Challenges - lamp irons and footboard supports

andrewnummelin
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Challenges - lamp irons and footboard supports

Postby andrewnummelin » Sat Jan 16, 2021 1:37 pm

I'm (after decades) progressing with building some TVR coaches using Trevor Charlton etched sides and I'm coming up to two difficult items.

Firstly the lamp irons shown in the following photo and drawing: these will be vulnerable as they project out from both side and end. Does anyone supply this type or do I have to design a bit of origami in the style of Masokits? (This type is not on Mike Clark's etch.) I suspect these items should be pinned rather than relying on adhesives - soldering is not an option because the coaches have already been painted so I could try lining and lettering.
Any suggestions of how to approach these items would be most welcome.
scan1.jpg
scan1.jpg (102.16 KiB) Viewed 1005 times
scan2.jpg


The second difficulty will be with the footboard supports. I guess that etched kits would normally have these made of flat strip but ideally the main bit should be round and tapered. Are there any commercial castings available? If not, can anyone suggest something better than flat strip with top step support soldered on, or is it origami again? I have in the past with goods brake vans used wire with an end flattened but I've never been really happy with the result. The support on the headstock is a "fun" shape!
scan3.jpg
Regards,

Andrew Nummelin

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Guy Rixon
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Re: Challenges - lamp irons and footboard supports

Postby Guy Rixon » Sat Jan 16, 2021 2:13 pm

For the steps supports, I suggest wire bent or joggled at the top to locate into the solebar. If it were a plastic solebar, then a bend of around 15 degrees lets you glue in the top of the support firmly and set the rest vertical. The flat part of the support could then be added from plastic strip. I've done this and it worked well enough. If the solebar is of thin metal, then a joggle in the wire support might allow the same approach.

I suspect that if the supports were made thick enough that a taper could be turned or cast in, then they would be noticeable over-scale. I'm guessing that the flat part of the support was about 2" wide, beaten from a bar about 1.5" at the top and drawn down to about 1" at the bottom where it joins the crow's foot. It would be fun to reproduce the taper, but anybody close enough to actually see it at an exhibition needs to be driven off with a broom.

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Will L
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Re: Challenges - lamp irons and footboard supports

Postby Will L » Sat Jan 16, 2021 3:02 pm

Yes I can see the Lamp brackets are going to be a problem. In an ideal world I would wonder about lost wax castings, as the cast brass is much more resistant to something bent up from strip.

As to coach footboards, these are a real problem particularly as they are in the firing line when the stock gets handled. Not too much of a problem when on a bogie as they are very close to the bogie frame and can be made quite tough. But very inclined to unintentional adjustment when suspend well below the coach underframe, often being pushed out of line and the footboard itself bend down. I will admit to cheating by soldering two or three strait wire supports from one foot board to the other. This keep them in place and stops he footboards being bent down. They are all but invisible when painted black. I do the footboard on guards vans the same way.

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Guy Rixon
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Re: Challenges - lamp irons and footboard supports

Postby Guy Rixon » Sat Jan 16, 2021 3:05 pm

Has anybody tried making step supports from spring steel wire?

Terry Bendall
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Re: Challenges - lamp irons and footboard supports

Postby Terry Bendall » Sun Jan 17, 2021 9:22 am

Guy Rixon wrote:Has anybody tried making step supports from spring steel wire?


I think that would be hard to do with the wire in its natural i.e. springy condition. If it was annealed, bent to shape, and then re-hardened and tempered it could be a good solution.

Terry Bendall

andrewnummelin
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Re: Challenges - lamp irons and footboard supports

Postby andrewnummelin » Mon Jan 18, 2021 7:55 pm

Gents,

Thanks for the comments and suggestions: I've now got some ideas to work on.

For the lamp irons I've two options - fold-up etch (to be included in a future etching project) or casting (I'll be posting questions in a different part of the Forum). This is the rough design sketch for a lamp iron etching:
lampiron.jpg


For the footboard supports it is probably going to be fabrication from wire and strip but there's a choice in materials. I noticed in Sidney Stone's classic work that his drawing shows the support being made in parts, an L shaped (folded bar) piece at the top, welded to the leg (splayed at the top), welded to the bottom footboard support: the leg being tapered (1.5 to 1.25") and actually formed from two pieces welded together. So if I'm to have a round leg (but not tapered) I might go for something like the following (will need a jig for assembly for consistency).

