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

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Allan Goodwillie
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Re: West of Scotland Group's "Starters" Build a loco project

Postby Allan Goodwillie » Sun Jan 24, 2010 4:13 pm

Setting up the coupling rod jig

This is how I set my coupling rod jig up ,if I am only going to use it to produce the coupling rods.

I take the chassis sides with the holes drilled in the axle centres and having slackened, a little, the nuts and bolts held captive by the aluminium angle, I slide the bolts until they engage with the three axle holes. With everything lined up I tighten the bolts at the back of the jig so that the spacing is maintained when the chassis sides are removed. This leaves the bolts set to the correct wheel base.

Next mark the top of the jig surface with a letter F to indicate where the front of the locomotive is according to the drawing as you set it out. Set up your jig so that the front is to the right, then you are preparing coupling rods for the right hand side of the locomotive. Lay out the parts on the bench for the RHS coupling rod. Now lay out the parts for the LHS coupling rod.

Note that the oil boxes are towards the top of the coupling rod bosses.The coupling rods can be cut to length to suit any locomotive and made up plain or fluted. It will probably take you a little time to work out how to put them together as different combinations are needed for different locomotives.

At this stage I put a little grease on the bolt ends and nuts etc. this will stop them being damaged by the solder. You may also wish to use a cigarette paper to cut back on splash back and again stop couplings and jig soldering up solid. The paper goes between the two.

The small boss parts I solder on away from the jig on my wooden block, but the larger sections I cut to size and fit together on the jig.

Fit the ones for the RHS onto the jig for soldering,the oil cups to the top.

Then assemble the coupling rods on the jig. Each piece of coupling rod is made from two halves.
You will find soldering paste is ideal for soldering them, but you can put flux on the surfaces you are about to join and take solder to the work and allow it to sizzle and run into the joint. I clip mine together using heat sink clamps (crocodile clips would also do the job).
Once you have made up the RHS coupling rods take them off the jig and lay them aside, coupling them together by putting a length if wire or multicore solder through the centre holes and wire them together and put them aside. Then lay out the LHS parts on your jig, having taken the jig from your vice and reversing it so that the F is on the LHS. Using the same spacings build your LHS coupling rods again with the oil boxes on top.

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

Postby Allan Goodwillie » Thu Jan 28, 2010 4:24 pm

We now should have a set of left hand coupling rods and a right hand set of coupling rods. They should have identical spacing due to making them up on the jig and be a mirror image of one another.

Double check at this stage that you have made up the coupling rods correctly, that the spacing is correct, that they have been made with the oil boxes correctly towards the top of the coupling rods and that the outside faces of the rods are of the correct type fluted/non-fluted. They also have to be correctly handed, a left hand side and a right hand side.

If you have managed to get any of this wrong, don't panic, simply work out where you have gone wrong, de-solder what needs to be done, clean up and resolder until you are happy that you have managed to correct the fault. Most people will put a set together incorrectly at some point, but it is rare to end up with something that cannot be corrected. Once you have a set of correctly made up coupling rods shout hooray :!:

The coupling rods are important to the accuracy of the chassis you are about to build. You have completed an important stage in the construction of the locomotive. Well done!

Allan :)

To keep them together, I normally thread a piece of thin resin cored solder through the shared centre crank pin holes to keep them in their pairs. You will need them during the construction of the chassis.

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

Postby Allan Goodwillie » Thu Jan 28, 2010 5:33 pm

The chassis

The construction of the chassis comes next. I am building two simple 0-6-0T chassis to begin with, one will use Gibson sprung horn blocks and one will use MJT horn blocks and compensation beam. Both locomotives will have a fixed rear axle. and will be driven using a motor and gearbox on the rear axle.

Some of you will be building something more complicated for your first effort and may require more than an 0-6-0 (having pony wheels for example). We will deal with other carrying wheels and tenders later. It is best not to tackle a 4-4-0 or 0-4-4 for your first attempt as this combination requires a bit more thinking about.

I would highly recommend reading Russ Elliott's Scalefour Digest 41.0 at this stage "The principles of Model Locomotive Suspension."

This can be downloaded from the Scalefour site, Copies were sent out to everyone some time ago (2004) and most people will have put them in their digest folders. If you joined the Society recently then it will be on the disc that came with the initial pack.

I do not suggest you to read it all at once, as it covers many methods of suspension and everything from the simplest to some of the more complicated scenarios.

Read the parts covering sprung and compensated chassis, as one of these methods of compensation is what I would suggest for your first locomotive. If the locomotive uses a Comet chassis then there is another method, which is simpler to a degree and which you may prefer to use. You will need a set of Brassmasters horn blocks and springs to go with them. We will look at this method later, although the chassis can also be adapted for either of the methods we are covering first.

