# BR Fell



## ralphbrades (Jan 3, 2008)

I am absolutely positive that I have started this thread -but I will be damned if I can find it!!!

Anyway -this will detail my attempts to produce a diesel mechanical locomotive in Gauge 3. In some ways this is the prototype locomotive for the highly successful Class 43 series of "Inter City" locomotives still going strong on UK rails after 25 years. The steel plate for the traction chassis and the steel square tube have arrived on my doorstep and so I can start production. Anyone who has read the entry for this loco on my web site will find that research and fluid dynamics calculations have been the main problems so far.

So, here is your official notice that construction has started...

http://www.cabbagepatchrailway.co.uk/fellpic16.jpg 

regards

ralph


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## SteveC (Jan 2, 2008)

Ralph

Model Making'Topic: Just when you thought it was safe...[/b]


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## ralphbrades (Jan 3, 2008)

After some delay caused by domestic priorities, (my son has to choose his Yr 7 school and I have been ferrying the assembled to the various “Open Evenings” at schools that are available). I can now return to building a loco. This Wednesday I plan to order my wheels from Walsall Model Industries. They are not the “correct” wheels for the loco -but they are a fraction of the price of the “correct” wheels. 


The ones I am going to use are GWR ones....


The bogie wheels are going to be the 3 feet 3 inch bogie wheel part number: T1818 and can be machined between 39mm and 44mm. As the size I need is 40.5mm this is well within par. The main driving wheels will be the T1841 casting the size of this is between 49mm and 55mm and is thus a little “shy” of the required size at 57mm, but to be honest it would cause the model to sit 1mm lower, have 2 spokes less per wheel, and at a saving of £60 -I can live with it!!!


I have never worked with cast iron so this is going to be a “first” for me. All the books say to take a heavy first pass to get rid of entombed grains of casting sand and the toughened skin that forms as the shock cooling of the molten iron occurs. It is also in the books that this is going to be noisy, so I have alerted the Domestic Goddess to go out to the Summer House and quilt etc -whilst I am busy at the lathe. 


regards

ralph


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## ralphbrades (Jan 3, 2008)

Well the wheels have been ordered and then steel is starting to be machined to size. The Mill has however done its usual trick of blowing the fuse holder -*not* the fuse.... (I will buy another one from Maplins tomorrow!) As I have written elsewhere both the Mill and the Lathe are very nice pieces of equipment -but the quality of just a few of the components could do with some examining. To replace the fuse holder is not a difficult job -it is however very fiddly and to be honest it not something I feel like doing at the moment. SO, the pieces of steel that have been cut to size are the bogie side plates and just one side of the lower cross member for the central power chassis. The vertical worm shaft will be held in position by the upper and lower cross members. At the top of the vertical shaft will sit the reversing dog bevel system. This part of the drive system is at the “I know how it works -but how do I get it to work?” stage of operations. In theory all I have to do is slide a shaft to connect with a forward facing bevel and then slide it back to connect with the reverse bevel. Thus the shaft still rotates in the same direction but the take off is in one of two directions. The shaft will have to “lock” in a Forward Neutral and Reverse manner. This is going to have to work from a sort of “notched” pyramid shape. The central notch will have to hold the slide shaft centrally clear of both bevels and then lock it solidly in either fwd or rev. All this now has to be interlinked to the pump from the torque convertor so that the pump fills the convertor in the Fwd/Rev whilst it empties in the chamber in the Neutral. Time for some serious brainstorming and an ample supply of tea!!!


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## ralphbrades (Jan 3, 2008)

Believe it or not less than 24 hours after having placed my order (via wife) over the telephone my castings arrived on the front door step held by a very pained looking Postie... The castings are of very high quality and errrm weigh a tonne!!! Well perhaps not that but the larger ones come in at 450 Grammes and the smaller ones at just under 350 Grammes. Since this is a 2-D-2 loco the poor Postie must have had a hernia carrying the crate from his van up the garden path.




















I have the new fuse holder from Maplins -but it is going to have to wait until Thursday Afternoon at the earliest because of domestic commitments. 

regards

ralph


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## SteveC (Jan 2, 2008)

Sounds like the Royal Mail needs to re-institute their physical fitness program.


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## Torby (Jan 2, 2008)

Sounds like the Royal Mail needs to re-institute their physical fitness program.

Ralph does his part for the good of the service.


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## ralphbrades (Jan 3, 2008)

Well over the past couple of days I have been busy, some of it to do with this loco -but quite a lot of it to do with my fettling my sons bicycle.... The next shot shows the Mill with its vice clamping the work piece safely. (D.Ennis Esq please note). The ends of the plates are now “square to themselves” and as far as I can tell exactly square as well!!! The stack of squared off primitives now await the scriber and rule for their holes. 












While this has been going on I have been having a “practice” with one of the wheels. I have never “done” cast iron before and I thought it an opportune time to have a go with it. Having spoken to “them as does” to quote a Southern Derbyshire friend -I changed the jaws of the lathe over to external and then fitted the wheel casting in -nose first(?)












The cutter then passes over the rear of the casting to produce a flat face. This is a vile operation as all the black iron dust clings to any slightly magnetic object and soon the lathe resembles a magnetic iron filings demonstration in 3D.... A few flicks of the trusty paintbrush and things are again visible. The now flat face is needed to clamp it against the face plate, (to be used later). The next operation is to centre bore the casting. The next shot shows the Slocombe fitted to the chuck about to start boring. I have always found the double ended Slocombe drill to be a very strange thing to look at!!! 












