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Randy
26-Aug-2018, 10:04
As usual, I just can't leave well enough alone.

I purchased a little Velostigmat Series II 9 1/2" lens with the softening ring. Lens is in barrel. The aperture, while working, was a tad stiff - as is the case with some of these 100 year old lenses. I was worried that I might damage a blade during use, so I decided to try to damage a blade (or two) by trying to clean it up - success!
I popped the little brass post off the end of two of the blades - *&#!
I tried to epoxy them back on but it would not hold.

I guess I could fabricate two new blades out of a thin plastic or film, and perhaps two little posts from Teflon or some such material, but securely affixing them to the aperture blade...?...I have no idea. And this thing has 20 blades - I can't afford to damage any more.

Anyone found a suitable fix (other than not damaging it in the first place)?

In the meantime, so I can get some use out of the lens, I have made a few (f/5.6, 8, and 11) water-house stops out of black paper, but I have to unscrew the front cells in order to change f/stops - which sucks.

gypsydog
26-Aug-2018, 10:10
Yes it is fixable, by a professional. The same one that should have fixed it in the first place.
Otherwise make 4.5 your new best friend.

Randy
26-Aug-2018, 11:12
It only took 6 minutes to get the first entirely unhelpful condescending comment of this thread - thank you internets!

Bernice Loui
26-Aug-2018, 12:02
The pins at the end of an aperture blade is often swaged on in much the same way as a rivet. Over decades of being moved, the joint can work loose. It is possible to replace the pin or try re-swaging the pin back on with a very tiny amount of epoxy to help the pin to blade joint stay put. Check the condition of the hole in the aperture blade, it could be deformed or enlarged (typically flared-stretched out). This would need to be addresses before making try to join pin back to blade.

Another way would be to try and find a good replacement aperture blade or make one. Old aperture blades are often thin sheet steel, later ones are often plastic. Pins are often brass or steel.


Bernice

LabRat
26-Aug-2018, 12:05
Figure out what the blades are made of first. If brass, you can clean up under where the pivot pin sits, tin with a tiny amount of solder, and press the pin down with a very hot soldering iron to join them again...

Steve K

duff photographer
26-Aug-2018, 13:21
It only took 6 minutes to get the first entirely unhelpful condescending comment of this thread - thank you internets!

Had to laugh at that - seems the first 2 or 3 hours after posting brings them in for some reason.

Your problem....

Both Bernice and Steve are correct. Any chance you can post an image or two of the 'accident' - not to gloat over of course but to determine the type of repair that'll work.

Duff.

Randy
26-Aug-2018, 18:01
The pins at the end of an aperture blade is often swaged on in much the same way as a rivet. Over decades of being moved, the joint can work loose.
Your description fits my blades. I believe one of the pin holes is torn.


Figure out what the blades are made of first.
My pins are brass but I believe the blades are a plastic - they are very thin and flexible - do not feel like a metal.


Any chance you can post an image or two of the 'accident'...
I'll shoot some very close-ups tomorrow.

Thanks for the input.

LabRat
26-Aug-2018, 18:39
You can tell by taking a pin and scratching somewhere near the pivot where hidden, and examine what color the scratch is... Plastics will feel very slightly warm to the touch, as they reflect your body heat back to you... Metals will draw away your heat and feel cooler...

If steel, a magnet will stick to it...

Steve K

jim10219
26-Aug-2018, 19:40
I’ve used JB Weld to reattach a pin. You have to be careful with it though, so it doesn’t get everywhere. Also, sometimes, especially with a 20 blade aperture, you can remove one entirely and it’ll still work alright. With 20 blades, there will barely be any difference. However, sometimes it can cause the aperture blades to fall out, bunch up, and get damaged. So if you go that route, take it easy and pay close attention to it, and rotate the shutter around to different angles to test it with other directional pulls of gravity. But most of the time it’ll be fine with just one blade removed. Sometimes it’ll even work with two missing blades.

Jody_S
26-Aug-2018, 20:30
It's happened to me often enough that I bought a used watchmaker's staking tool set (example (https://www.youtube.com/watch?v=xhuOj76A8EM)). Of course I haven't had to repair a lens since I bought it, and I haven't bothered to re-open any of the lenses I 'fixed' by removing 1 or 2 damaged aperture blades.

gypsydog
26-Aug-2018, 21:08
It only took 6 minutes to get the first entirely unhelpful condescending comment of this thread - thank you internets!

