Where possible I have re-cycled! The buffers were machined from plough shear bolts, pipe reducing unions, square washers and rewound bedsprings. The towing hook is part of a turnbuckle with a nut machined as a collar on the front.
The boiler feed axle pump was machined entirely from old brass plumbing and stock trough fittings. The stainless balls for the pump valves came from a ss ball race. It can push over 400psi off the dial of my test gauge! The axles are recycled bright round bar courtesy of the local tip, and the slip eccentrics were machined from a couple of 50mm tow-balls.
The smokebox was fabricated and welded from scrap steels, with the massive brass fittings on the stack coming from some huge phosphor bronze bushes from a friends junk-box. The handrails on the cab started life originally as flower pot hangers, but a few threads and bends changed that.
The crosshead slides are 3/8″ keys, with the crossheads fabricated from 11mm key and 3mm sheet steel silver-soldered together. They slide up and down just fine.
The majority of things are held together with 4mm bolts and nuts, cheap and readily available. So far everything has been done with only a Taig micro lathe, a drill press, portable drill, bench grinder, disc grinder, inverter welder, belt sander, and hand tools.
I have access to milling machines and large lathes at a friends around the corner, but much prefer the satisfaction of overcoming challenges and doing it myself. Quartering the wheels was an experience, but they measure up spot-on. The only major stuff-up to date was when I was drilling the holes in the wheels for the crank pins. The jig slipped or vibrated loose and I ended up with one wheel out by 0.5mm.
Took a while to figure out why the wheels were binding, then tracking down which crankpin was out of kilter took a lot of thinking carefully. The solution – I machined a new crank-pin for that wheel with a 0.5mm offset, keyed it and fixed it to the wheel. Works perfectly now with no binding of the gear.