FED3b lens focus stiffness

[garythegit]

Hi guys! I'm a recent convert to Russian rangefinders and must admit have been trolling in this forum for quite a while! 😀 It's just too damn good a source of information!

My first FSU camera (otherwise known as crack in camera form!!), a fed 3b arrived last week and I've been tinkering about with it since. I've managed to calibrate the rangefinder at infinity and cleaned the lens so far. My problem is this:

After reading the fantastic guide to relubing these interstar lenses by Matt Denton, I decided that I was probably not *that* confident with my repair skills yet so I went as far as removing the focus ring and cleaned off as much old grease as I can. Then I had a inspiration and reached for that ever trusty can of WD40. Indeed, with a small squirt of it the focus ring started to move like an eel in a waterpark!! I careful reassembled the lens and put it back onto the camera. Now the focus is working much better than before but It's a LOT stiffer than it is when NOT screwed into the camera. i.e. it turns but needs a bit of effort. I'm totally baffled by why this is. Any suggestions? As far as I can make out the usage of WD40 hasn't affected the focussing movement as it still moves smoothly when not screwed in.

Thanks guys!!

Just a word of warning, I have a fed5 winding its way to me too so expect lots more stupid noob questions!! 😀 😀 😀

 

[JoeFriday]

I'd suggest going back to Matt's website and following his procedure.. I received an I-61LD a few weeks ago and its focusing ring was pretty sluggish.. I followed Matt's directions and an hour later it was silky smooth.. it's really not that hard to do.. just take your time and make sure you have the right tools.. a precision screwdriver set is about all you'll need, other than some degreaser and synthetic grease

just be sure you don't get frustrated and strip any of the screw heads

 

[garythegit]

Hi Greyhound, can I ask how I can check the RF arm on whether it's lined up corretly? Are there any sites with pictures? I've got a feeling this might be the problem...

 

[darkkavenger]

I had such problems with an Industar-50 on my Zorki-4, I dissassembled the lens and cleaned the grease (it had solidified) and now its very smooth 🙂

 

[pshinkaw]

If a Russian lens binds after it is disassembled and re-assembled, but it did not do so before servicing, it is frequently caused by not assembling the parts EXACTLY in the same position they were put together in before. The back bearing ring that is usually taken off has several screws. If the ring is not aligned with the original holes, it may off very slightly, but enough to bind. If you didn't matk it before taking it apart, you may have to use "trial and error" to put it back.

Also, if you removed the lens flange from the body at any time, you could have unevenly torqued the flange back into place. The flange screws have to be replaced in an 1,3,2,4, 1,3,4,2 pattern (like an automobile wheel) in order to evenly torque it. Otherwise it will war enought o bind. This can even happen with a Leica!

WD-40 uses a lubricant/solvent that is similar to (or perhaps identical to) kerosene. It is one of the worst things to use in a camera lens because it initially penetrates everywhere and spreads a residual layer of hydrocarbons. Themn it evaporates without leaving much lubrication where you need it. Even molybdenum/lithium SAE axel grease (which I also recommend against) is better. I suggest cleaning the entire helical with Rosonol or ethanol and then relubing with a white lithium grease which can be obtained from an electronics shop. These tend to be less volatile and will be less likely to leave a hydrocarbon fog deposit on your internal lens surfaces.

Good luck!

-Paul

 

[garythegit]

Wow you guys are great! Sorry to have bothered you all with such a newbie question and a jolly silly newbie mistake with the wd40!!! I shall try and reassemble the lens exactly as instructed once i've got some grease. Cheers guys!

 

[JoeFriday]

well, some of us learn.. and there are others like me

 

[garythegit]

Just one last question.. the RF arm, the little silver boat shaped 'bit' attached to the arm that is shown in the photo. Should it be FIXED onto the arm or should it be able to move? My one is fixed and doesn't feel like moving. Just curious!

 

[wyk_penguin]

O.T. But I've always wondered why Leicas and Zorkis use round cams while FEDs have that 'boat-shaped' bit.

 

[pshinkaw]

It's a lower cost alternative to highly precise machining. Whe you use a cylindrical cam like a Leica or a Canon, the radius has to be very precisely machined.

Replacing it with the "pie-shaped" cam with an adjustable shaft, essentially creates and infinite range of radii. That way you can, with careful calibration, obtain a precise rangefinder focusing position even if you can't meet the initial tolerances.

It's a pragmatic, cost-effective solution that kept the manufacturing cost lower (among many other things).

-Paul