PART 3: A Boiler Feed Pump

摘要

Valve chest: Figures 4 to 6 show the details of this item. The casting didn't have the steam connection flange (it was easier to cast without it) so one was turned up and silver soldered in place (photo 24). The two faces were fly-cut (photo 25) and the casting then moved in the vice for drilling and tapping for the shuttle and the pilot valve rod (photo 26). The DTI is there to make sure the casting doesn't move. The hole for the shuttle (furthest from the camera) is reamed. The pump operation relies on the shuttle being a close but free moving fit in the valve chest. In case you don't have a 13/32 inch × 32 tap to hand, the threads at the ends of the shuttle hole can be cut on the lathe. I made a tap but still had to cut the threads on the plugs.