Stirling Single Wheeler in G3

Jon Nazareth

Western Thunderer
IMG_2175.JPG

This picture has come out darker than I thought that it would but, one can still see 'things'.

The thing about scratch building is that it takes time, well, it does for me, to work out how to do 'things'. The 'things' in this instance are the brake blocks or how to hang them. I've managed it now but it took a bit of head scratching in order to work it out. As can be seen, the top of the blocks touch the wheels but, when given a gap of say, 3/32" between frame and axle box, they do look a bit better. I've said 3/32" as I don't know how far the finished tender will sit down onto the coil springs or even, how much I should allow as a gap. If needs must, I'll trim back the top of the blokes to get them to sit better against the wheel rim. The hangers are silver soldered onto a length of tube which also acts as a spacer between fram side and top of hanger. The next job is to make up the brake rods, another fiddly 'thing' to do :D.

Jon
 

Jon Nazareth

Western Thunderer
I've put some 3/32" temporary packing between axleboxes and frames and the brakes hang perfectly. Not sure how to maintain that gap when all is finished. Any ideas?

I'm looking at making up the brake rods et al but am stumped at the moment not knowing the size of the cross shafts that connected the brake blocks across the width of the tender. Can anyone come up with a rod diameter for me, please? I shall post this in the 'Questions' section as well.

Jon
 

Ian@StEnochs

Western Thunderer
Hi Jon,

I have built a few similar Stirling tenders but from the G&SWR. In S7 but similar construction to yours all be it a bit smaller. Remember Patrick started at Kilmarnock and his brother James followed on.

My springing is a coil on top of the box hidden by the centre strap on the dummy leaf springs. It is difficult to work out just how heavy the vehicle will be and how much compression the springs will be under. My method is to put the spring top support such that there is a little, around 1mm, compression on the spring to begin with. Ride height is adjusted by adding shim washers when the body is finished.

The cross shafts. I’m not sure which ones you are referring to but on all the GA drawings I have the pull rods are either side of the wheel and independent and fixed to the bottom of the brake hangers by 1” rods. The wooden block is held on by screws but located against a raised part on the hangers which I assume are wrought iron. Each hanger is attached to the one on the opposite side by a 3/4” rod with an eye at each end held by a single nut and bolt to the hanger. I suppose this is just a stay arrangement to keep the brake gear in line.

Having given you this info I realise that probably by the time the GNR tenders were being built there would have been some improving developments. I know David Smith described the ride of the tenders at anything above 30 miles an hour as akin to a ‘jigger screen’, the shaking table used to screen coal at the washery!

Ian.
 

Jon Nazareth

Western Thunderer
Ian
I think that you are right, I now don't think that there are any cross shafts connecting the heel of each block to it's mate on the opposite side of the tender. I've just been looking at a poor picture of the present tender in York and I'm blowed if I can see one at the rear.
I'm interested in the way that the rods are connected to the blocks. Is there any chance of you posting a picture of this detail, please? I can understand if too difficult though.
I must admit to not ever having built a tender, especially from scratch, before and it does feel as if I'm stumbling about in the dark. Are there any books that you know of on the subject. It won't be holding any water which is a bonus.
Talking about coil springs, I don't think that mine are anywhere near strong enough and will have to look out for some stronger ones when the time comes.

Jon
 
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Jon Nazareth

Western Thunderer
IMG_2185.JPG IMG_2187.JPG

The top picture shows the little tubes that I've silver soldered onto the knee of the brake hanger together with the brake block and hanger for the other side. The small tube will be trimmed back when I'm sure of how long it needs to be in order to clear the wheel(s). The small tube is to take the brake rod which will be held in place with a 14BA nut and bolt. Thanks for the tip, Ian.
The second picture shows the brake blocks perfectly in line and the 3/32" spacers needed to achieve this.
I've ordered a copy of the G1 'Project Book' hoping that it will give me some ideas on how to build the body of the tender.

Jon
 

Ian@StEnochs

Western Thunderer
Ian
I think that you are right, I now don't think that there are any cross shafts connecting the heel of each block to it's mate on the opposite side of the tender. I've just been looking at a poor picture of the present tender in York and I'm blowed if I can see one at the rear.
I'm interested in the way that the rods are connected to the blocks. Is there any chance of you posting a picture of this detail, please? I can understand if too difficult though.
I must admit to not ever having built a tender, especially from scratch, before and it does feel as if I'm stumbling about in the dark. Are there any books that you know of on the subject. It won't be holding any water which is a bonus.
Talking about coil springs, I don't think that mine are anywhere near strong enough and will have to look out for some stronger ones when the time comes.

