In the last month or so I've begun construction of the 2mm Scale Association kit for the BR Class 08 shunter. I've found Graham Ross' blog about the construction of this kit very helpful.
Here is an early view of the frames, with bearings and PCB spacers attached. You can also make out the phosphor-bronze springs, following the method of Mick Simpson. The frames have half-etched holes intended for these. As recommended, the springs came from straightening out Farish N-gauge coupling springs. With this method you also have to shorten the muffs on the axles, which I did by a combination of stanley knife and filing.
This view was taken this morning, showing the chassis with all wheels and gears fitted for the first time. I opened out the muffs on the axles with a 1.5mm drill, so that the wheels are an easy push fit. Hence I will be able to correct the misaligned balance weight on the right-hand wheel! I think when I am happy with the drive I will have to glue the wheels in, by means of the perpendicular hole drilled in the centre of each muff. Unfortunately one of the large balance weights disappeared in between cleaning up and glueing in place, so I had to make a replacement by carefully filing a piece of spare nickel-silver fret.
Finally here is a video of the first "test run" with the motor attached. There is still work to be done in getting it running smoothly. Before this video was taken I found that one of the spur gears was locking, which I seem to have cured by opening out its bearing hole slightly (perhaps it was a result of the axle bearings being opened out to 1.6mm for the springing system?).