An approach to building a GWR 1854 Saddle Tank

[David B]

Squires, p305 http://www.squirestools.com/files/13-16.pdf

[Andrew Bluett-Duncan]

Thanks David
Andrew

[Andrew Bluett-Duncan]

For a bear of very little brain CSB's are becoming a challenge and I'm beginning to wonder why I publicly said I'd have a go....beams would have been so much easier!

I've set up the jig to measure out the dimensions that Will gave me, initially using the High Levels jig. However I've done this with the chassis as supplied, and prior to cutting out the hornblocks slots. Indeed I've yet to plan where the chassis spacers are to go, so I may have to revise either their positions laterally or their height.

So I'm now concerned that if the fulcrum points need to be accurate to the nearest half millimetre then this could go out when I'm fitting the hornblocks in place.

Am I on the right lines here or missing something major?

Advice gratefully received.

Photos show the four fulcrum points that I've marked on the chassis with a 0.5mm drill, using the jig.
Andrew

A223E6FA-8DFE-4222-8B2E-189242643C15_1_105_c (1).jpg

[petermeyer]

I've done this with the chassis as supplied, and prior to cutting out the hornblocks slots. Indeed I've yet to plan where the chassis spacers are to go, so I may have to revise either their positions laterally or their height.

So I'm now concerned that if the fulcrum points need to be accurate to the nearest half millimetre then this could go out when I'm fitting the hornblocks in place.

Am I on the right lines here or missing something major?

Advice gratefully received.

I first set up the chassis by soldering the spacers in and then cutout and remove the hornblock slots but one at a time leaving tophat bushes soldered in the others temporarily. This helps with alignment. I do have a chassis jig that helps a lot at this stage.

IMG_1693.jpg

[Will L]

For a bear of very little brain CSB's are becoming a challenge and I'm beginning to wonder why I publicly said I'd have a go....beams would have been so much easier!

I've set up the jig to measure out the dimensions that Will gave me, initially using the High Levels jig. However I've done this with the chassis as supplied, and prior to cutting out the hornblocks slots. Indeed I've yet to plan where the chassis spacers are to go, so I may have to revise either their positions laterally or their height.

So I'm now concerned that if the fulcrum points need to be accurate to the nearest half millimetre then this could go out when I'm fitting the hornblocks in place.

Am I on the right lines here or missing something major?

Advice gratefully received.

Photos show the four fulcrum points that I've marked on the chassis with a 0.5mm drill, using the jig.

All is OK so far Andrew, but don't go cutting out those horn block slots till I've got back to you. I will explain further but just past midnight isn't the time to do it. I'll post again in the morning. Well have a little think about those frame spacers then to.

[Will L]

Am I on the right lines here or missing something major?

Advice gratefully received.

Photos show the four fulcrum points that I've marked on the chassis with a 0.5mm drill, using the jig.

All is OK so far Andrew, but don't go cutting out those horn block slots till I've got back to you.

Morning Andrew.
Lets start with the Hornblock cut outs and how you correctly align the Highlevel hornblocks with the fulcrum points you have already drilled out using the jig. There should be no question of loosing this alignment.

When using the jig on the the middle axle only. There is a hole in the jig directly above the axle hole which you need to drill out too. This corresponds with a hole you will find the the highlevel horn block etch. When fitting the hornblock etch to the chassis you pin the two together with a wire through this hole. Y marks the spot on your picture
Much of the bottom part of the jig instruction leaflet in you photo relates to this. Once that's done, when you cut out the hornblock slots this alignment hole will be in the metal above it.

The other 4 hornblocks will be aligned with the first two just as you would with a fully compensated chassis. i.e. single axle jigs or a full chassis jig as as Peter illustrated.

BUT, looking at your picture, before you do any of that that, we need to have a think about the chassis spaces.

This all depends on what form the chassis spacers will take on this chassis. Rather than speculate on the various options you might have, let me know what the spacers are like. Also it will help to know which of the three possible holes in the carrier tags you drilled the fulcrum holes for. A B or C. again see that instruction leaflet.

Will

[Andrew Bluett-Duncan]

Hello Will
The picture below is roughly where I'm hoping to be able to put the chassis spacers. As it stands the front one looks a little tight, but the purpose is to secure that end of the bus bar for pickups and the leaf strings...a similar system to the one I think you use, which when unscrewed will allow the wheels to drop out, inc the gearbox (I hope!)
Andrew

37B2A2FD-3823-46C5-85E4-C4346C288D5F_1_201_a.jpg

[Will L]

...
The picture below (now above) is roughly where I'm hoping to be able to put the chassis spacers...