Jon

Jon,

Sorry for delay in replying, family wedding, but herewith some scans which may assist. These are from the James Stirling tender for passenger locos. First used on the 8 & 60 classes of 2-4-0 but then the 6 class 4-4-0s. You will see it is quite basic and would have been a bit hairy at speed!

As built the brakes were wooden blocks but were modernised later with iron shoes. My copy had the modifications drawn on for the iron shoes when I got it and I am pretty sure that they were done by Kilmarnock works drawing office. I don’t have a drawing showing ends for this tender but you can see the cross stay on the 4th sheet which shows the plan. The photo of 271 with a similar tender coupled to an 0-4-2 coming up from Portpatrick clearly shows the stay.

Ian.

DF0E1EC7-90AF-473A-A56F-F04B2B6855AD.jpeg E6F01709-3F0E-4A5A-8060-F87BD7E4128D.jpeg 4D50003E-7BE8-4FA8-8D0E-B1BB6B40DA8C.jpeg 09AF896E-D6A8-47C2-AEA0-C766E0428C05.jpeg E100D030-E4B3-453B-B867-6E0273585B7F.jpeg
 

Jon Nazareth

Western Thunderer
Ian
Thank you very much for the copies. I've yet to look at them in detail but they look very good. My task today, too hot in the garden, is to make up the Guard Irons that were fitted to the rear of the tender. I have noticed that these aren't a feature on the photograph that you have sent but, nothing ever stays the same. Below is a picture that I'm going by, it's all that I have but, I'm sure that I'll work something out.

Jon

real_tender_01.jpg
 

Ian@StEnochs

Western Thunderer
Ian
Thank you very much for the copies. I've yet to look at them in detail but they look very good. My task today, too hot in the garden, is to make up the Guard Irons that were fitted to the rear of the tender. I have noticed that these aren't a feature on the photograph that you have sent but, nothing ever stays the same. Below is a picture that I'm going by, it's all that I have but, I'm sure that I'll work something out.

Jon

View attachment 89385

Funny but none of the G&SW tender locos had guard irons on the tender until Peter Drummond came on the scene in 1912. I don’t understand why as there was quite a lot of tender first required.

Ian.
 

Jon Nazareth

Western Thunderer
These guard irons were very fiddly and time consuming things to make but it's done now. I won't have to bother again until the pair for the loco itself are needed and that won't be for a while yet.
I don't like the way that I have the brake hangers on those cross shafts so, I'm going to change the set up. What I have in mind are some individual 'pins' soft soldered in place with a threaded end to hold the hangers/blocks in place.

IMG_2190.JPG IMG_2191.JPG
 

Jon Nazareth

Western Thunderer
IMG_2197.JPG IMG_2205.JPG IMG_2208.JPG

The first picture shows the pins soldered in place that I made up to hang the brake blocks from and there is a thread on the end for a securing nut. I like to turn down the first few threads as this locates to nut and stops it falling off before it is threaded onto the pin.
The second picture shows the framework et al pretty much finished with the rivets in place each side of the axle box and the small dummy bolts along the frame side. These were placed into a .5mm drilled hole and riveted over on the inside as were the rivets.
The third picture is just a close up of the bolt heads.
I realised, too late, that there should have been bolts each side of the axle box but I'd already drilled out the holes for the 1/32" rivets so, no going back there. The other faux pas is to do with the paintwork on the wheels. My head has been in wagon mode for so long that I treated the wheels as I would have done for a wagon and cleaned the paint from the faces of the wheels. These should have been left painted green to match the loco :(.
The steel parallels on top of the frames are to bring the tender to it's working height and I was surprised at how much weight had to be added to get it down on the springs. When all is finished, I may have to either buy shorter springs or reduce the length of the once in situ.
One thing that I noticed as I rolled it up and down the track is that not all of the wheels turn at the same time. Logic tells me that the centre springs may need to be that much weaker than the others so that preference is given to the two end sets. I've never built a six wheeled tender before so, can anyone offer any advice, please?

Jon
 

simond

Western Thunderer
Jon,

You’re out in territory which I’ve never explored, so with that proviso I’ll offer two thoughts;

I agree that softer springs on the centre axle seem like a good idea, and I do this on my O gauge locos and tenders. It’s really important to prevent the see-saw effect on a high bit of track.

Don’t cut coils off your springs to shorten them, unless the coils are wound closed at the end, in which case grinding the ends is fine. Reducing the number of coils makes a spring stiffer - though it does reduce the preload, and will therefore lower the ride height. You may want to source softer / lower rate springs, or reduce the top of your axleboxes, or increase the cutout of your hornguides, or grind the ends of the springs, or a combination of the above, to get it to work well.

