I would say 60's but Drumaholic can give you a more definitive answer.

Scott

Looks like 60's to me too.

Try this site:

http://www.ehow.com/how_7712019_tell-age-zildjian-vintage-cymbals.html

And then when you want the right answer, go back and try this site.

Hey Bill, I wonder if you tried these instructions (just for a lark) and classified some of your A Zildjian cymbals -- how accurate would it be? 20% 40%? 60% 80% ??

Just curious. Oh, and using all Istanbul made Ks doesn't count since they seem to have forgotten about them. DOH

You can't classify anything with certainty from what's there. What's needed are photos of every type with detailed explanations as to what unique characteristics apply to each. By far this is the worst possible source for information on this subject on the internet.

I agree. I tried to use the criteria but it is vague and subject to interpretation.

I appreciate the value of experience.