SECOND PLACE - The Machine of Inspiration
Inspiration can strike at any time, whether you seek it out or not. Some of the best inspiration can come from family, and for Bob Harbrige, an Engineering Handbook (Mechanics’ Pocket Memoranda, 6th edition) from 1900, which belonged to Bob’s grandfather, depicted a simple design for a stationary steam engine. After some time, that steam engine design transformed into a completed, fully functioning, Wooden Air Engine.
The machine measures in at 39" x 20" x 19" and was constructed using a Wood-Mizer LT15. Over the course of four months, Bob used hickory, white oak and black cherry totaling an approximation of 30 board feet. The machine is designed as a decorator item and, as Bob shares, “This engine has been used to run a small generator powering LED lights. It has a three inch bore and a six inch stroke and works on approximately
four psi of air pressure created by a vacuum.”
The detail of the air engine is stunning and the work that went into the four month project is so detailed. “The engine block was made of 1.5" quarter sawn black cherry blocks glued together crossgrained. The center of the block was drilled for a three inch PVC pipe used as a cylinder sleeve. It has a hickory piston with a black cherry quarter sawn piston rod. A wood lathe was used to form the crankshaft, flywheel spokes, flywheel hub, pulley, reverser handle, roller wheel on reverser, piston rod, slide valve rod, piston, spacers on crankshaft and feet for base. Three pieces of 3/16 planed quarter sawn black cherry were glued together crossgrained to make plywood sheets. These were used for the reverser piston slide, block glide, slide valve slide, block guide and slide valve port plate. The air chest was made from quarter sawn black cherry and has a Lexan window to view the slide valve operation. The base was constructed from eight 1.5" x 3.5" cherry boards glued together and held with 4 bolts. The plaque on the front was made from quarter sawn oak with custom decals. The eccentric straps, connecting rod, crankshaft journals, main bearing blocking and valve guide bases were all made from quarter sawn black cherry.”