake modification there is a pair of big springs doing that job so we aren't asking very much of these.

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While in turning up mood these arrived too. They are the castings for the body mounting brackets. These bolt to the chassis rails and then mountings that are bolted to the oak bearers mate with these. I think the idea was to try to keep things flexible. For some reason this photo is upside down.

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And the S can't go out because the boiler inspector isn't coming out yet because lurgey so a historic wrong is being righted. When the paint was put on in 2008 something went wrong with the sides and we've not bothered to put it right. Here is some paint being subject to some major correction. Fortunately all of the paint which has gold leaf on it is fine. This is a relief.

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And at last we come to something that is almost, sort of related to the work of Autoshite. If you jump back to page 1, picture 1 you will see that the dominant feature of the cab are the two oddly shaped plates that fill in the gaps between the windscreens and the front panel which we shall call the cheek plates. Originally these were pressed and then "fitted" into whatever shape each finished waggon took. If you consider the manufacturing techniques, the materials involved and the tolerance between bolts and the holes shown in the drawings there must have been a lot of variation. Anyway, pressing them isn't an option so we'll have to do these by hand. This is a shame because I'm not a tin basher.

What we did do was bought a copy of the DVD from this man here https://metalshapingzone.com/  . Which I would strongly recommend buying. I am sure there are others but this one is very helpful for no other reason than the rather important lesson that if something is going wrong just keep hitting until it goes right. The early stages of shaping something seem to be very disheartening and it was reassuring to see that when someone who knows what they are doing starts a job it also looks like you've driven over it.

Anyway. some bits of 18swg sheet steel cut roughly to the right sort of shape so you have enough metal but not too much. The rotten piece of steel is roughly what we are trying to make. It was pulled from a river bed in Cumbria in the late 1980s so it's had a hard life. If you look carefully at the pattern you'll see felt tip pen markings on it. I came up with a plan to make it in three pieces. and the black lines show roughly what the three pieces will need to look like.

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And you need some hammers. We have amassed a fair collection of body hammers, spoons, slappers and dollies. If only we knew what we were doing with them. You can probably make out that the square faced  hammer is a shrinking hammer.

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And because we are bashing curves then some stakes are a good idea too. A few years ago we found a job lot of stakes which I suspect came out of a school workshop and they come on all sorts of shapes and sizes. This is the one I have found the most useful. What I don't have just now is a picture of the leather sand bag which is also essential for hitting things.

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And off we go. I started by taking a best guess at the development of the slightly conical shape is was aiming for and formed it in the folders. I am quite sure those who know what they are doing are laughing already and I'm going to need to spend an age dressing out the fold marks but it was a start. Once the cone shape was there you need to start forming the flange where it fixes to the apron plate (they are rivetted in). Here is the start of the offside one. You can probably see that the flange is pretty tight at the top and then eases as you come along the front apron. The exact curve is difficult to get right but when it is wrong you can see it straight away so you just keep working until it looks right.

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And you just keep working it until it goes right. It is painfully slow. You can also see I've been messing around with a slapper dressing out the fold marks. I reckon that it is fitting pretty well here.

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And from the side. You will also see that the offside door got made and fitted too. You should be ble to see why the flange has to be stretched and dressed into shape because you are trying to form more than one curve. I am pretty sure that this is why apprenticeships used to be seven years long.

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The panels are handed so while we have a pattern for an off side one there isn't anything to copy for the nearside. What I decided to do was to get one bit of the offside done then straight away do the same section on the near side. That way I wouldn't forget how I made the bloody thing and the chances of making things look right from side to side got better. This is the nearside one somewhere near. It is not easy to make out but it should be possible to see where the curves are and why they have taken a lot of stretching and dressing to get the flange right. The piece of angle iron is part ofthe cab. That is what the windscreen sits over.

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Then flushed with success I pressed on with the second section of the nearside one. You can't make it out but the apron is curved across the front (about a 12 foot radius) so there was yet another curve to fit this to. It is about this point that the clamp situation became critical so more were ordered.

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And from the side. The join between the apron plate and the cheek plates is "hidden" by a D beading that is formed around the top of the apron plate. Note clamps everywhere.

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The butt hasn't been fitted properly yet but it is getting there. Once it is in the right place it I'll gas weld it. You see both the inside and the outside of these panels so the welds will need to be good.

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And that then leaves the spherical bit to fill in the corner. I only got this started last weekend so it is still a work in progress. Stretched it with a ball pein hammer over the sandbag and then just keep dressing it over the stake until the shape starts to appear.

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See? It curves in both directions. Note the elderly Sykes Pickavant body hammer. Nice hammer that.

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So this weekend's job is to keep hitting that until it fits and then start tacking things up.

