Very interesting topic. Does any expert know what years were more prone to lathe chatter - or can it occur in any year?

Yes they can occur in any era. But the eras from 1954 through and including all 3 Large Stamp eras are the ones most likley to have it.

With the K's it's the Intermediate Stamp era.

Your eyes are seeing what looks to me like either a small scratch or a stain or mark on the cymbal. I won't try to dissuade you from your morning crack, though ;)

Hmpf, it sure does look like a nasty crack to me. I mean crack, like, on the cymbal.

By the way, that 50s K I owned had this lathe chatter too.

I've always wondered what that was! I have a few 50s As with lathe chatter on them. I just figured that it must be some spinforming technique they used back in the day, maybe to quickly dry a tempered cymbal or something.

So, what exactly IS lathe chatter? What I imagine is it's when they're lathing and the lathe, for whatever reason, goes "b-b-b-b-b-b-b-b-bump" and the lathe vibrates like mad due to friction. Is that right?

Yes, that's the essence of it. Without getting too technichal here, it has to do with something in physics called "resonant frequency".

The lathe chatter is not generally caused but the lathe as such,it really should be called tool chatter,The cymbal is spun on the lathe against a former,the turning is done with a hand held cutting tool rather like a woodturning chisel. The cymbal can bounce against the former,the cymbal may not match the former,then the cymbal is unsupported in some areas and so moves away from the pressure of the chisel which then starts bouncing leaving chatter,also this can happen when the tool hits a had spot in the cymbal and the tool bounces on the tool rest.Once the chatter is on the cymbal it is very difficult to remove as the tool just repeats it., because the tool is held in the turners hands which give, not mounted firmly on the tool post.

Most of my working life was spent turning and spinning metal.

hope this helps to know why,it just adds individualism to the hand made cymbals.

Looks pretty too.

Do'nt it just.

Forgive my ignorance - I don't know which are the three large stamps - are any of those in the 60's or are they all 50's?

I've seen a very helpful reference on the 60's stamps (that you wrote) - is anything you've written on the K's available?