diameter of thread on 1.25" eyepiece? (1 Viewer)

i am still trying to find an eyepiece for an older 80 mm scope. It will take a threaded eyepiece. So, what is the diameter of the thread on 1.25" eyepieces, or, better, are they threaded or do they have bayonet mount?
I don't have a set of calipers, but it looks like the thread in the scope is around 30-35 mm.
Does anyone know of eyepieces that have threads, rather than bayo mounts, like my Swarovski scope?
Thank you.

Otto,

1.25" eyepieces have smooth barrels. They're usually held in place by set screws or compression rings. Many old Japanese spotting scopes used the same thread; Bushnell, Kowa, Mirador, Celestron many others. Bushnell, Eagle optics or Orion Telescopes might still have EP's with that thread.

Henry