Build Your Own Steam Engine – Part 2

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.

Using salvage parts, combining engines

The writer has taken the remains of an old engine of one make and design and the parts of yet another, and with simple engineering and cautious work has turned out an engine that performed nicely.

The writer has at the present time two steam engines that were built basically from reciprocating steam pumps of the twin cylinder design. These old pumps were picked up as salvage, but they turned out to be in good mechanical condition. So, with these basic parts, which were the cylinder and steam chest, valve assembly, etc., about all I had to build was the crosshead assembly, connecting rod assembly, crankshaft assembly, crank disc, bearings and, of course, the eccentric cam, and I was in business.

These engines, made from these old pumps really are attractive performers and the onlookers seem to enjoy watching them more than some of the other engines. So, from this picture any one can see how easily it would be to modify an engine.

Almost any reasonable length cylinder can be used, so that the stroke can be made to suit and this length of travel can be picked up at the crank disc by bolting the connecting rod knob on at the correct place. This, of course, is established by doubling the radius of the crank movement.

I have built several steam engines from scratch, starting out with machined hollow bar for the cylinders. In this particular engine, we used piston valves. The valve cylinder is usually about one-half the size of the drive cylinder. The reason for using hollow bar is because the wall thickness allows for veining for the steam channels. This added thickness allows room to bore for the head cap screws and also for fastening to the base, etc.

The connecting rods from big diesel motors make a good connecting rod for your steam engine, provided you cut it into two pieces; preferably about the middle. Then bolt each end on a level jig to give it the proper length and a splice is welded into place, after the rod ends have been bolted down tight, so as to hold it in perfect alignment. This added length to the rod makes it a better looking rod and it performs better. Usually, these connecting rods have large bearing surfaces which are very essential in the successful operation of your steam engine.

The general appearance of this job can be improved by filling in the irregular surfaces caused by cutting and welding. This connecting rod can be filled and smoothed out with auto body filler. After this filler has dried thoroughly, it can be sanded down to a smooth finish and painted. After painting, it can be polished and given the appearance of a manufactured rod that was especially designed for your engine.

Fitting the crankshaft

Now is a good time to place the crankshaft in the lathe. After it has been centered on both ends and dogged tight, it is now ready to be fitted to the bearings, the disc wheel, eccentric and any other accessories that may need to be added now or later.

After the crankshaft has been worked over is a good time to make permanent anchors for the bearings of the crankshaft. This probably won’t be much of a task, but it will have to be done. Now is a good time to install a small pulley to accommodate the flyball governor you may want to install now or some time later on. Above all, always center the crankshaft so that it may be put back into the lathe at any time for any repair or adjustment. You will really be proud you did this, should you ever need to put it into the lathe.

Overcoming a lack of information

I would like to state now that since I started several years ago to do a lot of research work on the steam engine, I absolutely failed to find a book, or books, or anything, that really explained anything about how the steam engine was made. I ran the library at our state capitol, the library at out state university, mail order correspondence courses and exhausted every avenue of information I could think of.

So, as I was now desperate, I wrote to my congressman for help. He replied with an answer that he had at his disposal plenty of help and he would send out someone to run the Library of Congress and he felt like they would come up with something. After a while I finally heard from my congressman saying they had searched the Library of Congress thoroughly and had failed to come up with any information of any interest to me. With this news, along with the other disappointments I had received, I felt that it was hopeless to proceed further.

I immediately set out to re-invent the steam engine, for I did not even have one to go by, or to copy from. Well, I suppose I was successful to a degree at least, for I now have several steam engines that I have built in my home machine shop. I suppose the engineers thought that the steam engine was so simple, that there was no need to preserve the plans and specifications. I just naturally thought that if some of the old timers could build them, I could also. I am sure, men of today, with all the modern machinery and material, can really build a better engine than the old timers built. This I believe to be true, as I will show later on in this article.

Boiler basics

The steam generating plant known as the boilers is also an important part of the steam set up, as it really furnishes the power. The life of any boiler is comparatively short compared to the life of the engine, due to the fact that we have to deal with so many enemies of metal.

First, and probably the most important, is the fact that a boiler has to be strong and kept strong by watching rust and corrosive accumulations, from within and around the flues. Tests have shown conclusively, that the surface of the boiler should be clean on the inside. Rust and corrosive accumulations on the inside, is an insulation and also a metal destroyer.

Also, the flues should be kept clean at all times. Again, the accumulation acts as an insulation and too, it takes up valuable space and therefore slows draft. The draft problem alone is worth mentioning. Practical tests have proven that a boiler let go for three or four days gradually became harder to steam up and in several tests, we have noticed it almost doubled the time required to steam up.

Cold water is not explosive at any pressure, because it is not compressible. Hot water, however, is and if hotter than 212 degrees, will in case of explosion turn a large amount of water into steam and become very dangerous. I wish to emphasize the necessity for keeping this force under control. Steam can be a good servant or a merciless destroyer, depending on how it is handled. I have heard men say, “I am not afraid of steam at all.” That man was not brave; he was just a plain fool. The good steam man will not make such remarks. He understands, and will not take any unnecessary chances. He should have plenty of nerve and a cool head in case danger does arrive, or he will be a poor man to be in charge of this operation.