But after having done its job of cutting the initial exact hole and pilot through the casting it is time to change over to a more conventional HSS drill and cut through to the other side of it.


The next shot shows the casting with an M6 hole through it. The bolt will be aligned with the centre of the face plate and make “chop and change” of the castings that much easier.












regards

ralph


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## CapeCodSteam (Jan 2, 2008)

Ralph, I look forward to watching your thread


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## ralphbrades (Jan 3, 2008)

*Monday Evening.* All of the Driver wheels have been faced and drilled to M6, there are 3 Bogie wheels still to do and to be honest my “eyes” have gone!!! However I am not displeased with the evenings work and the stink of hot iron chippings has almost certainly killed all the bacteria that may lurk in my shed... I have found cast iron to be remarkably easy to work on -bar the smell and chippings that seem to somehow get everywhere. Do I prefer cast iron wheels to the ones I normally make from steel? 


Well the answer really has to be *no*. 


For ease of machining and gripping in the jaws of the lathe steel wins hands down every time. I worry that pieces of the castings are going to fly off whilst I am machining them. One actually *did* on Sunday Afternoon and although it was not very large, it left quite an impression on the safety shield...


*Wednesday evening.* All of the wheels have been faced and the flat faces bolted together. Some “fun and games” were had as I machined off the casting “buttons”. I had originally intended simply to pass a cutter around the end of the casting and thus cut through the button leaving a ring of cast iron to be disposed of. This worked -sort of... It did in the end prove to be simpler and quicker to knock off the spare cast iron with a cold chisel and then turn the complete wheel as a pair of ends. Something to remember for the future.


The next problem that faces me is the axles for these wheels. I think that I have some silver steel rod of the correct diameter but I have always found silver steel to be very difficult to machine and in this case I think I will have to order some mild steel rod to make them from. The bogie wheels will have to have an allen cap head bolt fitted to the non rotating axle shaft as this is what the floating bearings will be mounted onto (see the NER EE-1 for more explanation). The drive axles will be 8mm turned down to 6mm for the wheels and the bearing for these will be in the horn blocks. Fixing the drive wheels to the drive axle is going to be “fun” as well. My best option is the drill and tap an M3 hole in the wheel boss and then use a grub screw to secure it to the axle. 


*Thursday Evening.* I have begun to prep up the wheels for their finest moment. The first step is the face the fronts of the wheels. The next shot shows a driver wheel in the jaws of the lathe.












The next shot shows a bogie wheel still with its button casting. The axle hole will be enlarged by 0.5mm and then an end mill will be used to cut the “blind hole” for the ball race to fit into.












This shot shows the tread for the bogie wheel being cut on the lathe. This is actually very easy to do as the button allows me plenty of room to get my cutters into position.












Unfortunately the same thing cannot be said for the driver wheels... These have had to be mounted on a coach bolt and then “nutted up” in the jaws of the lathe. This does wok reasonably well -despite the chattering of the cutter. But the main problem is that the jaws have to be tightened up so much that it destroys the thread on the bolt....











regards

ralph


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## ralphbrades (Jan 3, 2008)

Well a few days later and all the wheels have been “roughed out” on the lathe. They are now the correct size for loco the bogie wheels have come out at 48mm and the driver wheels have (just!) come out at 60mm. I will admit to cheating like mad and using part of the button for the flange for the drivers -however I have (mostly) got away with it. There will be a couple of “dings” in the flange edge -but this would have happened anyway with wear.... (he says....) So, at the moment all the wheels are set for machining the flange angle and the coning on them. This means using the one piece of equipment I have for my lathe that I really HATE!!!


This is the Compound Slide.


It is a very simple piece of equipment but for some reason it seems to delight in; fouling the saddle, bashing against the tail stock, or being in such a position that it is impossible to fit the cutter to the work piece, or, (its favourite trick) of being just right to foul the chuck/faceplate at almost the end of the cut...


Here you can see the slide set up for cutting the back angle of the flanges for the Driver wheels.












I have been going through the suppliers catalogues for suitable bearings for my Bogie wheels and there is only one real choice... This is a bearing of the tiny type! It is 8mm diameter with a bore of 4mm and a width of 3mm -as is my norm I intend to get it from Technobots. They stock it as part number 4255-122 at a not unreasonable cost of 65p inc VAT! The load is a little light for my liking at only 395 Newtons -but spread over four bearings per axle it should take the strain. I know the STATIC load would be over 40 Kilogrammes but the DYNAMIC load is far higher. This will mean boring “blind holes” in the Bogie wheels to take the bearings and some “Loctite Green Sleeve Retaining Compound” to hold them in place. I have no idea what that stuff is made from -but it has held together things that I would have never hoped to stay together for durations that I would have called impossible!!!


The bearings for the Driver wheels (part number 4255-182) that will have to fit into the horn blocks are of a similar loading at 1,252 Newtons. Alas they are 16mm diameter which means that I am going to have to unship the 3 jaw and hernia on the 4 jaw and take out the 12mm hole to 16mm with a boring bar. I like the 4 jaw but at 2.5 Kilogrammes is it slightly awkward to “nut up” whilst held up by two fingers and a thumb...


