Construction of the chassis of my 7mm scale Scrap Tank is well advanced and the mechanism progresses smoothly under power along the test track in the studio, so a test run on the club layout in Carlisle at this stage might be a good idea. There is still much detail to add below the footplate which I will leave for a later stage of construction; meanwhile I'm looking into the possibility of 3D printing some components, particularly the sand-boxes and driving wheel springs and maybe the rivetted wheel balance weights. The coupling rods were made for me by WMI; the connecting rods I built myself. The gearbox is an ABC Mini7E mounting an M1833 motor. The footplate assembly is screwed to the frames through the front frame spacer; the rear frame spacer slots into a housing fastened to the inside of the back buffer beam.
 |
Phosphor-bronze pick-up wires (0.5mm) are arranged to bear on the tops of the centre and rear drivers which will locate inside the engine's spacious side tanks; those that bear on the front driver have not been resolved yet. The left hand driving wheels are shorted by means of an 0.5mm p/b wire soldered between hub and tyre and slotted behind a spoke. |
 |
| With the front driving wheels are in position, the axle screw is masked by the slide-bar/cross-head assembly and inaccessible. To overcome this the axle and its brass bearings is retained by a keeper rod soldered to a plate. The removable plate slots in place against the front frame spacer and is retained by a screw. |
 |
| Clearance between the chunky cross-head casting and the coupling-rod is minimal and much metal had to be removed warily from the rear of the casting and from the head of the protruding crank-pin screw to achieve free movement. |
