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

Hmm, sounds like an excuse to learn how to make your own gears. I wish
I could make an excuse like that, but my lathe has a quick-change
gearbox.

About the multiple gears, do many setups use the 60's and the 55's? If
they were used in almost every common setup, it would make sense that
Myford might anticipate unusual wear and include a spare of those gears
likely to wear down fastest. Besides, those gears sound like some of
the largest in the set. Large gears have more teeth, so the
probability that a tooth will become broken or damaged is higher than
on a small gear.

Hmm, sounds like an excuse to learn how to make your own gears. I wish
I could make an excuse like that, but my lathe has a quick-change
gearbox.

My lathe has a QC gearbox too. But I cannot cut metric threads without
using some change gears ahead of the QC gearbox.

chuck

Large gears have more teeth, so the
probability that a tooth will become broken or damaged is higher than
on a small gear.

That's an interesting theory. Can't think of a reason why it would be
true, though. Actually I'd think the smaller gears would be more likely
to fail sooner.

I have owned three myford lathes. The first 2 were both change gear
machines and were 50 years old. The myford gears are nice steel gears
and the only gears that showed any wear at all were the small gears
on the reversing lever.

Apparently this metric conversion can also be used to cut threads
other than metric (BA) so there must be a setup that requires 2 of
the same gears. I will cross that road when I get to it.

Right now I need to find a 40 to complete the set. The ebay seller
was clever on this auction. He stated what it was and listed the
gears that were included. I just didn't realize that one gear
was missing. I'm sure I can buy it from myford.

chuck