A little more progress on the Steam Railmotor ...
Over the last few days, I've been trying to finish off the roof. At the end of the previous update, I had fitted some fine wire to represent the rain strips and the lamp tops had been fixed, so the first task was to cut a suitable piece of nickel silver for the engine room roof panel. I elected to cut this from 0.004", but in the end wish I had cut it from 0.008" instead - once rolled to shape and temporarily placed on the roof it didn't seem to provide quite enough relief, so I tacked a couple of strips of 0.004" along the lower edges to raise it up a bit. By marking diagonally from corner to corner, the centre was marked and a hole drilled to line up with the chimney hole previously drilled in the main roof to help when aligning and soldering the panel in place. Before fitting though I had to remove a little of the upper rain strips where the panel overlapped them.
According to the drawings I had, a strip of L angle was attached 6" up from the lower edge of the panel (possibly as a rainstrip) - I tried to fabricate a bit of angle from 0.004" but with the foot and upright being less than 0.5mm wide I gave it up as a bad job and elected to just solder a bit in 0.25mm wire 1mm inboard of the lower edge instead!
The top half of the chimney was turned on the lathe (predominantly with gravers), and was cut off with a 1.5mm diameter locating peg on its bottom (to fit into the hole in the panel/roof). The prototype has a weather proof cowl just below the copper cap of the chimney (to help keep the rain out of the engine compartment), so a piece of 0.004" was cut to be a snug fit around the chimney and shaped into the oval shape of the prototype (quite why the cowl is oval rather than round I have no idea as photos show that the chimney projected through at one end of the cowl not centrally as one might expect). Anyway, once filed to shape the cowl was soldered in place around the chimney such that there would be a slight gap between the roof panel and chimney cowl. The next stage was to complete the roof panel by drilling a 0.35mm hole where the whistle will eventually go, and also drilling then filing an oval hole above where the safety valves were attached on the boiler (oddly, although the whistle has a little weather proof cowl around it, the hole for the safety valve exhaust doesn't).
With the engine compartment cover panel done, I then lightly scribed the lamp pipe runs on the roof. The pipes were made from 0.2mm copper wire (having first rolled it between a metal ruler and flat surface to straighten it). It was then a simple matter of making the bends in the main pipe runs and tack soldering in place before making good the soldered join along the full lengths of the pipe. Further short lengths of wire were added between each lamp and the main pipe before trimming the wire (one end soldered to lamp pot, joint made with main pipe then the excess cut off). It would appear from photos that the gas feed pipes of the different lots came up through the roof in different places - No. 93 has the pipes appearing fairly centrally, but No. 61 (which I'm basing this build on) has the pipes appear above the driving vestibule at the non-engine end of the carriage. In both cases though a small cover is positioned over the place where the pipes come up through the roof, so I filed up a bit of 0.014" brass to represent these covers and positioned them over the tail ends of the wires representing the pipe runs.
With all of the solder work complete, today I have fitted the shell vents. The exact position of these has been estimated from photo evidence, and holes for each vent were drilled before Ultima vents (available from the 2mm Association) were super-glued in place.
The photos below show the current state of play (the body is just plonked on the under frame for these photos) :
At the moment, the chimney and its cowl are just pushed into the hole in the roof - its an interference fit (in actual fact the hole is big enough to allow small screw driver access to the motor bogie retaining bolt, so I may leave the chimney as a removable feature!)
The next step will be to add the mouldings needed to the central doors to finish the conversion of the single access door to the double doors that I'm trying to represent. This can now be done in 0.005" plasticard now that all of the soldering is complete on the upper works.
Once the upper works are done, I will then move onto the undreframe (including fabricating the headstocks and buffers - I hope that N Brass will have suitable auto coach buffers at TINGS when I'm there helping out on the Association stand in a few days time), then it will be on to trying to make that flipping Walchaerts knitting that I keep putting off for as long as possible
Thanks for looking
Ian