West of Scotland Group's "Starters" Build a loco project

[Russ Elliott]

Concerning the Crank pin throw jig,

The U section of brass can now be soldered into the end of the square tube at A making sure all is square.

Where is 'A'?

Now fit and solder the square end piece in place and fit and solder spring and spring plate in place, ensuring spring is under pressure. This is just insurance to stop the crank pin gauge slipping out during operation.

I presume the spring is in compression? What is the actual implementation of this spring - a bit of wire? I don't understand the function of the spring during operation.

[Allan Goodwillie]

Hi Russ

Thank you for reading the material I am putting up and asking for clarifying here and there, it is most appreciated having a second pair of eyes. I have gone back and reworked the diagram which now has the letter "A" in the correct place.

You are right about the spring being in "compression" and I have made that clear as well. The spring material could be steel sprung wire or any other springy material for that matter, I have used a scrap strip of springy nickel silver sheet. The only purpose of the spring and plate is to make sure that the sliding section holding the crank pin bush, is not too slack, as once you set the jig for the first wheel, you want that setting to be constant for the other wheels in the set. It may not be completely necessary, but I like to be sure that there has been no movement once set.

Allan

[Russ Elliott]

as once you set the jig for the first wheel

How is the jig 'set'? Do you clamp or lock the sliding crankpin section in some way?

U-channel 4mm x 4.5 mm. To be a sliding fit in square brass tubing 4.5mm. (specify sliding fit, when ordering)

Sounds like this needs a rummage at the Finney & Smith stand to get a suitable matching pair. On a brief perusal, I can't see a 4.5mm hollow square section across flats yet from their catalogue, nor from Eileens. I might have a look in the shop this afternoon to see whether there are any suitable imperial pair fits from K&L.

[Allan Goodwillie]

Hi Russ,
I am going to show how each of the jigs work in the next section as I will follow the build of two sample 0-6-0 chassis. The chassis are near complete and I am sorting out the photographs this morning and adding text. I hope to get it up this weekend, if possible. The reason for the jig, like the other jigs is to make sure that all components are accurate in their relationships to all others and are consistent, using the minimum of measurement.

During the war my father designed jigs for making aircraft production, which allowed sometimes complicated processes to take place in the hands of unskilled production workers without any engineering skills. The quality of production was dependent on them and allowed swift assembly.

The essential relationships here are the correct distance set for the crank pin throw and the parallel relationship between axle and crank pin and their eventual relationship to the wheel rim. It may not be clear at the moment, but it will become clear, I hope, as we go along.

Allan

[Russ Elliott]

Allan - yes, no problem, fully understand that the jigs' 'how to' will be revealed in due course, and it is difficult perhaps in a thread like this to proceed in proper order without having the odd diversion or two or a premature 'jumping ahead too much'. Such is forum life. And please, don't feel the need to hurry to post new stuff up - I'm enjoying this thread, and a day or two of cogitating is a pleasure.

Anyway, at the risk of giving you a bit more grief, could you post a larger pic of the quartering jig when you get round to describing its use, because I'm not too sure about the blue and yellow bits and exactly how the axle rests in:

quarteringjig-detail.png

[Allan Goodwillie]

I will do no problem Russ,

as I say this is all very useful. I do realise in all my years teaching, that things are not always clear on first reading, but this is one of the joys of the 4um, as against reading a book on the subject, in that, you can make direct contact and clarify things. pictures of the parts and assembly of this jig will be forthcoming I promise.

I also know, as a number of people have contacted me via email, that some are planning on doing a download of this and print it out. I have been giving a bit of thought to this and I will ask Keith if it would be possible, at a later date, to assemble all the main elements ( I am quite happy to do this) and upload them in a separate place so that they can be downloaded in a nice clean form with any updates etc. and without all the asides.

Allan

[grovenor-2685]

I have been giving a bit of thought to this and I will ask Keith if it would be possible, at a later date, to assemble all the main elements and upload them in a separate place so that they can be downloaded in a nice clean form

Allan,
That won't be a problem at all.

As an aside Bill Bedford does a quartering Jig that looks very like yours. I have been using it successfully, I'll take a picture next time I have the camera out.
Regards

[Allan Goodwillie]

Thanks Keith, that's good to know,

The quartering tool or the one I use, was based on one I was shown made by Jim Pugh during the early 1980's. I have no intention of taking anyone away from buying any commercial item, especially that good fellow Bill, who produces very fine products, Bill's wire bending Jig can also be recommended and I will be recommending it at a later date myself. I am not expecting everyone to make all the jigs themselves, although it will get beginners making things, some may wish to purchase some of the articles if they are ready made, it is a case of cost vs. time.