Russ did an excellent job putting many peoples ideas together, as well as his own, in a very clear and understandable form. I am sure he will not mind me referring to this very useful piece of work at this stage. It saves me covering the theoretical side of things and allows me to concentrate on the practical.

Something I want to emphasise at this stage is that I believe in designing chassis which you can take apart readily and during construction, be able to make up and test sub assemblies as you go along.

The sub assemblies for the chassis will include:

    The coupling rods (already completed)
    The horn block units and compensator, or sprung units
    The motor / gearbox unit
    Wheels/axles/horn blocks and gearbox units
    Brake block units
    Under axle spring units
    Pick up units

The horn block / compensator units, sprung horn block units and the gearbox motor combination can be assembled before constructing the chassis. All of these can be done during the odd twenty minutes here and there. :idea:
We will look at these next, find your packets of bits and pieces, open, then read the instructions on how to make them up.

Allan ;)

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

Postby allanferguson » Fri Jan 29, 2010 12:44 am

A most interesting thread, Allan, and excellent that an experienced builder can put across the basic "how to" stuff from which we can all take something, however experienced.

I was glad to see Russ had picked up on the issue of the quartering jig while I was still trying to create an illustration to demonstrate the point he has made, that the "Bill Bedford type" jig does not give true 90deg quartering. Many years ago, when I first essayed to build a locomotive I built my own jig which, though a tad more difficult to use, does give true 90deg quartering. I think it's also easier to make!
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Allan Ferguson
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Re: West of Scotland Group's "Starters" Build a loco project

Postby Allan Goodwillie » Fri Jan 29, 2010 8:34 am

Very good Allan, :D

the studding and washers/nuts would allow your jig to become a multi gauge jig. Looks a nice solid , dependable job as well.

I will be adding a considerable amount today, but with us working on Burntisland this weekend and Richard Chown's this evening I have had to put off the leaf springs and the pick ups until next week.

I also have another couple of locomotives to finish for Richard Darby before we go over to Holland with the layout, so the bodies will probably have to wait until I return. I will probably cover another couple of chassis types before then, as the West Group members have other things to deal with including tenders and bogies.

The bodies of the two tank engines I may cover as a separate thread under basic scratch building. I realise that people who would want to follow that thread will probably need a small lathe and be wanting to do something different, it may follow some of the other locos I have to build for Burntisland. :|

Thanks for your kind and appreciative comments
All the best Allan :)

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

Postby Allan Goodwillie » Fri Jan 29, 2010 11:08 am

Assembly of horn block sets :)

A note of caution :o :cry:

Most beginners assume that all the components available from manufacturers must be accurate, after all, many articles in magazines quote figures to thousands of an inch. Most of us who have been building for years know however that this is occasionally not the case and can lead to problems.

What I am advocating is that you make good habits from the beginning in that you should not take anything for granted and check your components at all stages , even when you are buying them. Most manufacturers will not want to sell components that are incorrect, as they want to maintain a good reputation. If you are buying, take your Vernier gauge with you and make a few simple checks, if necessary, before you buy. All is not lost if you have been buying components for years and now you have all this leisure time in retirement. You will be able to use what you have already purchased - there are ways around the problems and we will deal with some of these next.

With the MJT blocks I have not come across any problems so far, as they have been most consistent, I still check them out each time however, just to be sure. I have come across several types of sprung horn block where the holes have been off centre. This may not necessarily be a problem, as I would match pairs and if the holes were not right I would turn the blocks to have the off centre holes towards the top of the horn blocks so that the displacement is not horizontal but on the vertical plane, as this can be sorted at the levelling stage.

This, however, assumes that the holes are only out one way, if you are really unfortunate they may be out both ways. :evil: In which case do as I have suggested with the worst part of the displacement and make a mirror image of the two blocks before fitting them to the horn blocks. This can be coped with without having to do anything drastic with the components - just carefully match them. :)

Once you have made the best fitting of each one, mark the bottom face of each horn block with a permanent marker ( I use the ones we have for marking CDs as there are four colours in the packet. At the same time put a similar marking on the horn block guide so you now have matching horn blocks

I lay out the guides and the horn blocks on the bench sitting on a piece of card, which has been covered with double sided tape. I have a standard colour code for each axle end, for example looking from below, front axle RHS Red, LHS Green. ;)

Compensated horn blocks

The MJT horn blocks come with full instructions and can be built effectively using them. They suggest using a suitable glue (Araldite type) to glue some of the parts together. It needs 24hours to set properly before being cleaned up. I prefer to solder as many components as possible and it is possible to solder the units with a small tip on the iron. The soldering has to be done from the rear and the minimum of solder used ,otherwise you could have it flooding the working surfaces of the unit. Use a small brush and place the flux only where you want the solder to go. Once you have made up the guides check for any problems with the horn blocks.

