Canon nFD 50mm F1.4 frozen focus helicoid

[Aoi Usagi]

My Canon New FD 50mm F1.4 lens has a frozen inner helicoid. I have stripped the lens down but am unsure which direction i need to turn the helicoid (the silver part in the image) to loosen it. Any help is greatly appreciated.




Canon nFD 50mm F1.4 lens

If it matters, turning the silver part clockwise makes the lens go to minimum focus distance and visa versa for the reverse side.

 

[ProfHankD]

My Canon New FD 50mm F1.4 lens has a frozen inner helicoid. I have stripped the lens down but am unsure which direction i need to turn the helicoid (the silver part in the image) to loosen it. Any help is greatly appreciated.

Frozen usually means no lubricant, so the metal has ground/welded together. I don't think there's a direction to turn as much as a need to get lubricant flowing in between. If you're lucky, it might just be the lubricant decomposed and hardened, in which case the magic of something like WD40 might work. Temperature cycling can sometimes help too -- outer ring warmed to expand a bit.

Good luck to you. The one lens I have that is frozen I was unable to free-up no matter what I did.

 

[Aoi Usagi]

Thank you for your help. I had the assembly soaking in WD-40 for about 8 hours now. Hopefully I can get it to loosen.

 

[Aoi Usagi]

The answer is Counter-clockwise if anyone is interested. After soaking the assembly in WD-40, the helicoid did loosen and come apart. Unfortunately, the person who serviced it last, cross threaded it and now it wont go back on smoothly. Looks like this lens is going in the parts bin. Too bad because the optics and aperture blade were like new.

 

[Tom Caldwell]

The answer is Counter-clockwise if anyone is interested. After soaking the assembly in WD-40, the helicoid did loosen and come apart. Unfortunately, the person who serviced it last, cross threaded it and now it wont go back on smoothly. Looks like this lens is going in the parts bin. Too bad because the optics and aperture blade were like new.

Cross threaded is probably the last thing we would normally think of ....

Of course the standard mechnical mind would think “if the resistence is significant then don’t force it stupid .... “ as something is wrong. Someone must have had a wonderful time “tightening it up”.

A pity indeed.

 

[Aoi Usagi]

Yes, I suspect it was serviced by an idiot.

One thing to note is that Canon did not use brass for the inner helicoid, instead using what looks to be cheaper aluminum. Brass has a self lubricating property and is a softer metal, which wouldn't have destroyed the outer helicoid as much. Maybe that's one of the reasons the owner cross threaded it. Or he's just a idiot.