queensquare
Western Thunderer
John,
Don't you build your 2mm locos with split frames. These days it seems the way to go.
Indeed, 2mm finescale has been using split axle pickup since the 1920s. Nigel Hunt's chassis use the principle devised by Mike Raithby. Thin, >1mm, pads of double sided PCB are sweated to the inside of the frames to coincide with the spacers. The chassis can then be assembled using etched spacers in the normal way, see Laurie Griffin and my 4F in MRJ235.
Jerry