Build Your Own Steam Engine – Part 2


| September/October 1969



Continued from “Build Your Own Steam Engine – Part 1.”

Creating a cylinder

As low pressure steam is very dense, the tolerance of a steam engine can be very loose compared to an internal combustion engine. Therefore, the wet sleeve of a large internal combustion engine is ideally suited to make a steam engine cylinder. As a rule, very little machining is required to make the transformation to steam engine use. Generally, this sleeve has to be cut off slightly lengthwise, but usually the wall is thick enough to stand any welding that may need to be done.

The piston that was used in these sleeves is usually of close enough tolerance. Even the piston rings are good, as are required, for the dense low pressure steam. The piston will, however, need to be cut to the desired length, which is usually in the bottom ring groove. Then the piston will need to be placed in the lathe chuck and center bored to the correct size to fit the piston rod.

As the front head of the cylinder is permanently welded, it is now drilled out to suit the counter bored packing nut and it is also ready to fasten to the connecting rod at the crosshead by means of a wrist pin action bearing. While we are in the area of the drive piston it is well to stress the importance of not giving it too much tightness as aforesaid. If the piston fits too tightly, it will actually jam. If it should run at all, it may not have the desired power. It is almost unbelievable, just how easily a steam engine piston can be caused to jam by being a little too tight.

Working with components

Usually in building a machine of any kind, one would begin with the foundation, but not necessarily so in the building of a steam engine as the different assemblies are built up individually, and later aligned and put into approximate location and checked. They are now ready to be shimmed, if need to be, for final location.

As stated at the outset, this engine is built up piece by piece so to speak. It surely has many advantages over the old-time cast iron models which so far as strength is concerned was strong enough, but was unnecessarily bundlesome and heavy and did not afford repairable qualities that a steel fabricated job does. The history of most enthusiasts is that they can’t decide for certain just what model they really want to build and this is a healthy attitude, for they have now begun to see the big picture and are now stricken with the fever. Many modern ideas, such as style, model and general appearances can now be dealt with regarding the proper procedure of work on your engine.

It will almost be a must, to put modern ball bearings into the building of this engine as it surely needs as little friction as is possible, Then too, it eliminates all the frequent lubrication that goes with the old-time boxing bearing and the brass sleeve bearings. Most of all it rolls many more revolutions for a given start, than does a bearing of the above mentioned ones.

Keeping appearance and use in mind

As the parts of this shop-built steam engine are generally milled to a great extent, it is an easy matter to install very nice cowling and superstructures, to give the authentic appearance of the real old timers. This is also advantageous toward keeping your engine clean and keeping it in a nice condition for exhibition purposes.

Also, it is a good time to think about the various ideas or devices to handle this engine as to ease of portability, for you surely will want to move it from time to time. If caution is observed, it can be made into a better and more practical engine than some of the old timers. At this point, the writer wants to impress upon the reader and prospective builder of a steam engine that these theories and methods have been proved practical.