A little more progress with the Metro Tank, this time with the Boiler and Smokebox.

The Boiler itself is simply a length of 11/32" Round Brass Tube, cut slightly overlength (finished size 35.4mm long), and the ends sanded off so that they were perpendicular to the outside of the tube. This was done by carefully rubbing the end on a piece of emery, and every now and again checking against an engineers square on a flat piece of glass (tube standing on it's end and the square offered up to it, then rotate the tube through 45 degrees or so and check again to find the area to be sanded some more until the tube was at 90 dregrees to the glass in all planes). The other end of the tube was treated in a similar manner until I was happy with both the length of the Boiler Barrel and the ends being at 90 degrees to the length.

The Smokebox was similarly formed from the same material and finished to a length of 5mm. Once I was satisfied with both length and ends of the Smokebox, a slit was sawn through it to allow it to open up sufficiently to fit around the Boiler Barrel.

The Smokebox saddle was formed from a length of 5.5mm wide 10thou nickel. This was marked out so that I could fold it up into a 'U' shaped channel, with the bottom of the 'U' being 8mm long, the uprights of the 'U' were made about 3mm long. I scored the nickel across its width at the above points along its length, making sure that the scoring was perpedicular to the length. Once happy, I folded up the 'U' with the scoring on the outside of the bend (this gave me a reasonably sharp corner). The inside of the bends was then re-inforced with at fillet of 188 degree solder.

The uprights of the 'U' of the Smokebox saddle were then sanded until the Smokebox was a good fit, and was supported at the correct height above the footplate.

It was then a simple matter of fitting the 3 parts together - the inside of the Smokebox wrapper was tinned with solder, as was the outside of the boiler where it would sit. These two parts were assembled ensuring that the Smokebox wrapper aligned with the end of the Boiler Barrel before with plenty of flux the pair were sweated together.

The Smokebox saddle was then positioned across the split in the Smokebox wrapper and tack soldered in place ensuring that it aligned with the rear of the wrapper (this gave an overhang at the front of about 0.5mm that was ultimately sanded back to the end of the Boiler and Smokebox). Once I was happy with the fit of the saddle, plenty of flux and solder was used to secure it (the excess solder made sure that any gaps between the Smokebox wrapper and saddle were filled).

The next stage was to carefully sand back the saddle to front face of the Smokebox/Boiler assembly.

The final stage was to clean off the excess solder from around the Smokebox, and blend the wrapper and saddle together by sanding away the excess solder at the joint with emery wrapped around the handle of an X-Acto knife handle (any suitably sized round object would have served though).

The images below show the assembly as it is now, after it has been cleaned up.

The next phase in this construction will be to mark out and drill the holes where the Dome and Safety Valve will sit, and drill the handrail holes. I intend to sweat the chimney in place on the Smokebox so that probably won't require a hole (although I may drill one to assist the siting of the chimney and also allow me to apply solder from within the Smokebox). Once I have made the tank sides and top, the lower half of the boiler in that area will also be removed.

Ian