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## ralphbrades (Jan 3, 2008)

Tuesday evening. The work on the wheels progresses and now I have (finally) 8 Driver wheels ready for final mangling... The off set inclined hole for the grub screw has yet to be done and I will admit that I am not looking forward to doing it. I have used this time to experiment and apply my own personal theories.... Well it is my model so I am allowed to. I accept that the standard coning is 3 degrees and all but four of my wheels are cut to this. The outer drivers are cut to 5 degrees as this (I have worked out) will give me “just that bit more” cornering ability -something that I need on my tight curves


The Bogie wheels have come along in leaps and bounds and all that they require doing now is the coning and the flanging angles cutting on them. I have bored the “blind” holes for the bearing on each side of the Bogie wheel. This was a truly nasty operation as the Slocombe insisted on clogging with iron dust and and having to be withdrawn from the work piece and blown clean -thus covering everything (and me) with fine iron dust... Once I had got a lip of about 1mm I could then change over to the end mill and bore down the hole to provide a flat bottom to it. This was very quick easy and (I am told) unbearably noisy!!! I bored in 5mm deep on each side of the Bogie wheel and I decided to take out the centre hole to 6mm while I was there. This will provide a good oil reservoir when I assemble the bearing.


The next shot shows the Bogie wheel being bored with the end mill. If you look at the two bogie wheels on the saddle you can see the bore holes on either face. 












The same procedure is (I think) going to have to be done when I start producing all the carriages and wagons that I will need. Despite “certain persons” claiming that my locos could pull a house around my garden I think that the use of fully floating bearing into my rolling stock will produce a more nicely behaved item. This will mean that instead of relying on the coning to provide the difference in radii (and hence linear speed) The wheels are free to move at differing rotations. This will place more load on the flanges as the steering effect will mostly be down to them -rather than the continuous “sliding down the coning” that provides the additional side thrust to the axle.


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## ralphbrades (Jan 3, 2008)

Now that the wheels are almost finished and the shed is getting rapidly colder.... I have been sat near the cooker in the kitchen working out things from my old text books. I have an old book from the company PIPER FM ltd that has all the formulae in it. I will confess that I am not sure if the company still exists(?) however it does explain the reflection supercharging of a 2-stroke exhaust system -probably better than I am about to! When the exhaust port opens a shock wave travels down the exhaust pipe. As the shockwave expands it slows down and draws the exhaust gasses with it and pulls clean air and fuel with it -hence the first cone section. Then it travels at a speed along the straight section (the length of which is time dependant) when it is compressed by the second cone section and exits the exhaust system. As it exists the exhaust system a secondary shockwave travels towards the exhaust port of the cylinder and pushes BACK any clean air and fuel as the exhaust port closes. This then adds to any shock wave charging from the inlet side of the cylinder...


I hope the diagram below helps to explain!!!












The length of the timing cylinder is dependant on 2 things; the speed of sound and the contents of the exhaust gasses. The speed of sound through the gasses increases as the temperature increases -but (Ha Ha!) not in a linear fashion... The content of the exhaust gasses depends on what is being burnt... Fortunately the book contains three sets of tables from which I can “perm” my exhaust gasses. One table contains Nitro Methane mixes, another Petrol mixes and finally (thankfully) Methanol. I know that what I am going to burn is NOT “Straight Methanol” but this is the only data table that I have -so I will have to use it (and abuse it!)


Based on my design for the convertor I have to pump in figures that will force the system to supercharge at my desired rotation -8,000 RPM I end up with an impossibly big exhaust system with an infinitely thin timing cylinder 48mm wide and the system is 478mm long!!! For obvious reasons something is going to have to “mangled” -seriously. The best bet is to fit the exhaust system with some form of cooling fins to lower the temperature of the gasses and then to force cool the fins. The draught from the radiator fan should do nicely and the fins will provide structural strength, rigidity and something to bolt it all into position with... 


If I can cool my gasses using the coolant water then things become manageable -but the heat still has to be dumped via the radiator. The best bet would seem to use the coolant water from the cylinder head to cool the gasses as they enter the expansion chamber. This would mean using a co-axial tube for the “Header” section from the exhaust port to the start of the expansion chamber. This cools and (more importantly) lowers the speed of sound through the gasses. Curiously enough this does not affect the length of the system -but it does cut down on the width of the pipework and I can now use more “delicate” 15mm pipes.


The Resonator chamber is going to have to be build in sections -or built as a core with end flanges -I haven’t decided yet. Each “chamber” of the Resonator has to be 1.4 times the volume of the previous one -this has to do with the adiabatic modulus of the air and the central pipe is very “flute like” in its construction. There have to be holes drilled in the walls between each part of the chamber that are 35% of the surface area and the whole lot internally “lagged” with some form of dampening medium (probably glass fibre!)

regards

ralph


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## ralphbrades (Jan 3, 2008)

A couple of evening at the calculator and I will admit I had to unearth a teenage “A” level Physics text book that (errrmmm....) never seemed to have got returned to my old school(!) At the end of the maths and the brain creaking with node and anti-node plus reflection and constructive and destructive interference I have emerged from the trauma with the following rather large full scale drawing.


www.cabbagepatchrailway.co.uk/fellpic31.png -this is big drawing!


Now, this is an ideal drawing- and not a real world practical one. I cannot see how I could possibly fit that lot into the loco shell along with the tanks and pumps etc that are already having to be shoe horned into it!!!The first part (going left to right) is the expansion chamber. This is a “Brooklands” type which gets its name from the race track where they were first used. They are very simple to work out, having a 45 degree expansion cone and a 45 degree compression cone. Being a lazy mathematician -guess which angle has a tangent equal to 1.00? Being of a “flat” design rather than conical -this removes Pi as well. The inlet pipe has perforations along its complete length as well as being open at the end. The shock wave then hits the 45 degree end and gets bounced back on itself. The exhaust pipe from the chamber is similarly a length of perforated pipe open at the end. This type of expansion chamber has one serious flaw -it produces the “bark” like sound that is so characteristic of old time racing cars. The resonator chamber is similarly a classical design from a racing pedigree -this time Buggatti... The inlet pipe has perforations on the top facing the curved part whilst the exhaust pipe has perforations on the bottom facing the curved section. Both pipes are open at the ends.