While the words of caution just spoken of may seem to inspire fear of a boiler, the fact is; no such result is anticipated. There is a difference between fear and respect. This caution is intended merely to inspire respect for an almost limitless force, with the hope, that it will induce these men who read this to be very careful. If this care and respect is regarded, the steam boiler is safe and a pleasure to attend to.

Types of boilers: Internally fired and externally fired

There are several types of boilers, and forms of firing them, but only two types apply to men with this hobby. One type is the internally fired boiler and the other externally fired boiler.

Internally fired boilers are provided with a fire box or furnace within its own walls. All old-time steam locomotive boilers, old-time steam traction engine boilers and many marine boilers are of this class. Externally fired boilers are placed over a furnace built especially for them, and generally in a masonry setting. They are not designed for portable work and are used most generally for mill and factory work.

These two classes may again be divided into two more classes depending upon the course taken by the heating hot gases. One is composed of shell or tubular boilers, known as fire boilers and the other as water tube boilers. In a fire tube boiler, the hot gases pass through the inside of the tubes or flues on their way to the stack and water circulates around the outside. In the water tube boiler, these conditions are reversed. Water occupies the space inside the tubes and the hot gases pass on the outside. Both boilers have certain advantages. The water tube boiler is a quicker steamer than the fire tube, because there is no large amount of water in one body to heat by the gases. Boilers of this class are less liable to a dangerous explosion. If an explosion does occur at all, only one or two tubes are likely to let go. In this case, no great damage to life or property is apt to take place.

Boilers may also be classified to form, as either horizontal or vertical. Vertical boilers are not as efficient as horizontal ones and are not preferred, except where floor space is an item to be considered.

Boiler construction

Steam boilers can now be built by men who several years ago, would never have thought of such a thing. After you have studied and found out that mild boiler plate steel is fairly easy to work, it becomes a task not so dreaded by a hobbyist. Mild steel boiler plate is easily cut and welded. Drilling also is easily done in this mild boiler-plate.

A great many boilers today are cut and welded construction throughout. “Big Inch” gas line tubing of correct size makes a good outer shell for a steam boiler and is perfectly reliable for safety sake. They are being used to transport petroleum products with pressures far greater than anyone would want on a steam boiler. Boiler plate can be bought any place where they sell structural steel. The boiler heads can be cut from these sheets, along with the flue holes. These flue holes however, should be held to a reasonable tolerance, so that the welding can proceed.

You notice I speak of welding almost constantly regarding boiler construction, because it is not as time consuming as expanding the tubes or beading the tubes. I believe it to be better in many respects. One important reason, it can be welded absolutely steam tight and with this mild steel, stays welded steam tight. With welded joints there are no cracks and leaks due the many inches of joint expanding and rolling.

One objection, however, is that if a flue should become defective for any reason, the whole tube would have to be cut out. Therefore, in most cases, having to enlarge the hole, this also can be overcome by using a shim or slightly larger tube, fortunately the writer has not had any trouble of this nature, and I believe the welded jobs will last many years, for hobbyist use. Again I wish to repeat, that these statements in this article are purely for hobbyist use and no pretence is made intentionally to make a machine to do hard, heavy work on a continuous basis. But, they are more than capable to do the job that they are designed to do and do it safely and dependably.

The writer has built several boilers of this design and size that has just been described and never had an explosion of any degree, and scarcely any trouble of any kind. Therefore, I can’t help but speak with some degree of knowledge and advice. I might add to this statement, these boilers have had literally hundreds of hours of service, which has been witnessed by many, many people. The boilers that I have made have been the vertical type and, as stated some time back in the article, are not generally considered as good as the horizontal type; but again, space was scarce with me too.

The writer has also, a 20 hp vertical boiler that I fire with hardwood scrap and in fact, any thing in the way of wood that I can get handily. I have had good service with this boiler and have never had any trouble to speak of, in keeping up steam and in quantities to run my larger 20 hp engine and my 10 hp engine.

Steam pressure guidelines

Now mind you, I call high pressure steam, 125 psi, because this is the maximum pressure that this boiler would carry without popping off into the atmosphere. This above described high pressure steam is wholly unsuitable for hobbyist’s use, because of some danger, due to water injection and any malfunction that could present itself. So for this exhibition purposes, I carry low pressure of about 20 psi to 30 psi. At this high pressure, and without a load the engines would run away and cause great damage and danger, should the governor or any of the structure fail. So this 20 psi or 30 psi steam is safe from explosion point of view, provided, of course the whole operation is reasonably well supervised and attended to.

The good reasons for carrying low pressure are almost too numerous to mention. One really good reason is that water can be forced into the boiler with more safety than with a head of high pressure steam. The writer considers the boiler or steam generating plant almost as fascinating a project as the reciprocating engine itself.

Safety features

After having secured all the various outlets or pipes, such as the steam gauge, safety valve, try cocks, etc., I pipe steam and water from the boiler into a water leg, at the level of where I wish to carry my water level in the boiler. This water leg can be a choice of several inches from the boiler.