I quite like the idea of cheating by drilling a diagonal hole through the solebar for the leg but I'm not sure about getting the bend correct if using steel rather than brass wire.

The other alternatives are to accept flat strip for the round leg, try casting, ... or prevaricate and think about a totally different project!
Attachments
footboard.jpg
Regards,

Andrew Nummelin

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Guy Rixon
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Re: Challenges - lamp irons and footboard supports

Postby Guy Rixon » Mon Jan 18, 2021 8:38 pm

Andrew, my instinct is that the arrangement in your top sketch would be weak where the top, angled strip meets the steel. In fact, I think it would flex and later fatigue-break at the bend in the strip. You would need Will's lateral bracing.

Your lower sketch looks a lot stronger to me. I also think it would be easier to make, as the grooves in the solebar would hold the wire for soldering. That's providing that the grooves can be made deep enough to hold the entire thickness of the wire, as I suspect that the wire can't be filed flush in its springy state and grinding it flush would be rather tricky. If the solebars have detail overlays, then hiding the wire might get easier.

If you use one of these schemes, would you represent the curves in the bottom-step supports? I don't know TVR practice, but other railways used a sickle shape for the end supports and a fork ("crow's foot") for the middle ones.

bécasse
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Re: Challenges - lamp irons and footboard supports

Postby bécasse » Mon Jan 18, 2021 8:57 pm

In my experience trying to fold up a long multifold etch accurately is well nigh impossible. My solution would be to fold up two lengths of suitable width strip, using a simple jig made from plasticard, and solder them together. The resulting short double-thickness link would probably not be unacceptably obvious but, if it were, it would probably be quite easy to file a slight chamfer each side to reduce its apparent thickness.

lampiron(rev).jpg
lampiron(rev).jpg (7.48 KiB) Viewed 730 times

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Paul Willis
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Re: Challenges - lamp irons and footboard supports

Postby Paul Willis » Mon Jan 18, 2021 9:10 pm

andrewnummelin wrote:Gents,

Thanks for the comments and suggestions: I've now got some ideas to work on.

For the lamp irons I've two options - fold-up etch (to be included in a future etching project) or casting (I'll be posting questions in a different part of the Forum). This is the rough design sketch for a lamp iron etching:
lampiron.jpg


Hi Andrew,

It's funny, but I reckon that everyone who has ever thought of etching lamp irons has a scruffy sketch somewhere like that ;-)

GER lampirons sketch.JPG


Cheers
Paul
Beware of Trains - occasional modelling in progress!
www.5522models.co.uk

andrewnummelin
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Re: Challenges - lamp irons and footboard supports

Postby andrewnummelin » Fri Jan 22, 2021 4:51 pm

bécasse wrote:In my experience trying to fold up a long multifold etch accurately is well nigh impossible. My solution would be to fold up two lengths of suitable width strip, using a simple jig made from plasticard, and solder them together. The resulting short double-thickness link would probably not be unacceptably obvious but, if it were, it would probably be quite easy to file a slight chamfer each side to reduce its apparent thickness.

lampiron(rev).jpg

Nice suggestion, thanks - I may well give this a try.
Regards,

Andrew Nummelin

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Will L
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Re: Challenges - lamp irons and footboard supports

Postby Will L » Fri Jan 22, 2021 5:53 pm

andrewnummelin wrote:
bécasse wrote:In my experience trying to fold up a long multifold etch accurately is well nigh impossible. My solution would be to fold up two lengths of suitable width strip, using a simple jig made from plasticard, and solder them together. The resulting short double-thickness link would probably not be unacceptably obvious but, if it were, it would probably be quite easy to file a slight chamfer each side to reduce its apparent thickness.

Image

Nice suggestion, thanks - I may well give this a try.

I think the shape of the lamp irons is rather more complex that that, the iron faces out ward from the coach side while it is bolted to the coach end. So the faces of the two vertical sections should be at right angles to each other .


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