Whilst it is well known that Buggatti came from a background of furniture making -he also liked music...


The five chambers damp out the frequencies generated by the ”Brooklands” expansion chamber. The effective length of each being 1.4 times that of the last. Between each each pipe there are loosely packed glass fibre strands to break up the shock wave and render this to a pressure flow across the chamber.


So far so good. I now need to do some real world investigations as to the exhaust temperature etc of my engine and the water temperature that will result from water cooling the exhaust manifold. Hopefully at the end of the experiments I will have some hard data to plug into my dimensions and end up with a somewhat smaller exhaust system!!! The design is based on a gas temperature of 450 Kelvin and even if I can only knock down the exhaust temperature by 20 Kelvin -I can shrink it by 25% due the lowering of the speed of sound.


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## TrotFox (Feb 15, 2008)

Ralph, 

Find a suitably sized dowel which will slide into your spindle with a reasonably tight fit. Clamp that with the 4-jaw, then go at installing it. The dowel will support the chuck while you have at the nuts! 

Just a trick I learned from the Internets.  


(edit to say If you then re-chuck the dowel when removing the chuck you can leave it in for next time and have it reasonably well centered without much effort.


Trot, the amateur-machinist, fox... =D


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## Torby (Jan 2, 2008)

We call that a "Tuned Pipe." The idea is the shockwave traveling down the expansion part draws fuel/air mix through the cylinder from the crank case, then reflects when it hits the other cone, and shoves the extra fuel/air back into the cylinder just before the piston closes the exhaust port.


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## ralphbrades (Jan 3, 2008)

Work progresses at a slightly slower pace... The Mill having decided to misbehave(!) Despite this I have started drilling the plates for the bogies using the pillar drill. This is slightly more powerful than it requires by a factor of FOUR but it did mean that the drill would not bind and just cut through the metal. Here you can see the plated for the power bogies in the vice.


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## ralphbrades (Jan 3, 2008)

Due to the appalling weather I have been forced to spend a morning (or two) in the shed (shame!!!) Armed with my sticks of “B6” and “Easy Flo2” I started assembling the bogies (of both types). Having unearthed my “hearth” from the shelf I then put the 4mm bolts through the holes and nutted up the other sides -being careful to apply plenty of pencil lead to the thread before I did so... When silver soldering steel I tend to use MAPP Gas -which I like -despite it evil and disgusting smell. The ends of the bolts glowed a nice red and the B6 clung lovingly to the steel and then flowed around the bolt head. Before it could get much further I threw the flame to the next one in line and continued along the line until they were all done. The next step was to change over to Propane and then affix the bolster between the two plates.












The reason I switched gasses and solders has to do with the differing temperatures of melting of the two solders. The cooler Propane cannot reach the temperature needed to melt B6 -thus the bolts remain firmly fixed and will not fall out... The bolster was held in place by the simple method of clamping it in place with a very long M4 nut and bolt (which also held the side plates vertical-ish). I will be the first to admit that I do not like Easy-Flo2, I find it far too liquid -but on the other hand this extreme liquidity is just right for getting into the gaps between the plates. You can see how it has just SPREAD everywhere along the joint -but it has penetrated right through the gap to the other side. So, typically enough for me -the joint is ugly but strong!!!


The next shot shows the rough assembled bogie.












Here you can see the bearings inserted into the left hand side wheel -the stub axle nuts up nicely(!)












The next step of operations is to start assembling the traction bogies. The plates were bolted together as seen below. There were I will admit a few panic stricken moments as I had to really check that I had all the pieces in the right order -not only are there a right and left there is also a mirror positioning because of the fully floating aspect. (Check once twice -maybe again???) In the sure and certain knowledge that if I got this wrong, I screwed it up royally -I hit it with the MAPP Gas and B6.












The product of my labours -a slightly rough collection of wheels and plates.. However I am not displeased with it as you can now see the basics of the loc. This is a first for me as my normal method is to build the bodywork first and then cram everything into it. It feels very strange to look at the naked bogies!!!










regards

ralph


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## wigginsn (Jan 9, 2008)

Great to watch Ralph. Keep the pics coming. 

Cheers 
Neil


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## ralphbrades (Jan 3, 2008)

Well as they say “these things are sent to try us”..... After having drilled all the 5mm holes in the steel tube and located my pack of 5mm pop rivets I duly cranked the gun into the hole crunched up the rivet and “THWUNCCHHH”. “This”, I said to myself, “is not a good sound”... Sure enough it wasn’t. The pin had bent inside the rivet gun and jammed it solid. The next two hours were spent persuading the rivet gun to come apart. However by dint of brute strength, dire threats and main force I got the thing apart and lo and behold the spring had broken. Thus the tension on the jaws was never removed when the barrel moved forwards. I duly replaced the spring with a couple of new ones from my box of bits (where would the world be with a box of bits???) and then in under 5 minutes had the thing back together...


