I need a 40 tooth Myford change gear.

I bought a Myford Metric attachement for my Super 7, but it
is missing the 40 tooth gear which is needed for numerous
metric threads. Anyone got one setting around??
(I didn't see one on ebay)

I got a few oddball Myford gears laying around I could trade
if that is an incentive.

BTW, this attachment comes with 12 gears, but I don't understand
why. For example it comes with two 60s and two 55s but I don't
see any setups where you ever use more than one of each to cut
a metric thread.

chuck