That focus ring fight on a 1978 Canon FD 50mm

I spent almost four hours yesterday fighting a frozen focus ring on a 1978 Canon FD 50mm f/1.8. The helicoid was completely seized, and I thought it was just dried grease or maybe some corrosion. After soaking it in lighter fluid and then heat, I finally pulled the whole lens apart and found a tiny brass chip wedged between two threads. That little thing was jamming the whole rotation, not any gunk or rust. I've torn down a dozen vintage lenses and never seen that exact failure mode. Has anyone else had a metal shaving or chip get stuck in a helicoid like that, and did you manage to clean it out without scratching the threads?

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1 Comment

the_avery1mo ago

Four hours on a single helicoid sounds like a lot of patience for a lens that's maybe worth fifty bucks. A tiny brass chip is annoying for sure, but I've found that a solid flush with compressed air and a soft brush usually clears stuff like that without needing a full tear down. Are you sure it wasn't just old grease that looked like a chip after you heated it up?