Allan

[Julian Gascoyne]

U-channel 4mm x 4.5 mm. To be a sliding fit in square brass tubing 4.5mm. (specify sliding fit, when ordering)

Sounds like this needs a rummage at the Finney & Smith stand to get a suitable matching pair. On a brief perusal, I can't see a 4.5mm hollow square section across flats yet from their catalogue, nor from Eileens. I might have a look in the shop this afternoon to see whether there are any suitable imperial pair fits from K&L.

Does the U-channel have to be 4mm x 4.5mm?

Eileens do 4mm x 4mm U channel (approx 5/32nds I think). So that might be a sliding fit inside either the 7/32 x 7/32 or 1/4 x 1/4 square brass channel that they do. Would these sizes be suitable for the jig Allan?

Also re: the 8BA threaded rod, Eileens doesn't list any imperial studding but does have metric. So would M2 do instead?

[Julian Gascoyne]

2 x 180mm. Lengths of brass strip 1mm thickness x 5mm. width

The diagram shows brass strip 5mm x 2mm thick. I guess the diagram is correct?

Julian

[Allan Goodwillie]

I have checked the dimensions of the material used on the U channel and also the square brass material. The U tube is 4mm x 4mm and the outside dimension of the square material is 4.5mm x 4.5mm with an internal dimension of 4mm x 4mm. I have only bought material from Eileens - (metric) or from the brass section range - imperial from K&S Chicago. As long as one is a sliding fit in the other, other sizes would work. You don't want sideways slop. There has to be clearance for the bush and axle.

M2 Threaded rod , nuts and washers, will also be fine. The strip can be almost any thickness so 1mm or 2mm is fine as it is used purely as a guide for the aluminium angle. Whatever comes to hand will do fine as long as it is straight.

I am coming to realise that it is probably better that I answer queries at the end of each day, rather than try to do them as they come in, hope that is OK by you fellows.

Allan

[Allan Goodwillie]

Before we begin

Organisation

How to organise the workspace with a few simple ideas to make things go better.

You may be limited in your workspace, so how do you work without tying yourself in knots? Here are a few simple suggestions.

Each time I start a new engine I collect all the pieces I need and put them in a flat box so that I know that I have all the parts needed and they are all in the one place. When I finish at the end of each session I put them all back there and tidy up.

My mate Jim Summers maintains that all the space needed as a work area where the actual work gets done is about the size of a large tray. The photograph of my workbench would seem to suggest that that also applies to my work area.

I have an area I use for laying out items ready for assembly as well as an actual assembly space. This helps to keep everything organised, as it is obvious what work is ready to be done, so if called away it is easy to see where you are, when you resume work. Notice the chassis and their parts being worked on.

Allan

[Allan Goodwillie]

Although my workbench looks busy I have a number of little boxes filled with expanded polystyrene where I keep all the tools used regularly. I also have a magnetic bar where I clip my pliers and cutters and a couple of tidies where I also keep tools that I only occasionally use. When I use a tool I try to put it back to its original position rather than have a pile of tools to hunt through – try to get into good habits – it does save time in the end. A few tools out at a time is normal, but a short tidy every hour will keep you organised. Nothing too swish here, but it works.

Allan

[Allan Goodwillie]

I have a number of what people would deride as scrap bits and pieces, which I use regularly. I have a wooden block with two pieces of strip wood at right angles along two edges. On the top surface I put temporary pieces of thick card. This along with a G clamp is very useful for holding metal sheet being drilled or right angles to be soldered etc. It can be turned upside down on a vice for soldering up. Yes it does get burned and cut, but is movable and it does mean that your bench takes less damage.

I also have a block of balsa wood, which is for temporary lash-ups where I pin components together to allow hands free soldering. There are other small blocks of MDF, which I use regularly to support and prop things up in a temporary fashion. I also have a pair of helping hands which my dear wife bought me as a small present , I do find them useful especially to hold a chassis during testing, while I run power through the motor.

I have made a wooden V block that fits into the vice for cutting and I have two vices, one (large) for really rough work and a (smaller) machined vice – looking a bit worse for wear around the edges, but it still has good mating surfaces.I also have the centre of the vice marked for reasons which will become evident as we go on. Sometimes I use the two vices together, which allows me to turn the small vice using the rotary base of the larger. It also gives extra height off the workbench, which can be useful sometimes. Nowadays you get some really lovely modellers vices that allow you to hold things at a multitude of angles. I really must get one sometime.