The frame is now ready for welding.The pop rivets will I know melt when the steel welds -but by that time they will have done their job. The next shot shows the rough assembled frame. There are only two really critical measurements that have to be held “true”. They are the centre lines for the frame -the rest of it can be “about there” as most of it will be hacked to fit the components and brackets that will hold tanks and radiators etc












Another thing that I am starting to look at again is the final connection from the gearbox to the drive axle... I had intended this to be a vertical worm wheel to a spur gear on the axle -but this is starting to look increasingly vulnerable to; dirt, grit and the odd piece of herbaceous border plant. My new option is to drive the axle from a toothed belt from above. This does have the added benefit that it keeps all the vulnerable parts of the drive chain above the dirt line and the toothed belt is fairly coarse so muck etc will not really hamper its operation. This will entail producing a floating platform that will move in the same axis as the bogie, (this is not much of a problem!), and a flexible joint that connects the drive from the reversing gear system to the platform which will also be fully floating along with the bogie, (this may require some thinking...) 



regards

ralph


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## ralphbrades (Jan 3, 2008)

Well after a couple of nights sleep, (I have also not been too well -cough cough!), I think that I have most of the new drive system worked out. Everything remains as it was in the original setup -just that the worm dive is now inverted and drives a spur gear above the chassis plate. This is going to require some 4mm pierced plate, (it looks like sheets of “Mecanno”!), to be assembled and soldered into place.


Having returned from the shed covered in Paxolin dust from sawing the base board for the loco I return to my thread. Why Paxolin??? It is oil and water proof, cuts with some difficulty and it is rather strong -plus the fact that I happen to have a large sheet of it in the shed left over from building the Krokodil... The 3mm sheet was duly chopped to 12cm by 64cm and most of the saw marks filed off it. It does not have to look too pretty as its primary function is to be: drilled into, glued to, screwed to and generally abused -during the life of the loco. Its secondary function is: to stop things falling onto the tracks(!)


I have scored a centre line along its length, and now that the base board is there I can doodle onto it the positions of all the bits and pieces -that have to fit there. Some of the shapes for the tanks that I am going to have to build are “not pretty” and I have resigned myself to the fact that both the oil and water pumps are going to have to sit at the bottom of the tanks and be driven by long shafts from overhead motors. This makes the construction of them a little awkward as to examine what the pumps are doing will mean that either I have to make the pump out of transparent material (PolyCarbonate) or I simply “trust to luck” that things are going around as they should do... People who know me know that “luck” is something that I devoutly disbelieve in. However, the innate perversity of situations, the vile nature of happenstance and Murphy’s Law are things foremost in my credo system!!!!


The tanks for the oil and water are going to be a problem. Although I have a 30cm “fabricator” (bend/cut/roll) I have never really used it -other than to make square and rectangular plant holders for the greenhouse. The tanks are going to have to made from Brass or Copper sheet and this then silver soldered together. I have a feeling that I will be fighting over the cornflakes boxes for supplies to attempt my tank designs with. Some of the “joints” are going to have to be hand beaten with a dolly and planishing hammer to get the seams smooth enough for the solder to creep along the joint.


Decision time for the motor is coming.... Do I buy a 0.91cu (15cc) motor or a 0.46cu (7.5cc) motor? The maths says that a 0.46cu motor is perfectly adequate for the job. However I favour the larger motor on the factors that: it being the larger motor it will be less stressed throughout its life and thus never have to get into high rev situations and (being the larger motor) it is Guaranteed to be powerfully enough!!! The price difference is not that much either, £80 buys me the big 0.91cu motor and £65 the smaller 0.46cu motor. Ok it may be £15 that I have wasted, but then I have not gambled £65 -and lost!!! 


Having ordered it over the net the winner was the 0.91cu motor. It is big brutal and honestly weighs a lot. Now that this final part of the design is in place -but where do I put it??? Delivery will be in the first week of December 2010 and probably by that time the shed will be too cold to sit in for any length of time and static engine tests will have to be done in the lee of the kitchen door -despite pleas of the cold draught coming through the open doorway....


After running in the motor the first job will be to accurately measure the heat generated by the cylinder head by means of a constant flow calorimeter experiment. This was one of the “nightmare” experiments of my “A” level physics years. Measure the temperature of the cold water going into the electrically heated calorimeter and measure the temperature of the water coming out of the calorimeter. Measure the flow by counting the number of drips per minute. However adjusting the flow of the water to get a constant drip rate across the device was the nightmare. However with a home made pump the rate of flow can be adjusted with rheostat(!)


regards

ralph


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## ralphbrades (Jan 3, 2008)

Due to the famous English weather it is now the weekend and I have still to set rod to steel... Somehow rain and arc welding is not a good combination. So I have been shopping for the gears and cogs that will form the basis of the transmission side of the loco.











The small 12 tooth spur gear is the “output” from the front reduction gear chain of the torque convertor. This then drives the 60 tooth spur gear to which is coupled the first of the four bevel gears. These form the fwd/rev mechanism and the output from the bevel directly opposing the 60 tooth is then fed via two U/Js (not as yet bought) to the worm gears. The worms then turn the 45 tooth gears which drive the 10 tooth cogs and then via chains drive the 20 tooth on the axles. The chain is of the self assembly type and four sections are required to be assembled to produce one “link” in the chain. As my wife said “this is something for long cold winters evenings when there is nothing else to do”.


The first bevel is bolted to the 60 tooth by four M2 nuts and bolts and the hole is enlarged so that it sits on a length of brass tube that slides on the output shaft -but does not grip it. The “cruciform” bearing for the other two bevel is (I think) going to have to be made from some scrap Aluminium bar that I have.


