Two things:
1. Stripped and cleaned a NOS Shimano type D coaster hub which turned out to have a rusty LH ball race. Must have been in storage for decades. The balls and cages are toast but the races aren't too far gone and wlll run in to be smooth.
2. A s/h replacement boiler for the big steam engine (Mamod SE3) came this week, so I fitted valves and plugs to it and steamed it as a test. It's all fine and, moreover, the regulator valve I desoldered yesterday doesn't leak.