There are areas set aside for a couple of regularly used tools - saw, drill, etc and a set area for the soldering iron and flux and solder.These are all on my right hand side as I am right handed. Stops you having solder on one side and flux on the other with the work in between. I have a lamp and magnifier, something I regard as essential and cocktail sticks, as well as, little clamps (I think sold as heat sinks, crocodile clips would also do the same jobs)

I work with a towel on my lap, preferring that to wearing an apron. When I was a student at Art College I did silver work and our benches had a semicircle cut from them and a leather sheet draped across the cut out. This allowed you to rest your elbows as you were working and the leather caught anything that may fall on your lap. I have never in all the years managed to get around to making such a bench – shame on me, but I do use the towel. It is amazing how small items fall to the floor to get lost in the carpet without it, with consequent loss of modelling time.

I like music and have found that useful to set a working mood. My friend Richard Chown who also has a good working habit told me that he has a system in that, even if he does not feel particularly like working on something, he still makes the effort to go into his workshop at his set aside time and starts on something. If after 20 minutes he does not feel like its working, then he accepts that, and goes and does something else instead. He reckons that most times he finds it is rarely he can’t get into ”the mood” within this time.

Allan

[Allan Goodwillie]

A general look at building chassis

I have built many different types of chassis in many different ways and have come to a number of conclusions over the years, which dictate most of my locomotive building nowadays.

There are always new ideas coming along and I would not want to put anyone off trying any of them, doing something just for the hell of it and trying new things is something I do myself, but what I am hoping to cover here is very basic, but should give success. Purely for interest, here are the basic principles, which I work by.

Basic principles ( in no particular order)

Build everything so that it can be disassembled easily if anything should go wrong, it also makes for easier painting, it will not take longer and in fact will save you time and frustration
Build in an organised way using sub assemblies
Use jigs where possible to speed up building
Check construction at all stages for consistency
Test components work correctly before and after fitting
Build with a degree of refinement, but not if it compromises robustness or operation
Assemble where possible by soldering or nuts and bolts only, glue when it is the only option
Work from accurate information, learn from others who have had success
Set your parameters and work within this - know your minimum curve (My Pacifics and 2-8-0’s have to be able to get around a 38’’curve)
Allocate time according to difficulty of the processes and do what you can when you can
Use appropriate tools and materials and proven components
Work safely and continue to tackle the more difficult bits - resolution!
Final finish is more than engineering
Care at all stages – take nothing for granted especially manufactured components
Keep it simple the more complex the more that can go wrong, good design is deceptively simple
Enjoy it – it should give pleasure, take heart from your successes

This is probably the only design geekery you are likely to get out of me
Allan

[Allan Goodwillie]

Cutting out

The material I am using for the two initial chassis is 10 thou Nickel silver half hard sheet. Normally 15 thou is recommended for general building, but 10 is fine. Both can be cut using scissors and a knife, 10 thou being easier to deal with. I believe 8 thou is now available which will be even better for rolling. Brass is softer at these generally but can also be used. It has a slightly greasier surface for working and tends to be softer and more likely to take a bend. 15 thou is still fine but I would recommend using tin snips for cutting, with a little gentle flattening with a hammer covered with a piece of thick cloth or leather to keep the surface right. N/S is a better material to work with and worth the extra cost. It also cuts and folds cleanly using a knife which makes things quicker and rarely requires any straightening, unlike brass.

I made a check at this stage with the drawing in front of me that the motor / gearbox would fit by placing it on top of the drawing. If I have downloaded a gearbox and motor combination drawing, then I would use that just to confirm that it will fit before cutting out.

I started by sticking the drawing on to the back of the N/S sheet using double sided sticky tape from the pound shop 4 rolls for a pound.

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[Allan Goodwillie]

It is best to divide up the sheet initially into one or two manageable pieces. To do this, like most modellers, I use a scalpel or Stanley knife , steel ruler and cutting mat. When cutting do not try to cut right through in one shot. Three or four scores then snap the material is best.

Always work away from your holding hand

There are many ways to snap the material - place the line to be folded along the edge of the workbench , place a ruler along the edge to clamp it in place and gently fold along the edge a bit, then a bit more all the way along then repeat again until the material is well folded over as in the illustration.

Smaller pieces can be folded a bit at a time using the jaws of the vice, again don't try to fold over to the full angle all at once, start at one side and fold a little and then move the metal over in the vice and fold again and again until you reach the other side of the material then work back and bend a little more - be patient and you will find you get an even bend across the full width of the material.

Fold back as far as you can go and when you start to fold the other way you will find the material will snap cleanly along the line.

I wanted to cut out the chassis sides at this time as well as cut out the footplate which also contained the spacers. If you remember,in the drawing, I had arranged the chassis sides so that they would form a mirror image joined along their top edges and used the wasted space in the centre of the footplate to give me my spacer material - logical if you think about it.

Do not separate the chassis sides at this stage they should be folded along their top edge to allow for drilling and cutting prior to separation.