Hopefully tomorrow will be drier(!)

regards

ralph


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## ralphbrades (Jan 3, 2008)

OK. Having sat down with a pot of tea some serious brainstorming has had to be done... As far as I can tell EVERYTHING has to be linked to the main servo that controls the throttle. I need at least two “takeoffs” from the same channel. The throttle linkage has to operated via an eccentric thus regardless of the direction that the servo turns the throttle cable is still pulled. The next bit is I am afraid -simply weird.... I have a duplicate servo that turns a series of cams to micro switches and on the side of each of these there is a sector plate with contacts. Hopefully the drawing below will explain some of the madness.









regards ralph


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## silverstatespecialties (Jan 2, 2008)

Fabulous, Ralph! I learn more from your posts than I could from any of the engineering books I have collecting dust on my bookshelves. Thank you for sharing!


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## ralphbrades (Jan 3, 2008)

Monday Morning... Well it dawned bright and dry and I was hopeful of finally getting some welding done. I unlimbered my workmate, clamped the frame into the vice and put my foot on the trigger plate. Then the mains power in the house went out and the burglar alarm sounded... After having reset all 16 of the RCBs(!) I dug out my trusty black “smiley” model 8 AVO and put the probes across certain terminal taps. The windings in the transformer core had broken and there were at least four taps that shorted to the PE connection... My much loved green Oxford was now 25 Kilogrammes of oil filled steel and copper scrap. I should not really complain. It was after all older than my wife. How it came out of the BREL works in Derby I have no idea, but it was fixture of my childhood and we all learned to weld with it -even my sisters...


So after a little research on the net and a nibbled credit card I will have to get a new one -probably from “Machine Mart” as they are practically next door to the school where my son has his extra-curricular lessons. So it will be dump the child and then dump the welding plant into the back of the car and then position it in the shed -just in time to collect the child....


Monday Evening... Well I have a nice shiny new welding plant which is going to have to be classed as my Xmas present to me! It is a nice shade of red, which my wife finds visually more pleasing than Hammerite Green. But she is still not too sure of the 400V connection plug! Tomorrow I will start (hopefully) to use it with avengence. Some of the parts are riveted into place and require seam welding and others will require “persuading” to stay in the right place whilst I hit it with the rod. I do have a few NIB magnets that can be used to hold the steel pieces in position... These have the added advantage that they have a very low Curie point of 80 degrees Celsius. At higher than this they cease to be a magnet and will drop off the hot metal. I used them this way some time ago and although it worked perfectly, I did have to lever off the NIB magnets from the steel toe caps of my protective boots...


Tuesday Morning... Well everything worked bar the expected problems of the learning curve for the new plant. The dial indicator is only a “judge” rather than the “specific” taps of the Oxford. So I started off with around 60 Amperes and worked up to what the indicator on the slug said was 80 Amperes. At this point the arc held true and steady as it would have done on the 60 Amperes tap on the Oxford. The welding is rather messy, even by my standards -but it does hold everything together.


The central strap for the traction bogies has been unified with the transverse pieces of square section tube steel and then the hole lot joined to the rectangular frame. I did not in the end bother welding up the end pieces as they seem to be quite happy with the rivets. The next step is to dig out the angle grinder and make things look pretty prior to paintwork. Yes -it is going to be Hammerite green. Well I have to use it up somehow now....



regards

ralph


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## ralphbrades (Jan 3, 2008)

Tuesday Evening... The rolling chassis is now complete -all I have to do is power it!!! The leading and trailing bogies have been positioned with their M4 pins and arms -but the transverse tensioning with springs to force them into “guiding” the loco has not yet been fitted (or even worked out!) The traction bogies have had the M6 bolts that are their pivots welded into place at the bottom of the U. Slight “adjustment” will have to be made to ensure that they sit perfectly vertical, (pass the hammer). The sheet of Paxolin has been drilled and bolted to the frame -it awaits daylight for the rubber grommet treatment, (my eyes have gone!) The chassis has been tested on the sharpest curve that I have and nothing binds. The tensioning spring between the two traction bogies may be a little weak for the job (?) but it provides enough tension to force the traction bogies back into alignment after exiting the curve. One of the most annoying aspects of the day was the discovery that my nice beautifully machined cast iron wheels where now starting to to show slight but definite signs of RUST. Time to move the chassis out of the shed into the warmth of the kitchen...












Wednesday Morning.... I should have moved the model into the kitchen last night(!) The temperature in the shed fell over night to minus 2 degrees C -thus the steel of the model was “sticky” to my fingers and quite frankly painful to touch!!! So, after having disassembled the rolling chassis from its curve I moved it to the piece of board on the cooker to warm up. I dutifully covered everything splashable with pages from The Express, I dug out the first pot of primer that I reached. Typically enough it had this nice crust on it -of ice... More tea! Once the paint had thawed I stirred it and slapped it on. I does look rather more attractive in the photo than real life. The nice red colour dries to a mud brown. But since the last loco that had to be primed prior to painting ended up a fetching shade of beige when it dried -I don’t think this really matters as it will all be dark green soon.











regards

ralph


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## ralphbrades (Jan 3, 2008)

As the motor is due sometime in the next week, I have sat down and begun playing with pieces of cardboard to find out where everything will sit. Breakfast food cartons are cheap(ish) and they take several rubbings out before I wear a hole in them(!) What the cardboard cutouts have shown me is that the area that I have to play with is even smaller than I thought. Some of the gears are going to have to be mounted directly onto the sheet of Paxolin and I plan to use the 4mm perforated steel strapping to provide the spacings for all the gears. Once they have been secured then I simply bore through the holes in it into the Paxolin and everything is rigidly mounted (hopefully!!!) 


