7mm On Heather's Workbench - small and perfectly formed

flexible_coupling

Western Thunderer
Heather,
Quick question as I'm contemplating one of these kits in the next few months to replicate ex-BR 7754 for Mountain Ash. Do you fancy, with the motor/gearbox vertical as you have it, that there is any clearance for the larger 1830/1833 motors, or to have a flywheel of any size on the 1824 motor you've got there?

It looks extremely good-looking from your photographs so far! Feeling like it'll be a good choice of kits.
 

Heather Kay

Western Thunderer
Do you fancy, with the motor/gearbox vertical as you have it, that there is any clearance for the larger 1830/1833 motors, or to have a flywheel of any size on the 1824 motor you've got there?


I think it unlikely there's room for a larger motor, or a flywheel, frankly. The recess in the firebox of the cast boiler is 25mm across the loco, 30mm from the firebox opening towards the boiler, and 35mm top to bottom.

All of which is not to say there may not be other motor and gearbox combinations that might fit. With careful work, it might be possible to open out the boiler barrel to take a flywheel with the motor horizontally mounted.
 

flexible_coupling

Western Thunderer
It's all good. I expect with such a well-engineered-looking gearbox and stay-alive capacitor with the DCC, the mechanical effect of a flywheel wouldn't really be necessary - just hard to let go of some of the old principles!
 

Heather Kay

Western Thunderer
Hello. Me again, on the cadge.

I'm worrying at the brake rigging at the moment. The instructions illustrate a vacuum cylinder, akin to a coach cylinder, which is intended to vaguely fit somewhere beneath the bunker. What I have in the bag of castings is a much, much smaller cylinder which could be mistaken for an air brake cylinder.

I can't find any clear images to show me what is supposed to lurk in the murk beneath the bunker, or how it's actually supposed to fit. Any clues, please?

Ta.

Now, back to the nickel-silver knitting for a bit.

Update: What I appear to have is a steam brake cylinder. Still no clue as to fitting it.
 

Dog Star

Western Thunderer
Update: What I appear to have is a steam brake cylinder. Still no clue as to fitting it.
Under the bunker... attached to a brake cross-shaft upon which there ought to be four levers (steam cylinder, hand brake column and two for brake pull rods).

I have looked through the parts photos at the beginning of this topic and I can see the steam brake cylinder... and I cannot see anything which looks like a brake cross-shaft, neither can I see anything which represents the extension of the hand brake column for connecting to the same shaft.
 

Heather Kay

Western Thunderer
Thanks Graham.

What I've decided to do is make up the outside pull rods from the NS etch, soldering on the supplied washers to give adequate space to clear the wheels. I plan to make the brake gear removable, partly to make it easier to paint, but also for future maintenance.

To make this work, and to better represent the chunky cross shafts I see in the photos, I've ordered up brass tube of sufficient inside diameter to let me push 0.7mm diameter wire into it. Once side of the gear will have the tube fixed permanently, and the other will be a push fit into it. The same tube can be used to represent the cross shaft with all the brake operating mechanisms attached to it.

While I wait for that order to arrive, thoughts will turn to the upperworks for a while. I need something topsides so I can figure out where to fit pickups.
 

Heather Kay

Western Thunderer
It seems a lot longer since the last update, but here we are.

For the past couple of weeks I have been mulling the brake assembly over in my mind, while working on the other stuff on my bench. I think I have a strategy to make some progress.

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First was how to make a suitable cross shaft under the cab and bunker for the steam and hand brake. I've used some brass tube with wire passed through that lets it fit in the frames. The steam cylinder is attached to a couple of NS cranks, which come on the frames etch. The dangly crank on the right is for the handbrake. Although I have access to some useful GAs for this loco, I don't have clear dimensional info so I am leaving things floating until I have the location for the handbrake column at the back of the cab.

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Next up was the blow down cock. I noticed this pipework in various photos, always on the driver's side. Both preserved locos I'm working from show something here, by funnily enough close inspection of L94 showed this exact type of valve found in the super detail kit. The other preservation loco has a slightly different style.

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First stages of working out the brake rigging cross shafts. As I said in the last post, this is tube. As best as I can work out from the photos, the leading and centre driver brakes have cross shafts, but the rear drivers have the pull rods doubled either side of each wheel and no cross shaft. I'm still trying to work out exactly how the pull rods are connected to the main brake cross shaft...
 

Heather Kay

Western Thunderer
A quick question for the experts in dark green engines with copper tops*: I have clear photos that show 7752's ATC battery box mounted just behind the driver's side cab steps. I also have an as-built image of 7751 that clearly shows no battery box.

My question is would fitting the visible box be more or less correct for a loco in mid-1930s condition?


* I do realise this breed of loco did not actually have a copper top to the chimney. ;)
 

Heather Kay

Western Thunderer
Cheers Ozzy. I think I will go with fitting the ATC gear, since the period the client wants is generally from the point the loco was built until about 1939 or so. I'm pretty sure the equipment would have been fitted during that time, and since I've got the parts in stock...

Earlier this week, my mojo left me. I'm not sure what caused it, but a distracted sleep pattern might not have helped. Anyway, come Thursday afternoon and things began to revive.

