With the slide bars in place at the cylinder end it was time to start thinking about the outside motion. I decided to do it as two subassemblies and then join them together as I secure the rear end of the slide bars to the motion bracket.

Aling with the Premier Components coupling rods, came a set of the rest of the motion parts many of them very nice but some just didn’t work (or at least in my view). These are the combination levers and the union links. Starting with the combination levers, those fitted to the Princess Royals were fluted and the Premier examples plain.

The union links in the Premier set are represented by a single dog bone shaped rod which is 0.9mm thick. The very visible, prototype union links have forked ends. After exploring options of combining the etches with the premier link I realised that they were each of different lengths so no chance of combining the two.

After consultation with the gent that I am building it for, I went with the DA etched combination levers and union links but used the Premier parts for the rest of the motion.

For me the most difficult bit of building motion, inside or out is “how do I fasten it all together”. For the front half I have tapped the valve rod 14ba and put a screw through from the inside. Visible in the photo below.

The union links I have riveted with 0.8mm brass rod. I have a small piece of steel that I use as an anvil so I drilled a shallow depression in one corner to use to form rivet heads. Once inserted I peined them over with a small ball pein hammer.

I also turned up some oil pots for the connecting rods. Not quite prototypical but they do look nice.

While I am using the Premier Rods, I still need to use the DA etched expansion link and that’s where I was second guessing myself

On all the other outside Walschaerts valve gear that I have built before, the radius rod is connected via a pivot below the main pivot of the expansion link.

I thought I had assembled it wrong but after searching through a number of photos and reviewing the outside motion GA for 6203-62012 on page 38 of the Wild Swann book. It seems that on the Princess Royal there is no lower pivot point. Phew!

The forked ends on the radius rod were made from the ends of the etched radius rods that came with the kit.

Finally I was pondering the brass bearing cap on the eccentric rod where it attaches to the return crank. There are some etched covers included but since the whole kit is etched nickel, they are nickel not brass. So, I had a quick go at mocking one up on the lathe.

Although it doesn’t have the small screw heads and the oil pot it does look more three dimensional than the etch and of course it’s brass. I will sleep on it and see where I decide to go next with that one.