A bit of a milestone was reached in the Pulham household last night. I have been tinkering for a number of days with the inside motion, getting it all to fit in the frames. I had to mill the inner side of each crosshead to clear the eccentric straps etc. so they are now handed and I also had to enlarge the centre section of the motion bracket to allow the assembled eccentric rods, expansion links etc to pass through it. Then came the final job of determining the length of the connecting rods and cutting them to length.

Once they were cut and tried in place the length was right but they wouldn’t fully rotate because I hadn’t made the slots in the motion bracket deep enough. Much filing and testing ensued but I didn’t seem to be getting anywhere and then I realised that because of the constant assembly/disassembly for testing, I had the frames upside down. What I was viewing as the top was in fact the bottom so I had been adjusting the wrong side. More filing and test ensued and I got there in the end.

Having tested the pistons successfully with the valve parts resting outside the motion bracket I put it all together inside for a further test.