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Building a B12


Go_West

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Rog

yes your ideas along with Rob with the double end heater tube is now looking like it will work so once the frames and wheel are in place the space that s left can be used for the tank/boiler that  you have both described so thanks for your input.

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Because of this size problem making a water tank to fit this tender might be a square one as space is limited and has been suggested. Before this can be achieved the frames and pickups and wheels need to be made along with a method of fitting the body onto the frames. 

To start with two strips of brass for the frames are roughly saw out to a size a little larger than needed and soldered together.

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These are then marked out with the finished width but not cut to the correct length.Once the frames are milled to the correct size then they are coated in marking out ink again and the positions for the axle boxes are laid out and as in this picture these can then be set up and milled out.

Holding the frames up against the Hornby plastic frame stretcher the new position of the axles can be worked out as this engine has a 6 wheel tender unlike the A3 which is an 8 wheeled tender so thing will come in the wrong places on the stretcher.

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After I was satisfied that the wheels and axles were  going to be in the right place  the fixing holes for the brass frames to the plastic stretcher were marked out and drilled in place as in the picture here.

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Also needed at this point was a way to stop the wheels and axles from dropping out of the frames. The idea was to use a small length of printed board held in place by a number of screws in the same way that Hornby had but this would have 4 ears sticking out to attach the body to at a later date by 4 screws.In the picture here is the printed board the Hornby plastic stretcher the 2 brass frames and the wheels.

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You can see in this picture 2 of the ears that the body will fix to between the wheels. The wheels I want to change by machining the centres out and inserting some plastic spokes.

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The pickup were cut to fit the new positions of the wheels and axle boxes and the screws fitted to hold the pickups in place, holes for screws to take the power up to the heater in the boiler need to be worked out.

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I had forgotten that there is electrical pickup involved here and this whole loco and tender is made from brass so there has to be a certain but definite amount of isolation side to side hence the Hornby plastic bit to start with And the reason you can have plastic spokesmon your wheels.

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Rob

yes using brass as the body does create problem but can with stand the heat have spent some time building up the tender and it's looking good once the model side is finished then the boiler side and wiring can carry on the wheel mods re the spokes can wait till a test run can be under taken.

ps. I like Rogs video clip of the happy steam engine is he from the USA as it's a Us loco?

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Rob

yes using brass as the body does create problem but can with stand the heat have spent some time building up the tender and it's looking good once the model side is finished then the boiler side and wiring can carry on the wheel mods re the spokes can wait till a test run can be under taken.

ps. I like Rogs video clip of the happy steam engine is he from the USA as it's a US loco?

 

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Rob

waiting for some brass tube which I can turn into a square tube rather than fold up some sheet brass if it works then test can begin first I'm think of running the tender behind an A3 for the first test and run in the axles then on the engine for a second run and in both cases log the time each engine runs for with one filling. Having built an inside cylinder engine how about an A4 with 3 cylinders? 

Also does anyone know what would the coaching stock look like for the S69 can I buy or reprint some that are out there.

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Ken

I'm sure back a piece I did the big-sums to see which diam tube was needed to make a rectangular pipe to fill the chassis as dimensioned on your drawing, but not having the stock catalogue I was no further forward. No doubt you already know exactly the size and how you are going to anneal and reform it over a mandrel.

 

So you want a loco challenge, a 3-cylinder A3 or even a 4-cylinder King or Princess Coronation are probably too easy for you, how about a Garrett, or double Fairley, or one of those vertical cylindered Shay logging locos with geared drive shafts like this beauty:

https://en.m.wikipedia.org/wiki/Shay_locomotive#/media/File%3AClassCShaySonoraJuly2006.jpg

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 Hi Rob

no working just a hunch but going back 300 years we were thought when softening brass to mark it with a bar of soap and when it turns black chuck it into cold water so will see if it still works old granddad might have had all the rules on metals when at Stratford works.

now just gooogle it.

Garret is one I have thought of with fixable steam pipes but not the gear driven engine did see one on a video years ago with the cylinders almost above the running boards going like mad and the small wheels turning slowly. I know there's a brass kit for the garret but not sure about the other engine.

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@Ken

Tallow was the active ingredient in the old indicators, found in soap, candles and other waxes. Nowadays you can get marker pens of different temperature values.

 

Annealing brass can be difficult depending upon its copper/zinc ratio and some recommend air cooling rather than quench, whilst others recommend cooling to a particular colour and then quenching as you do when tempering.