The nasty that has arisen is the expected problem of changing gear...


I had hoped to be able to do this with just one set of dog bevels but no matter how hard I fiddle with the layout I end up needing two sets... Likewise I was originally using one solenoid -but now I have to have two.


But, all is not doom and gloom as it might appear. This does make the solenoid a simple pull-pull fed by a DPDT relay. The gear shift will resemble a slotted plate that is pulled forward and backward by the two solenoids -not unlike the standard set of points motor used by my son’s Hornby.


The cardboard also reveals the positions of the tanks -and it is not a good one. The shapes that they are going to have to have are dictated by the volume that I need to store in them and the pump that is going to have to sit at the bottom of each one. The tanks are going to have to sit towards the radiator end of the loco. This was rather expected -but it does produce plumbing problems. The torque convertor will require a drain back to the tank -this means that the drain will have to exit above the surface of the oil -it will do this via a “Swan Neck”. The pump will pressurise (slightly) the torque convertor and there is the “environmental problem” of an oil leak. This also means that I am going to have to figure out some form of oil seals for it.


“How do I start the motor?” is another problem starting to rear its head. I have a plan in which I extend the motor drive shaft out past the end of the torque convertor to a hex end. This connects to a battery drill fitted with a over run coupling. The idea is that I power the drill and the motor starts. The Glow Plug will I feel be of the “permanently live” type, in that it will have a current running through it all the time. 


Normally Sunday Morning and Afternoons are times when I am very productive -however due to the incredible cold snap that we are having this means that I am keeping warm in the kitchen -so work will slow down -but it will be nice and warm....


This particular Sunday Afternoon was spent in the kitchen on the floor mat -near the cooker... 


I did some trials with the positions of gears and shafts. The first shot shows the initial trial on the piece of Paxolin.












The next shot shows the provisional working arrangement. This is not as “elegant” as I would like -in fact it could be quite difficult to service. However, I feel that this is the correct arrangement for the system as it can be manufactured in modules and then “layered” together. Moving the worms towards the centre of the model allows me to fit a larger gears to the “input” shaft.











regards

ralph


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## ralphbrades (Jan 3, 2008)

Wednesday 1st December 2010.... Possibly the most successful day ever with this model!!! Although at least 25cm of snow had fallen over night and the outdoors was in the less than balmy temperature I set to work on the kitchen floor. The previous night I had completed drawing §4 of the gearbox and miraculously it seemed to fit al the parts into the right places and nothing clashed (too badly). Braving the cold I stepped out into the white wilderness and retrieved my set of marking instruments and made some hot tea!!! Well this shot shows the the §4 drawing and the transcribed positions on the sheet of Paxolin bolted to the frame. Drawing in 16 pretty colours is normal for me -a 0.3mm felt tip is more transportable than a Unix workstation running AutoDesk...












The next shot shows the progress after a couple of frustrating hours. I had to chain drill the slots with a 3mm drill and then “pick” the chains apart with a floor board saw until there was enough room to get a proper saw in there. I had to smooth up the shape first of all with a Rasp, then a ******* file and finally a half round to smooth it all off with. Paxolin dust of course went everywhere and “Henry” spent quite some time sucking up the mess... Cutting the final slot for the central gear was I admit risky. I nearly cracked the sheet twice -I am going to re-enforce it with some transverse hard wood strips later.


I drilled out the gears to 4.5mm and inserted a CA’ed length of K&S brass tube -giving me a 4mm bore to the grafted gear made from a bevel and a 45 tooth spur. Whilst the CA sets hard over night the grafted gear will then be drilled and pinned in the morning. These stand on M4 bolts that fasten through the steel frame and emerge onto the Paxolin sheet. The central 60 tooth spur gear was fitted to its 4mm shaft and the two worm gears duly bashed along the shaft until the hit the right position, There will have to be a further bracket and ball race besides the gear as the only supports are at the ends at the moment.- and you can just bet the thing will wobble madly without it... All the raw brackets are going to be drilled to take M10/4mm bore ball races.












The next two shots show the rough assembled final drive and reversing system.


The blue self assembly chain on the small sprocket is obvious as it vanishes through the slot to the large sprocket on the outer drive axle. The dog bevels are on the shaft and (hopefully) you can see how moving them along connects first with one side and then the other. 












This shot shows how the input drive from the torque convertor reaches the central gear. The grafted gear JUST misses the shaft by 2mm and the 20 tooth gear drives the 60 tooth gear cleanly.












After some discussion via “chat” I have taken the advice of a friend and purchased the 0.46M motor as “thats too big an engine for a toy train” so we will see... The big motor 0.91M is special order -but the 0.46M is an off the shelf part. I wonder which will arrive first?

regards

ralph


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## ralphbrades (Jan 3, 2008)

Well the snow still falls so I spent the day in the kitchen. First job of the day was to strip off all the test stuff from the Paxolin sheet and dig out my bow saw and start sawing up the framework for the gear box. “Why Wood”? I hear you ask -because it is nice to work with and quick!!!


I drilled out the brackets to take the bearing -rather painfully having to “wind out” the hole from 5mm to 10mm a millimetre at a time... I have found it is better to be bored than to twist the bracket. The next shot shows the worm gear with a bracket and bearing. the basic framework for the reversing “Ballista”(!) can be seen in the top right.












This shows it all far better. The throw arms sit either side of the central gear and the whole thing is assembled with “Croyd Aero” and then bolted and glued to the Paxolin with epoxy. After 2 hours I could start again. It may be me but I have found the slower 2 hour epoxies to be far stronger then the 5 minute ones(?)












