W-Nikkor 3.5cm F1.8 Focus Helicoid Clean Need Help

[cqing]

Do you guys know how to remove the focus helicoid of this lens? I have one modified to M mount. When I sand the focus cam to adjust the focus, some particles dropped inside the focus helicoid and the focus helicoid became a bit stiff. I think I need to remove the helicoid, clean&lube it to make the focus smooth again. Do you have any guides or suggestion? Thank you!

 

[Peter Jennings]

Loosen the focus ring by removing the 4 small screws and the optical block can be unscrewed from the mount. There is also a screw that needs to be removed from the bottom side through a small hole in the mount. Be sure to note the exact point where the two units join together so you can put it back together correctly.

 

[richardHaw]

that's it..i am going to write a guide for this lens soon. 😱😱😱

this can be a delicate thing to do depending on the sample because some are so tight. putting it back together is the tricky part 🙄

 

[cqing]

Loosen the focus ring by removing the 4 small screws and the optical block can be unscrewed from the mount. There is also a screw that needs to be removed from the bottom side through a small hole in the mount. Be sure to note the exact point where the two units join together so you can put it back together correctly.

Thank you Peter for your help. I cannot find 4 small screws... There is only 3 screws in the black focus ring...

 

[cqing]

that's it..i am going to write a guide for this lens soon. 😱😱😱

this can be a delicate thing to do depending on the sample because some are so tight. putting it back together is the tricky part 🙄

I'm looking forward to your guide! To adjust the focus for this lens is a pain... Focus throw for this lens is about 300 degrees I guess...

 

[Peter Jennings]

Thank you Peter for your help. I cannot find 4 small screws... There is only 3 screws in the black focus ring...

Yeah, you're right. There are only three. Sorry for the confusion.

 

[cqing]

That's fine. Currently I don't have screw driver of that small size. I bought a few of size 0.6mm 0.8mm 1.0mm. I'll try after they are delivered.

Yeah, you're right. There are only three. Sorry for the confusion.

 

[jonmanjiro]

Welcome to the wonderful world of hacked converted lenses 😱

I had exactly the same problem when I fixed the focusing on a reissue W-Nikkor 3.5cm F1.8 converted from S-mount to M-mount by Miyazaki-san of MS Optics. I ended up having to pull the focus helical completely apart and polish the scratch out of the focus threads using a dremel and polishing brush. it took me several polishing/relubing attempts to finally get it right.

I would completely separate the optical cell from the focus helical before beginning any repair work. How to do that will depend on how the lens was modified. Can you show us some photos of the rear of the lens from dofferent angles?

 

[cqing]

 

[cqing]

Thank you everyone. I managed to remove the focus helicoid and cleaned&removed debris. The focus is accurate and smooth now! I've shoot 2 rolls with it on my M4 and will post the results once they are processed. I used my m240 with live view to adjust focus.