Having been bogged down with brake gear - this seems to be a theme with my builds - I decided I needed to have a better idea of where the handbrake column was located. What better excuse to begin work on the bits that sit on the frames?

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The footplate in this kit is made of a brass fold-up cradle, to which an thinner half-etched overlay is fixed. There's a deal of riveting to do on this overlay, and to make sure I didn't miss any I dabbed around with a black marker pen.

Of course, I punched out the rivets for the lamp brackets (some of those circled), forgetting the SDK includes cast ones...

I have a Graskop riveting tool, with a couple of different sized punches and anvils. What I didn't notice was one of the anvils I used hadn't seated properly, causing the punch to drift slightly on impact. This imparted a slight offset on the resulting rivet, and also caused a subtle bow to the etch. Lesson learned.

IMG_7628.jpg

Here's the main footplate cradle. I've bent up the lamp brackets. The etches hadn't quite eaten through parts where there should have been gaps, so I had to run round with a craft knife to open them up. This slight under-etch has had a knock-on where I've had to open up slots and clean back the edges of tabs to ensure they seat nicely.

There are various holes, strategically located to aid soldering (or gluing if you prefer) the overlay to the cradle.

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As I said, I forgot I had the cast lamp brackets for this kit. Out with the various tools to clean off the half-etch bracket bases.

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The etched lamp brackets can be seen here, including the lamp storage brackets by the leading splasher. Off they come!

Fixing the overlay to the underlying footplate etch, while aided by the holes in the latter, was not my finest hour of soldering. It's a bit messy, but at least it's fixed now.

The instructions show the buffer planks etched as part of the basic cradle, designed to fold down and have detailed overlays fixed on top. Of course, this isn't how it works in the kit itself. The buffer planks are separate etches, and the fixing seems to rely on the top edge sitting in a rebate in the footplate, formed from the overlay and cradle, and butt joints on the valance, or hanging bar (as Mr Beare reliably informs me the GWR referred to the stuff under the sides of the footplate). This caused me some oaths of sweariness, as a couple of failed fittings led to me to rethink things. A bad solder joint here would have ramifications if the model was subjected to a bad shunt, or a heavy train snatched the coupling. I wanted to make sure such an eventuality did not occur, so I slept on things.

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My solution was short lengths of brass angle, fixed to the inside of the hanging bar.

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The brackets gave a firmer fixing for the ends of the planks, with some RSU work to get some solder in the top edge along the plank. The cradle bracing struts are not best placed for working on the inside of buffer planks, making it very hard to get a soldering iron, or the RSU probe, in to apply heat. I got there in the end, and after some cleaning up the buffer planks are pretty firmly fixed.

At last, thoughts turned to building things upwards from the footplate.

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The front and sides of the cab went together very quickly. A basic thick etch carcass is folded up, and front and sides are sweated on top. A couple of errors were noted at this stage: first, the cab handrail fixing holes are etched on the carcass and not on the overlay; second, a line of rivets down the edge of the door opening is missing. These things you fail to spot before you've soldered it all together.

I managed to punch through the handrail holes, but elected to ignore the missing rivets. I could, I suppose, add them cosmetically from spots of PVA or similar before painting begins.

Thoughts turned to the idea of fixing the number plates at this stage of the game. While they could be left until painting is complete, I always fret over the danger of misalignment and subsequent damage to the finish. I have decided to fix the plates while the cab is in parts, so I can get things aligned properly. They can be masked for painting, or at worst cleaned up afterwards. They're still in the pack, so if there are any thoughts on this, shout up!

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A dry fit of the cab front and floor. It's starting to look like an engine now.

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A view of the rear buffer plank. There are half-etch overlays to go down the valances, but they come later in the construction sequence. Sadly, the cradle prevents trial fitting of the footplate to frames, so I can't pose the part-completed model and pretend it's nearly finished.

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The value of dry fitting components: I felt the slots in the cab front plate for the wheels could do with widening to match the footplate opening. My worry was the possibility of contact and shorts. A quick pass with the whizzy disc and a file sorted that out.

IMG_7642.jpg

Now we begin to add details. These are the beading strips for the cab side cut-outs. You'll note there is a hole at one end. The 57xx class doesn't have a handrail inside the door space, so I surmise these have been cut and pasted from another kit etch drawing. They are longer than needed, which is good, so I gently annealed them in a propane torch to make it easier to bend them to shape for the cut out. I tinned the slot, and the edge of the cab frame, and used the RSU to fix them in place, with a little supporting role from the normal iron to make sure it all stayed put.

IMG_7643.jpg

I couldn't resist. Here we are, posed with the tanks and boiler with the dome and chimney balanced on top. This gives a false sense of being close to the finish, but there remain about half a million little details to add before I can begin to think this build is approaching a conclusion.

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This was the state of play last night. The bunker carcass is ready for its overlays, and the cab back panel is in place. Today, I shall finish the bunker and perhaps consider fitting some of the cab interior fittings. :drool:
 

Dog Star

Western Thunderer
I shall pinch the idea of using brass angle between the footplate and the buffer-plank / hanging bar as we have had fun with this in the past... too much on the hook revealed poor soldering on my part.
 