The next shot shows the first assembly of the transverse shafts. The brackets are bolted in place and the dog bevels “tapped” into distance along the shaft. This is tooth plus 4mm -so the “shot” from the Ballista is 6mm in total.












Ok -over head shot. You can see the third bearing on the central gear -this should remove any wobble from it (please!)












The next shot shows the end of the days work (and my eyes have gone too -So I have had to use AutoFocus... I need to ream out the small sprocket to 4mm and start trimming everything to size. I will admit that it has been a very rapid couple of days progress!!!










regards

ralph


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## SteveC (Jan 2, 2008)

Ralph

Just wanted to say thank you, for taking the time and expending the effort to document your undertaking. It really is very informative and helpful in following and understanding what and why you're doing things. I believe it goes a long way in bringing others along and gives them confidence in trying something similar.


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## ralphbrades (Jan 3, 2008)

It is still snowing -so I am back to work in the kitchen (what a shame!!!) The first thing to do today was to construct the gear shift arrangement. This, as I have said before, uses the same mechanism as a set of file cabinets. The slide is made from a 3mm bolt (suitably filed) and a length of U section brass. These were then silver soldered together -they will never come apart (which is how I want them). These now form the Pin Slide that transfers the longitudinal movement to transverse movement.












The next shot shows the pin slide with ABS sheet CA’ed to it to act as a lubricated channel. The top of the slide is not flush with the arms of the ballista. You can see the collets that will take the thrust bearings for the transverse shafts.












This is the base plate. The shape of the slot does not really matter as all we need is a line between the extremes of shift. The function of this is to hold the pin slide in its groove. A little CA holds it in place whilst I drill down through the arms of the ballista to hold the M3 nuts and bolts.












This is the top plate. The nice sections of L brass provide the smooth direction -regardless of the dire nature of the hole that they are covering... They are held together with a little solder and an M3 bolt is used to provide an accurate line between them.












The completed top plate. The slot can now be trimmed up with a needle file until the hole at the bottom of the plate matches the slot provided by the two L sections(!)












The reach rod is at the moment rough cobbled from a few lengths of wood (see above!) it has a 60 degree slot and captures the pin thus pulling and pushing it across...












This shows the completed ballista gear change system. The pin has been fitted with a cross arm to push and pull the shafts. The reach rod is held flush to the back of the gear change with a simple spring loaded shoe (a length of bent brass strip). One of the quirks I have noticed is the fact that the gear change is “upside down” -ie moving the reach rod forwards engages reverse... The pencil marks on the reach rod indicate the positions of Fwd and Rev.










regards

ralph


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## ralphbrades (Jan 3, 2008)

The last day of building before the seasonal madness...I trimmed a spring or two to get the correct rating to hold the pin against the reach rod and then press the pin into the capture slot. Too strong it made the pin act like a brake -too weak and it didn’t force the pin into the slot. So, after taking a too strong spring and slowly snipping off a quarter spiral at a time -I got one to work!!! The screw and swing flap will be replaced in the final version...


The next shot shows the completed ballista with the two “selector forks” I suppose I should call them(?) they are simply U channel lengths of brass with an M3 bolt silver soldered on to them. These sit on the shafts and push/pull the collets.












Ok -the glossy shots!!! Pulling the reach rod pushes the pin out, the ballista pulls the shafts across, locks it in the out position and the left hand bevels engage with the grafted gear.












The final shot shows the reach rod in the reverse direction. The custom tuned spring forces the pin and shafts across and the pin is captured by the slot and rammed home into the locked position. The right hand bevel gears now engage on the grafted gear and the loco reverses...











Q.E.D. (!)


The next problem is to transfer the filed and twiddled length of wood that is the reach rod into something made of brass. I have decided to ditch the idea of a solenoid and spring and simply have two opposing solenoids switched through a relay. Now that everything works it has to be taken to pieces and fettled into a reliable working device... 


regards

ralph


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## ralphbrades (Jan 3, 2008)

This Sunday afternoon has been devoted to the cooling side of the locomotive. I scoured the junk draw and extracted an XP1700 heat sink and fan. I know that I said I was going to construct a tube one -but this is a quickie. I am proficient at liquid cooling computers -so why not use the same techniques to cool my loco? The next shot shows that fan that has been grafted to the Paxolin sheet. 












More words were uttered as I had to cut a circular hole through the Paxolin by chain drilling it. But it fits nicely. The next step was to measure where the “exhaust” from the heat sink/heat exchanger would vent and then to cut a suitable hole in the correct position. This was then layered with Dacel Plait to act as a grill. The loco is symmetrical and there are similar aero vents at the other end -this is more for show than anything else. The central hole is there because it is there on the original(!)












The modifications to the heatsink are as follows: I drilled 3.5mm holes through the base and then drilled 3.0mm holes cross ways to form internal pipework. Into this I epoxied a length of 3.5mm copper tube. The hole lot is then topped with a 2mm thick sheet of ABS this too is epoxied to the heat sink. I now have my thin film radiator. The next step of the operation is to drill and tap M3 into the heat sink through the ABS sheet. I then slap on top of this a sheet of polycarb -this will enable me to see the liquid flowing, (or not as the case may be....)











regards

ralph


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## ralphbrades (Jan 3, 2008)

The 0.46 motor has arrived...










This is going to fit (just). The motor will be inclined at 45 degrees to enable the user to get at all the parts I need to.

regards

ralph


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