Author Topic: regreasing helicoids on longer MF (200mm) lens results in binding when focusing?  (Read 226 times)

whatdoido

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A question for folks who maintain / service their own helicoids.

I have regreased shorter focal lens with no issues but on a 200mm f/4 AI I have cleaned, regreased. remated and reassembled the lens.  However when I turn the focus ring it feels like its "bnding" as I turn the focus ring in the horizontal position- if i support the front for the extending lens then thers no binding and its nice and smooth and similarly front downon table, focus from infinity to MFD its nice. Can anyone suggest why this would be the cause of the apparent binding?

Individually, the regreased helicoids (before the helicoid key is reattached) turn very smoothly with no resistance so I don't beleive that I've over-lubed the helicoids - when attaching the helicoid key I also added grease to the key and the "notch" where it sits.

thanks in advance

Birna Rørslett

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To my ears it sounds there is too much grease -- a very minute amount is what is needed.

The lens hasn't received knocks from the side?

whatdoido

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I only regreased this 200mm as it had some spots where it felt like it was slipping when focusing (I'd turn the ring and it took a moment for the focus to start adjusting)  but otherwise it was nothing wrong.  In the years I've owned it, its never had a knock but I got it 2nd hand in immactulate condition from a colelctor.

When I regreased it (i've made the too much grease mistake before) I made sure i could turn the helicoids and they were very smooth and light with no binding feel - I've wiped off more grease (its Japan Hobby Tool #10) from the helicoids and its the same binding feel.

The binding feel is only after I fully reassembled.  Without the helicoid key, all the helicoids turn in place very smooth.

Erik Lund

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Sounds like the key is binding,,, or too heavy/Thick grease.
Erik Lund