When fitting the blocks into the horn guides check for a nice sliding fit of the blocks . What you want here is no slop, but an easy movement. You may have to scrape the working surfaces clean if you have managed to get any glue or solder on to them.

Sprung horn blocks

As to the sprung horn blocks,before starting, check for problems and follow the guide above. Make them up according to the instructions. The one thing to be careful about is that it is possible to solder everything up solid when fitting them to the chassis, if you have the horn blocks in place. I would make sure that everything is bent up properly and that the blocks are a good sliding fit with little sideways slop, I would place a cigarette paper between the blocks and their guides to stop solder penetrating to the sliding surfaces, or use grease on the sliding surfaces to stop solder penetration or Carr's solder mask if you have it. I will remind you of this when we are assembling the chassis.

May all your problems here be minor ones.
Allan :)
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Re: West of Scotland Group's "Starters" Build a loco project

Postby Allan Goodwillie » Fri Jan 29, 2010 5:46 pm

Motors and gearbox units :)

I do not intend to say too much about these at this stage, except for a few comments about what types are satisfactory for the suggested method of construction. I am using a couple of Portescap motors to save a little time and simply because, I had been saving them for this particular project, other locos I have already built for the project use them. They come already assembled, but can be separated between motor and gearbox if necessary. ( I must point out however that in doing so you are going against the conditions of the guarantee.) :!: :shock:

I am not, however, going to push for everyone going down the Portescap route. Some people do not like them :( claiming they can be noisy, I have one that is, but most of the ones I have installed run very well and quietly. I have found them very reliable and have used them, from the time they came out, on many types of locomotive. The oldest ones seem to be the quieter ones. I am not here to push Portescaps or any other motor or gearbox for that matter.

The modern skew wound motors made by Maschima are powerful and efficient. I use them, much the same as most modellers, nowadays. They are powerful for their size, well made and reliable. There has been much written in past Scalefour News articles about motor speeds and gear ratios and getting the best matches, there is also some information on this subject in the Digest.

Simplistically the choice normally comes down to -

    "What is the largest motor and gearbox arrangement possible within the restricted space within the locomotive body?" ( I am leaving out the possibility of fitting a drive from the tender into the loco as I would not recommend this to anyone beginning.)

    I personally, would not want any of the drive unit showing and like to have a proper back head in the cab. motors up to 16mm dia. can be used in the majority of modern locomotives, especially if you buy the flat sided motors which are 14mm across the flat sides. They will slip out between the frames if you make allowance for that. Much depends on the narrowness of the firebox so check for this when measuring for the drive unit.

    "Which gear ratios suit which locomotives?"

    The answer to this is partly in response to "What kind of layout are you building? High or low speed?"
    Passenger locos around 40:1 or 50:1 depending on the top speed you wish, 40:1 being the faster one.
    Mixed traffic locos 50:1 and 60:1
    Freight locomotives 60:1 to 80:1
    Shunting locomotives 80:1 and higher for ultra slow

There are a huge range of gearboxes available. Some are very fine, but I have found, from personal experience, they will wear out fairly quickly . Then again I have heavy locomotives working long trains on my Grayrigg layout. I go for the more robust gearboxes. Most companies selling motors and gearboxes will give some help when choosing. Multiboxes which give a range of options are particularly useful and narrow versions are available for split axle where they are required - I hope to cover this later. Most gearboxes are good nowadays and once assembled according to instructions will function well.

If using the construction system I am suggesting, I would suggest you use a type of gearbox, which uses grub screws to attach gears on to shafts as they can be released again for free running tests. You can tell I am not keen on gluing gears either, as I like to be able to adjust and disassemble, if necessary, without any trouble.

When assembling your gear sets follow instructions and take care to make sure all is square.
If you have gears with grub screws file a flat on the axle, as suggested in most of the instructions. This allows for tightening up without distortion of the gearwheel.

Once your gearbox has been assembled, put an axle in place and screw up the final drive gear, test that all is working without the motor's worm wheel engaged. Fit motor and worm wheel,to gearwheels, (A cigarette paper placed between the two should give a working tolerance on heavier gear sets) tighten everything up. remove the paper and try turning the motor shaft to make sure that all is turning over OK. before trying power through the power unit.

If everything is turning OK, then apply some power. The gears should run smoothly without much noise. If there is any sign of catching check to see what may be doing this under a good light and a magnifier.

1) It could be the worm wheel is not driving by its centre.

2) It could be that the worm wheel is offset to the primary drive wheel. You may have to add thrust washers to get everything in line.

3) It may be that the grub screw is catching on something.

If all is well and there is no sense of the motor or gears sticking in any way, try running in the mechanism. This can be done, while building other parts of the locomotive. I use my helping hands to do this.