Actually I thought it very helpful. It all results in a lens that is functional.
How many minutes did it take to damage the lens?

andrewch59
26-Aug-2018, 21:25
I had two pins come loose on my cooke series iia 15 inch, I didnt attempt a fix but sent it straight to sk grimes for repair.
Wasnt hugely expensive albeit the postage.

pjd
27-Aug-2018, 03:09
I tried to repair aperture blades on a shutter with a similar problem, I didn't find a way to get the metal stub to stick in the blade. I remember trying a dab of thread locker, that didn't work and I didn't have anything else that felt worth trying. That was a 20s or 30s dial set shutter. On the other hand, I did manage to replace a set of blades in another dial set shutter, the blades were intact but a couple had jumped out of place somehow (heavy impact at some point, possibly). It took me a good couple of hours to get the blades back in, the first 17 or 18 blades are simple enough, the 19th was a nuisance but getting the final blade in place was tough. A few times during that process I wondered if there's a secret knack to replacing the blades, I suppose the answer is lots of practice and small fingers.

Before anyone points out I shouldn't have bothered; I received both lenses in that condition - and a professional repair would have cost more than a replacement lens. I hope Randy can fix that lens, I'll be interested to hear if there are any tips about getting the stub to stick in place in an aperture blade.

Randy
28-Aug-2018, 10:30
The blades are plastic, and about 6cm end to end. The pins are brass, and about 2mm in diameter and height.

182002

182003

I may just try as has been suggested - leave the damaged blades out and try it with just 18.

Jac@stafford.net
28-Aug-2018, 12:36
I have a lens with a totally whacked aperture - it has broken blades stuck in an oval shape. I thought it might have some interesting qualities - it does not. The lens is on the bench awaiting a postmortem.

Tin Can
28-Aug-2018, 12:44
Looks like it was originally peened.





The blades are plastic, and about 6cm end to end. The pins are brass, and about 2mm in diameter and height.

182002

182003

I may just try as has been suggested - leave the damaged blades out and try it with just 18.

LabRat
28-Aug-2018, 12:49
If the pin is almost a snug fit, you can try superglue gel or thin, just keep it off the pivot pin moving surface, and it is beneath the surface of the iris blade...

Note that if there is a blade issue, it is usually because there is a resistance or binding of the blades, inner rings, or the pivots that don't allow the blades to move freely... Check for migrated lubes, oxidation etc...

If you try to fix, make sure the pin comes perfectly straight off of blade or blade will not sit correctly and repair point will be strained...

Steve K

neilt3
28-Aug-2018, 16:49
I don't know about repairing your existing aperture , but would it be possible to replace it as a unit with one of these off ebay ?
https://www.ebay.co.uk/itm/New-4-60MM-Iris-Diaphragm-Aperture-Condenser-18-Blades-Camera-Microscope-Adapter/253162719787?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D51875%26meid%3Da8b582e400304547a78059a8ff9181d4%26pid%3D100005%26rk%3D3%26rkt%3D12%26sd%3D253163895269%26itm%3D253162719787&_trksid=p2047675.c100005.m1851

domaz
29-Aug-2018, 10:45
I'm ashamed to say that I've fixed a broken aperture that was missing pins by sculpting new "pins" out of JB Weld. It works better than you would expect. The lens has been working for a year or two now with no issues.

Tracy Storer
29-Aug-2018, 11:20
Wollensak made a lot of lenses, and I mean a lot. Maybe you can find another (damaged / broken / cheap) lens that uses the same size aperture blades.

Randy
29-Aug-2018, 15:37
Good suggestions folks - I'll keep an eye out for another parts lens, but I suspect that as old as these things are, pins are going to fall out. I may try the re-manufacturing the pin from JB Weld or epoxy. Heck, I might be able to trim down a wooden or plastic tooth-pic for a pin - just so darn small.

neilt3, I like the aperture you linked, but I have no idea how one would adapt such a thing to the existing lens barrel.

LabRat
29-Aug-2018, 17:35
If you have the old pins, you have the pins already... I wouldn't make them, as they need to be smooth, round, and perfect as possible... A considerable amount of force pivots over these, so they need to be bonded well, and no drag from the pivot rotation...

If you need pivot material, a good hobby or model train store has different metal rods so look there...

When bonding the rod to the iris blade, it's very good to make a jig of a very flat material with a precision hole for the pin to align it precisely...

For the heck of it, just price Grimes for the job of re pining it as suggested, if the blade is out, it shouldn't be too much to do, and it's easy to screw it up...

Steve K

jim10219
29-Aug-2018, 19:15
Wollensak made a lot of lenses, and I mean a lot. Maybe you can find another (damaged / broken / cheap) lens that uses the same size aperture blades.

Iíve done that too. You have to find the same size and type of shutter, but if you keep your eyes out, youíll likely find one at a good price sooner or later. I bought a broken Compound #3 shutter and used the aperture blades to fix one shutter and the mainspring to fix another!