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05-21-2011, 07:49 AM   #1
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Join Date: May 2011
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Cosina PK Mount 35-70mm f:3.5

Hi! I grabbed an old, cheap, Cosina PK Mount lens 35-70mm f:3.5. I found that the lens was infested with fungus, so, I tried to dismantle the lens by myself. Perhaps not the wisest decision because I had none experience in that sort of works.
I wasn't able to clean all lenses, since I couldn't unscrew the name ring, so I decided to give up.
Before that I unscrewed the aperture ring and the back of the lens. When I was trying to assemble it back together I noticed the aperture ring didn't stop at each number. Instead, It slided loosely through them.
Well, I figured I may have lost the tiny ball bearing and that turned out to be correct.
The problem is: What is the ball's size? 1.5mm? 1.0? 1.2? I have no idea

I'll be glad if I find some help.

Kind regards.

05-21-2011, 09:52 AM   #2
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Join Date: Jul 2007
Location: Brampton, Ontario
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Those tiny ball bearings are usually clinging onto something by static electricity; so chances are they could still be attached on another part of the lens that you took apart. Hopefully you can use the cheap lens as a learning experience. As for the name ring removal, depending on the size, I get one of the those rubber stopper from the plumbing department, and they work well. Make sure you get the right size though. Another option (last resort) is to drill a tiny hole into the ring and then use a small screw driver to unscrew the name ring. The important thing is to have fun taking it apart and re-assembling it back correctly.

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