This is for a chrome rigid Summicron. Non-DR.
This is for a chrome rigid Summicron. Non-DR.
You might have to send the lens to Youxin, Sherry or DAG to get it done properly.
If this is a V2 Rigid Summicron, you can do this. If it is a DR o later lens, disregard what is written below and just send it in for repair.
If you are mechanically handy and aren't afraid to get in there then you can do some work yourself but you could risk really making the lens stiffer by attempting to remove the optical module from the rear. If you decide to do that, make sure you have the right weight lube for the collar which you'll remove from the helicoid before you begin. Don't worry, it's cake compared to taking apart something like an 85mm f/1.4 AIS Nikkor's helicoid that was soaked in orange juice over a decade prior.
First, screw the front ring/element back into the optical module. They don't have to be tight, you just need some more surface to grip and don't want to use the aperture collar as your gripping surface.
Make sure you mark things with sharpies, paint pens, scratch awls or whatever you use to ensure you put these pieces back together exactly as you found them.
Take a sharp, properly sized spanner and remove the locking ring from the rear of the lens. This ring is circumferential to the rear element which is inset a few millimeters. Unscrew the locking ring and then very carefully pull the remaining optical module STRAIGHT OUT of the helicoid. If you do this on an angle, you can score the brass follower/collar and your lens will work but it won't feel as smooth as before.
Unscrew the grub screws which hold the aperture ring to the body and slide it off towards the rear. If you can't get it all the way off, you're going to have to make due. Set the screws aside, maybe on a magnet, so they don't get lost.
Next, you're going to want to measure the diameter of the part that the front ring screws onto (so you'll have to take it off once again.) After you've measured this, go to a hardware store and find a close PVC or ABS inner diameter size. Buy a foot or so of it but you only need about 4-6 inches. You want this to fit around the thread with only 1-2mm gap total. You may need to sand down the outside to give it a bit of a bevel so it can fit between the aperture control ring and the brass core you're trying to unscrew.
Then get a piece of thin bicycle inner tube and cut it so it generously covers the front threaded portion that the pipe is going to fit around.
If you got the aperture control ring completely off then stick the whole optical module back into the helicoid and hand tighten the spanner. If your aperture control ring had a lip on the inside that prevented you from removing it completely, slide it as far back as you can and then stick the inner tube on the front end of the lens, then the pipe over the inner tube THEN seat it into the helicoid. You may need an extra set of hands for this.
Anyway, once you get the brass follower into the helicoid, push and twist till your hands get blistered (happened to me) and until you loosen the lens. You can stick the pipe into a vise, of course (recommended) but then watch out how much force you're putting on it in case the pipe is stressed too much or your grip slips, you don't want to jam the rest of the summicron into the vise.
Once you get it loose, clean all the parts well, lightly lube the parts that move including the thread that the optical module screws into. Clean the front ring well and do not lube it before reassembling. Then all you have to do is put it back together. You should have: optical module, brass follower that slides into the helicoid, rear locking ring. That's it after you've put the aperture control ring and the front ring back on.
It may sound daunting but it's quite simple. I had to work on my DR Summicron with a vise, channel locks, a file and Swiss Army knife after it was dropped onto a marble floor in one of Saddam Hussein's military base support buildings back in 2004. That lens had a looking over by Sherry K. but she said that there was little she could do but clean the dust and haze out since the mount was fine.
Good luck!
Phil Forrest
