John R. Bentley 2006.
I have taken a few photos of the engine which I hope will show some detail.
(I just thought it may reveal some details that are not present in more natural lighting.)
Another view from the back.
Stainless steel (used for the large steam valve, piping and flanges, railings, stanchions and column base supports) was etched with printed circuit etchant from Radio shack.
The cylinder and steam chest are cast iron, machined from an old fashioned window weight. The brass parts were from a discarded propeller shaft.
Here are some measurements that I made of the finished engine:
The plain cylindrical sections of the columns are 5 5/8" x 3/8" diameter.
The little capitals at the top of each column are 3/16" high x 1/2" diameter (at the maximum point).
The round bases are 1/4" high x 5/8" diameter (maximum)
The square column supports are 1 1/8" long x 5/8" x 5/8".
Just in case there is any error in the vertical dimensions, the top of the upper table should be 7 3/4" above the top surface of the main base.
The dimensions of the upper table are actually 1 1/2" x 2 7/8", but the "lip" around the bottom of the table extends outward 1/16" more in all four directions. The overall height of the table (including that lip) is 1/2".
This all means that the bottom area occupied by the four columns on their bases is 3 3/16" x 1 3/4".
The stroke is 1". I think the bore is 5/8". (the smallest outside diameter of the cylinder is 3/4", so I bored it as large as possible).
The cylinder end covers are 1 1/16" diameter, and the cylinder assembly sits on a square baseplate about 1 1/8" x 1 1/8" x 3/16". This little baseplate is raised on four legs 3/8" above the main base surface.
The steam chest is 7/8" x 1 1/4".
The top of the bronze bushing on the piston rod guide is 5 1/8" above the top surface of the baseplate. The fork-type connecting rod is 4 3/4" between the centres of its end bearings.
The flywheel is 4 1/4" in diameter and the rim is 5/16" x 5/16". The spokes are 1/4" x 3/16". The largest (central) part of the hub is 3/4" diameter.
The 1/4" diameter crankshaft centre is 9/16" above the top surface of the table.
The 4-groove pulley wheel is 1 3/8" diameter x 1/2" thick.
The curved baseplate is 5" x 4 1/4".
