Today I made the retaining collars for the rods, these were relatively simple turning jobs on the lathe. The front collars are completed, the rear/driving ones still need to be drilled and tapped for a grub screw to hold them in place.
Here's a really rough set of adjustable coupling rods, these were fitted on the loco, then adjusted till the wheels rotated freely, and will be used to jig drill the second crankpin hole in the coupling rods. I've just recently turned up the two pins at the front, the front one goes through the existing coupling rod hole, and one end of the jig, the second fits in the other hole of the jig and has a 5mm hole to spot drill the other end of the coupling rod.
Here's the first coupling rod partially assembled, at this point I had only machined and threaded one end of the rod, but both ends are now done. The pic' does give a good idea of how the finished rod will look though.
So I got some 12x7mm BMS offcuts from ebay, and am using these for the centre part of the coupling rods. A relatively simple matter of cutting to length, then turning the ends down to 6mm and threading them M6, so as to screw into the bosses. Only relatively simple as this is about as long as the little Taig II lathe can take between centres; the centre drilling being done by careful marking out, then drilling in the bench drill. Here's the rod being set up in the lathe, tool post still missing from the cross slide.