7mm On Heather's Workbench - the only one left

Remodelling the Ashpan

Heather Kay

Western Thunderer
Still not motorised! Instead I was sidetracked by what comes in the kit for the firebox bottom/ashpan. I carefully folded it up, then attempted to fit it. After much surgery, it fitted around the cast springs. It would need some remedial work to plug gaps, but it was in.

Then I looked at the real thing.


While the kit etched part is probably a faithful reproduction of the shape it ought to be, looking at the real thing you can't see much of the bottom of the firebox at all. I guesstimated about six inches show below the frames, and there's no real shape to it. I could just as easily have soldered some strip along the inside of the frames and be done with it.

So, out came the hacked about etched part, and out came the piercing saw and various measuring implements.


That's about what I see on the real loco.


The gearbox is an ABC one, which is mostly hidden within the frames. The kit affair probably allows for other gearbox designs which may be lower in profile.

Right, so with the motor installed again, and literally lashed up while I ponder a better strapping arrangement, time to get some wiring in there.
Tender Buffers, or Not

Heather Kay

Western Thunderer
In my ongoing pursuit of avoiding the actual wiring up of the motor in this model, I've been contemplating joining the loco and tender together. I think there's enough "give" between the pair to help it negotiate something approaching the client's somewhat unreasonable curve demands.

However, I do need to organise the tender buffers. The kit has generic JLTRT cast brass jobs. I need something sprung.

Now, I have a couple of leftover 4mm buffers that could be repurposed. One pair are possibly Maygib sprung coach buffers, whitemetal bodies and steel heads. They might be adaptable with some hacking about. Otherwise, I have some brass turned heads, but I'd need to make up suitable bodies. Finally, I have a set of assembled brass and steel sprung buffers, probably intended for LMS wagons or similar.


I've let the braincell run over the options, but I've not come up with something I'm satisfied with. The whitemetal bits seem to be the most amenable to adaptation, and do sort of fit the available holes. So, I open it to the floor: any ideas, particularly about how I might construct a working sprung buffer using the brass head?


Now, back to wiring up the motor. No, really.
Inside Motion, Sort Of

Heather Kay

Western Thunderer

Close. There's a good reason why I normally contract this malarkey out to people who know what they're doing!

I've spent the morning cleaning up and fettling the eccentrics, valve rods and straps. There's smooth movement to be had everywhere, so I reckoned it was time for a dry run assembly before I commit to fixing the eccentrics to the axle. It shows I was right to allow the axle to drop out easily, as it looks like it'll all need assembling on the bench - attempting to locate the valve rods on the eccentrics is akin to juggling bagpipes!

Before I flight tested things, I've decided to stop.

Oh, by the way, I did power the motor up yesterday. Wipers on driver's, though, well, that's another matter. I rather think the only pickup will be tender-based.

So, more thinking about slide bars before I call it a day properly...


Western Thunderer
Hi Heather,

Well it looks to me as if you are making a splendid job of it all. The eccentric straps and expansion links look just perfect. Do you solder them or are they nuts and bolts? Currently using MOK parts for a Bulldog and they take M0.8 bolts and nuts. Very fiddly to do up the nuts but at least you can take them apart if you need to.
The flat valve rods in the 'Swindon' box need to slide beautifully. Assembling them on the bench is good if you can do it but it is extremely fiddly getting the axle in again whilst trying to line up the piston rods and the valve rods. Just take it slowly you will get there in the end. The relief and satisfaction of getting it all together is worth it though, I promise you!

Heather Kay

Western Thunderer
Aw, thanks Paul!

The valve rods will be a static representation. Most of the kit gubbins is notional, moving just enough to show something happening, and limited to valve operating rods, reversing lever and drive connecting rods and crossheads/piston rods. In fact, the eccentrics for the main piston rods mean the crossheads don't travel as far as they should if I was doing it all with proper cranks - which is actually helpful.

So far, everything is held in place with 0.9mm wire, soldered in place. As long as critical parts have been chemically blackened - thanks to Colin @eastsidepilot for that little tip - the solder holds the pins and doesn't gum up the works. I've aimed for loose but not sloppy.

The headache is the slide bars. As I outlined way back, the kit provides castings which cover outside cylinder types, and look wrong. Stupidly, I opted to hack 'em off and will be substituting something that looks a little more like it ought. The piston rods slide fairly well, at least for the limited travel they need. I plan to tap the crossheads and run small brass bolts through to hold the connecting rods.