As it’s unlikely that Stirling, or any of the other chief engineers, had to consider the dreaded see-saw, it might be interesting to try to make the springs to the same rate, relative to the mass of the tender and the permissible spring travel. Not sure how you’d find out what the laden and unladen tender heights were, but it might be useful to know!

Best
Simon
 

Spitfire2865

Western Thunderer
For the tender, do all 3 axles have to be sprung? Perhaps you could follow American practice sorta and have one end axle sprung while the remaining two sit on compensated beams hidden behind the frames bearing down onto the axleboxes? That way you are effectively building a 4 wheeled vehicle according to the springing system. You could probably even sit the beams further back to bear directly on the axle centerline, hidden far enough away from the edges as to not be seen at all. Although you would have to ensure your ride height is even.
From the 4-4-0 Im designing, its effectively a 4 wheeled loco according to the springing.
 

Jon Nazareth

Western Thunderer
Simon, Trevor
I think that I may just go for a softer pair of centre springs. A much easier solution especially as the frame etc., is virtually complete and, what is more, I know nothing about compensating beams :confused:.

Jon
 

simond

Western Thunderer
My o gauge experience suggests (getting hat and coat) that springing might be better than compensation. Compensation is definitely better than rigid. Mixtures of the two may offer a good solution in some cases.

Springing where the axles actually float, rather than the chassis sitting on them and them being able to drop only, is ideal, but so tedious & fiddly to get weight distribution and ride height right. So much so that I’ve pretty much standardised on the ride height being set by a screw, with sprung droop on outer axles and sprung both ways on the inner one(s). Works with locos and tenders.

Slaters provide hornblocks & axlebox kits in 7mm, sorry this doesn’t help in larger scales, but you could copy them I suppose.

Best
Simon
 

Jon Nazareth

Western Thunderer
Simon
Thank you for your suggestions, much appreciated, but I'm going to carry on with the building of the tender and then see how it 'rolls' along. In the meantime, another problem has reared it's ugly head, read below.............

IMG_2209.JPG IMG_2210.JPG

Whilst looking to see where the wheel cutouts should be in the tank base plate, I noticed that the rear pin that holds the brake hanger prevents the cheese head screw from moving rearwards when the buffer head is pressed, I hope that makes sense. This means that the buffers on the rear of the tender need to be self-contained. I've seen a scheme somewhere on how to make this sort of buffer but I'm sure that it was in relation to parallel sided stocks. If I can't think of a way how to overcome this one then, the brakes will have to go. Any suggestions from those more knowledgeable than myself will be gratefully received (that will probably be everyone on this site) :D.

Jon
 

jamiepage

Western Thunderer
Jon,
Presumably the buffer body rear spigot is currently long enough to go full depth of buffer beam and that rear block?
Could you reduce the length of buffer rear bits, and the retaining screw, such that required movement is contained entirely within the thickness of buffer beam/ rear block?
The buffer beam itself is iro 1/4in (?) thick; that would suffice to take a reduced length buffer body rear spigot. The CH screw could then move back and forth within the block behind.
Jamie
 

JimG

Western Thunderer
Jon,

As an alternative to Jamie's suggestion, reverse the method of supporting the pivot for the brake and provide a bracket from the buffer beam or the block immediately behind the buffer. Reduce the length of the spigot and the bearing on the top of the brake arm so that access is available to the screw and it can also move inwards with buffing action.

Jim.
 

adrian

Flying Squad
Could you reduce the length of buffer rear bits, and the retaining screw, such that required movement is contained entirely within the thickness of buffer beam/ rear block?
After the effort to get the brakes looking right I think this would be the solution I would consider. The only difficulty would then be trying to get the buffer retaining screw in with the brake pin in the way. Would there be some way to shorten the brake support bush slightly to get the buffet screw past it. It would then mean that rather than a nut on the inside of the frame the brake support pin would be a bolt from the inside - fitted after the buffer was assembled. Does that make sense?
 

simond

Western Thunderer
I’d also try to contain the buffer shank movement within the thickness of the “beam plus backing piece”.

My approach would be to replace the brass backing piece with angle, shorten & cross drill the shank, and to use a pin through the cross-drilled hole to retain the buffer. This might be a pain to assemble, but should save you sufficient space to allow the buffers to compress. If the tender body will be detachable from the chassis, the pins can simply be dropped in from above, which will simplify things.

Best
Simon
 
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