7mm On Heather's Workbench - a baby Small Prairie

I ought to thank Percy Veerance for helping me beat the misgogs and the motion, and Best Beloved for ably assisting by pushing things while I held the camera!

Nicely done.

Paul

Recovered from managing to get a working set of motion - please don’t mention Walschaerts! - I spent some time peering closely at photos trying to discern what the heck was going on with cylinder draincocks on these early locos.



In the end, this is what I’ve come up with. Happily, I have several spare brass castings of the later cock form, with the J-shaped outlet pipe. I reckoned they could be easily transformed into the earlier form by simply snapping off the Js. The overall shape was about right otherwise, and the copious Bits Box coughed up some small brass brackets and levers and some strip that could be formed into the lever mechanism.

The jury is out on whether I shall fit some wire to the pull levers heading inboard. If I do it will be some time later in the build, when I get the brake gear under way. For now, aside from the valve linkage, I think this is about where I’ll call a halt to the cylinder area. Next, I think I should turn my attention to the pony trucks, and have a good think about sanding equipment.

Today, I am working on the pony trucks.

I built up the cast SDK versions ages ago, and became very aware that the rail guards would need attention at some point. The brass used is like aluminium cooking foil, and even so much as looking in their general direction would bend them. Time to have a proper look at what can be done to sort things out.



First, this is how they look after being carefully straightened again after a mild knock. I’ve worked out the bottoms of the guards should be at most a scale two inches from the rail head. As they stand, they’re not far off.



From the front, however, it becomes obvious they will be way out once bent to shape. Finescale distances, too.



After a bit of a struggle, and a near snapping-off, here they are bent. Surprisingly, the height thing is still about right, but they’re definitely not really any good at protecting the wheels. The soft metal is going to be a liability in any case.

So, I could replace the cast bits with the nickel silver etched bits. My worry is they, too, will be a mite short. I’ll test one after feeding time, but I think I shall end up getting the scrap etch out and starting from there.

Heather,

if I may, it looks to me as if your pony truck is tilted fowards (pitched down) and bringing it back to straight & level will inevitably increase your woes with the guide irons.

sorry to be negative!
best
Simon

simond said:

it looks to me as if your pony truck is tilted fowards

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I think you may be correct. I need to get my jommetry 'ead on to work out how long the replacements need to be be.

I’ve had a look at the pony trucks themselves. There’s all kinds of wrongness going on there. I rather feel I’m between a rock and a hard place with them, so I may have to put up with them being all the wrong shape.

It would be a shame to have to replace them, but there’s no guarantee the etched ones are any better. I shall report back.

Right, here we go!



You can see the general shape the front pony should be here.

(I generally get the crayons out on drawings as it really helps me see what’s what and where. I also like colouring stuff in.)



Here’s the cast pony truck. I rather think this is not meant for the 4400 or 4500 classes. I rather think this might be intended for their bigger brothers.

Be that as it may, I sort of stuck with it now. The etched frames are another matter, being clearly marked for EM/S4 and therefore blown up to 7mm scale. They’re a bit two-dimensional, lacking any detail around the front wheel area at all. I am going to try bushing the pivot to let the cast bottom frame sit almost horizontally. That would make the front sit properly, at least.

If you shorten the top strut so that it meets the lower one where it should then that will tilt the main structure backward and retain the current pivot location.

mickoo said:

If you shorten the top strut so that it meets the lower one where it should then that will tilt the main structure backward and retain the current pivot location.

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That would seem logical. Having had a discussion with someone more clued up than me, I have, however, taken a slightly different tack.

Simply packing the pivot to get the bottom strut nearer horizontal proved a near miss. The issue was there would be a fairly intrusive bolt and nuts fairly visible from low angles. I trimmed out the etched parts with a view to seeing if an amalgam of the etched struts and cast front might work. It wouldn’t, sadly, as the etch design doesn’t work like the cast parts.

However, it did make me wonder. What if the bottom strut casting was adjusted with bends to mimic the etched parts?



Forgive the humongous bolt. This will, of course, be trimmed back, and I might as well file down the nut as well. My shonky soldering let the V-struts fall off so I could work at them more easily. I formed a bend on the bottom struts, as you see, which shortened them slightly. The top V-strut now sits a bit further aft, misaligning the cast bolt detail. I can live with that, as like the vertical stiffeners, which are no longer touching the upper struts, this will be lost behind the cylinders in due course. The pony itself now sits pretty much horizontally. I think I’m happy with this. I shall now see what needs to be done with the rear pony.

