Where to find M50x.9 retaining ring for Xenotar 150?

[EdSawyer]

Ok, so I acquired a nice 150mm f2.8 xenotar in barrel. However it lacks the retaining ring, which I believe is a 50mm x 0.9mm (M50x.9) thread. Anyone have something like that lying around or know where to find one off the shelf?

thanks!
-Ed

[Jon Shiu]

skgrimes.com

Oh, I just found one that may work:
9084890849

pm send

[EdSawyer]

I did check with SKGrimes, they don't have any, and will have to make some, which means 6-8 week lead time...

Jon, diameter looks right, replied PM, thanks

Ed