Into this water leg, I have installed a copper float on a crank, on a shaft which is made compression tight by means of a packing nut. The outer end of the shaft contains another crank that operates an easily operated mercury switch. To this mercury switch is connected a high pressure electric water pump. Owing to the very short degree of travel of the float in the water leg, the water level in the boiler is held almost at constant level, automatically, this appliance is easily made by the hobbyist in his home machine shop and it sure will add a lot more pleasure in the operation of your steam generating boiler.

Another device that I have made and used with a lot of satisfaction is another water leg located at a point that would be considered a dangerous level. This water leg contains a copper float also, and is operated in the same manner as the above job, except, it operates a cutoff valve for the natural gas feed. These two water level jobs, connected to these automatic control devices surely make this boiler a pleasure to operate and too, it is really a safety feature.

The fact that you have built these safety features and understand their mechanism, gives you a lot of pleasure in being around your project with your friends and loved ones, who are sure to be around a lot of the time. Your knowledgeable conduct will automatically give your friends and guests confidence and afford them more pleasure. It is natural for even a novice to have fear of a boiler if he doesn’t think that the operator is knowledgeable and has good judgment in handling this equipment.

Steam hobby in a class by itself

So, as the whole set up is for amusement, as proven by the literally thousands of people who regularly attend these shows, it is important to be an expert in the hobby you have selected. At this point, it is well to realize that you are surely in a hobby that is all by itself, for there are definitely no more steam engines being made. It is very doubtful if any more engines will ever be made, except those built by men who have taken up the hobby in a serious way.

At any rate, the field of steam engine building will never be crowded. There is in existence, records and specifications of steam engines of many types and designs, but that is easily understood after some thought, for when steam was used extensively it was about the only source of power that was obtainable. Engineers tried to build engines to suit the many needs and requirements. But only in rare cases, have we ever seen the hobbyist trying to build anything but the more simple designs. After the hobbyist has gotten started, he will automatically see where he can modify and otherwise improve his engine.

The writer has even built twin cylinder steam engines, both cylinders tied to the same crankshaft, but with two cranks that were 90 degrees off center, thereby making it a self starting job. This of course is best made by having the cylinders spaced wide apart, so that the flywheel might be in the center of the crankshaft. The bearings, eccentric cam and crank disc, of course, are located on each end of the crankshaft. This makes a very pretty performing steam engine.

When I was a small boy, I remember seeing small engines of this type pulling the old time merry-go-rounds and because these engines had two cylinders, and off center from one another, made it self starting. This was necessary because of the constant starting and stopping. Probably the reason I never managed for a steam engine before I did was because I was always trying to get hold of one of these little pop corn popper steam engines. These little engines had about a 1-inch cylinder bore and about the same stroke. They were built exactly like the big steam engines, having the old-time flyball governor, etc., but these engines were never available, except by buying the whole pop corn popper, which was at that time quite expensive. This size engine, I could have kept along with my other personal belongings, while a big steam engine would have been an impossible hobby for me at that time, as I was constantly traveling around.

I have seen literally hundreds of these old-time engines that met up with the acetylene cutting torch and landed in the scrap pile, to be melted up and put into metal for other kinds of machinery. But fortunately, there is a few of these old timers, that are in the hands of people who guard them almost jealously, but yet these good and kind people enjoy helping and encouraging other people who are getting interested.

It is hoped that enough young men and boys of today will pick up this steam engine hobby and preserve it for many generations to come. The writer personally knows men who have built 24 gauge live steam locomotives complete with cars. This of course, is a lucrative field and surely gives the hobbyists a fair sized workout. These men did not even own their own machine shop, such as lathes, milling machines, etc., but had the engineering ability to have them built, according to their own plans and specifications.

This form of operation surely had its advantages due to the fact that the man hired to do this work is a full-time machinist, who is an expert and will give the hobbyist a nice job. Usually the hobbyist is a full-time employee of some other business and will have about all he can do, just to assemble these components. One of the men I speak of as the builder of a locomotive is a traveling salesman and naturally doesn’t have a great deal of spare time. But, after long weeks and probably months, has really accomplished the job of building a good looking and performing engine, that I personally have seen haul lots of people.

Probably one of the most thrilling things about the steam engine show is hearing the steam whistle blow. This sound can only come from a steam whistle! No other type of whistle or horn can imitate the steam whistle. The writer has had crowds of people that wanted to actually pull the steam whistle cord and generally did, this was a thing that they never had done before and probably some will never do it again as long as they live.

These things that have been discussed in this article will evidently start most of the people out on the right track. This information has been very hard to get and did take a lot of time and trouble chasing down the authenticity of the various ideas and statements that have been recommended. I do not believe anyone who hasn’t lived back in the days of the famous old engines could really grasp the true picture. As simple as the steam engine is, it would be hard for most people to re-invent it, which is about what it amounts to. So it is my wish that anyone, learning the principle of the old time steam engine would pass it on to others who are not so fortunate. IMA

J. Arless Jenkins is from Magazine, Arkansas.
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