I've put it all back in the box for now. When I feel strong enough I will tackle fixing the eccentrics in place on the axle, and hopefully work out how to fit slide bars that are parallel!

Heather Kay

Western Thunderer
Having left this build lurking on the test plank while other builds made some progress, it was time to bring it back into the limelight.

Having asked around about the best method of fixing the eccentrics to the centre axle (I can't really call it the "driven" axle, as that would confuse since the electric motor and gearbox drives the rear axle…) I pondered on my options. As there is no split in the axle itself, and the castings ought not encounter any severe stresses - if I've got the rest of the parts set up properly - then I reasoned epoxy resin and pinning should suffice. I don't have a good track record with two-part epoxy, but the last couple of times have worked as they should, so I plan to arrange the gluing session later today and leave things overnight to set properly. Then I'll have a think about how to drill and pin without making it all fall apart again. Anyway…

I needed to sort out the slide bars. After a fruitless morning attempting to get things to work, I realised I had no alternative but to undo the work I'd done previously. Where I'd used the hacked about castings and some brass tube for the piston rods to slide in, it became obvious there was a serious mismatch in angles. So, they had to come out. I replaced the brass tube, setting the angle for the piston rods. Then, thankful I hadn't discarded the cast slidebars I had chopped off previously, I fitted them one at a time so the crossheads could shuffle up and down. Clearances are tight between the crossheads and the axle bearings, and I've had to compromise by removing some of the cast detail I had hoped to retain, but things actually fitted together.


Feeling a lot better about things, I mocked up the eccentrics on the axle, fitted the crossheads and connecting rods, and managed to assemble things as I intended by fitting the axle up from underneath. As a dry run, it looks like it will actually work. The next job, then, is to fit the eccentrics properly, as explained earlier.


With something of a gaping void between the motion bracket and the back of the cylinder block, I fabricated representations of the valve rods from some brass tube and wire. They don't move, but they look okay. Once the eccentrics are fixed, I can work out how best to mount the valve gear, with some representation of the connections between the rods and the links - most of which is out of sight below the horizontal plate, so that will hide a fair amount of sleight of hand.

I think I shall consider loco brake rigging for the rest of the day, then break out the Araldite.

Heather Kay

Western Thunderer
I realised I hadn't really explained clearly how the inside motion is faked in this kit.

A proper set-up would involve webs for the cranks, cutting and joining various parts in order to give a prototypical driven crank throw, plus the valve eccentrics. What JLTRT have done is provide a pair of large eccentrics to simulate the cranks. In reality, it doesn't look anything like the real thing, but inside the frames with various bits wiggling about it seems to suffice for most people. It's also intended to be almost idiot proof, but we won't go there!


Here you see the eccentrics. At the top are the crank axle substitutes. I've flipped one over so you can see the cast collar which allows a little space to the paired valve eccentrics below. The trick, if there is one, is aligning things on the axle.


Here's one I did earlier… :)) Referring to a works arrangement drawing of the valve gear, I did the following:

I attached one wheel to the axle. Standing the assembly wheel down, I slid one axlebox on, followed by a spacing washer. Then I plopped some cling film over so the axle poked through. This, hopefully, would prevent any glue gumming the bearing up.

Next, having mixed my epoxy resin, I laid the first "drive crank" eccentric so it was on the opposite throw to the crankpin. This seems to match the drawing. Both valve eccentric castings went on next, followed by the other drive eccentric set so it was opposite where the other wheel's crankpin is. All were aligned to be best match to the drawing.

Happily, the epoxy worked, as did the cling film. My next job, really, ought to be drilling and pinning to ensure nothing moves if the glue should ever give up.

I didn't get very far with the brake gear. Lots of drilling and fettling, as ever. I have replaced the brass cast shoes and hangers with 3D print ones from Simon Thompson (@SimonT) so there ought not be any shorting issues. While I'm fitting the brake rigging, I am also considering if there is a way to fit wiper pickups on any of the loco wheels, and how to run subsequent wiring so it's unobtrusive.

First, I must recover from a dose of ostepathic treatment. I may be a while.
Loco Brake Rigging

Heather Kay

Western Thunderer
Baby steps. It's one of those weeks, where I'm finding it a little hard to concentrate on the tasks at hand.

