Metals / Materials / Construction

Hi Guys,

Total newbie to the scene, but have practical experience in making models and CAD, not much but it gets me by. Usually making dolls house things with my girlfriend at the moment. I have a desktop CNC machine with a 300x300mm cut area, not massive but does some nifty stuff, and powerful enough for aluminium.

I'd quite like to get into livesteam though. My grandad use to have a couple of models running in the garden when I was little, and I loved them. I've bought various plans off the net and although some are not so good, some are, and I have enough dimensions to get me through. But...

How do you know what material types to use? Is there a rule? I'm guessing the frames are made from steel, but what grade? Can you use stainless? I also notice there is quite a few casting available for different models of locomotive, but things like wheels, can these not be CNC'd or done a lathe? I'm guessing they can, and it's just a time/expense option to make castings. However, it's all guess work, so wondered if I could get a few pointers.

Many Thanks

I think I have a found a solution to the type of materials in this book LINK which David Littlewood posted up in another thread. Some pointers and tips would still be appreciated

Hi Monk,

You could use stainless steel for the frames, but it's hugely more expensive and also hugely harder to machine; I suggest you would be better off with normal quality bright mild steel. You can buy frame steel from casting suppliers such as Reeves, or from the normal ME suppliers such as this one: **LINK**

I don't know enough about CNC to know if it is feasible to make wheels that way, but I suspect you would find it a whole lot easier to use castings, again from places like Reeves. The frames of most locos may be too big for your CNC setup; if you go for the manual method of machining them, then unless you have a big milling machine with DRO, you will need to mark out as shown in the books you referred to. The best coating for marking out IMO is a 10% solution of copper sulphate (easily obtainable on eBay) with about 1% of sulphuric acid (unfortunately it doesn't work at all well without the acid). Battery acid should work, but allow for the fact that it is already diluted somewhat. The copper coating, unlike most other methods of marking, will not come off with cutting oil.

David

Edited By David Littlewood on 10/09/2012 23:09:26

That's great thanks David! No doubt I'll have a million questions once I get going! I've got some plans from Reeves which were hard to read, and some from pollyengineering which are clear and easy to read, although the dimensions seem a little peculiar to the Reeves. Holes seem to be odd sizes in the decimal format whereas reeves use nice fractions albeit a bit hard to read.

"Nice" fractions? Well, if you like them. Personally I bought a couple of sets of metric drills 25 or so years ago and now rarely use anything else, even when drilling tapping holes for imperial threads. And putting fractions on with a DRO is clearly not possible; I find myself reaching for the Zeus chart to see what 17/32" is in real numbers.

David

Well I say nice as fractions are the easy way to read imperial for me! Normally I'm all metric. Guess it's what I'm use too! Pollyengineering have things like a 0.122 hole which I'm not use to.

Hi Monk,

Personally I would not begin with a complex build like a larger locomotive, attractive as the proposition is. You need a lot of knowledge, skill and experience, not to mention patience, persistence and cash to complete a project that can often spread over years.

Why not build up some experience and extend your skills with a more basic project such as a simple stationary oscillator such as the Elmers engines whose plans are available here on the John Tom site. Such projects will increase your skills and will not test your bank balance as a mistake on a bit of bar stock is not as disastrous as an error on an expensive casting. There are even simple 'De Winton' type locomotives which use simple oscillators and can be built in a relatively short time. Examples of the latter can be seen here (scroll down the page to 'Idris'  and here drawings are all downloadable for free from both sites. Dave Watkins has even built a larger scale version of a De Winton and has videos. You can have great fun with those.

A single cylinder stationary oscillator can be built in a few sessions and is a great motivator when you see it running, you can even run them on compressed air, without a boiler (boiler making is another art where it pays to start small). I have even run them from a garden sprayer!

A benefit of this approach is that you will build up skills, knowledge and confidence leading to a much faster build when you undertake a more complex locomotive and help to keep your interest alive. Loco builders often intersperse smaller projects to freshen up their motivation.

A main line steam loco looks really impressive but are complex machines and can be very difficult to build, and costly - and it is easy to make disastrour errors leading to piles of expensive scrap.

Have fun whatever you decide,

Best regards

Terry

Cheers for the advice Terry, those Elmers engines look quite fun to make so will have a gander through those at home tonight. Although a newbie I do have some support from a few people who have trains, build them, have fully kitted workshops etc... So not totally in the dark. I like to see how far I can get on my own, which means reading through forums, asking random questions, playing etc...

If you'v got ME 4438(got mine the other day), theres a good starter in there that will only take a few hours to make, a Single Cylinder Oscillating Engine Steam Plant, or at least use the boiler if you want to make another design of engine. Ian S C