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?
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

That should be .789" OK, .7577" base diameter, so tooth height is .031"
So this gear is about the size of a half dollar, and about 3/8" thick
My apologies.
Rex