Hi Andrew

Good, L shaped spaces, I like it. Of course you need clearance holes through the vertical element of the spacers for the CSB wire (but just watch that the horizontal element are clear of the wire).

As for whether you can have an issue with the frame spacers and the fixed fulcrums interfering with each other, there should not be a problem. You do get a choice, and this may sound a bit obvious, either the vertical part of the space can be clear of the fulcrum points, or they can coincide exactly.

In the normal case when they don't co-inside, a clearance hole through the spacer is needed for the CSB wire.

Alternatively, if a vertical spacer element is getting too close to a fulcrum point, just make it coincide exactly with the fulcrum. You then substitute a hole through the vertical spacer for the fulcrum point/handrail knob.

To achieve either case, mark the fixed fulcrum centre line (FFCL) on the inside of the chassis sides and use that to transfer it to the frame spacers. Just check you get the same answer on both sides. For a clearance hole, centre it 0.5mm above the FFCL and 1.5mm from the edge of the spacer. Drill 1.5mm just to be sure, although a 1mm hole ought to be good enough. To make a fulcrum point in the spacer, centre a 0.5mm hole on the FFCL and 1.5mm from the edge.

The standard Highlevel CSB tags hold the CSB wire 1.5mm (or there abouts) from the face of the chassis and while it isn't absolutely necessary for the CSB wire’s path to be as parallel as possible to the chassis sides, if it zig zags down the side between the fixed and axle fulcrum points, it won’t be very easy to get it in.

To ensure you do get a straigh CSB wire run, when you finally get round to soldering in the fixed fulcrum point handrail knobs, do it once the Hornbloks have been fixed in the chassis side and use the axle CSB tags on the axle blocks to space the wire from the chassis side and solder in the handrail knobs spaced from the chassis side by the wire. I've been over the whole think about which knobs to use and how to keep the wire straight here.

Finally, if you used the A hole in the CSB tags, remember you need to modify the hornblock slide sides as the instructions sheet explains.

Good Luck

[Andrew Bluett-Duncan]

Thanks very much Will, your explanations are both thorough and clear. Admittedly, (and this is connected with dyslexia I think) I had to read them two or three times to fully understand, but I think I've got there in the end. A lot to think about.

I've just finished making up the six hornblocks and adding the CSB tags to them(pic taken before tags added). Before I can go much further I'll need to get the coupling rods made I've just realised, so I better get on with that shortly!

Kind regards
Andrew

IMG_1018.jpeg

[Andrew Bluett-Duncan]

The chassis / Frame built on an Avonside jig. The line of the CSB drawn in pencil and the proposed spacers(in RED) two of which will need clearance holes drilled in them.

Just realised that I've photographed the wrong side and its the reverse of the pictures above it. No time to correct it now....

IMG_1025.jpeg

[Winander]

Very tidy work Andrew. Is it possible to extend the spacer on the right (of the actual frame) to coincide with the nearby fulcrum position?

[Andrew Bluett-Duncan]

Very tidy work Andrew. Is it possible to extend the spacer on the right (of the actual frame) to coincide with the nearby fulcrum position?

Hello Richard
Yes it may well be, thank you for the idea. If I've understood correctly, using a 0.5mm hole in spacer would replace the handrail knob in that position?

Kind regards
Andrew

[Lindsay G]

Is it not better to have the downward plate of that rear spacer as a stop for the CSB wire that can then be threaded in from the front and retained in place by the front buffer when the body is added.

[Will L]

... If I've understood correctly, using a 0.5mm hole in spacer would replace the handrail knob in that position?

Correct

Is it not better to have the downward plate of that rear spacer as a stop for the CSB wire that can then be threaded in from the front and retained in place by the front buffer when the body is added.

My CSB wires always have about 2mm at one end turned into an L, so that end won’t pass through a fulcrum point. It also gives you something to hang on to. Then you don't need a stop at both ends, just at the end you insert the wire from. What you do need is a stop that isn't there when you assemble the chassis, and yes this is usually the buffer beam. I make the wire long enough that when the L runs into the stop, it will still be in the fulcrum point at the other end. Even though the CSB wire should never be fixed to anything, I have never actually noticed any tenancy for them to work along in use, but even if it did, fitted as above there is no danger of them falling out.

One more quick tip. When you build the chassis use as thick a CSB wire as will go through the fulcrum points. Usually about 20 thou. This means that it is effectively rigid when you test the bare chassis, which enables you to see if you’ve got anything wrong and the chassis doesn’t sit quite flat and level. Yes, a sprung chassis will make up for minor errors, but it is better off without them. Assuming the track you test it on is nice and flat, it will run perfectly well with the thick wires in. When the body work is finished, weigh the loco and fit the appropriate wire.

