My Grandfather's Engine

by William Johnson

Mechanical Models, January 1938 Modelmaking has become nearly as exact a science as any other branch of engineering, but when my grandfather made this little engine, even the word "Modelmaker" was unknown. Most of the models of three quarters of a century ago seem to have been made either by engineers or blacksmiths. The engineers spent years in turning out what looked like a piece of mechanical jewelery, while the blacksmiths made the kind of models that the disciples of Tubal Cain might be expected to create. My grandfather was a blacksmith and this was his model. Criticize it if you like, but put yourself in his place afterwards. Few mechanics, nowadays, could have done as well with the few crude tools he possessed.

The beginning of the whole thing was a visit he made to a mill in New Orleans. A new type of steam engine had just been installed and he spent hours watching it run. No wheezing, clicking or groaning, just smooth motion, faster than anyone thought a steam engine could run and stay together - "Two hundred and ten revolutions in a minute, boy!" he told me years later.

All the way up the river he thought of nothing else but the new engine, so when he had some time on his hands later on, he began making a model. All he had was the memory of the swiftly moving machinery and a volume of Nicholson's "Mechanic" published in 1821! Even then it was an old book, but the slide valve was shown and explained and a country blacksmith was a man of parts those days, so the engine gradually took on the shape and character of its prototype.

The bed was cut out from a flat piece of cast iron. The work was done with files and chisels. Large holes had to be drilled by using a hand ratchet drill and an "Old man" which was an iron arm to hold it up to the work. Small holes were made with a "fly-drill" consisting of a weighted shaft with a loose knob on one end which was held in the hand, while the other hand pulled a string, which rotated it alternately in each direction. The knack was to let up on the drill pressure sufficiently to allow the momentum of the weight to wind up the string.

The drawings have been reconstructed from sketches made for the original. I hope this very unmechanical history will be considered of sufficient interest to merit publication.