One of the old steam rollers at the museum where
I spend a bit of time as a volunteer,is up for
restoration.
We have removed the wheels and gear train covers
to find that the final drive gears are badly worn.
The pinion has 14 teeth and the bull gear has 72..
The bull gear is about 1160 mm diameter on the
pitch circle. As we haven't removed the shafts
yet, I don't have exact centre to centre
distances. Looks like a straight forward exercise
in gear cutting, except for one problem. The gears
appear to be epicycloid in profile. The bull gear
, we (I) intend to draw in a cad program and send
a DXF file to a contractor with a CNC plasma
cutter.The pinion will have to be milled I think..
Anybody have any thoughts on if there are any
standards for epicycloid gears? They were
supplanted by involute profiles many years ago on
just about everything but clocks. I've found a few
web sites by Googleing , but any help will be
appreciated.

Regards

Tom Miller