No expert on these things but I have made a few and I am always astonished that they work. Usually there is a branch from the steam pipe which enters the lubricator, the main steam pipe continuing on to the cylinders. As the steam which enters the lubricator condenses and sinks it displaces a quantity of oil which then flows back along the same pipe where the steam is coming in the opposite direction and thence to the cylinders. How it does this I do not know and having no knowlege or qualification in fluid dynamics I am quite prepared to accept that it must work by magic. The Roscoe is sometimes known as a dead-leg lubricator. It can be proved to be working by two methods. Firstly, if the Roscoe is drained after running for a while, water will drain out usually followed by an oily emulsion. Secondly, after it has been running for a while, if you run the tip of your finger around the rim of the chimney, there will be an oily film left on your finger which can only have come from the lubricator.

I find that the most difficult part to make for a Roscoe is the drilling of the hole between the steam pipe dead leg and the lubricator body. This hole must be as small as you can get, about 0.015", and I just haven't got enough speed on my kit to drill small holes. Even with a tiny hole, there is a tendency for these lubricators to use their oil up too quickly and I have seen it recommended that a fine piece of wire is inserted into the hole to reduce its diameter even further.

I hope that I haven,t told you what you know already.

Mick

Hello David,

There are some photos of a chassis in the Station Road Steam Archive section. The oil pipes from the lubricator appear to connect directly to the steam chest below what I presume are the exhaust pipes.

**LINK**

John

Having seen the picture, I think that I would go along with John's suggestion that the chamfered pipes are exhaust pipes. At least that is the area where exhaust pipes usually emerge from. They are then usually connected to a T piece and then to the blast nozzle. Again, apologies if you know this already.

Mick