To Run In

Put a touch of light oil on the gears and turn the motor over slowly. Then run on half speed for half an hour in each direction.
Oil again if necessary, then run at full power for half an hour in each direction.
(In olden times Brasso was recommended for running gears in, but given the quality of gears now I would be reluctant to do this, as it will only wear the gears out prematurely.) :cry:
Modern motors are meant to get warm in operation, so don't be surprised when they do. Stay with the mechanism just in case anything works loose, you have lots of other things to do. As the gears bed in and become more polished they should become quieter and smoother. After running in try running them as slowly as you can and see the difference from how they were when you started running.

Allan :)

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

Postby Russ Elliott » Sat Jan 30, 2010 12:46 pm

Allan Goodwillie wrote:Russ did an excellent job putting many peoples ideas together, as well as his own, in a very clear and understandable form. I am sure he will not mind me referring to this very useful piece of work at this stage. It saves me covering the theoretical side of things and allows me to concentrate on the practical.

Thanks Allan. I tried to keep Digest 41.0 reasonably free of the detail of constructional method, which is why a practical thread like this is such a useful complement. Incidentally, if you do feel the need to show a specific diagram, this can be done by pasting the url of the image (obtained from the image 'properties' on right-clicking) between image tags, e.g.

Image

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

Postby Allan Goodwillie » Sat Jan 30, 2010 9:23 pm

Thanks Russ, :)

I do appreciate this and will use it as I go along, since you have been kind enough to facilitate this. :D

I was having a chat to my, old friend Alasdair Taylor today (Alasdair has a very nice model of a section of the Waverley route.) and hope to persuade him to tell of his ideas on how to convert ready to run. It is a cracking good method he has and he has recently bought a Hornby Clan loco and intends converting it, I have a DJH Clan kit ready to go , but my guess is that the ready to run will be difficult to beat. I have asked him to time the work for an interesting comparison.

I have been aware of the " Getting it all right thread" , although I have not been involved. Much discussion has been around the "Have I enough time to build my dream layout if I try to get it all right?", the answer is yes, but you have to use methods that will give you a satisfactory result in a reasonable time. I don't like wasting time and have built a number of large layouts and hope to help others to get the most out of their own." Dubbieside " stretched to 50+ feet and my Grayrigg layout is also of some size and of course I am heavily involved in the East Group's "Burntisland" so I do know about building large scale layouts and being able to construct good working models to S4 standard in a reasonable time.

Alisdair has done a Brit recently and it may compliment one I am building using Brassmasters springs and horn blocks along with a Comet chassis. This method which is being extolled elsewhere is excellent but is surprisingly quite old. I built an A4 pacific based on a Pro Scale kit (which became known as Anchoridge kits) about 35 years ago, it won the S4 Chairman's cup at the time. It has run well over the years and I have built several others including, recently, a B1. The idea has been around for that time. It is very good, depends on the quality of the components and is very straight forward to put together, providing you are careful, I would also recommend it for beginners, but it is limited to kits with the proper design and which are accurately etched. I will cover it sometime soon although Jim's notes on John Brighton's approach will give enough incentive to tackle one this way. I hope by doing one it may encourage other beginners to have ago.

I hope we can meet up at Scalefourum some time. I believe it is intended that I have a demonstration stand at Scalefourum this year. Wouldn't it be wonderful if everyone brought their new engines built or part built to Scalefourm? I will take photos of any that turn up finished or unfinished, as I am sure I will run a clinic over the weekend as part of what we are doing here. Anyone making a new loco using any of the methods here will be most welcome to bring them and discuss development , I have already had a number contact me and anyone starting out wishing to have a go, please feel free to contact me as I can see that it will be more than confined to the West of Scotland group.

All the best and thank you again.Your sharing Geek :geek:

Allan

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

Postby grovenor-2685 » Sat Jan 30, 2010 10:41 pm

from allanferguson:
I was glad to see Russ had picked up on the issue of the quartering jig while I was still trying to create an illustration to demonstrate the point he has made, that the "Bill Bedford type" jig does not give true 90deg quartering.

As both I and Russ illustrated, there is nothing wrong with the "Bill Bedford type" just with the Bill Bedford execution, a small adjustment to the etch will make it correct. Your version is of the same 'type' just turned through 45 degrees!
Regards
Keith
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Keith
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Re: West of Scotland Group's "Starters" Build a loco project

Postby LesGros » Sun Jan 31, 2010 12:51 am

grovenor-2685 wrote:[
Your version is of the same 'type' just turned through 45 degrees!

Keith,
Surely that would depend upon which faces are used?

It appears that with the 90 degree cutout to the left and the axle into the corner, there are two ways of positioning the crankpins.

On one side of the jig there is a horizontal face (a), and a vertical face ( b) at 90 degrees to (a), and on the other side, there are two horizontal positions, let's call them (a) and (c) at 180 degrees.

