Cutting Frames

I must apologize for not making more posts recently but when I started this blog I said I’d only post when I had something to say. I’ve been laid low recently with a lung infection and I’ve also been busy writing for a couple of model railway magazines, so have made precious little progress on my most recent project, the scratch built NSWR 20 class. That is until this past weekend.

Perhaps my lack of progress had something to do with the fact that I’ve had this project on the shelf for something like 12 years. With that amount of inertia built up it took a little bit to get things moving again. I find when I start to build a locomotive kit that I put enough trust in the designer and manufacturer to believe that, as long as I follow the instructions, I can actually finish the project. However when you scratch build there is no such provided guarantee, either implied or explicit. The box of bits and pieces I had accumulated over the preceding 12 years were saying to me loud and clear “you’re on your own Trev!”

Anyway I got my bum into gear this past few days and actually started work. The first order of business was to tack solder two lengths of nickel silver sheet together that would provide the frames. I was up and down about what thickness to use for the frames: I had some .010″, .015″, .028″ and some .036″ or there about. The frames from Pioneer in the recent rebuild were cut from .015″ but I thought this thickness would be just a little flimsy (at about .55mm) so I opted for the .028″ material, about .7mm thick. I also went on the P:48 US Yahoo group and asked what thickness they used for frames and the answer came back that they start with approximately .095″ and work up from there. And I thought .028″ was going to be a bit stiffer! 🙂 I’ve made plenty of kits and chassis from material approximately .7mm in thickness and it works fine, scaling out at about 1 1/2″ which, if I’m not mistaken, isn’t too far from the thickness of the frames on the real thing. Anyway I always say that physics doesn’t scale down so .7mm will do. It’s going to have to 🙂

In this photo I've posed the frame blanks next to the chunks I've cut from them. The paper plan is glued to the NS blanks with plain paper glue stick. I think it's UHU.

In this photo I’ve posed the frame blanks next to the chunks I’ve cut from them. The paper plan is glued to the NS blanks with plain paper glue stick. I think it’s UHU.

There’s a bit of excitement about starting a new build but there’s not too many fireworks in cutting out frame blanks. In the photo above you can see the two pieces of NS with a slice from the appropriate part of a 20 class plan (in 7mm scale of course) glued to one side of it. The plan provides some guidance where to cut with the saw. You just follow along the bottom edge. The blanks are 19mm wide X 238mm and I had to make a slight adjustment to the positioning of one of the axles to match my etched side rods. Cutting a 1.4mm thick slab of NS by hand takes some effort and I only got one cut finished (the large part on the far left) last night. Tonight I decided to check the blade in my piecing saw. It was blunt so it was no wonder it took me so long to do so little cut last night. The cutting tonight went a lot more smoothly. I actually find this task quite therapeutic. The cuts are carried out with nothing more high-tech than a piece of 12mm ply with a V cut into it and a small piercing saw. I keep a white candle handy to apply some wax to the blade to act as a lubricant. When I’ve completed the cuts I’ll drill some holes for pickups and brake hangers and then separate the blanks into two. Then I’ll punch some rivet heads and simulated bolts into the single thickness of each frame following the plan to provide a little detail. I’ll then cut out some spacers and assemble the side rods from the etch they come on. All very exciting! 🙂

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