Nickel Silver Rod or alternative

[John Bateson]

On detailed reading of John Quick's book on GCR liveries I discover that the front of the cylinders is actually polished bare metal which is oiled to make it gleam.
At the moment these parts are turned from brass rod and I suppose could be tinned with solder, carefully cleaned and then varnished.

It might be nicer though if I could turn these parts from NiSi (which needs to be 8.5mm after turning) but am having difficulty sourcing this.
Would silver steel be an alternative, it needs polishing to a high degree, anything less would look an obvious a fudge.

Any ideas please would be welcome.

John

[David Knight]

John,

Have you considered stainless? Not sure of a source as I'm on the wrong side of the pond for your purposes.

Cheers,

David

[Natalie Graham]

It might be nicer though if I could turn these parts from NiSi (which needs to be 8.5mm after turning) but am having difficulty sourcing this.

http://www.metalsmith.co.uk Ref NS375 Nickel silver round bar 3/8" diameter x 1 foot length (9.5x305mm) Price £8,00 plus, no doubt, whatever they charge for P&P.

Edit: i see they also have a minimum order value of £10 but I am sure they have something else on there which would come in handy.

[John Palmer]

Metal Smith Ltd offer nickel silver round bar stock - try this URL: http://www.metalsmith.co.uk/metals-materials.htm

I have only to wave a finger in the direction of steel and rust blooms on it, so I turned the lever caps for my frame from 3/32" N/S bar I've had kicking around for years. I then mounted the caps on a mandrel and applied metal polish to bring them to final finish - they have retained a bright, untarnished finish for months without attention.

Also found what I think is a length of monel amongst my bar stock, which might yield a slightly less 'yellow' final finish then N/S - but I understand it is exceedingly hard to machine due to its work hardening propensity. I haven't yet found a use for it, and have no immediate plans to move into boiler stay production for a 5" gauge GWR locomotive!

[Terry Bendall]

Personally I would go for mild steel on the basis that it will look more like the real thing. There may be a risk of rust but I would have thought that the likelyhood was low, no more than using steel for coupling rods. Mild steel can certainly be polished in a lathe (with care) using increasingly finer grades of emery cloth. Not something the purist would do since if the tool is sharp and you use a slow feed it should be possible to get a good finish from the tool.

If the covers did rust, apply a thin layer of oil.

Terry Bendall

[Tim V]

Why not solder a piece of sheet nickel to the end of your brass bar, turn that, then unsolder it?

[John Palmer]

When I first looked at this I thought John was referring to the cylinder end covers proper, which would be iron castings and likely to have a distinctive patina as such, even when cleaned. However, after looking through some pictures of GC locomotives I think he may instead have in mind what appear to be sheet metal pressings of similar thickness to the cladding sheets. I am wondering whether the GCR chose to press cosmetic covers from stainless sheet, or perhaps chromium plated them.

If the aim is to simulate polished sheet metal with a high chromium content then silver steel may well be the best bet, and will be more resistant to corrosion than mild steel. I would shy away from a smear of oil as a rust inhibitor, as I would fear it attracting a coat of 12" : 1' dust - but you could apply it only for periods when the engine is in storage (common traction engine practice!)

[Phil O]

Personally I would go for mild steel on the basis that it will look more like the real thing. There may be a risk of rust but I would have thought that the likelyhood was low, no more than using steel for coupling rods. Mild steel can certainly be polished in a lathe (with care) using increasingly finer grades of emery cloth. Not something the purist would do since if the tool is sharp and you use a slow feed it should be possible to get a good finish from the tool.

If the covers did rust, apply a thin layer of oil.

Terry Bendall

Why not give it a coat or two of varnish to keep the moisture out. I would tend to put the item(s) in the airing cupboard first to make sure there was no moisture content in the steel first.

Phil

[John Bateson]

The cylinder ends are apparently steel which is polished, along with a number of other components such as smoke box ring, reversing arm, coupling rods and connecting rods and various other small parts. Small wonder that the LNER painted everything black as soon as they got the chance!
Given that the coupling rods are etched from NiSi it would seem to make some sense that the cylinder ends are the same so I will place an order on Metalsmith (thanks for the link) and try my hand at turning it and polishing it.
I think I will give the smoke box ring a miss because it is too thin to mask when spraying, but the smoke box door hinges and the reversing arm can be done.
John

[John Bateson]

NiSi rod arrived today, good service from Metalsmiths wil report in when I have done a few polished turnings
JOhn