>>3427108>SEETHINGOut of production for 35 years. But yeah - for something so cheap and simple as a ring of brass with a hard plastic tyre - ebay is a fail.
These things would've been torn to shit by pro-use so they would make sense be a consumeable part. They're obviously designed to be swapped easily, but the parts supply ended when the lens did.
On the plus side, when it's not doing a dozen rolls of film a day racking back and forth between shots it might last with the fix. And it's an easy fix to make even allowing for making the parts.
Pic is one of a a few test shots after fixing.