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On 7/10/2020 at 4:37 PM, JimH said:

The rotten piece of steel is roughly what we are trying to make. It was pulled from a river bed in Cumbria in the late 1980s

I'm intrigued.  Was an entire Sentinel pulled from a river bed? Or just that piece and by some miracle someone knew what it was?

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18 hours ago, adw1977 said:

I'm intrigued.  Was an entire Sentinel pulled from a river bed? Or just that piece and by some miracle someone knew what it was?

Not quite an entire one. One went down a ravine in Cumbria back in the late 20s (one story says it ran out of brakes, another says it was an insurance job) and for years what was left after the locals had salvaged what they could lay in the river. A lad from Appleby had known about it for a while and finally got round to sorting out the ownership of the wreckage so he could recover it. By the time it was dragged up what was left amounted to the boiler, the front part of the chassis, the front axle and wheels, the steering box and the remains of the cab. The waggon hit nearside first dso that side of the cab was mashed. The offside at least survived to be of some use building a few cabs. 

The waggon got rebuilt (as a flat bed on pneumatics rather than a tipper on solids - not that I am complaining because I hate tippers), lived in Scotland for a couple of decades and I think it has gone to live down in Cumbria again. I believe it is black these days.

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1. They're ugly. The S4 doesn't look too bad but that just looks like a short waggon with a big body. This was down to the location of the water tanks. On the S4 the tanks are in the cab whereas the Supers and DGs has the tank slung under the chassis behind the rear axle. On a tipper it had to be relocated to just behind the cab and the tipping body gets pushed back and I really don't like that. On top of that most Sentinel tippers are three way ones so they have to have stupid rear wings on them. Our S4 is an end tipper so it has standard rear wings which helps to keep things looking more normal and less tippery.

A Super Sentinel tipper, yesterday.

WAfBA4uNFgzqWMPupLbZ4MyZ-super-sentinel-

2. Tipping bodies are nightmare to build. There is a lot (and I mean a lot) of rolled sections, teak and mahogany go into a tipping body. They are complicated, take a lot of riveting and a lot of wood. This is a lot of effort to go to for something that doesn't look good.

3. They are heavy. Like properly heavy. The tipping body on the S weighs about a ton which is a lot of weight to lug around for no good reason. It is worse on the Supers because later Sentinels used the boiler feed pump for hydraulic power whereas the earlier wagons used an injector (black magic device that produces a pressure higher than what you blow into it - real voodoo stuff) which needed a much bigger tipping cylinder. By big I mean about 12" bore. It is a truly massive bronze casting. Depending on the design of the body you are carrying 1 to 1.5 tons more than you need to be.

4. This doesn't apply to the Supers but the S4 tippers had a very short wheelbase which meant that the engine is pushed hard up against the boiler and is very close to the rear axle. That doesn't sound terrible until you want to slightly modify the valve timing...

- Remove the cam gear covers.

- Realise the cam gear covers cannot be removed because the boiler is in the way.

- Opt to lower the front of the engine down to allow the cam gear covers to be removed.

-Lift up the tipping body and prop it in place.

- Realise that lowering the engine will mean removing the prop shaft.

- Once the prop shaft is unbolted find out that because the shaft is so short there is not enough movement in the sliding joint to let the UJ clear the flywheel nut.

- Block up the rear of the waggon and remove the pins from the rear springs. Now you can move the rear axle back a couple of inches.

- Now you can remove the prop shaft.

- Now with the overhead crane you can fight the engine mounts off and lower the engine to the ground.

- Remove cam gear covers.

- Modify valve timing.

- Refitting is the reverse of removal.

And some people thing they have it hard with Citroen CXs. The S4 was rebuilt as a tipper because it was built as a tipper and it was one of the few end tippers left. We regretted starting down that road from pretty much the first job we did and we are still regretting it now.

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With a Super you should be pottering along at no more than 4 gallons to the mile. With the standard 170 gallon tank that gives you about 30-35 miles before you need to start looking for water which is a pain in the arse if you are trying to get somewhere. The S4 has a 450 gallon tank inside the tipping body which helps the range enormously. With the new Super there wil be the original tank behind the rear axle and then we'll make a pair of tanks to sit inside the body. My calculator tells me that will give us about 350 gallons which is a bit lower than I would like but shouldn't be too bad. That means you can bimble along at about 70-80 miles between stops.

You can see the water tank in this photo - this should be pretty much the same as what the new one will look like but without the solids. We'll sit the tanks inside over the rear axle to keep some weight over them.

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I can imagine finding water on the road is a pain. That’s the advantage we have on the railway, we know exactly where the water columns are. 

Do you use any boiler treatments at all?

