Building a B12

[96RAF]

Those axle housings are doing a good job of acting in lieu of standard cross frames Ken.

 

The whole thing looks fairly rigid now, and as you say will be even more so when the working components are reinstalled.

 

Did you ever find out if those outside connecting rods could be reversed so the rigid link was between the leading drivers and the centre valve timing wheels to give more positive valve timing or is the gain not worth the effort.

[gowest]

hi Rob

looking at the connecting rods the flexiable joint is only etched in the rods so will not be a problem but have finished off the inside connecting rods as a better job.

 

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Now it’s the supper heater, regulator and oil tank that need to be looked at and again the space in the smoke box is very limited for these parts 2 ideas might be the answer they must have had the same problems when building this new engine on the GER this engine was a replacement for the Claud Hamilton 4-4-0 design which were getting under powered for the new faster trains like the boat trains only once again axle loading was to play a large part in its design so a 10 wheel arrangement seemed to be the answer plus it seems that a shorter engine and tender must be built as the turn tables on much of the rail system would not accommodate anything larger all this is tying us down to the same Problems. But having said that it is believed that this engine was one of the best 4-6-0 inside cylinder designs in Europe .

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Two ways as said might be to adopt the A4 oiling system but maybe make some improvements or go for the A3 oiling system which is much better but make it smaller and fatter. above is the standard supper heater and the copper pipe connecting to the safety valve.

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In the drawings here which are not to scale might be to use the snifter valve as a filler if the A4 oil tank idea is used, the snifter valve was fitted to most engines and the idea of it is to let air into the cylinders when the drivers shuts the regulator otherwise the engine will not roll freely as energy will be absorbed by this pumping action of the pistons and the vacuum will built up in the cylinders and valve chest which would then lead to soot and ash being drawn into the valve and cylinders which will created wear and damage.

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You can see from this picture with the smoke box door removed that the smoke box is getting a little full of parts so I will need to give some thought to what might work out best .

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At least the chassis fits in the body now that the servo motor has been mounted in a different way I’m hoping that there’s still space above the servo for the safety valve and pipe work again a rough idea is in the drawing as to how this will fit. You can see the little snifter valve just behind the chimney.

[96RAF]

Ken

Inside con rods re looking good and even though you say the drgs are NTS the second version looks better with a bigger oil tank nd better access for filling.

 

Safety valve may be a pest to rig.

Rob

[gowest]

I'll try the second idea first as i like the filler idea using the snifter if a valve is made for the top of the tank.

[gowest]

I think its time to recap where we are with the engine and what’s to come as I’ve got so much going round in my head I need to clarify things for my own sake if not yours.Weeks of fitting and refitting parts wandering if an inside cylinder engine could be built

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making new parts and mod’s to old parts like new valve rod and changes to the valve block and making a more condensed servo unit all took us to the point that might end the build.But despite all that just soldier on and see what happens when it comes to the test on compressed air and this then showed as the wheels spun round it might just be a runner.

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The following now needs to be worked out like the oiling of the engine and the safe valve, will we get it in the space remaining and vent out through the models own safety valves in the body for some proper realism. 

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. Also the electronics my own design pictured here along side the Hornby unit is from my GWR King for the control of the servo motor built from solid state components and have over the years worked well and are quite robust and are smaller than the Hornby unit but will there be space for the printed board as small as it is or can i make it smaller? plus my flashing light in the fire hole door?

Then the last part will be the tender which is smaller than the A3 and A4 engines in fact the tender for this engine when built at Stratford have some of the coal space remove so that more water could be carried. Which turned out very well as these engines were very good on coal but they would not have known that till it came to use them on the main line doing a job of work.

[gowest]

Thanks to Ben as he has let me use one of his pictures of the chassis of a B12 and shows looking from the cylinder block to the cab area that there's a frame stretcher at the end of the cross heads which I must now consider.

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i think i need to look at this and draw up and make plus the cross heads and slide bars so its 3 steps forward and 5 steps back.

 

 

 

[96RAF]

Well, your one is worlds apart from the original Hornby model Ken.

So far so good.

Rob

[RB51]

Amazing. R-

[gowest]

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A start was made on the new oil tank, you can see a rough drawing here of what I want it to look like.

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I keep noticing that every time I take a picture of my mill the milling chuck seems to be stopped in the same place with the name TITANIC I hope this has no reflection on the parts that I make and it all turns out OK in the end.

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With the main part of the oil tank/regulator complete all the passages are needed to be drilled in place and fixing holes and the check valve made.

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As for the safety valve if you look at the picture of the Hornby supper heater and safety valve the unit is to long for my engine and would end up almost in the tender.

