I bought a Nikon FE with three prime lenses. The 100mm has a stiff acting focus ring. So I decided to refurbish the lens after I reviewed a number of YouTube videos.
The lens in question is a Nikon Lens Series E 100mm 1:2.8 and in good shape.
One thing I learned from the videos is that disassembly from the from will expose the glass and disassembly from the rear will expose the mechanics of the lens. So, I will begin with the three screws on the rear face, aka the bayonet ring.
When I released the third screw I notice that the plate rotated several degrees CCW.
So, I closed the aperture down as far as it would go, f-stop at 1:22, as shown in the left image. Now I could lift the bayonet ring assembly from the body of the lens.
I don’t need to do more with the bayonet ring assembly, so I set it aside.
Next is the aperture ring, to be lifted from the body.
I carefully note the position of the ring on the body, including the indexing notches and tab matching a groove feature on the ring. So, now it is free from the body.
Now some of the smuts that has collected in the lens is apparent.
Using some water-based cleaning solution, so that I don’t affect the plastic, I wipe away the dirt.
Now that I have cleaned away the layer of dirt above the ring, I can proceed.
Please note that I have not cleaned away the lube that appears on the various functional surfaces on the ring or the body! I need to document these applications specifically before I apply fresh (the lube is on its way to me as I write this blog).
Now I rotate the lens drum CW (when looking at the camera mounted end of the lens) while holding the focusing ring to release the lens drum from the helicoid.
The focusing ring needs to be removed from the aperture ring.
I set the focus to infinity (i.e. ∞) so that I know the position of the key tab on the aperture ring is between the ends of the “C” ring in the focusing ring.
Before you remove the aperture ring from its base, observe the orientations between the aperture ring, its base and the helicoid.
One of the last component assemblies to figure out was the aperture helicoid assembly, which is shown above here with the aperture ring attached.
Above I have removed the aperture ring. Below here I have separated the two rings, which gives me the aperture helicoid assembly.
Here is where I begin the reassembly.
I bought this helicoid lube on eBay from a company in Tokyo, Japan. I am using a clean #7 brush to apply the lube on surfaces.
I begin with the aperture helicoid assembly rings.
The aperture helicoid is left hand and i screw them together to about 1 mm within closing.
Now the focus helicoid gets lubed.
Mount and lube the key.
Assemble the aperture ring on the aperture helicoid assembly.
Align the hole pattern in the aperture helicoid assembly with the tab so that the focus ring finds the stop for the focus to infinity.
Wow. the action is really smooth. What a difference!
Screw the focus helicoid together.
To begin with, take note that there are 44 starts on the helicoid and you need to make sure that you find the correct match so that the index on the lens drum correctly finds the key on the helicoid.
Be gentle as you turn the focusing ring onto the drum. When the threads match they will glide together. You have no need to force them together.
It took me several tries to find the correct starts before I finished. But, now the lens works smooth as silk.