7mm On Heather's Workbench - another other Twin

Heather Kay

Western Thunderer
I have a dormant thread on building a JLTRT LMS 10001 (click here to read it so far). That build has stalled for a couple of reasons, but I hope it might kick back into life soon.

To save some repetition, you can see the box contents and other interesting stuff on that thread. Suffice to say the other build is for 10001 in about 1953, just after it arrived on the Southern Region, while this build is the same loco but in 1948. It may prove instructive to see what differences occurred in the time between first emerging from Derby Works to the time on Southern metals.

Differences in the builds come down to the addition of electronics in this one. As an as-built representation of the loco, it will be paired with 10000 by its owner. In order that both will run more or less as expected when in multiple, I've been asked to rebuild the power bogie of his existing 10000 model, and match the DCC for both. More on that in due course, I suspect.

To begin with, I settled in for a spell of armchair modelling. Well, it was more a "spread it all out on the workbench with references" session.

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The kits from JLTRT cover both locos in "early" and "late" configurations. Out of the box they make into attractive and reasonably accurate representations. For the true pioneer diesel nerd, though, there are areas that need attention if we want it "just like the real thing".

The worst area is the roof casting. The engine room access hatches are moulded as symmetrical when they are not. There's a fair amount of surgery involved to rectify that, so I'm inclined to leave well alone. The boiler room vent panels, and boiler vent need reworking, as well as some screwed plates at that end. Some new vents need making for the fuel filler overflow, and some more screwed plates around the cooling fan.

On the body sides, the lower skirt panel lines need scribing in. There are two access panels on the No2 left hand side, below the boiler room grille.

For the noses, the raised waist strip needs to be trimmed back in front of the cab doors. The triangular plates for the SR lamp brackets need to be removed. The gangway door hinges need to be modified. I have a feeling the side blower access panels are not as flush they could be, but again that's serious surgery I'm inclined to overlook. The MU connector area is not quite correct, but this may be hard to rectify.

There is a shore supply box fitted to the battery box area, and I need to check the bogie suspension is correct, or correctable. I will also remove the large cast equipment cabinet from the No2 end bulkhead. As explained in the other thread, this equipment was moved into the clean air environment of the engine room itself on 10001.

So, a fair amount to do. I think I shall kick things off with getting the bogies built up and powered.
 

Heather Kay

Western Thunderer
One powered bogie, using the recommended Slater's GB14 14:1 gearbox with Mashima 1833. Delrin chain to the leading axle, leaving the centre axle to slop up and down.

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I might need to add a tensioner, but it works. I spent much of the afternoon trying to pin down a slight wobble that's particularly evident while on the rolling road. Running on plain track it is still slightly wobbly, but it's not as noticeable. I can't find where the wobble actually is, and I've spent ages watching things carefully.

Perhaps it'll run in once I've wedged the gearbox and organised the pickups. The kit is designed for plungers, but there is insufficient space when using the chain drive, so it'll be wipers on the power bogie. If the wobble doesn't disappear on its own, I am not looking forward to extracting the driven axle!

I would complete the unpowered bogie, but one of the wheelset axles has a split in the square shank. I'll take it to Reading next week and get a replacement. I'm surprise it passed QC checks, if I'm honest.
 

OzzyO

Western Thunderer
Heather, can you please explain why you have decided to run the chain above the middle axle? When if you you run it above and below it you maybe able to fit a driving sprocket on the middle axle, or you could fit two and have the drive moving across the length of the frames.

The wobble, it can be down to a few causes. Have you cleaned up the back of the wheels? Have you cleaned up the squares on the ends of the axles using a 3 square file? If you have done these things try revolving the wheel by 90Degs. and seeing how it runs then.

For plunger pick-ups think about using the Gibson 4mm ones, less drag and a bit smaller.

OzzyO.

PS. it maybe an idea to ask Laurie about the body and roof parts as they do produce a number of body styles for 10000/1 and you "may" have the wrong ones for your loco or time!
 
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Steph Dale

Western Thunderer
With plastic bogies, surely the easiest and lowest - maintenance pick up approach would be to use 'American' style. Even split axles are a doddle with a completely insulated bogie frame...

I'm also rather grateful for you posting those photos as I'm now certain that I can fit my drive into those bogies, which will be useful info to store away!

Steph
 

Heather Kay

Western Thunderer
I am firmly in the "it was a bad move to stop using clockwork" camp. I do quite dislike working with gears and motors - even with the out-of-the-box gear/motor combos from Slater's.