The tipper power arrangements sound interesting, using injectors and feed pumps for powering hydraulics? I’m surprised it isn’t just a live steam feed into a ram - it sounds like adding the hydraulics when there is already a source of power is over-complication?

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Water is easy enough - you just carry a standpipe, hose and hydrant key. You aren't really supposed to do it but we've never been told off yet. Most of our running around is north of the border where the water is good enough to drink so we don't bother with any boiler treatments. The number of running hours is pretty tiny. If you were running day in day out then you'd probably take a lot more care over what you were putting in there.

The tipping rams are just bonkers. There were all sorts of problems trying to fit everything in around the axle(s) and engine as well as position the ram in such a place as would let the body tip in one of three ways. What it meant was that to fit it in and keep the ram short the tipping cylinder is very close to the pivot point of the body which means that the load on the ram is very, very significant and the pressure needed in the cylinder is very high indeed and way in excess of the boiler pressure. Very late in the day some people messed around with engine driven oil pumps coupled to proper multi-stage hydraulic rams  (I have  seen a photo of one Foden steamer with such a set up and I believe the Argentinian Sentinels had proper hydraulics) for the tipping gear but by then the game was well and truly up.

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Things didn't pan out quite as they should but it's mostly forward movement. Here are most of the bits to make up the nearside cheekplate.

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And here is 67% of the offside one

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You should be able to see why it needed so much hitting to form the flanges on them so they can rivet to the apron plate. It starts off tight at the top then eases as you move further down the curve. Our guess is that these presented some difficulty to Sentinel. Our justification for this is that to the uninitiated (YCRTA go to pubs and talk to girls) the Super and its successor the DG look pretty much the same. However, there is almost nothing shared bewteen the two waggons. About the only thing that is common between the two models is the front of the cab. Why did they go to the effort to update almost everything (mostly in the name of weight saving) yet these bloody cheekplates were just the same. Seems very odd. Anyway, you can probably make out that there is still a lot of dressing to do on these before they are presentable.

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It isn't very clear from the picture but this one is fitting around curves on three axes which is a great thing to cut your tin bashing teeth on.

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Yeah, yeah, all well and good but why are they still in bits and not welded together. Well, the main reason is that in the process of hitting them I became more and more bothered that the apron was not quite right. We'd made a bit of a faux pas when it was fitted and the curves around the front of the cab were not right. We'd sort of ignored it in a "we'll sort that out later" sort of a way but it became apparent that the only way of dealing with it was to throw it away and start again. You'll see a lot of clamps around the front. That is us forming some supports for the apron plate that aren't meant to be there but we added on the last one to keep the curve right at the top of the apron plate.

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Ah well, it's only money. This is 2mm plate (a frazzle thinner than 14gauge) which it turns out is somewhat heavier than it was meant to be. We'll take the opportunity (always look on the posititve side) to go for 18 gauge sheet. We also took the opportunity of this one being scrap to form the D beading around the top edge. This has to be done hot so it means we won't have to put heat anywhere near the new one. See - we should be glad that we made a mess of the first one. Once the new apron is on then the cheekplates can get fitted and finished off.

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What we will do now the front is off is do all of the pipework, make the chimney and make the boiler cladding. That is very much easier with the cab in pieces. What else has gone on? Well flush with success at hitting 18gauge I thought I would make a start on the water tank ends. Turns out that forming 14 gauge is a wee bit harder. Originally these were pressed which isn't really an option so like the cheek plates these will need to be made in sections and gas welded together. Take sheet of 14gauge and mark it out so the corners can be tweaked on in the folder. The ends slip inside the body of the tank and are then riveted in.

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What is then needed s to make up the curves for the top corners and the bottom corners. Look on the top of the tank and you will see attempt one at forming the big corner. It is very much harder to stretch 2mm plate by hitting it with a bossing mallet. This attempt was not successful and we've gone back to the drawing board.

We've had a picture like this before but what is that G Clamp doing there?

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It's holding the brake shoe on so we can measure things. Brakes that work. Well swanky.

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It took most of last weekend to do these bloody things. I don't know what the lining is made from but even touching it makes you itch like crazy. It was a bit of a pig to drill the stuff so it could be riveted on.

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The rivets were closed in the hydraulic press. I thought they looked pretty good.

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The upshot is that they fit spot on to the drums so we need very little movement on the shoes to apply the brakes fully. This is good because it leaves plenty of movement in the brake cylinder in reserve.

So now we just need the front springs to come back (yet a bloody gain - they made new top leaves but made them from the wrong stock because they had run out of the right size. This meant they didn't fit in our spring hangers *rolls eyes*) and the tyres for the back to turn up and it will be able to sit down on its wheels for the first time.

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