The angle with the crank pin against (a) and (b) is, as you point out, the same as the Bill Bedford Jig, resulting in less than 90 degree quartering as previously described. However, placing the crankpin clockwise against the vertical (b) and on the other side placing the other pin clockwise against (c) voila! 90 degree quartering.

regards,
LesG

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never made anything useful

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

Postby Allan Goodwillie » Sun Jan 31, 2010 8:55 am

Assembling the chassis using the chassis jig

Preparing the parts

What we are looking for in the assembly of the chassis is to make sure all is square and in line. It is worth emphasising care in the cutting out of the slots and spaces for the horn guides.

It is best to do it when the two halves of the chassis are still attached to one another. Cut out most of the material and then carefully file down to the line using a small file. If I was assembling a proprietary chassis, that requires slots cut out for bushes, I would clamp or solder the two parts together, before cutting, to make sure the two sides are the same. Do not use too much solder, a touch for each end will be enough, just make sure they are properly aligned. :idea:

As you file down to the lines it is worth taking the time to move the work in the vice so that the edge being worked on is always parallel to the top of the vice and seeing the lines that you are cutting to, as close to the jaws of the vice as possible. This will ensure that you do not bend the chassis as you are working on it, you may think you are taking slightly longer, but it will mean that everything stays nice and flat. If you do get things bent, :cry: then don't panic, but flatten it out by gently beating it flat again on a flat surface, before continuing to cut out. It is better to keep things flat, however, as once a piece of metal has taken a bend it is difficult to get back to a perfect surface, so just stay cool 8-) and take your time.

When doing this stage, make sure that your chassis gauges are going to fit the slots you are making. Do this as you go along. Leave the paper drawing on at this stage as it will keep everything clean on the outer surfaces as we tackle the soldering up.

When you are sure you are happy with the slots and have cut out any other small shapes in the chassis required, then double check that you have drilled all the small holes required for brake gear etc. Finally clean up your edges and place the chassis sides in your vice and with a file carefully file the top edge of the chassis keeping it level, if a flat top edge, file down until they separate. Check that all is level and separate and clean up. If you are using a proprietary chassis and have soldered it together in a couple of spots, reheat, separate and clean off the solder.

Prepare your spacers, carefully cut, file and fold in your vice. Take care in folding, make sure you are getting a right angle. I always use spacers with a hole in them, this allows for other pieces of equipment to be fitted at a later date if necessary - you may decide to use chips, sound units, etc.

You have checked that your motor/gearbox is going to fit against your drawing, if not, then check now. You can also check that the horn block guides you have made up also fit the slots. So to the assembly. Little bits of solder may have to be taken off the guides to ensure that they will lye flat against the chassis sides.

The chassis is now ready for the jigs.

Allan :)
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Re: West of Scotland Group's "Starters" Build a loco project

Postby grovenor-2685 » Sun Jan 31, 2010 10:08 am

Surely that would depend upon which faces are used?

I suppose that comes down to what you mean by "type" as distinct from "example". As I see it Allan's, Bill's and allanfergusons are all examples of the same "type" which is identified by having inner plates to locate the axle and outer plates to locate the crank pins. Whether or not they give an exact 90 degrees depends on the detail location of the edges that the crankpin is to sit against in relation to the axle centreline.
Using an internal angle as in the first two, and the third for left hand lead, to be fully accurate they have to be designed for the axle diameter and crankpin diameter, if the wheelset differs in either of those they will be slightly off, but consistent. Using the external angle as in allanferguson's used for right hand lead then it will be accurate for any diameter axle and crank pin.
The angle with the crank pin against (a) and (b) is, as you point out, the same as the Bill Bedford Jig, resulting in less than 90 degree quartering as previously described. However, placing the crankpin clockwise against the vertical (b) and on the other side placing the other pin clockwise against (c) voila! 90 degree quartering.
Well, it could give 90 degrees or not in either or both positions depending on the edge/axle centre relationship, but as built, which is the simplest for home manufacture it will give 90 degrees with the wheelset as pictured and a bit more than 90 the other way.
But lets not keep this up, it will detract from Allan's excellent articles.
Regards
Keith
Last edited by grovenor-2685 on Sun Jan 31, 2010 2:04 pm, edited 2 times in total.
Reason: Have gone back to the first half to make it consistent with the conclusion, I hope!
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Keith
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Re: West of Scotland Group's "Starters" Build a loco project

Postby Allan Goodwillie » Sun Jan 31, 2010 8:06 pm

Thanks Keith,

It is of academic interest, I am sure, and of course each to their own, :| but I don't want any beginners worrying about the jigs. :shock: I rather liked Allan's jig as it is easy for anyone to make and I know it works well and is probably more likely to give a proper 90 degree angle, as the relationship between the two wheels is based on the same side of each crank pin, if used correctly.
As long as all wheels are done with the same jig then they will work in tandem and it rules out one of the bodges that people make - trying to get several sets of wheels set the same. The first locos I built I quartered by eye, like most people, but a gauge like any of those shown will give conformity and have the wheels sorted in no time, which is what we are after.

