Repair lens iris blades

[Colin D]

I've pulled apart a lens because it was seized, result is a few of the iris blades are bent and buckled. I'm thinking of how to straighten them out again, if it is possible at all. No shutter so that isn't part of the problem.

One suggestion I've found on the web: put blade on flat metal surface and roll a screw driver shaft with pressure over it, sounds reasonable enough but I'm wondering if there are other suggestions. Would heating up the blade with a blow torch to soften it before flattening be an option?

Any ideas, or are they too difficult to repair?

 

[Andrew K]

Colin - what lens is it?

I've done it before by running the back of a pair of large tweezers from the pins to the tip (in that direction only) with the aperture blade resting on a thick cutting mat - the slight give seemed to help with the flattening..

 

[AgX]

One suggestion I've found on the web: put blade on flat metal surface and roll a screw driver shaft with pressure over it, sounds reasonable enough but I'm wondering if there are other suggestions.

You can't really flatten sheet metal by pressing it on a flat, hard surface. There must be bending in a direction opposite to the bend.
Only thing that may work on a flat surface would be rolling over it if it is flexible, like from rubber sheet.

 

[athanasius80]

Are the iris blades metal, hard rubber, or paper?

 

[Colin D]

Colin - what lens is it?

I've done it before by running the back of a pair of large tweezers from the pins to the tip (in that direction only) with the aperture blade resting on a thick cutting mat - the slight give seemed to help with the flattening..

Yep, thanks Andrew, that's exactly what I've done except by using a round metal handle to roll over the blades on a surface that has a bit of give, seems to have worked.

 

[Colin D]

Are the iris blades metal, hard rubber, or paper?

Metal, very fine metal.

 

[Colin D]

You can't really flatten sheet metal by pressing it on a flat, hard surface. There must be bending in a direction opposite to the bend.
Only thing that may work on a flat surface would be rolling over it if it is flexible, like from rubber sheet.

You've hit the nail on the head. I did some research on metal work forums and this is exactly what I learnt. I've put a test blade on a surface that has some give and rolled a metal handle over it, this works but it also curves the blade up at either end. Next step was to put it on a hard surface and flatten it out which has also worked, so far so good. I'll do the rest of the damaged blades and re-assemble the aperture mechanism and see if I have bee successful. It's been a journey of perseverance so far, after all this time and effort of getting it working again, I'll had better do it justice on the camera.