M.O.G Trioplan 1:2.9/50 diaphragm nightmare

[AberratedSoul]

Good evening everyone. Excited to be here! Upon buying into mirrorless after a hiatus from DSLRing, I've come to find I am absolutely obsessed with manual focus vintage glass cans. The thrill of treasure hunting on eBaying probably contributes to the recklessness.

Anyway, I found a Trioplan attached to some sort of camera (I'm not so much into film cameras...yet), advertised as being somewhat crippled, and received as such. Optically, it's gorgeous (by my loose standards). Externally it's quite nice. Unfortunately, it had aperturitis exhibited by a bent/dislodged blade or two, resulting in a very irregular iris shape and limited range (f/4ish to f/16is). So I tentatively opened her up and reassembled a few times before diving into the lens block and fiddling around until I realized I probably needed to remove and reset each blade. Maybe I didn't need to go that far, but hey, I'm naive and kinda impulsive. But also determined. Or, at least I thought I was.

Those 12 little blades are the most amazing test of patience since 2-year-olds became a thing. It doesn't help that a couple of them are a little bent. But wow, I tried every which way to get them back in there and got oh-so-close, but getting each little slug(?) into its hole and making it stay there while trying to lay in the next one just gets super crazy. I did the thing I hate most - I gave up and put the lens back together sans iris assembly.

So, my question is if there's a trick to helping them all in there? Right now they're in a bag and the lens is performing with a fixed f/2.9 (maybe a little bigger?) aperture...which really isn't the worst thing ever...but gosh it'd be nice to capitalize on a 12-bladed iris during those times I might actually want some DoF.

Thank you for you kind thoughts and words.

[kypfer]

Can offer nothing but sympathy, I'm afraid.
I have reassembled a couple of lenses with somewhat fewer blades … more by luck than judgement, I feel, but I too have a 35mm Ennalyt with it's aperture parts in a zip-lock bag awaiting that day of revelation
I anticipate the original construction was performed with some kind of jig to hold all the parts in place before they're inserted into the lens barrel.
In the meantime, much of the "character" of the Trioplan is achieved at full aperture, so maybe all is not lost.
Good luck

[Alun Thomas]

The small lenses are the trickiest.

It may be worth seeing if the lower ring can be removed from the lens body. If so, you will then have much more room and can fit the blades facing outward and not interfering with one another, then slowly arrange them back inward until they are circular, then carefully refit to the body. I doubt this is an option on a shutter lens assembly though.

Another thing that helps is to make sure you're using tools that are non magnetic, this stops things being moved by accident just when you get to the last blade.

If absolutely nothing else works, I have at times used a tiny bit of heavy grease on the locating pin, which 'sucks' it into the locating hole, making it less likely to be removed. You can subsequently wash thoroughly with acetone or some other de-greaser whilst working the aperture, to remove as much of the grease as possible.

[Pancolart]

Show image of the lens, i can guide you with the same one probably.

[caspert79]

I’ve cleaned a few diaphragms in the past, but fixing apertures with bent blades sounds like trouble to me. Good luck!

[kiddo]

I wonder if for avoiding blades to bent over the time, would be better store them close down totally or not etc.? In theory ,I e read is better to be closed down, but I'm still not 100% sure about it ( I guess it's not normal to happen)

[caspert79]

[AberratedSoul]

[Lloydy]

If the blades are bent they will be very difficult to get back in, layering the blades in rotation would be a nightmare.

As for straightening the blades?? I would be very careful.. the metal is extremely brittle spring steel, I have a few lenses with broken blades that broke in the instant the blades stuck and became dislodged.
Maybe heating the blades would temper the metal and make it possible to flatten them?

The Schacht lens a classic, and it's a simple lens. I would do a proper CLA on a lens like that, it's a risk to do this "repetitive twisting/pumping action on the clickless front ring" - as you say, it's gone tight again. The problem hasn't gone away.

[AberratedSoul]

To give an idea of what I'm working/dealing with, here are some pictures of the blades recently released from their sandwich baggy tomb. The bends and warps don't look that bad to me. Someday I'll get around to trying again, but for now I think I'll concentrate on lost cause lenses to gain risk-free practice. A box of six very ugly and dirt cheap doozies just arrived, from which I'd actually like to salvage the 500mm f/8 mirror lens, if I can. From the rest I figure I'll just poke around as I attend Lens University, or I suppose Lens-TT Tech?

[macheck]

AberratedSoul: if you are still interested in fixing the aperture, sometimes, if possible it is better to assemble blades outside of lens body reverted and then inserting whole iris assembly by means of a "special tool" and other techniques as shown in my rather lenghty yt film:
https://www.youtube.com/watch?v=3bDwyXHL4Z4

[jamaeolus]

I found that a tiny piece of silly putty (sold in stationary section of box stores as Blu-Tak(TM), used to mount posters to walls, hold a piece of paper in place while you type the info into the computer, etc) will keep the "ring end" of the blades in place while you set the last most difficult part, which is sliding the blades at the very end of the sequence under those already in place. It holds well enough but comes away clean. Fashion a bead about the size of a BB and push it on the outside of the ring and over the top of the pin that is used by the aperture to move the blade in and out. Tedious but effective. If someone has a more effective technique I am all ears.

[BrianSVP]

A trick I've used, IF i can disassemble the lens down just to the aperture mechanism, is to put a tiny drop of oil on each blade with a syringe. , which allows it to stick to the previous one by surface tension. Once everything is in place and the retaining ring set, i give the mechanism a nice solvent dip to remove the oil, which I imagine leaves less of a residue than the heavy grease suggested above.

Doesn't really work for obvious reasons if you still have the focus mechanism or optics in place.

[AberratedSoul]

Thank you for the suggestions and insights! I was also pondering Modge Podge as a soluble temporary adhesive. At this point, my lens and camera worklist has gotten pretty extensive, so the Trioplan operation is on a faraway backburner. Before I dig in again, I'd like to take her out for a spin to see how she performs without the blades. So many different M.O.G lenses to shoot...so little time.

[Ernst Dinkla]

While it is a good advice not to use magnetic tools like screwdrivers, a custom made magnetic tool like a magnetic disc that fits nicely on the aperture body will make fitting the blades way easier. I learned that when reassembling the 8 blades aperture of a salvaged Petri 45mm 1.8 lens.
Blades more warped and damaged than what I see in your images. I had to use scissors to cut a heavy curled edge off for example, with care of course to avoid a light leak. A fitting coin glued to a magnetic neodymium disc for example can be a fine tool.
EDit, when an aperture has blades warped, usually two or more next to one another, it is wise to distribute them between the good ones so they are forced to behave better. Of course some reverse bending, twisting, to get them plane before assembling is part of the job.

[Alun Thomas]

[BrianSVP]

[AberratedSoul]

[Ernst Dinkla]