F. George McDuffee wrote:
Rule to find metric module [there is an inch module but seldom
used now] is to measure the OD of the gear in mm and divide by
the number of teeth + 2.
16t +2 = 18
.789 * 25.4 = 20.046 mm
round to 20
20/18 = 1.11 module [doubtful]
assuming 1.00 module
16T +2 = 18 X 1.00 = 18mm OD
18 MM/25.4 = 0.7087 inches
Any chance of a decimal slip?

I doubt it. I read 20.05mm off a Mitutoyo digital caliper. This was off
an identical undamaged gear. The damaged gear has all the teeth laid
over a little, so I did not trust any measurements there.

BTW -- almost all metric gears are 20 degree pressure angle.

see
http://www.littlemachineshop.com/pro...ProductID=1523
for 1 m/m gear sets for mini lathes or see
http://mdmetric.com/kgear.htm
http://www.qtcgears.com/RFQ/SpurGears.htm
http://www.google.com/url?sa=t&ct=re...MpeQsQHi-fG9Dg
http://www.sdp-si.com/herb/spk/sdp-si/D780/D780cat.htm
and a bunch more

I'll study on those later - thanks

Rex