Allan

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[Allan Goodwillie]

Here are all the parts separated and ready for the holes to be drilled out. Drilling will be done on a wooden block and care will be taken to drill each hole with the correct size of drill. It is worthwhile going over the hole positions with a centre punch and small hammer. Do not be too heavy handed. Drill the larger holes with a small drill first as a pilot hole will help to stop a larger drill wandering off. Remove any rough edges from the holes and the cut edges using a fine file or wet and dry paper - keep to the lines as marked on the drawing , do not take off any more material than is necessary

Handrail knobs, handrails, brake supports , smoke box door handles 0.7mm drill
Compensator 0.9mm drill
Axle holes, coupling holes, 1.5mm drill
Buffer centres 2.0mm drill

The 1.5mm drill for the axle holes may be a surprise, but we are going to set the coupling rod jig directly from the drawing attached to the chassis metal.
Allan

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[Allan Goodwillie]

Some parts need the "V" block and saw to cut them out. It is worthwhile drilling holes in strategic positions to allow for the saw to take different directions. Pass the piercing saw blade through one of the holes and place the metal in such a position that the blade is right in the "v" and the metal is well supported.

When choosing a blade make sure it is a fine one. The thinner the material the finer the blade as a general rule. If you run out of fine blades, try cutting the metal with a piece of thick card underneath, you will find this works and stops the blade chattering against the thin metal. If a blade should break, if you have an adjustable piercing saw you can still use the larger part of the remaining blade. The adjustable saw is also easier to keep in tension using the upper adjuster to place the blade under tension.

Allan[attachment

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[Allan Goodwillie]

Dealing with awkward pieces when cutting from the main sheet or separating strips from some shapes can be tricky.

Here the chassis has to be separated from two strips that are needed for the body later. It required cutting using the saw up to the line across, then scoring and bending in the vice to remove. This way the parts came away cleanly without distortion. Using several holes here and there can also get around awkward shapes. This technique was required when the other parts were cut out from the sheet later.
Allan

[Allan Goodwillie]

Before cutting out the horn block spaces I like to check that the drawing fits the components. I place the fixed bearing plate on to the drawing and check using a steel rule that I have my cut outs correct. You can use a fine line pen and a square to mark them more clearly if you wish at this stage. I make the verticals at right angles to the footplate / top of the frame, which I use as a datum line when making a model. A simple drawing square is fine for this.

If using the MJT blocks, then the simple bearing plate, when fitted to the rear axle spacing should have a slot cut from the bottom of the frame to allow the rear axle and bearing to drop out.

Note In the case of the sprung chassis the rear axle will pass through the frames using brass bushes, this means that you will have to drill a suitable hole for it using the pilot hole already driven through the material. When cutting out, the hole should be slotted in from the bottom of the frame to allow the bush and axle to drop out. When you get around to cutting out the other spaces leave the line on and using a fine flat needle file and your vice, file down to the lines very carefully.
Allan

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[grovenor-2685]

Anyway, at the risk of giving you a bit more grief, could you post a larger pic of the quartering jig when you get round to describing its use, because I'm not too sure about the blue and yellow bits and exactly how the axle rests in:

quarteringjig-detail.png

Excuse my just going back to the quartering gauge for a moment, I have managed a couple of pics of the Bill Bedford version. Not expensive and would save some building time.

Quartering-18m.jpg

Quartering-21m.jpg

Only problem is that the when drawing the etch Bill assumed crankpins of zero thickness, so you don't get an accurate 90 degrees, but you do get all the same. This could be fixed with a few file strokes and will be before I use it again. (It became a lot more obvious in the photo session ).
Regards
Keith

[Allan Goodwillie]

Thanks Keith for illustrating the Bill Bedford sample.

I checked my own gauge and it is 90 degrees as well, but I won't be changing it as all my engines are set to it and if I have to replace a damaged wheel I want the registration to remain consistent. Anyone starting may want to alter the gauge to give 92degrees or so, but I would not recommend it necessarily, as 90 degrees is easy to check by using a small square or a machined 90 degree gauge, like the S4 society one,where you can simply drop the B-to-B gauge on top to check that everything lines up correctly.

There cannot be many people who can detect by eye a couple of degrees difference on either side of the locomotive. It is true that if you quarter by eye and your loco happens to have spokes which should line up when quartering, you may notice some degree of being out.

It is not particularly a route I would revert to, despite my early locomotives being done using this method.

[grovenor-2685]

Anyone starting may want to alter the gauge to give 92degrees or so,

Actually the angle should not change at all, unless you increase the diameter of your crank pins with radius!
It just needs half the crankpin diameter shaving off each side while retaining the 90 degree Vee, still checkable with a square.
Regards
Keith

[Russ Elliott]

Only problem is that the when drawing the etch Bill assumed crankpins of zero thickness, so you don't get an accurate 90 degrees, but you do get all the same.

Ah, what would we do without a few Bedfordisms?

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