Paul, I had been through the recommended clean-up with the wheelsets before assembly. As far as I can tell, everything checks out just fine in that regard. The chain over the middle axle is to stop it drooping into view. Before anyone says, yes, it is the right length, as I tried taking one link out and couldn't get the ends to meet! I had been at great pains to ensure the drive cogs were aligned on both axles, too.

I like the idea of driving all three axles. I'm not sure it will enhance the tractive effort, and this model is destined to pull only a short train, and most likely coupled to its twin as a pair.

Anyway, I stripped everything down this morning, cleaned, fettled and generally faffed. I checked the gearbox on the bench and it was all true. I checked the axle bearings were all true and square, and the wheelset could be spun freely. I reassembled it, and have been running the driven axle only on the bench for a spell.

It's better, but there's still a tiny shimmy as it runs. I'd like to think this will be all but invisible once the body is fitted and its on the track, but the OCD part of me would like to make it go away. Therein lies the problem.

Leaving aside the annoyance at extricating the driven axle from the Delrin cog - boy, that is a good interference fit and no mistake - I think there are inherent problems with the resin moulding for the chassis. No matter how good the master, how good the casting process, the unit has some inevitable flexibility. At the moment, the axle bearings take all the load of the motor and gearbox, plus the weight of the finished model. In a way, I'd be happier with a properly engineered metal inner chassis with the motor and gearbox properly supported and fixed.

Still, we are where we are. I am currently considering a further strip down to try one more thing before I accept the inevitable and hope that running-in will help.

As ever, thank you for the input. It's much appreciated.
 

Heather Kay

Western Thunderer
Well, I've faffed about with the power bogie until I'm blue in the face. It still has a slight wobble. You know what? I reckon it's the final drive gear. Let me explain.

The Slater's box has a final drive gear with a single grub screw to clamp it to the axle. When in place, and under careful observation, I can see the gear moving ever so slightly as the axle rotates. My engineering advisor reckons this could be fixed by having another grub screw on the other side. I shall consider that as an option.

So I started putting together the outer frames. I love the bogies under the LMS twins. They seem so fussy, covered in bolts and rivets.

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The idea is you glue two side frames together with the ends, and once detailed up the assembly is bolted to the inner chassis. Here you see one set of frames, viewed from the inner end. Some of the brass castings for the brake rigging have been fitted.

I found the thin section of the end castings very easy to accidentally crush. Happily I spotted the problem before I had done too much damage. The lesson learned here is to drill out the holes for the brake and sanding castings before assembling the side frames and so on.

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Flipping things over, here's the outer brake gear detail and the sanding valves. It took a few minutes peering at numerous photos and drawings to work out the angle of the valves. I took the precaution of opening up the fine holes in the castings with a 0.5mm drill for later fitting of the actual pipes.

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And the leading end. Can you spot the obvious error? There should be a cast pot for a sanding valve, but it's missing. At this point I stopped, checked the other bogie parts, and realised I would need to make some new ones before I went any further. A job for another day, I think!

I'm not really happy with the fit of the frame parts. I need to spend a bit of time fettling and filling things.
 

OzzyO

Western Thunderer
Hello Heather,

Re. the gear wheel you could file a flat on the axle where the grub screw will fit and just tighten it so it only just touches the axle (so that the gear wheel will move a bit) and then fix the grub screw in place with nail varnish.

Re. the chain, you could fit a chain tensioner that runs on the top run of the chain, this could be made out of a length of Phos Bronze strip that is wider than the chain. It should be in an inverted curve so that it can't catch on the pins (links) of the chain.

Re. bogie sides, at some time in the life of 10000/1 did they loose a pair of sand boxes on the bogie frames? If they did it could be that you have one or two of these!

OzzyO.
 

Heather Kay

Western Thunderer
Cheers Paul. :thumbs: I shall have a good think about the power train when I get back. We off out to a local model engineering supplies company to stock up on sheet and strip metal.

This loco is intended to be as built, so anything later than the end of 1948 doesn't count! ;)
 

Heather Kay

Western Thunderer
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No, it's not nearly finished. I wanted to gauge the weight of the bodywork and chassis on the centre axle springing.

I've actually got as far as wiring up the unpowered bogie. I need to work out a plug and socket system that allows the insertion of electronics later. The powered bogie is currently in stasis while I consider my options regarding the minutely wobbly main drive gear.

