A trick for cleaning old lens helicoids that actually works

I used to fight with old lens focus rings all the time, especially on 70s SLR glass. My old way was to soak the helicoid in lighter fluid and scrub with a toothbrush, but half the time the grease would just smear and gum up again. About six months ago, a guy at a camera show in Toledo told me to try a 50/50 mix of white spirit and isopropyl alcohol, warmed up in a jar of hot water first. I was skeptical, but it's a game changer. The warm mix breaks down the old grease way faster without hurting the metal. I let the part sit for maybe ten minutes, then rinse with clean alcohol. The threads come out spotless and dry ready for new grease. Has anyone else found a better solvent mix for this nasty job?

3 comments

3 Comments

tessa_lewis2mo ago

That warm solvent mix is a solid tip. I read a repair manual that said never to use straight alcohol on helicoids because it can dry out the metal and cause binding. They recommended naphtha for the initial clean, then a final wipe with isopropyl to remove any residue. Your warm bath method probably gets around the drying issue.

diana872mo ago

So @tessa_lewis, which repair manual was that?

hollym121mo ago

Hold on @diana87, I gotta push back on that manual logic. Using naphtha on precision parts like helicoids is asking for trouble in my experience - that stuff leaves a film that attracts dust and grit like crazy. Straight alcohol dries out the metal? Metal doesn't "dry out", it's metal. The real issue is using cheap alcohol with water in it that can cause flash rust on bare steel, but a good 99% isopropyl is totally fine. These repair manuals get parroted around without anyone actually testing if the advice holds up in real shop conditions. A warm solvent method works because heat helps contaminants release, not because alcohol somehow damages helicoids. @tessa_lewis, have you actually seen binding from alcohol on your own bench, or is this just what the book says?