After having done our weekly grocery shop, and performed our civic duties at the polling station, it was time to attempt the brake rigging.


Despite having a drawing, I wasn't entirely clear about how the brakes were connected to the vacuum cylinder under the cab. I therefore set about fitting things together from the front of the loco. The brake hanger shafts went in, plus tube spacers so the printed hangers and shoes went on consistently in the same place. Quite how this arrangement can be made demountable at a later date remains to be seen, but I suspect recourse to PVA will be favourite. For some unaccountable reason, the loco braking is less detailed than the tender, but I shall put that down to them being separate kits from which the modeller mixes and matches to make the combination required. I'm still pondering the safety chains. I don't have anything in stock, so if twisted wire doesn't look right I'll be doing some jewellery shopping!


With the main rigging assembled, time to figure out how it's all attached under the cab. The drawing I have, plus the incredibly useful photos of the loco in preservation, have been perfect. They have, equally, shown me that various parts are in need of replacement or surgery. The slack adjusters, for example, are too long by nearly 10mm, and the brake cylinder lever is also rather too lengthy. Some cutting and shutting looks to be in order. I wonder which loco these parts are meant for? Presumably, something further up the food chain, like a Castle or King. While I'm complaining, the cross bars are also not quite right, but I'm prepared to overlook that.

Depending on the outcome of national events, I may or may not get to correct and assemble things tomorrow. If you don't hear from me, I'll probably be safely resting in a padded cell. Send tea and cake. :confused::p

Heather Kay

Western Thunderer
Hello. The padded cell remains unoccupied for now, but I'm still open to offers of tea and cake. ;)


Well, that was a right old faff. Is it me, or does everyone find loco brake cylinders always want to be exactly where a bolt goes through to attach chassis to bodywork? In this case, it was almost bang on top of the bolt hole, but some filing away of the casting, and providing more of a slot on the cross member, seems to have left sufficient room to wiggle a bolt into the hole. I've mocked it up for size in this shot. The slack adjusters have been shortened by about five millimetres in all. The cut'n'shut has been drilled and pinned, just to make the join more robust. As was pointed out to me elsewhere, and obvious on the drawings, the brake rigging should really be straight along the longitudinal axis of the loco. We are, however, where we are.

Time to get back to sorting out the internal wiggly bits, I think.
Inside Motion - It Moves!

Heather Kay

Western Thunderer
Well, well, well.


It's all been in, out, in, out, shake it all about, umpteen times over the past few days. Yesterday I bit the bullet and assembled the cranks and straps with the axle. Some trial fitting, more filing, and some mild swearing later, and it actually rolls without any serious binding issues. There's a slight bind, but I hope some running in will cure it - I can't actually see what is causing it, despite scrutinising closely from all angles.

The proof in the pudding will be to refit the motor, coupling rods, and trying it under power. Before I do that, I think it might be wise to get things painted. I supposed I should take it all apart again, then. How many times will that be? I've stopped counting!
More Loco Details

Heather Kay

Western Thunderer
Thanks for that tip, Steph. Happily, the more I roll the chassis in and down the easier it becomes, so I'm confident whatever is binding will bed in eventually - or something will fall off!


Feeling somewhat light-headed from e experience of something actually working (or it may be the pollen) I decided to sort out something that's been bothering me for a while. Just a low level kind of bother, but the cast brass top feed pipes were actually too short to reach the holes in the running plate. I chopped off the pipe, leaving the flanges, which I drilled out to take some copper wire of suitable dimension. These can be fitted properly once the various main components have been painted.


Finally, a shot to remind me that although there's a way to go yet, I'm quite some way towards completion after all.

I ought to sort out a "to do" list, because I keep remembering odd little things that should be attended to. Unimportant stuff, like loco to tender coupling, injectors, sand boxes, those sorts of insignificant details.


Western Thunderer
is the brake cylinder in the correct place? I only ask as the 2251 and the 94XX are exceedingly similar and on the 94 the brake cylinder is tight up against the right hand frame. I only know this because I am doing a lot of looking at 94X drawings. Of course the drawing could be wrong!



Western Thunderer
sorry to have used up a few of your heart beats. Now to work out why they were different.


Active Member
Presumably you could use the MOK crank axle for this? That said, this looks very good indeed.