I've scribbled notes on the body castings where I need to do work. Feeling rather out of sorts with the world ("Events, dear boy, events.") I shall probably limit myself to completing the outer bogie frames today.
 

Heather Kay

Western Thunderer
It's funny the things that intrigue. I was spending a bit of time today armchair modelling, re-reading the Wild Swan books on the twins. Mention was made of two Pyrene extinguishers strapped to the bulkhead in each cab.

Off I went into the rabbit hole!

I can't find any photos that show the extinguishers in place, but there is a photo of 10000 under construction where the bulkhead of No 1 end is visible, along with a pair of straps that look like they would hold extinguishers. I've done an image search for contemporary extinguishers, so I know what they ought to look like. I found some 48th scale military modelling extinguishers of the pump type fitted to many vehicles between the world wars.

I think what I may do is either ask Laurie nicely for a bag of the BR Mk1 guard's compartment extinguishers, or play with some brass rod and a lathe for a bit.
 

Heather Kay

Western Thunderer
Blimey! Two months, more or less. Well, I have been working on other things, so it's not like I've been wasting my time…

Odd how my last post was about fire extinguishers. I was mulling them over again yesterday. When you spend time poring over the photos of both locos in the Wild Swan books, you can actually see an extinguisher on the bulkhead wall of No 2 end. It's not where I expected. I thought perhaps it would be closer to the bulkhead centre door, but in fact it seems to be right by the second man's cab door. I took a while longer trying to confirm the same relative location for the No 1 end extinguisher, but with nothing absolutely conclusive I am going for an educated guess it was the same at both ends.

Now, the extinguishers themselves were Pyrene, but I'm not sure if they were CO2 or foam type. It would be nice if they were those lovely vintage copper and brass ones, too, but the only clear image that shows an extinguisher implies they might have been red. This supposition is based on the way red sometimes appears pale grey on some black and white films of the day, and the fact it certainly doesn't appear to be metallic at all. Whatever the case, the JLTRT extinguisher castings are pretty much ideal for the job.

I hacked off the resistor cabinets from No 2 end bulkhead, and filled the gaping void with styrene overlays. I'm sure there was something else on the bulkhead wall, but with nothing to prove anything it shall remain pretty blank.

On to modifying the sides and cabs, then.

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With reference to the detail drawings of the various changes and differences between the two locos, I added the skirt panel lines, added screw detail on the skirt and around the boiler vent.

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The same on the other side, plus two inspection plates, presumably to access the rear of the train heating boiler.

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Getting pernickety, the cabs got their fair share of attention. On the left, as it came in the box - aside from additional skirt bolt detail around the cab step. On the right, note the waist strip no longer meets the cab door. The book says the distance it stopped short was the same on both sides of the door. As the rear is covered by a bolted strip, moulded to the end of the sides, I took that as the width to trim back. The colour variation is down to the partially assembled model having sat on my test track being exposed to daylight from a window on one side. The exposed side has yellowed somewhat.

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The noses, with the unmodified one on the left. Aficionados will note the supplied cab suits the locos as running after their sojourn on the Southern Region and having returned to the London Midland. The triangular plates supported extra disc brackets, which were removed but leaving the plates. Such fripperies were added late in 1952, so off they must come. The extra marker lights were plugged with some styrene rod, and then carved and sanded away, along with the plates. Holes in the waistband were drilled out slightly larger and filled, then sanded smooth. (These were supposed to be threaded holes to hold back the gangway doors, supposedly with plugs that usually got lost. Apparently extra holes were added in 1960, so well beyond the period being modelled.) Although it's barely noticeable, the gangway door hinge pins were extended in 1951, so they have to be trimmed down. In this case, it's just a gentle slice of the top, as the bottom appears to be the right length according to photos. The bottom outer lamp brackets are apparently 2.5 inches further out from the centre line, so the cast holes have been plugged and new ones drilled. Finally the bottom centre lamp bracket was fitted higher on 10001. I've filled the cast hole, and will drill a new hole with reference to the lamp bracket casting pin later.

So, with that lot out of the way, it's time to set about the roof modifications.
 

Heather Kay

Western Thunderer
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Adding missing panels, correcting the boiler room ventilation panels, and correcting the boiler flue.

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Marking out for various vents and panels. These are going to need some work to replicate the mushroom vent style. I will probably find some brass rod of the right diameter and do some nifty work either with the Dremel or a lathe.
 

