Nikon S2, grinding noise on close focus

[Larry H-L]

My Nikon S2 rangefinder has developed a "gear-grinding" noise when focusing closer than about 6 feet.

The focus seems to tighten up as I focus closer, and it gets progressively more stiff as I continue to focus up close.

This happens with both internal (50mm) and external mount lenses.

Any ideas on why this happened suddenly and what could be going on?

 

[Erik van Straten]

Does it also happen when there is no lens mounted?


Erik.

 

[Larry H-L]

Hi Erik,
Yes, same noise and progressive resistance, with or without lens.

 

[Erik van Straten]

Hi Larry,

Could be that some dirt got into the threads or onto the coupling gear train.

When you are handy, you could simply remove the front plate of the camera by removing the four screws on the corners. Do not bow too much, but this is easy to do. Use a good, well fitting screwdriver, do not damage the screw heads. Then you can see if something got onto the gear train of the focusing mechanism. Don't lose the screws.

Erik.

 

[Larry H-L]

Took a look under the front panel that surrounds the lens mount, nothing obviously obstructing the finger gear and finger lock, it looks clean.

Do you know what the interior “spinning focus mount” rides on? Is it on roller bearings, or does it simply sit in a groove that allows it to spin? It almost looks like it is spinning with a wobble, as if something is wedged in its track.

I'm going to shake the camera while focusing in hopes that something might drop out.

 

[jonmanjiro]

The focus helicoid is just two interlinked helicals. There’s no bearings in there.

Sounds like you got a contaminant in there. The solution is to disassemble, clean, and reassemble. It’s easy enough to do if you’re semi competent with tools. Otherwise, best to send it to someone who can do the job properly.

Details on the work required at the link below:

https://richardhaw.com/2017/03/04/repair-nikon-s2-front-overhaul/

 

[Highway 61]

I'm going to shake the camera while focusing in hopes that something might drop out.

😱

Shaking the camera will sooner or later put the rangefinder out of alignment, vertically probably. Then you will be left with a rangefinder adjustment job to achieve, which is very possible without dismantling the whole shebang but delicate nonetheless, with the risk of losing or breaking a tiny headless set screw.

Your problem is probably caused by some tiny sand grains or whatever trapped into the helicoid threads, so nothing will pop out, even if you shake like crazy.

For now, you just have to take the focusing helical apart, to clean its bronze diamond shaped gears with some good dishwashing soap and an old toothbrush under hot tap water in your kitchen, and reassemble the unit once clean, well rinsed and dry (use an hair dryer to make sure it's really dry). The only caveat is to notice well the engagement/disengagement point of the two parts of the helicoid, so that you reassemble it the proper way with the correct focusing run (three possible engagement points).

Also, there are some shims under the screws which attach the helicoid unit to the camera cast. Secure them on a sheet of paper with some adhesive while the helicoid is out of the camera thanks to a drawing sketch, because they are here for the correct lens mount flange to film plane distance and they aren't all of the same thickness.

Take your time and be careful, but it's an easy job. You will have to remove the two screws which attach the infinity lock release arm to the helicoid so that you can take the helicoid apart once the focusing unit taken off the camera.

Be careful not to wipe the distance indexes off while cleaning the helicoid parts as the old black paint may be prone to go away (if this happens, re-filling the markings with new matte black paint isn't difficult anyway).

 

[Larry H-L]

Thanks everyone for the tips and link.

By “shaking” I mean a gentle wiggle with the camera at different angles.

I’ll take another look and see if my repair skills are high enough to take it apart. If not, who is a good Nikon RF repair person in the U.S.?

 

[Highway 61]

By “shaking” I mean a gentle wiggle with the camera at different angles.

The Nikon S2 rangefinder is a bit sensitive to "shaking" and little bumps (it is designed not to break and to get out of adjustment quite easily, which is good because even a strong bump won't break it) so I really advise you not to play the shaking game for the sake of nothing.

Another thing you can do easily without taking anything apart, and which might provide some good results :

- remove the camera back and any attached lens,
- set the shutter speed on "T",
- cock the shutter, fire it, the shutter will stay open,
- you will see the focusing helical from the rear, through the shutter gate,
- focus to minimum focusing distance : this will let you see a good part of the focusing threads,
- with something soaked in lighter fluid (avoid something which will leave cloth fibers behind : you can, for instance, make a small ball of kitchen wiping paper which you will hold using a small pair of tweezers or a wood pick thanks to some adhesive), you will clean the visible part of the focusing helical threads until you get the feeling it's clean enough (a small, clean brush with a long stick will be useful to achieve the job as well).

Once done, you will also, using a syringe, drop some tiny amounts of lighter fluid in there, so that it gets into the focusing threads, before actuating back and forth the focusing helical several times.

Then you will set the shutter speeds on "1" so that the shutter closes.

 

[Larry H-L]

Following up on the "gear grinding noise" problem from January.

Got out the camera today, twisted the focus, it wouldn't focus closer than 6 feet without grinding and increasing resistance.

With plenty of time on my hands because of "sheltering in place" and the end of the academic year this Friday, I decided to get out the screwdrivers and jackhammer and took the helical off.

I followed Richard Haw's fantastic repair website, and got the helical out without any issues.

Spun the helical around in my hands.. smooth as butter, no grinding noise. Checked the finger wheel.. spins freely. I could not find anything in there to cause any grinding.

Again checked inside the camera and blew it out with a blower bulb, but nothing obvious rolling around in there. Looked on my work surface for something that might have fallen out, but nothing.

So, I put it back together. It is now working smoothly again.

The issue disappeared as mysteriously as the initial problem. Whatever boulder from a parallel universe was in there, it is now gone.

Thanks for the help with this issue.

 

[Huss]

Something must have gone out of alignment, which you fixed by taking it apart/putting it back together!