Allan :D

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

Postby Allan Goodwillie » Sun Jan 31, 2010 10:19 pm

The frame assembly :D

The jig I use holds the two side pieces, while spacers and other components are soldered into place. I normally set up the frame sides using the temporary frame gauges. Fit the gauges first and check they are sitting parallel and sitting properly within their horn guide slots. Use a square and a steel ruler to ensure they are straight and in line.

The frame is assembled upside down in the jig, even chassis which are shaped along the top edge following the wheel backs can be assembled using the jig. (In a case like this I would solder the two end spacers in place on one side each just to hold them in place prior to assembly in the jig.) The frames, with their spacing jigs, are fitted between the sides of the frame jig and clipped in place so that the frames sit vertically.

Placing of spacers

The placing of spacers is logical to a certain extent,

generally-

The two end ones are normally used to attach the chassis to the body, if you are using them to do this you will have to work out exactly where they go to align with the body fixing points. Some people like to use the front one to slide under a slot in the underside of the body and fix with a single screw at the rear of the body.

There will have to be at least a couple of vertical spacers to give some vertical structure and strength to the frames.
One of these can be used to eventually support the motor. The other can go further forward.
I use another two below the frame to support the pick ups and brake gear.

When placing the spacers make sure you leave enough room for the axles and compensator if you are using one. Keep clear of the holes you have drilled for the brake gear. Just give a little thought to this, if you need to use a spacer to support a bogie, for instance, then the correct height and position along the chassis must be considered.

Having given some consideration as to where the spacers are going to be used. These can be placed and soldered in place one at a time. The way I do this is as follows:-

I tend to solder one end of the first, then the other end of the second then the other end of the third and so on down the loco until I reach the other end, then I go back and start at the other end again and solder the other sides of the spacers one at a time. There is less chance of warping, or tension set up in the chassis, due to problems of expansion and contraction. We do not want any banana chassis! :o

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Allan Goodwillie
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Re: West of Scotland Group's "Starters" Build a loco project

Postby Allan Goodwillie » Sun Jan 31, 2010 11:32 pm

Fitting the horn blocks

The next stage is to assemble the horn guides and fixed axle guide. Remember which horn blocks fit which guides as you have paired them up, remember you have already marked them! I use a set of coupling rod jigs and these have a spring which presses the horn block guides against the frames in the slots. When they are laid out in their proper places in the chassis then the coupling rods are fitted on to the ends of the gauges, starting with the fixed end. If you have been good with your cutting and folding you may find all is well first time! If so jump up and down, pretend you can fly around the room . Well done :!:

If everything is correct :shock: then solder the guides in place, do not overheat as you will not want to disturb the solder in the guides ( or Glue , if you have used glue)

If you are marginally out :o I would start from the fixed axle and move the centre horn block guides until the rear coupling rod sections fit on both sides. Do not solder yet. It may require the slot to be opened out in one direction, (a smidgeon) at a time.Tackle one side and then the other, it will not require much. Once you are satisfied that the middle pair are placed OK, then fit the final pair using the front coupling rods, again further smidgeons may have to be taken off making sure that the coupling rods fit properly on both sides. Completing this should mean that the coupling rods and the horn blocks should align. if happy with your efforts and all is well solder the horn guides in place. :)

I would normally make up the compensating lever at this stage from two pieces of brass tubing. One cut slightly narrower than the inside of the chassis. The other piece of tubing make long enough to straddle the two front axles, be careful not to make it short. A piece of wire should be cut to slot through the hole in the frames and the cross piece. Carefully solder the pieces centrally and at right angles to one another. The compensator can be fitted at this time if you wish.

The coupling rod jigs can be taken off at this stage and the horn blocks fitted. Make sure they fit and slide as you have planned and marked. A small piece of masking tape can be used to secure them temporarily until you are ready to fit the wheels, alternatively you can secure them using brass pins in the securing holes at the bottom of the guides. The pins will have to be bent in place, take care not to bend the horn guides.

Springing units are fitted in much the same way and I will illustrate this next.


Another stage, but an important one is finished. :D

Allan

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

Postby Allan Goodwillie » Mon Feb 01, 2010 12:09 am

Having checked the horn blocks fit correctly then fit the Brake hangers.

Fitting brake hangers

The brake hangers can be soldered into place next. They can be cut wider than needed at this stage to be cut back when the wheels go in. Once fitted then any other attachments can be fitted to the chassis before cleaning up.


