Plumbing the Mikado's tender pump

So, after seeing that the fuel tank was installed without issues, I decided to finish the tender by building and installing the tender pump. Here is another example that shows all one really needs other than the kit, instructions and tools is common sense. Where the instructions dictated one part number, my exploded diagram showed a different part number. Well, looking at the part and visualizing how it was going to work and how the drawings showed it assembled, I got er done.

It was a joy seeing the final pump assembly after looking at all those parts and having the question in the back of my mind, "are all the parts here?", certainly gave me a bit of concern. My kit had the pump kits added after market and some were in bags written on by the dealer. I am still looking for the pump handle that the drawings show, but I have a replacement pump handle on the way, so no worries there.

Now it was on to installing the copper pipes that will feed the boiler and allow the return water back into the tender when the bypass valve is open. The purpose of the tender pump is to inject water into the boiler both when starting up and under pressure. There are steel balls that act as clack valves which only allow water to be sent in one direction. This is at least the theory of how they work. Sometimes dirt and such can get in there and cause the functionality to change a bit. In writing this blog, it is the author's assumption that those reading it have a basic understanding of how the parts that make up a small scale live steam engine work. If you are interested in learning a lot more there is a good book I can recommend. A PASSION FOR STEAM by Marc Horovitz.

After seeing how I wanted to arrange the pipes, I mounted the pipes into their unions after applying some packing compound to give a good water tight seal between the tender and tender water receptacle which is made up of sheets of brass soldered together. There are holes where the water pipes from the water pump must connect with the copper lines underneath the tender, so you don't want all your water wasted because you didn't seal up the holes good.

I then mounted the tender hand pump and connected the lines inside the tender to the outside lines. I also had to bend a few small wrenches to better fit the unions in the tight corners. No, those aren't forged steel wrenches, they are thin steel ones. It sure beat going out to hunt down something which would work.

After assembling and installing the water lines and tender pump I put on the rubber hoses and attached the threaded fastener which will connect one of the lines to the boiler supply line that will be on the engine.

Next it was time to put those trucks I had assembled yesterday onto the tender. Everything went together a bit easier than I had expected, but I did have some moments where I had to stop and think how it would be best to do something. I am very pleased so far. Next I will add some detail parts to the tender and make a "dummy" coal load for aesthetic purposes when it graces my shelf between steam ups. There will be no storage box for this loco.

Tonight after the packing compound has dried, I'll do a water test to make sure I won't be wasting any water needlessly. I'll also give the pump a few strokes to test it as well. I will be taking a break for the summer vacation so I will not be working on the engine until I return later in July. I hope all who have read this have been both entertained and enlightened. I am really glad to have the chance to build this engine to both better understand it's workings and to have something which will last me to share the fun with my son and daughter.

Packing dried, so I tested it. No big leaks, but there was a droplet of water forming under one of the mounting screws of the pump, so I added a touch more caulk around that screw.