Heather Kay

Western Thunderer
Another two months pass…

I did a little fettling of the model at Telford, but nothing to write home about. I think I managed to glue a sum total of four parts together during the whole weekend!

Back at the bench, and with other builds either finished or working their way through the paint shop, I have been doing some more fiddling about with 10001.

I have been mulling over how to reliably form the hornguide lubrication pipework. There are twelve of each, left and right handed, to form. Thoughts included some form of jig, but before I set about that I thought I'd try forming by hand first.

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The wire is 0.3mm brass. I have managed to drill location holes into the oil box. What I can't - and won't - attempt is the pipe unions at the bottom of each oil box! The attempt sort of works out. With things being quite small overall, I don't think I could make a jig that would let me form the bends reliably, so I'm prepared to fall back on a certain wastage rate to form with pliers. This is a spare bogie side. I have a few in stock for various projects.

Okay, leaving lubricating pipes for a day when I feel up to it, I started thinking about the other odd details around the underframe. As recounted earlier, 10001 was fitted with a shore supply box at No2 end of both battery boxes. It also had lubricating oil filler pipes at the No1 end.

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The shore supply box is noted as being a 9in cube. I had some large section Evergreen styrene that was over size, so I measured it up and sanded it down to as close to the right size as I could. Some holes were drilled in the bottom to take brass wire detailing to represent the wiring conduit, and once it was glued in place on the underframe I added simulated caps for the various connectors. The pipe at the other end is some brass rod of roughly the right diameter, with added cap detail. I also added the battery box latch handles. If I can source suitable etched wheels, I might add the battery clamp handles on each end of the boxes.

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I fitted the vacuum brake rigging yesterday. The cast cylinder brackets are a bit of a fiddle to locate, but it looks the part once glued in. I understand there was a water scoop in the space between the battery boxes, as well as a couple of brake connecting shafts. As they're not ordinarily visible, I can quite understand why the kit maker hasn't bothered with them. Neither shall I.

I need to make up some safety cages for each of the coil spring sets on the bogies. I guess some scrap etch will do, if I can find a decent image to show how they ought to look. Once the hornguide lube pipes are done, the bogies can be painted, as can the underframe. Then it's final body details before that, too, gets some paint.

The shimmying bogie has pretty much been solved now. I refuse to go into the gory details, suffice to say the wobble is certainly much less marked than before. The one thing it has taught me is there is no such thing as a perfect gearbox, and I need to consider my choices much more carefully in future.
 

Heather Kay

Western Thunderer
Today has been about coil spring safety guards.

For some reason, the designers and builders of these prototype locomotives felt the bogie coil springs needed something to prevent them pinging off all over the place like Zebedee. 10001 was fitted with these from new, and 10000 received them in February 1948. Either way, I need to actually make some guards, because they are not in the kit, despite being something both locos carried - for 10001 all bar two months - for their entire careers.

I toyed with styrene sheet. I mulled thick paper. I ended up with brass.

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This is the item in question, this image being from the Wild Swan LMS Profile No 9 Pictorial Supplement, and reproduced here for informational purposes. As you can see, there were differences between the inner and outer cages, as well as a lot of details of brackets and weight-relieving holes. I value what is left of my sanity, so I elected to produce a simplified cage for all locations. No weight relief, no extra brackets, just a representation of the cage surrounding each spring pair. I have to make eight of these things in total, so the simpler the better, really.

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I measured the kit parts up, and came up with a simplified shape thought would bend up and slot over the bottom spring retaining plates. The outside of the bogie frame is to the top.

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I transferred the shape to some thin brass sheet.

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I set about the brass with a piecing saw and files.

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I folded the result, realising I had mismeasured the end lengths so they were a tiny bit shorter than they ought to be.

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Despite the measurement error, I pressed on and test fitted the result. As a first run through, it works. Apart from the short ends, it fitted snugly, and I think is sufficient for this build. I suppose, not including the working out phase, this took about twenty minutes. That would make a couple hours of work, but I think it's worth the effort.
 

Heather Kay

Western Thunderer
I forgot, but I also found some 4mm scale etched signal pulley wheels which scaled out just right for the battery retention clamp wheels on the battery boxes.

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You can just make one out, centred on the battery box end. Another silly, but visible detail.
 

Dikitriki

Flying Squad
I am sooo glad I finished off my 10001 before The Book was published:)

The extra bits do show though Heather. I still have to fit Simon's engine block round an XL chip and fit some crew, but I'm not going back to rework the body.

Richard
 
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