... first TOU built to prove out the system before applying it to the layout and I hadn't yet cut the copper layer between the two tubes controlling the switch blades. These TOUs are actually used with tube in wire operation. The alloy section from B&Q is a "U" section- you can just see the bottom face of the "U" section in the picture. On this part is mounted a crank with a slot on one of its arms to engage the third bit of pipe on the PCB strip. 25_120602_100000000.jpg Here's a shot of the bit of hacked about "U" section. The slots are for the two holding screws and allow the lateral adjustment of the TOU. The other side of the "U" is cut back to allow easy access to the holding screw heads and this provides a platform for the operating crank. The crank pivots on an 8 or 10BA screw in a tapped hole in the alloy. There is just enough meat in the alloy section to allow tapping and a lock nut is used to fix the ...