There is not enough room above the servo unit to fit the safety valve there but looking at the engine it might just fit under the supper heater I have cut down the safety valve and can run the pipe work differently.

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You can see also in the picture here the new safety valve sandwich above the engines valve drive shaft and the supper heater.

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The drawing here gives a rough idea as to what is needed. The steam that escapes from the valve can be vented up through the copper pipe to the safety valves on the body. so i need to try all this out and see if this will work out alright.

Its amazing to think that the steam pressure in the boiler works many parts of an engine like steam for heating the carriages steam to put water in the boiler steam to blow the whistle on some engines steam for electric lamps and so on. i did here of and engine that went into Stratford one day for a boiler wash out they would drop the fire fill the boiler via the engines injectors and a fitter would drive the engine into the shed for the clean and checking of the boiler most times the boiler would only have about 60 psi but this was more than enough to drive the engine into the shed on this day a new boy was at the controls to drive it into the shed and when he went to stop he found that he had little or no brakes, the engine rolled on till with a mighty bang as it hit the buffers which when he jumped down from the cab all seemed to be ok and just maybe he had got away with it but little did he know that the buffer beam was fix close to a wall of which the other side was an office and fix to the wall was a glass cupboard which had crashed to the floor with glass and papers all over the floor. luck was on his side as the office was empty and no one ever found out why the unit had fell off the wall.

[RB51]

I don't think the quality of build was the issue with the Titanic - but just in case, are you able to build in a couple of life boats? R-

[gowest]

Hi R

with space now getting tight the only thing I can do is may be with an inflatable type boat which would work.

[gowest]

The oil tank construction was coming together nicely and for those not familiar with the Hornby parts I will try to explain how it works.

The regulator valve controls the amount of steam going to the cylinders and also supply steam to the whistle.The parts are shown here in this picture

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Starting with the pressure spring on the left of the picture which keeps the valve in good contact with the valve body port face Next is the valve with the 2 holes which emit the steam to the engine or the whistle if you look closely at the picture you will notice that the bottom hole is that just a plain hole where as the top hole has a comet tail leading away from the hole this will then emit steam on a more graduated effect so giving slow to fast running I hope that makes sense Next is the operating shaft that fits in the centre of the port face and turns the valve.Then comes the light contact spring which keeps the small drive shafts shoulder in contact with the valve body stopping any steam leaks and will stop the valve getting push off its seat.Then it’s a plain brass washer followed by the regulator arm and last of all the fixing nut.

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In this picture of the valve port face shows the red arrow is the hole for the whistle and the blue arrow is the hole for the main steam passage to the cylinders and oil tank.

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Now you can see the complete assembly of the regulator When the supper heater is fitted all this item is then out of sight.

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With the whistle in place the valve now starts to show it make up.

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The 2 holes grouped at the right hand end centre are the exhaust and steam to the cylinders.

Now for some more micro machining starting off with a 4BA stainless steel screw the reason being that these screws are made from free machining steel so will be easy to machine and thread and as I have loads of them cheap to.

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The part we are making is the oil check valve only fitted on the A3 engines and is a great improvement on the oiling of the cylinders on the A3 design.In the for ground is a pot of stainless cutting oil a must for this job and a collect lathe more accurate than a 3 jaw chuck and ideal for such small parts. What we are making is a screw with a slot one end for the screw driver and a point at the other so that as the screw is wound in it can be adjusted to control the amount of oil delivered to the main steam passage and then to the cylinders.

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The thread for this screw is 1.4mm so very small as in the picture here and after making about 3 I did manage to make one that fitted and worked ok thinking on from this part I did try to find the correct colour blue of this engine and the story goes that queen Victoria was going to give Epping forest to the people as park land a place that I as a boy did go on picnics with the family.

So as she was to travel by train the GER thought it would be nice to paint the engine royal blue and so it was and the GER board thought how nice this colour was so how about painting all the express engines blue with red and black lining I am told that the true colour should be Ultramarine blue and the paint is on its way.

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The oil tank with the check valve screw in position.

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Once the oil tank cover is in place with its 4 fixing screws and a gasket the check valve screw becomes sealed off along with the steam passage on this end so may make a cover with a small hole to adjust this valve once in steam.

Now complete and all the maze of passageways are drilled in place and this complicated part can be mounted in place and the attention now moves to the supper heater and safety valve assemblies.

[gowest]

also building some electronics for the engine then a steam test maybe

[96RAF]

More things of beauty Ken.

 

That whistle is asking for a church organ tuner to apply his skills to it. Image a bank of those with a sequential valve.

