June 2024

The June working party started on Saturday morning, with Erle continuing work on the new reverser base plate. He has now started cutting the slot in the middle of the plate. This will make it easier to clamp the plate to the bed of the milling machine when cutting angles on the sides. Erle's machining skills are in great demand, meaning that on Sunday he worked on the NG15 project. However, good progress is being made on the C2 reverser base plate.

Dave 1 spent Saturday sorting through the box of motion parts, identifying each part and creating a list. The Chinese modifications mean that previously we did not have a complete list. We now have a list of every nut, bolt and washer which will be required to complete the motion. Matt provided assistance by looking up photographs on the internet, which helped to identify how parts fitted together.

One revelation from the motion parts list was that we already have retaining collars for the joints at the upper ends of the lifting links. When Dave 1 drew the weighshaft crank pins up and then made them, we expected we would need to make new collars. But the existing retaining collars have a smaller bore than indicated on the drawings Dave had used to design the pins, so the collars would not fit onto them. James joined us briefly on Sunday morning, and quickly turned down the ends of the weighshaft crank pins so that the existing collars now fit onto them.

Andrew also joined the working party on Sunday, and busied himself drilling holes for split pins in a number of pins and collars which are used to hold the motion together. It's a fiddly task, since each hole has to pass through both parts on the same diametric axis.

With all the action being focussed in the erecting and machine shops, Dave 1 made a start on turning the motion bracket bushes for the expansion link trunnion bearings. These are made from Vesconite (a hard, low friction plastic) as we want to try and eliminate oiling points. The expansion link trunnion bearings see oscillating motion rather than full rotation, so we hope that the plastic can withstand the loads without overheating. We shall see! By the end of the weekend, both Driver's side bushed had been finished.

The final activities took place on Monday morning. Dave 1 and Andrew had a meeting with Jon Whalley (the FR's Chief Engineer) and Bob Yates (the FR's boiler designer and coded welder). Jon and Bob are preparing the C2 boiler design calculations and documentation for submission to British Engineering; the boiler approvals body. The final queries have now been resolved, so we are hopeful that the final design submission will be made in the next week or two.

Martin Greenland has kindly been checking the C2 boiler calculations for Jon, and has also offered to carry out calculations on the valve event timings for the C2 valvegear. Andrew has therefore started to sketch up a diagram of the Walschaerts valvegear linkages. This is initially based on nominal dimensions, but ultimately we will measure the existing linkages and update the calculations accordingly. This will inform us if any of the components need to be altered (corrected!) and will tell us the optimum way set up the valvegear.