Tim Watson
Western Thunderer
The Coronation continues to make progress. The sides of the carriages are from Worsley works and are etched in nickel silver.
Getting the tumble home neat and tidy needs a bending jig. I made this decades ago from a couple of bits of aluminium with alignment dowels and three bolts and wing nuts to tighten it up. I think it was originally used on my 7mm scale Finney A4 and certainly used when making the Silver Jubillee set on CF. It’s critical that the bend starts in the correct place and so a witness mark is made on the back side of the etched side using a simple brass jig to mark it out. This is laid down over the windows and the line scored.
This was then clamped in the bending bars with the scribed line just visible on the jaws of the bending bars and the brass jig; most importantly with the windows securely held. The tumble home was achieved by pushing a long brass rod firmly against the inside of the carriage whilst leaning on the outside with a coarse file - which gives a better grip on the sheet metal and bends the metal over.
The bodies were designed so that sacrificial pillars would be removed wherever they interfered with any windows. This was easily achieved with a fine diamond disc running at moderate speed; so avoiding any untoward crack propagation within the relatively brittle plastic. The original concept was that the glazing strip would be a simple strip held between the residual pillars and the etched sides. Unfortunately, due to an oversight, the rebate was made on the wrong side of the pillars: I had failed to notice this early on. That meant that the glazing strips had to be made in variable lengths to fit between the pillars but, fortunately, I have a guillotine which speeded up the operation. The close-fitting individual glazing components were held in place with model aircraft canopy glue, applied as a bead around the periphery of the opening.
Here we have the production line for coaches E & F - one of which has an extensive kitchen component as shown by the opaque windows.
So that’s four down, four to go…
Then I can think about the steps, buffers, ventilators and interiors.
Tim
Getting the tumble home neat and tidy needs a bending jig. I made this decades ago from a couple of bits of aluminium with alignment dowels and three bolts and wing nuts to tighten it up. I think it was originally used on my 7mm scale Finney A4 and certainly used when making the Silver Jubillee set on CF. It’s critical that the bend starts in the correct place and so a witness mark is made on the back side of the etched side using a simple brass jig to mark it out. This is laid down over the windows and the line scored.
This was then clamped in the bending bars with the scribed line just visible on the jaws of the bending bars and the brass jig; most importantly with the windows securely held. The tumble home was achieved by pushing a long brass rod firmly against the inside of the carriage whilst leaning on the outside with a coarse file - which gives a better grip on the sheet metal and bends the metal over.
The bodies were designed so that sacrificial pillars would be removed wherever they interfered with any windows. This was easily achieved with a fine diamond disc running at moderate speed; so avoiding any untoward crack propagation within the relatively brittle plastic. The original concept was that the glazing strip would be a simple strip held between the residual pillars and the etched sides. Unfortunately, due to an oversight, the rebate was made on the wrong side of the pillars: I had failed to notice this early on. That meant that the glazing strips had to be made in variable lengths to fit between the pillars but, fortunately, I have a guillotine which speeded up the operation. The close-fitting individual glazing components were held in place with model aircraft canopy glue, applied as a bead around the periphery of the opening.
Here we have the production line for coaches E & F - one of which has an extensive kitchen component as shown by the opaque windows.
So that’s four down, four to go…
Then I can think about the steps, buffers, ventilators and interiors.
Tim