Clean up

Clean up using files and wash any flux from the work using hot water and soap, (I sometimes use a basic toothpaste and brush.) You can also peel off the paper pattern under the warm water. The double sided tape I find comes off using Precision paints primer thinners, which seems to be the solvent for the tape. Once painted on using a small brush, the tape will come off easily using a finger nail in no time at all. Using the drawing directly like this saves much drawing out time. ;)

Now un-stick your fingers and clean your hands before touching any other surfaces :P :!:

Allan :D

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

Postby Allan Goodwillie » Mon Feb 01, 2010 4:44 pm

The colour of this print has been changed to reflect that we are talking about the second chassis that is being constructed using the same methodology - the only difference being the use of sprung horn blocks against the use of compensated ones. Where there are differences later in construction of the sprung type these will also use the same coloured text.

Now I thought we would look at the same chassis being built with sprung horn blocks. The frames and their assembly have been made in the same way and the horn blocks and their guides made up according to the instructions, (except for the flats to be filed into the tops of the boxes, for reasons that we will go into now.)

Again I would, if I were you, look closely at the blocks themselves as I have found that the holes are not always central as you would hope. :o In fact, this set I am using I found to be like that. :cry: I bought them some years ago and only discovered they were like that when I took them out of the packet - see what I mean about checking at the point of purchase? :?:

However, I was sure I would be able to use them, provided I could match them into pairs and set them up the correct way as shown earlier. Make sure that when you are doing this, that you take into consideration which way round the blocks have to face, as there is a left and a right! Read the notes here until you understand why. This I did and I marked them with colour dots to show which way up they should be, as seen from below and allocated them to particular guides which I also marked.


The guides and the horn blocks were made up with the guide wires in place and it is now that the flats were filed in the tops of the blocks as per the instructions and the units made up except for the springs.

The horn blocks with their guides were laid out on the work bench in their relative positions. Keeping organised through the next few stages until all is assembled is paramount.

When fitting the units using the coupling rod guides and springs, they would just spring through the frame sides, as there is no flat plate to help hold them in place, so I use the coupling rod jigs without the springs. ;) I have another means of putting this type of chassis together which I will cover later, but it is possible using this method just the same and that is what I have done with the second chassis.

If you have cut everything correctly and all is square then you can try a trial run of the horn blocks into the frames, you may have to file a little off ( again a smidgeon), (maybe even a gnat's whisker!) as in the second image. In this example I have started from the front end and added axle by axle to the back. In image 3 this shows them fitting into the first two axle slots and the third axle held aloft with the rear coupling rods held up while the spare guides are fitted in place using my small clamps. Nothing soldered at this stage until I am happy that nothing is forced, but everything fits properly according to the coupling rods.

The guides are a little bit more tricky to solder in place using this method, but what I do is place a cigarette paper between the guide and the block while soldering, or paint solder mask or grease between the sliding surfaces. :idea: This is just a precaution and takes a short time to do but saves on frustration and cleaning up time if anything goes wrong. I also hold the guide in place via the coupling rod jig using the old dodge of holding it by means of a damp paper towel, so as not to burn the fingers. The outside edge of the guide should not protrude beyond the outside of the frame.

Using a small brush paint some flux on to the join and solder in place. I tend to solder one side of each horn block, doing alternate blocks, so there is not too much heat travelling about the place, before going back to do the other sides of the guides.

Incidentally, nickel silver conducts heat away slower than brass and there is less chance of the heat spreading to areas you don't want.

When soldering together with a medium tip on my 25watt iron I put the solder to the frame and make sure the solder flows there then touch the brass horn guide with the solder and lifting it vertically up the joint as I take the heat away . The joint will fill more evenly this way than moving downwards where it is likely to collect anyway due to gravity. :idea:

I move on to the next guide on the opposite side and so on, coming back to solder the other sides of the horn guides in place at the end of the sequence. This ensures as even a distribution of heat as possible. It will also stop things like the spacers coming apart accidentally, due to there being too much heat build up. This is similar to the way the frame spacers were soldered up.


The metal heat sinks I use as clamps can help divert heat away from parts like this. Crocodile clips would also work the same way.

The next step is to double check that you have soldered all the joints between frames and horn block guides. If all are done then remove the blocks and the coupling rods and tape them in their correct formation. make sure everything is free to move.

If, unfortunately, you have soldered something up solid, then it will have to be taken apart and cleaned up and the errant unit re-done. If you have used any of the methods suggested above it is unlikely that you will need to do this. As long as the blocks move properly in the guides without too much sideways slop, that is fine.
Do not be tempted to alter the coupling rod holes at this stage, even if it seems a little stiff.

Patience and care - a Saturday morning job :)
Allan

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Russ Elliott
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Re: West of Scotland Group's "Starters" Build a loco project

Postby Russ Elliott » Mon Feb 01, 2010 10:34 pm

Allan Goodwillie wrote:The horn blocks and guides made up without springs

I think I must have missed a meeting, Allan. They look like MJT blocks and guides. So where do these springs come from?