3 LINK

Western Thunderer
Evening Heather,

Good luck with the bunker overlays and the cast corners, I wish I could give you a tip or two on the said construction but I can't, so just take a deep breath and say " I promise not to swear too much while I build the bunker " :thumbs: .

ATB,

Martyn.
 

Heather Kay

Western Thunderer
Good luck with the bunker overlays and the cast corners


:))

I had a bash at them last night. It sort of went okay, but they didn't meet in the middle of the back. I tried in vain to get things to sit neatly, and so the bunker carcass came off again, and all the overlays were removed with the help of fire.

If I feel up to it - as I'm feeling a little under the weather this morning, so we'll see if the workbench is enticing enough to pry me away the sofa - I'll clean things up and attempt adjusting the bends again.

:confused:
 

Heather Kay

Western Thunderer
The lurgy conspired to keep me away from the bench all day. Now I am trying to work out how to get the bunker overlays to fit in the least bodgetastic fashion.

NQLTRT strikes again! Where are the characteristic steps up the left side of the bunker? The tidying pixies appear to have hidden my CPL catalogue, so would some kind soul please take a look and see if steps are part of the range? Failing that, another supplier I can acquire them from?

Of course, I am not averse to scratch building, but if the right things are available from the trade...
 

daifly

Western Thunderer
Can't see anything suitable in the CPL catalogue. Warren Shephard doesn't appear to sell them separately - they are part of the etches for e.g. his 16xx. Sorry!
 

Heather Kay

Western Thunderer
Can't see anything suitable in the CPL catalogue. Warren Shephard doesn't appear to sell them separately - they are part of the etches for e.g. his 16xx. Sorry!

Okay, thanks for looking. I checked out the Hobbyhorse range, too, with no joy. Looks like a scrap etch job, then, and I'll bend JLTRT's ear at Kettering.

EDIT: You know, it's a funny thing. Having decided to scratch the bunker steps, I went off down a rabbit hole to seek out good photos and possibly a drawing. What do I find? A loco in 1934 which doesn't have the steps (Kerr Stuart build), another of North British build (and closer in sequence to 7752) which has the steps but which are a completely different style to those I can see on the preserved locos. I am now thinking that I should leave them off. The client can always fit them later if they want them.
 

Heather Kay

Western Thunderer
I really do think I need some new specs. The various etch sheets for this build are sitting beside me, and I just happen to glance at them just now.

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I could swear they weren't there earlier. They are definitely not mentioned in the instructions...
 

daifly

Western Thunderer
I could swear they weren't there earlier. They are definitely not mentioned in the instructions...
When I looked at your first post I assumed (wrongly it transpires) that the steps that you have now identified were the pannier tank-front steps. I have looked at dozens of photos of these locos this afternoon and although most are in BR livery, all have the cab steps. Even the GW-period locos had them in the photos that I saw. Looking at the RCTS book on 6-coupled tank locos, it says that locos built after Sept 1936 had steps at manufacture and earlier locos had them fitted when passing through the workshops. They were fitted by welding. An additional handrail appeared at the same time at the upper rear of the cab round onto the roof. I suggest that the model would be more correct with steps than without and now you've found them, you have no excuse!
Cheers
Dave
 

Heather Kay

Western Thunderer
It took most of a day to get the bunker in a form I felt fairly happy with. It's not perfect, and to be honest, it's never going to be.

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There's a slight gap between the lower sheets, and the upper sheets are a teensy bit long, resulting in a slight bulge on the sides just over the flare.

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The bunker steps, that were missing then found again.

So, thoughts turned to that gap in the bunker.

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This is what we have. Two brass castings, designed to form the complicated bits, and a bit of etch designed to fill in the gap. It's fun trying to impart a gentle curve in the etch, what with all those rivets. Even a gentle annealing didn't help, so I have had to be content with imperfections.

This rump is not turning out as nicely as one would have hoped. Wait, there's more!

I worked out a way to get the three parts in a form that made it easier to fit in the slot.

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A bit of scrap etch as brackets, soldered together. I got it all right eventually, after a couple of attempts revealed the etch to be up the wrong way. :oops::rant:

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A couple of further scrap etch brackets along the bottom edge of the bunker slot helped to keep things more or less in line.

Dry fitting commenced.

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I'm pretty sure that gap shouldn't be there. How's the other side?

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Hmm.

:shit:

:headbang:

As you can probably see, there's no neat way to form that lovely smooth join from the top of the flared bit to the overhang vertical face. I've had a go at some gentle panel beating to form a lip on the insert etch. As for the rest, current thinking is to take it to Kettering and throw it at someone remove the cast rivets, fill the gaps and try and make good. The gap in the plating will just have to remain, with the hope the tool brackets, train pipes and couplings will draw attention from it.

Why this complicated form hasn't been rendered in resin, like the boiler/tanks, is anyone's guess. I am actually a bit pee'd off that what was actually a fairly pleasant build is spoiled by this characteristic feature being such a mess to try and construct.

I am now displeased, and shall put it all back in the box while I sulk.
 
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