Nikkor 20mm f/3.5 AI disassembly guide

[whatdoido]

Nikkor 20mm f/3.5 AI - https://whatdoineed2do.blogspot.com/2025/11/nikkor-20mm-f35-ai-repair-service.html

Put off servicing this for years - the thing that threw me was the focus grip felt like it was solid, due to old age and glue, but once you get that off you're only to struggle with glued rear mount screws.  This is a rare one of the few Richard does't have on this site - this one seems so much simpler to do than the AI-S version that Richard covers.

[pluton]

Thank you for posting this look inside the famous 20/3.5 Ai lens. I don't have the patience or dexterity to completely dis- and re-assemble a nice lens like this.  I've done a few partial disassemblies of inexpensive used copies of the 50/1.8 Ai and 35/2.8 K/Ai.  In recent times I found an inexpensive former Nikon technician's shop in my area where the costs for re-lubing a lens are reasonable.

[whatdoido]

You’re welcome.

I was pretty much forced to service this copy as the focus started to bind and be very sticky in places.

FWIW, I found this lens much easier to service than the Nikkor 50mm 1.8AI as that 50mm lens has a helicoid key that needs to sit in a specific location in its slot when reassembled otherwise it binds at different lens orientations.  The 20mm 3.5ai helicoid key sits in its grove/slot so you can’t go wrong