This is, or will be, an 1883 "Dolbeer" Single
Vertical Spool Steam Donkey engine. So far I have the Gypsy
spool and frame, Fairlead, gearing and flywheel completed.
On the crown gears I wish now I had taken
pictures. They are cut at 45 degrees on a 45 degree face.
The math is a head ache for the small gear so I just cut it
up from a point to much larger diameter then I needed and
found the right pitch diameter and cut it down to what
worked. Calculating the exact pitch might have been tough at
such a small size. Grinding the cutter was tricky as well,
but at such small size the pressure angles are less
effective anyway, so I used a gear close in pitch and size
and used it as a template to grind the cutter from a 1/16"
drill bit. This was my firs shot at a crown gear and so far
it looks to working quit well.
This was a bit more challenging then my
other flywheel projects, a bit, but not at all as hard as I
thought it might be. The flywheel on the Dolbeer engine is
unique in that it was originally a cast iron curved spoke
The challenge was to fabricate the curve
spokes. I made the flywheel in the
usual way, I make them anyway, from individual spokes, inner
rim, hub and a final outer rim. The spokes are made from
.093 brass rod. I wound the .093 brass rod around a 1/2" bar
like a spring. Then cut the coils into thirds.
Copyright 2004-2006, Florida Association of Model Engineers
and engine builder as noted above,
All rights reserved.