 

I'll post some of the links up I have found later when I get the main pc back on its feet as the iPad is hopeless for live links (at least I find it so).

Rob

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@Ken

Here are some links that may be useful:

http://www.steamshed.com/annealing%20process.html

 

Page 2 of this

 

360 Brass  - plenty of specs listed for every stock size.

 

From a gun forum - "...about 800 deg. I've always used soap as an indicator. When it blackens (without direct flame) you are about right. For a hotter temp, put a light coating of soot on with an acetylene flame the heat with a slightly oxidising flame until the soot is gone. This gets you to around 1000 deg..."

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Thanks for the links the first link shows a round boiler for a Clayton steam lorry in 2 ins scale of which I have built 2 and had problems with as it needed a lot of staying after failing the hydronic test. Hope I get the brass tube in the post today will go and look in my post box.

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Hi Rob

most boilers are made from copper like an inner fire box and tubes and outer barrel as it transfer heat better but if you mix copper and brass the heat expansion rate is different and parts will tend to work against each other as they heat up and cool down and joints might break down over time so by keeping to say all copper hopefully keeps it all working together. There is the problem of electrolas with different metals and dc and ac volts which I think Brunel had with a brass fitting on a water pipe to the iron hull of the SS Great Britain. Brass is also used as it's a little more stronger than copper and a little lighter when I was working we did have for Royal Navy projects a brass which we called Naval brass which had no zinc in it a softer metal than the normal hard brass.

My brass tube has not turned up today so will finish off the engines electronics and body may be.

Ken

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What was needed next was the water tank/boiler as was said by others a square one might be the answer and still might be worth a go over a round one which was never going to hold enough water, but a compromise I think has been a achieved by combining the two ideas I’m not sure what you would call it but here I will go over the bones of the unit.

Starting with some 30mm brass tube about 60 mm long enough to fit into the tender body was sawn off.

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This tube then had the end turned in the lathe checking that is was still going to fit the body in the picture above.

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Then a counter bore was added to both ends so that when the end covers are made they will not fall inside the tube when soldering the parts together.

By adding the counter bore will also give a great fixing area making the complete job just that little bit stronger.

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in this picture is the body the brass tube and the chassis with the wheels and the Hornby insulator with the thermal cut out in place.

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Just trying the brass tube in the body you can see the problem from this side view. You would never get the chassis to fit with this amount of tube hanging out the bottom.

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Looking down on the body you can see the top of the brass tube and it was thought at this point that if the top could be drawn up in the available space just a little more water could be stored with in this space at the top and later the coal would cover this area in a bit of a heap.

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Once happy that the brass tube was about the right size it was heated up with a blow lamp to soften the brass making it more easy to work this action would be needed to be carried out a few time just to complete the shape that I wanted for the boiler.If to try and work the metal when it is hard will only cause it to crack and render the boiler as scrap. Granddad would have know this and no doubt all the different metals the he must have worked with. When it was at the right heat the tube was dropped into the sink of cold water.

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You can now see the shape that I am after it’s a case of trial and error just keep hammering it in shape till it fits in the body and the chassis and uses all the available space. With this onion shape the boiler will still retain some strength and not need to have stays fitted.

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The back section of the boiler was cut with a step in it so it would fit under the water filler section of the Tender. The large hump part in this area between the 2 fillers was to do with a water scoop which would allow the engine to pick up water on the move not sure if this could be utilized in 00 gauge.

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With the chassis and the body in place and the boiler tucked away in side things were looking good.You can see the reshaped tube with the raised section standing up almost as high as the 2 tool boxes.This section will also house the safety valve and the filler screw.

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This filler screw will be cross drilled to allow steam pressure to escape should it be unscrewed while still retaining pressure see drawing.The seal for the screw will be a plain “O” ring.

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With the fitting of the boiler going well it was the end covers next, cut from some sheet brass these covers will be just under the size of the boiler as was said so will fit inside on the small counter bore made earlier in the tube ends.

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Sitting in place on the end of the boiler there will have to be a hole about 3 mm drill in the bottom edge to take the steam pipe to the engine but this will come a little later as the more fiddly end of the tube is next with its step.

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Not a perfect fit I would say but lets see what its like after it has been silver soldered in place. This cover to will need a hole some 6.5 mm in the bottom edge to take the heater tube.

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We now need all the other parts that go to make up this boiler like the heater tube which is made from copper bar drilled and reamed 6 mm and the out side you see in this picture being turned down to reduce the wall thickness.