This is the reworked rear pony truck. It’s not quite there, but I think it’ll work.

Heather Kay said:

That would seem logical. Having had a discussion with someone more clued up than me, I have, however, taken a slightly different tack.

Simply packing the pivot to get the bottom strut nearer horizontal proved a near miss. The issue was there would be a fairly intrusive bolt and nuts fairly visible from low angles. I trimmed out the etched parts with a view to seeing if an amalgam of the etched struts and cast front might work. It wouldn’t, sadly, as the etch design doesn’t work like the cast parts.

However, it did make me wonder. What if the bottom strut casting was adjusted with bends to mimic the etched parts?

View attachment 94312

Forgive the humongous bolt. This will, of course, be trimmed back, and I might as well file down the nut as well. My shonky soldering let the V-struts fall off so I could work at them more easily. I formed a bend on the bottom struts, as you see, which shortened them slightly. The top V-strut now sits a bit further aft, misaligning the cast bolt detail. I can live with that, as like the vertical stiffeners, which are no longer touching the upper struts, this will be lost behind the cylinders in due course. The pony itself now sits pretty much horizontally. I think I’m happy with this. I shall now see what needs to be done with the rear pony.

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Hi Heather

I'm slightly confused by the bolt, your previous posts show a 'pivot' to secure the pony truck with Ozyo commenting on having to shift the point of contact did this not work? This build does seem to be presenting you with numerous problems but you are to be applauded for finding ways to overcome them.

Kind regards
Malcolm

Malcolm Trevena said:

your previous posts show a 'pivot' to secure the pony truck with Ozyo commenting on having to shift the point of contact did this not work?

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The kit has been designed such that the rear pony truck pivot is set further to the rear than the prototype. On the real thing, the pivot is close to the rear axle. The thinking behind moving it, I suspect, was to allow the rear axle to be driven on the model. The kit pony truck, both etched and cast, is designed to fit the model, and shifting things back to where they ought to be would entail making a new pony truck.

I read Ozzy's comment at the time, and I’ll be honest I couldn’t see how I could move anything from where it was designed to go. It is another of those annoying compromises, I’m afraid.

Be that as it may, my "adjustments" seem to have improved things nicely, and the ensemble trundles through my test track turnouts happily.

With the pony trucks more or less rearranged to my satisfaction, there’s not a lot I can do further to the frames until I can get brake parts arranged. We are going with the 3D printed shoes method, but while I have someone that is happy to print the bits, the drawings are currently subject to a house move. Hopefully we can get our schedules all in order to get those bits sorted out in time.

Meanwhile, I’m keen to consider Warren Shephard bits for the brake weightshaft below the cab - I found he makes a casting for the 4500 class, with the requisite handbrake lever outside the frames, so I shall hopefully have a decko at the upcoming Reading show. I found the brake parts by accident because I was seeking suitable bits for the valve operating gubbins.



This is what I have. It’s the bog standard trunnion and covers which were fitted to locos from, I think, about the 1920s. A lot of faff to avoid having outside valve gear! Of course, only a bit of this is absolutely correct for the 4400 original builds. I’ve studied the drawing, pored over photos, and I’m not sure I can make an exact replica of what should be there with what I have. Originally, the trunnion appears to have had daylight running through it, which puzzles me. I am currently considering a compromise that uses the trunnion barrel with the cast in cover cut short so it sits on the running plate, and fitting a facsimile of the various levers inside the frames.



While I let ideas on valve mechanisms roll round my noggin, I decided I could make a start on some upper works detailing. I fitted the "snifting" valve castings to the smokebox saddle, then refitted the saddle itself. There are white metal cast parts for the bolt plates, which shall go on later. I’m pondering sandbox lids, which were oval ones at the time I’m modelling, and whether the pull rods and levers need to go in. The rear fillers were in the cab doorways, and must have been recessed in the floor. I wish I’d known that earlier, as it’s not going to be much fun making holes for them now.