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

Postby Allan Goodwillie » Tue Feb 02, 2010 9:50 am

Hi Russ, not quite sure about the question, the first chassis has been made up using MJT compensator horn blocks the second chassis is being made up using the Gibson horn blocks. The photographs show them before fitting of the springs. I have modified them a little by taking the original end off the guides and have temporarily soldered wires across the ends instead.
I did mention in the text that I used a spare MJT fixed axle guide on the sprung chassis as well as the other one, so the fixed ends are the same. I will double check that I have put the photographs in the right order. If I have managed to get it wrong,I do apologise, put it down to me following Andy Murray on the TV while putting this together the other day. :!:

Allan :)

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

Postby Russ Elliott » Tue Feb 02, 2010 10:17 am

Allan - no problem - the mistake was mine, in a bit of late night confusion. I'd forgotten that you were using the Gibbo ones for two axles of the second chassis. Do the Gibbo ones now come with an etched hornguide plate that can be soldered to the frame? (I couldn't quite see the detail inside your frame pics, and am a bit out of date on the Gibson hornblock front, remembering only the plastic hornguide versions.)

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Allan Goodwillie
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Re: West of Scotland Group's "Starters" Build a loco project

Postby Allan Goodwillie » Tue Feb 02, 2010 11:07 am

As far as a horn guide plate goes I do not know, I am using the ones which have been available for a long time as I have been working through many packs bought years ago. I tend to buy all the parts needed for any locomotive when I buy the wheels for a particular project, so that everything is there.

The fact that the Gibson horn guides here do not have a registration plate is a slight problem, but as long as you do not use the Perseverance springs and simply use the coupling rod jigs on their own, with the coupling rods in place there are no major problems in soldering them into the right place.

One thing which could be considered would be to additionally hold the guides in place using some of Carr's heat resistant tape as this can be used on the outside of the frames to stop the horn guides going beyond the outside of the frames. I did not do that in this case as the coupling rods help to keep everything in place anyway and are a stiff fit.

If I were to use London road models tapered coupling rod jigs I am sure the results would be the same. The accuracy of the rods using the London Road models jigs I cannot vouch for as I have not used them. I think if I were to use a set I would aim to get all the coupling rod holes the same - a good, if slightly tight, fit on the crank pin bushes. I will go back and add this in the appropriate section as it is hoped that anything like this will be picked up on as we go along.

I know that the last chapter looks like deja-vu, looks like deja-vu :P
If this were a book then turning the page would be more obvious. When we get to levelling the chassis it will become more apparent that there are two chassis being built using the same system. I will go back and change the colour of the print so that the items relating specifically to the sprung version are more apparent - I will use the Purple print colour for this and hope it makes it clearer.

Being alerted to this is a good thing (even by mistake) thanks Russ. :)

I have also been asked to define a smidgeon and a gnats whisker to the nearest thousandth of an inch so I am off to photograph a gnat this morning and if I can find a smidgeon I will photograph that as well to give relative sizes.

Allan :D

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

Postby Russ Elliott » Tue Feb 02, 2010 12:11 pm

Allan Goodwillie wrote:The fact that the Gibson horn guides here do not have a registration plate is a slight problem, but as long as you do not use the Perseverance springs and simply use the coupling rod jigs on their own, with the coupling rods in place there are no major problems in soldering them into the right place.

Ok. So for the Gibson, the arrangement is something like this:

gibbo-guide.png


Vertical positioning on hornguides for compensated systems is not that critical, but I think will be a lot more critical on sprung hornblocks.

gibbo-guide-vertical-alignment.png
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Re: West of Scotland Group's "Starters" Build a loco project

Postby Allan Goodwillie » Tue Feb 02, 2010 2:23 pm

Russ

Here is the diagram to explain and clarify a number of things. The placing of the fixed axle sets up the datum and the springs on these horn blocks push down only when there is a dip in the track. I could make up a diagram of how this happens and fit that in later, but I am trying to minimise the theory here. :geek:

As you can see I have modified your diagram to take account of the off set of the guide wire to allow the screw to be adjusted without the chassis in the way.

There has to be some sort of spacer between the wheel and the block so that there is no accidental rubbing of the wheel against the chassis - on real locos this did happen! How to deal with wobble on the wheels I will come to later! It will also make sure there is no electrical contact. There still has to be side play to allow you to get around curves. Locos with outside cylinders require less side play behind slide bars - we will have a look at this later.

We are getting ahead of ourselves at this point, but similar questions may be concerning the beginners so it is worthwhile saying something before moving on.


Hope this helps.

Allan :)
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Re: West of Scotland Group's "Starters" Build a loco project

Postby Russ Elliott » Tue Feb 02, 2010 2:46 pm

Thanks Allan. I just wanted to make it clear that we were dealing with 'spring-assisted' hornblocks.


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