jupiter 8 too loose iris ring

I think the usual fix is to tear it down ,relube and on the aperture ring use heavy grease such as automotive wheel bearing grease. That will be stiff enough to hold it where you set it.........
 
Usually this problem is caused by worn parts or an incorrectly set or missing setscrew (there are three involved).

The easiest fix is to clean the parts and relube. However be careful with automotive lubricants. They can "out-gas" or volatilize gasous components over time that can cause cloudiness on the optical components. I use a white lithium grease which I obtained from an electronics store for the focusing helical. That's because I don't like the focusing to be too stiff. If the diaphragm ring is too loose, there is a gel lubricant in a tube from Radio Shack which is too stiff for focusing helicals but just right as a packing grease. It holds the diaphragm ring in place quite well.

-Paul
 
can anybody recommend a specific lubricant that I can buy in germany, or what these lubricants are called in german? My aperture ring is too loose, and I want to try to fix that, but I dont want to buy the wrong stuff.

thanks
 
lubitel said:
can anybody recommend a specific lubricant that I can buy in germany, or what these lubricants are called in german? My aperture ring is too loose, and I want to try to fix that, but I dont want to buy the wrong stuff.

thanks
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In my experience, you do not need a heavy grease. I use a lithium based grease I begged from work. A silicon based grease or any other synthetic grease would also work. Just make sure that, if you put a dollop on a piece of card or similiar, that it "stands up" over a period of time. If you are worried about the "right" type, you can get a selection from microtools in Germany but I find these somewhat over priced.

Kim
 
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