[Andrew Bluett-Duncan]

Is it not better to have the downward plate of that rear spacer as a stop for the CSB wire that can then be threaded in from the front and retained in place by the front buffer when the body is added.

Lindsay
Thanks for your idea. However, I really want to get the vertical part of the spacer further towards the centre of the chassis if I can.
Kind regards
Andrew

[Andrew Bluett-Duncan]

Hello Will

Thank you again for your full explanations. I follow what you say about the wire needing to be free and yet at the same time trapped, by a buffer beam for instance. And I'll try out the stiff wire approach when eventually I get to that stage.
Wish me luck!
Kind regards
Andrew

[Will L]

...Wish me luck!...

No luck required, if you can build a fully compensated chassis you can build a CSB based on, all you need is a clear view in your own mind of what your trying to achieve.

[Andrew Bluett-Duncan]

Sorry, but all the photos have come out in reverse chronological order.

Kind regards
Andrew

If you add each photo as it loads from the bottom of the attachment list as a "place online" in the body of the post you'll get them in order. Anyone not logged in will also be able to view them too.

Hi Andrew,

I've fixed it for you, by adding them "inline". Michael's suggestion is right that this is the way to do it.

Best,
Paul (with Forum Admin hat on)

Hello Paul and Michael
I've realised that I don't understand what "placed online" means. what button(s) do I press to achieve this, please?
Andrew

[Will L]

Hello Paul and Michael
I've realised that I don't understand what "placed online" means. what button(s) do I press to achieve this, please?
Andrew

Full instruction available here https://www.scalefour.org/site/help/forum-images.html

[Andrew Bluett-Duncan]

Progress so far.

IMG_1114.jpeg

But when I used the Avonside Jig to solder in the spacers, it came out with the sides out of alignment , hence the angle of the over long axel! So eventually I did it the old-fashioned way using my rather ancient MDF alignment board....

IMG_1117.jpeg

And all seems fine

IMG_1122.jpeg

Modification to the gearbox to allow the 2mm bearings to be withdrawn easily. 14BA nut and bolt provide the ability to do this.

IMG_1129.jpeg

The chassis with gearbox and motor precariously balanced in roughly the right place...

IMG_1130.jpeg

And miracle of miracles, it looks as though the body and chassis seem a match!

IMG_1124.jpeg

Wheels next, so time to prep the axel ends to stop them cutting their own hole through the wheel, fit the crankpins, and whip out the wheel press.

Andrew

[Andrew Bluett-Duncan]

Hello Paul and Michael
I've realised that I don't understand what "placed online" means. what button(s) do I press to achieve this, please?
Andrew

Full instruction available here https://www.scalefour.org/site/help/forum-images.html

Thanks Will...they were different to what I found on my laptop but its got me started and I then muddled through
Andrew

[Worzels Works]

Hi Andrew,

Just had a thorough catch up on the thread and enjoying watching this come together, very much a soft spot here for GW saddle tanks. Also very grateful for seeing the answers and explanations to the questions you have had! looking forward to more progress and seeing it completed when you get there, looks like lovely work with the soldering too!

[Andrew Bluett-Duncan]

Hi Andrew,

Just had a thorough catch up on the thread and enjoying watching this come together, very much a soft spot here for GW saddle tanks. Also very grateful for seeing the answers and explanations to the questions you have had! looking forward to more progress and seeing it completed when you get there, looks like lovely work with the soldering too!

Hello James
Thank you very much for your comments on my saddle tank build. And as to the help and suggestions I've received, its been considerable has it not, which is at least a part of the reason why I came to this site in the first place. So thanks again and I'll keep you posted as progress is made!
Kind regards
Andrew

[Winander]

Hello Andrew,

Are you sure that the spacer on the end nearest the motor is the same width as the others? In the second picture the frame seems to take a dive inwards, although it may be a trick of the image.

[Andrew Bluett-Duncan]

Hello Andrew,

Are you sure that the spacer on the end nearest the motor is the same width as the others? In the second picture the frame seems to take a dive inwards, although it may be a trick of the image.

Hello Richard
I agree it does look very off...infact the whole thing appears to have a curve in it...i don't think it was quite as bad as it looks in the photo. However, the version not made on the Avonsiude jig is pretty good, straight and untwisted. I've still not fully understood what I did wrong with the jig built version, but its certainly to do with the spacers and not having them at right angles to the side frames...how I managed that is a bit of a mystery.

Anyway so far as I can see all looks ok now. The next stage of wheels a coupling rods will sort out the men from the boys!

Kind regards
Andrew