Rob

[gowest]

Hi Rob

now you are talking about something I know nothing about I was involved with building some electronics for a fair ground organ a few months back and was surprised to find out the card that runs through the organ is still made! Other than that I know little or nort

ken

[96RAF]

Hi Ken

The reason I brought it up was that whilst in UK I went to Beamish and they had a steam powered Gallopers roundabout, which had a small organ attached. At the time I was too busy listening to it to take note of how it worked and what the automation was like.

 

I also took oportunity to stand under the mighty organ in Norwich Cathedral when it was playing for a posh wedding and as the third largest organ in UK it was impressively loud and clear.

Rob

[gowest]

Hi rob

thats one thing that stirs the blood is a well played church organ or fair ground organ 

ken

[gowest]

An old driver once when driving his engine from the shed with a new fireman on the foot plate slammed the brakes on throwing the fireman up against the back head of the boiler. The fireman said what did you do that for? the driver replied “I wanted to see if it would stop more than go”

And that is one thing that these small steam engine will do is go and controlling them is a problem to some but if the setting of the light indication can be made so that the light feed back to the driver is better and more of a warning as to when the engine is about to move off, must be an improvement to this system of control.

As space is a problem with this engine fitting the electronics is going to be a bit tight. Unlike the Hornby red and green light system I have fitted a flickering fire driven by some electronics that I have built on a small printed board with a few components which drives 2 LEDs.This time it was going to be a flickering LED and 2 resistors and the reed switch to save space.

And with this idea of a reed switch and magnet you have the ability to move the magnet arm forwards or backwards as its on a clutch type fitting a more exact and finer setting can be made.

So lets look now at what we are hoping to construct with the pictures and drawings here.

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How it works

With the reed switch open the LED would have 2 resistors in line with its supply voltage taken from the bridge rectifier on the motor servo printed board, the increased resistance would make the LED flicker much dimmer and will correspond to the regulator being shut as if the engine was stopped and in a station platform. But as the regulator is opened then the magnet would start to pass over the reed switch and at some point set by the arm and the steam port starting to open the reed switch will close and this action takes one of the resistors out of the circuit and leaves only one resistor there by making the LED flicker much brighter telling the driver that the engine is about to move off if the regulator is moved further on.

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This is the finished board with its resistors and reed switch.It fits in the same place as in the Hornby engines just under the supper heater and fixed with 2 screws.

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If you look at the LED which is a 3mm type flickering that the LED has been filed on a slight angle so it can be fitted better in the fire box door way 

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This is the board under test with both the resistors driving the LED so the light is a little dim.

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In the second picture you may just see the small round magnet on top of the reed switch and the LED is much brighter. That covers the control side of the engine as far as the filckering light so hope no problems there so back to the safety valve and pipe work to the tender.

[96RAF]

Fascinating Ken ....

 

Having gotten us sitting on the edge of our seats with the mini-metalwork, now we get to go even smaller with smd resistors on miniature pcbs and tiny actuator arms with magnets. 

 

Good luck with the tender and remaining pipework. We spoke about boiler heat affecting the paint if the boiler was made integral using the tender sides to maximise volume. I just wondered how hot pressurised water gets and what the paint (enamel?) can stand before discolouring. Any Humbrol paint spec experts out there?

 

As an aside - My daughter makes magnetic jewellery and I liberated a handful of those small neo magnets (a pair of which form the clasps of necklaces,etc) for eventual use for track sensors or uncouplers or something. They have a hole in the middle so can be pinned down temporarily for adjustment.

 

Rob

[gowest]

Hi Rob

i have some magnets with holes in too and as you say have very good power Hornby did supply gloves with every steam engine as they are to hot to handle a bit like me! 

if I bought some temperature recording gear I could carry out tests but that all takes time and I want to crack on with the engine but as we haven't got to the tender yet will look at the build then as for paint I have bought one of them tinny 14ml tins of the correct blue paint off the shelf but not Humbrol it is enamel paint but again jumping the gun a bit as still lots to do before we get to that bit.

[96RAF]

I was thinking of one of those infra-red temperature guns Ken.

[RB51]

You've got that right Rob - edge of seat here also. Brilliant. R-

[gowest]

Hi Rob

yes I was thinking the same thing as a gun but might give it a miss as not surewhat we are doing with the tender yet

ken

[walkingthedog]

You've got that right Rob - edge of seat here also. Brilliant. R-

Would you two mind not to keep standing up I can't see. Gripping stuff. 

[gowest]

To all that are following this project

thanks for the support that you post from time to time which does help push me along that bit further but behind ever great man theres a (what i say next i must be caerful) the other half who keeps asking "when will i get my kitchen table back?" so eating meals around bits of steam engine is now becoming a way of life in this house.

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