Rob Pulham 2022 Loco Build Competition Entry

Today I made up some connecting rods for the inside motion. They came from the scrap etch box and were originally for a Black 5. I cut off the big end bosses from all the pieces and then soldered them together in pairs. Once I had measured the length, I cut them to final size and grafted some Laurie Griffin eccentric straps onto them. I have calculated that the home turned eccentrics will give about 3mm of travel fore and aft but that will be sufficient to give the sense of movement though the holes in the frames.

 

Following a question about parts for the inside motion on the Guild forum, a fellow member posted how he had achieved a similar result to what I am working on but without the use of a lathe. I must off thanks to Harold because his post gave me the solution to one problem that I had been pondering (how to space them apart for soldering) and for prompting me to think that I didn’t actually need to solder them to the axle at all. I could solder them to the bush which acts as a spacer and would allow a hole to be drilled to make use of the taper pin that holds the axle together.








In true Blue Peter style, here’s two I made last night before I got my head into gear and correctly worked out the width. They will go in the spares box as I am sure that they will come in for something.

 

Back to the Princess this week after moving the J6 along.

In the end I decided to take a bit more of the edges of the cylinders and then I fitted the covers. Before I did that I soldered the slide bars in place as I didn't want the heat from soldering them in place to spring the cylinder covers loose. As it happens I had to adjust one of the slide bars as I hadn't got it quite square and the cylinder covers are such a good fit that although the solder softened, they never moved. Something to aim for on future builds.





After fitting the slidebars I mated them up with the motion bracket and realised that once I join the two together them crossheads become captive so I need to do work on the motion next to ensure that all is well before I solder the slide bars to the motion bracket.

The first hiccup is a result of using extras to the kit. I used the David Andrews Slide bars and crossheads for the simulated inside motion because they don't have as much details as the LG Miniatures versions. Now I come to fit the LG crossheads with the connecting rods which are replacements from Premier Components I find that the LG crossheads are different to those that I have used on other builds in so much as they have a slot in them rather than an open back. This means that I will have to mill the connecting rod ends to get them to fit in the slot.


A picture paints a thousand words as they say...

 

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!






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.

 

He is, but even if he wasn't, it wouldn't stop me from doing it. I find it very hard to do out of the box builds as I get my pleasure from all the added extras. If I need to make those extras myself, so much the better.

It keeps me out of the pub...

 

Hi Brian,

That's actually part of the reason that I am stopping doing builds for other people. I am just doing those that I have already committed to then that's it.

From then on it will all be my own stuff - I have plenty to go at....

 

I have really struggled for motivation this week so haven’t achieved as much as I might have liked.

I decided that the etched return cranks were a little under nourished and 2D so I added a bit of detail.




First a turned a spigot on an offcut of rod and soldered the rear etch to it and drilled out the four bolt holes using 90 degrees spacing on my Proxxon mini pillar drill using the dividing head.

Next, I soldered them to a piece of scrap etch from the kit drilled through the holes to transfer them to the other layer and cut around them with a piercing saw. I forgot to take photos of that bit.

Then I made up eight (actually nine) studs from rod and microbore tube filed to a hex head and cut to length.




And finally I assembled all the parts.



Magnified as they are they look a little rough around the edges but it’s not visible at normal viewing distances.