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The picture here shows all the main parts the 2 end covers one with the steam out let pipe, the 2 fixing point pillars the heater tube the safety valve base and the filler base and screw.

Next will be the soldering part when all these item will come together and hope it still fits.

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That is a handsome boiler Ken with strength gained from shape.

 

Beware stress raisers in the saw cut corner of that stepped area, just stop drill/file the corner into a radius and fill with solder at build time.

 

Water scoop in 00. The problem as I see it is the prototype is filling a large bucket whereas in your case you are trying to inject into a pressure vessel.

Rob

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Rob

i did think when posting the picture of the boiler with the non rounded corners and a saw cut that you would see that and comment so hers the same picture again after a bit of work in that area on the PC its nice to know just how close your watching your like my old teacher.  

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But back to the boiler.

The soldering process starts with the sub assemblies which will be all the small parts.You can use to different melting point solders for this operation with the high melting point solder first and using the lower one last this way the parts soldered in the first heat up will not re melt and fall or move about. When the final heat up takes place.

But as this is a small boiler I will just use the single temperature solder and any way haven’t got the 2 types so let get going. Starting with the small copper pipe and end cover add flux to the pipe and cover area and heat up when I always heat up the stick of solder at the same time as the job and when the solder wire is hot enough poke it in the flux pot for a second or two and the flux will stick to the solder wire.

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Starting with the boiler with the fixing pillars held in place by two small pegs to the boiler bottom turn the boiler over and press in place the safety valve base and the water filler base.Now we can solder up the barrel so as you see here heating it up cover I always heat up the stick of solder at the same time as the job and when the solder wire is hot enough poke it in the flux pot for a second or two and the flux will stick to the solder wire.

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While it is still very hot turn the boiler over and solder the to base fittings for the safety valve and the water filler in the same way.

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Last of the sub assemblies are the end covers first I did the small copper pipe and end cover. Do the same to the other end cover and solder the heater tube in place.Now we have the 3 main assemblies finished make sure all old flux is removed from the surfaces that are to be soldered next are clean and if not a few seconds in some old battery acid will soon clean them up.

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Now fix the two end covers in place you can just crimp the ends with a small screw driver just to make sure that as the metal expands with the heat they do not fall apart.

Solder the end covers in place starting with the one with the copper pipe fix to it then the larger cover last.

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Place the complete job in the acid for an hour or two and have a cup of tea.

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Once out of the acid a good wash under the tap to remove all old dirt and acid.What we have now is a nice new looking boiler.To do the job properly it should be pressure tested at twice the working pressure therefore as these engines run at 30 psi we need to test it at 60 psi it should hold this pressure for a minimum of 1 hour and no sign of leaks . Then a steam test to check that again no leaks and that the safety valve lifts and that the when lifted the pressure in the boiler does not keep climbing proving that the safety valve is doing its job properly.But being you’re a long time dead I’m skipping all that. part.And what I need to know is how much water will it hold?

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This pictures shows the boiler being filled with water the syringe holds 20 mls of water and slowly it was injected into the boiler until it was full to the top.Bearing in mind that the Hornby boilers have a air space at the top where the steam collects as it would be in a full size engine.As if the water level gets too high there’s a chance it will enter the cylinders and water will not compress so that damage will be cause to the pistons or even knock the cylinder covers off and buckle the rods. I say this as I have seen people write that there model Hornby engine has bent connecting rods.

This no doubt caused by oil and water condensing in the very small cylinders and when next the operator gets it out for a run he tries to turn the wheels and the damage is done. For you should remember that full size engines have cylinder drain cocks which are opened before the regulator is opened which will clear any water or oil from the cylinders. Some engines like the GWR had an extra valve set above the working pressure of the engine's boiler so that should water enter the cylinder they will lift off there set and the water clear automatically thus saving any damage.

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Back to 00 gauge we have filled the S69 tender with water and made a note of the reading obtained. Now for the Hornby tender.The same operation and the readings taken.

The results from the tests showed the S69 tender holds more water than the Hornby A3 tender.

Tender water volume tests

HORNBY A3 18 mls

S69                22 mls

This should give us a good 30 minutes run.

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With all the above done with a trial fit was under taken and the tender body was fitted with the boiler to the chassis and it went together ok.

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Next will be the steam testing but need to make the safety valve and the steam out let fitting to the engine.

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