While restoring a Kingerey steam engine, I remembered an event
back in 1926, when I was a young boy. I recall watching the
operation of a Corliss engine in a creamery in Grand Forks, North
Dakota. I will never forget the slow, positive strokes of the
crosshead and the quick cut-off actions of the dash pots!
While the small Kingerey did not belong to me, I decided to
Living on a small city lot with only a single-stall garage, I
was prevented from collection and restoration of actual size
engines of any kind, even the small hopper-cooled gasoline engines,
which intrigued me very much.
The decision was to build a miniature model of the ‘king of
them all’ the Corliss!
I first decided to learn about the history of the engine. I read
some information on George Corliss himself, and studied Audel’s
book on the Corliss engines. It was interesting to find out that
George H. Corliss, although possessing inventive ability, was
actually a harness maker. He was born on June 2,1817, in Easton,
New York, and died in Providence, Rhode Island, on February 21,
1888. Mr. Corliss was not fitted by any special education for his
great work of taking the steam engine from where it was left by the
immortal Watt, and bringing it to its present high state of
perfection. He never saw the inside of a machine shop until he was
24 years of age. He attended an ordinary village school until he
was 14. Working on leather harnesses resulted in the invention of a
harness sewing machine which long preceded the famous sewing
machine invented by the Howe brothers.
George Henry Corliss first came to Providence in 1844 to
complete an invention of his for sewing harness leather. He took
his work to the steam engine works of Fairbanks Bancroft & Co.
He showed such adaptability as an inventor and draftsman, that he
was requested by the firm to come and work for them and he
abandoned the harness sewing machine.
A professor in Providence, became interested in Corliss’
talents and gave him some calculations on the expansive action of
steam which had been made in 1830. Corliss gave his entire
attention to the steam engine and invented a valve gear for using
steam expansively. The great success of this invention made him
famous. He designed his first engine using rotary valves in 1850.
Essentially, the expansion of steam in his engine was cut off and
varied and controlled by the governor. The degree of expansion, on
a Corliss engine, is automatically changed to suit the load and
speed conditions. In 1856 he established the Corliss Steam Engine
Co. in Providence, Rhode Island, which at once came into
prominence.
Corliss, like most inventors, had to force his invention on an
unwilling public. He had to assume all of the responsibility, and
in many in-stances take pay in what he could save the customer in
fuel. In the end, this proved fortunate for him because in most
cases, he received far in excess of the price he had placed on the
machine. At the time Corliss was selling his automatic machines for
what he could save, the United States Government was spending money
on experiments to show that there was no economy in using steam
expansively.
Many Corliss engines were used to manufacture electricity,
especially by large manufacturing firms who chose to make their own
power. Some were also used in sugar cane mills and may even be in
operation today. Restored Corliss engines can be seen in various
museums today; some examples are in Dayton, Ohio; Greenwich, Rhode
Island; Henry Ford Museum in Detroit; Rollag, Minnesota; Pawnee,
Oklahoma, and the Smithsonian Institution. These are just a few
that escaped the cutting torch!
The extreme weight and slow RPM of these engines were distinct
disadvantages and eventually the high speed steam engines, diesel
engines and the steam turbines took over. As an example, I recently
had the opportunity of visiting the power section of the Henry Ford
Museum in Detroit. Some of the Corliss engines on display are
enormous. I measured one flywheel 25 feet in diameter, one lhalf of
its diameter in a pit in the floor and the face of this wheel 3
feet in width.
How does one start making a model? First of all an order is
placed for a complete set of blueprints. After receiving them, make
a thorough study of each part and make absolutely sure that your
machine shop can handle each size. At this time it is also a good
idea to make a list of the materials, metal barstock and small
parts, such as nuts and bolts; there are parts such as the
flywheel, crankcase, pillow block and the engine bed, which should
be purchased as raw castings. These will be machined later. There
are 14 large-size drawings so it’s also a good idea to make an
index so as to more quickly be able to refer to various details and
parts. It will also be necessary to buy some of the left-hand taps
and dies, called for in the drawings. These will be used in the
fabrication of the various turnbuckles used to adjust the various
valve rods during the timing of the engine. Procure a set of bevel
gears for the governor.
Probably the most critical machining will occur in the machining
of the rotary valves, four of them, and the four pockets in the
cylinder block which will receive them. These play an important
part in the timing of the engine and it is very important that
slots be machined as specified and located to the dimensions. In my
case, the valves were made a couple of thousandths oversize to
cause an interference fit. Then I rung-fit each one into its
respective pocket, doing this in the lathe and using a generous
amount of oil. The pockets in the block were reamed.
This engine is just about the right size for easy handling and
yet small enough so as not to present unusual problems of
construction. In my case, I own a 9′ South Bend lathe, a drill
press and the regular variety of inspection tools and gauges.
Although a power hacksaw and a belt sander come in very handy, they
are not absolutely necessary.
To machine the cylinder, dress the end surfaces of the block,
perfectly flat. Locate the center of the bore and remove most of
the metal with drills. The material is cast iron. To finish the
bore, which is 1′ dia. by 3′ long, mount in a chuck and use
boring tools, or mount on the lathe saddle and use a boring bar
between centers. The tools should be sharp and set the lathe power
feed at its lowest rate of advance. Open the bore a little at a
time. When you get up to the right diameter, traverse back and
forth several times at the same setting. This will produce a very
smooth bore, but avoid any chatter during this operation. Follow
this with a honing operation.
I would like to invite all of you miniature model engineers and
makersto submit your contributions as well as any questions or
problems, which you think would fit this magazine. Good photographs
of your building efforts are very welcome. We will be anxious to
hear from you.