It’s painful trying to lift these details from the period photos, where such things weren’t of interest to those wielding the camera. Just one single view from slightly above the running plate looking down would be of enormous help.

The lubricating pot on the motion bracket extensions was also fitted, with some scrap etch being used to make a simple bracket. This pot isn’t repeated on the other side, and I’ve never quite worked out what it might lubricate, unless it’s oiling a hidden part of the reversing linkage.

Further thinking will be done about drilling holes for the smokebox handrail to drop into on the tank fronts. That might entail fitting the smokebox again, and making up the handrail and fitting it temporarily to check hole locations. I may also make new tops for the tanks, as there are too many holes covering too many variations of vent, filler, tool bracket and lifting ring. Again a view looking down on the early build locos would save a lot of educated guesswork. The only things for which I can positively identify locations are the fillers and vents. Is that another compromise I see heaving over the horizon?

I think, despite the various shortcomings, this little engine is beginning to look about right.

Dear Heather, a great thread both inspiring, because of your dogged problem solving, and a bit depressing because of the problems you are finding in what is considered to be a top-end kit.
Re the tank tops, right now on Ebay there are several copies of shot taken from above at Lustleigh station (search for Lustleigh station), and featuring either a 44xx or 45xx; the loco is not crystal clear but may give you some idea re tank tops. It has the number plate on the tank side, so should be pre-WW1, though I stand to be corrected.
Hope this helps a bit.
All Best.

PS There is also another top shot of a 44/45 at Carbis Bay

I’ve been away for a spell. They say a change is as good as a rest, but in this case I needed more rest to recover from the change!

Anyway, back to the bench this morning.



Sandboxes. Oh, wait. Hang on! I was going to add some sheet material to the front sandboxes. They’re inside the frames, so I wanted a facsimile in there at least. Instead, of course, I managed to get sidetracked into sorting out the back head fitting. There was a gaping hole, and the side sheet returns were uneven, making it difficult to fit the casting properly. I chopped out the returns, and then decided to make a plate up to fill the cavernous gap and support the casting. I cut a shaped top section just slightly larger than the casting to resemble the surrounding platework on the real thing. Finally, some scrap brass sheet was formed into angle section to plug the remaining gaps in the corners.

I ought to check the body still fits with the motor in place.



There it is with the back head plonked in. Happy with that.

Now, I must ferry Best Beloved to the local ophthalmic unit for his regular checkup. I may return to sandboxes later today.

Some excellent work there Heather, amazing challenges you have to contend with working in S7. I suspect all these tolerance issues would stump the majority of modellers, possibly why so many stay with bog standard O Gauge. Carry on the great work.

Pencarrow said:

Some excellent work there Heather, amazing challenges you have to contend with working in S7. I suspect all these tolerance issues would stump the majority of modellers, possibly why so many stay with bog standard O Gauge. Carry on the great work.

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Thanks Chris! To be fair, I doubt clearance issues would be beyond many competent modellers. I recall enormous problems with clearances on the finescale WD I built, which ended up with me actually splitting the cylinder block plate to shift everything out to give some more space. Even with thinner profile S7 wheels, I think that would have still been needed.

Still, I guess that’s all part of the fun.

You’ll all be pleased to hear Best Beloved's peepers have been given the "all is stable; come back in a year". Today, then, back to the bench.

I fitted the facsimile sandboxes. It took some swearing, and a change of course, but it’s done. No pictures, because it’s not something I’m terribly happy with, but it’s done now and speak of it we shall no more.



I fitted the sandbox filler lids. I also intended on arranging the cranks and rods for the operating mech. However, despite some serious magnified peering at photos, I haven’t seen any evidence for the mechanism being mounted above the running plate level on these early versions of the locos. It’s there on the later rebuilds, but not that I can see before the First World War.

I have, therefore, left them out for now. If I find evidence, I can fit something later.



The rear box lids were a little easier. I felt that a plate would be in order, rather than plonking the lids directly on the etched floor boards.

It all seems to have taken way longer to achieve any of this than it ought. Some days are like that. Next, I think tank top overlays need to be dealt with. Thanks for the various links up-thread, by the way people. From what I can make out, tank top clutter was minimal, essentially being a low oval filler and a plain mushroom vent. Nothing obvious by the way of lifting rings can be seen. That’ll make life a little easier, anyway.

Onwards.