Mating Tele Parts..

[peter k.]

Finally went and dug out the old 35mm Cannon AE-1 Vivitar 400mm 15.6 Komine Auto Tele, as spring is here, and the birds need their pictures taken.
Repaired the lens movement at the junction point of the tripod bracket... that would wiggle, and it turned out all it need was to tighten three screws, hidden under the DOF ring. That was easy!!!
But alas, we having been having a heck of a time getting the camera mount area & aperture ring assembly reconnected to the rest of the lens.

The hassle is aligning up the aperture pin with the slot ..

Background,,, what we have tried.

The pin rotates counterclockwise, as the setting is changed from f32 to f5.6 where it is shown now. The slot, also will rotate counterclockwise from the spring tension of the lever, when properly put together, putting the tension on the mechanism to do its do.
With this thought in mind, out of a paper clip we have made a hook that will compress the lever all the way counterclockwise, accessed through the rear camera mount area of the left lens part. This allows me to try to mate these two together, with no spring tension changing the position of the slot, (AKA the left Pin & Lever image), while the slot itself is sitting with out any tension against its spring, (AKA the right slot image) with the lens aperture wide open as it sits now, unconnected.
It really shouldn't be that difficult. Drew pencil lines on lens body to help line up, but its obvious we have had no success, after trying for hours, on two occasions. Nuts, it only took me about a half hour to find the problem and fix it.

Soooo wonderful ones out there in APUG land, whats the secret of getting these to mated for spring?
Please correct me, or give me another way, ... because the dang gum, son of a gun, wonderful aperture pin does not want to mate into the illusive PIA slot.

 

[shutterfinger]

Is you 100% sure the pin mates into the slot? Has you measured both with a caliper? If yes eyes spiculate that the 2 pieces has to be precisely 90° to each other to mate. If'n the lever mates into the slot before the pin mates eyes would start the lever into its slot then turn one barrel or the other until the pin aligns with the slot then slide the two together and once together turn one or the other until the alignment marks align.
When making alignment marks 2 lines close together are more accurate than one and 2 or 3 pairs around the barrel unequal distances between pairs ensures only one orientation will be correct.

 

[peter k.]

you 100% sure the pin mates into the slot?

There is no reason why it shouldn't, but alas today to prove it, I unscrewed the pin and tested it on the slot. It fits.
Yes they need to be precisely set to each other, that's the challenge. One can see that the finger is hitting the slot, via the scratch marks on it, where I have pressed it to it, and then gently tried to rotate the end so it would find its home.
No luck yet.. have another idea that we will be trying in a little bit, as we will try try again.

 

[shutterfinger]

Masking tape at the center or edge of both or similar device to help you eliminate the parallax.

 

[peter k.]

Yeah.. been doing that, and today.. my time with it was cut short.. but going to place a small cut rectangular piece of masking tape over the slot, and see where the pin is hitting.

 

[shutterfinger]

Over a year ago I bought a Prontor S size 0 off ebay for cheap in non operation condition. Just after it arrived the first National Graflex arrived for repair. No service information available anywhere. I soon found out it was worn out but how to get it to work stumped me. I have 2 to 4 hours 2 to 3 days a week to tinker with such. 6 months later I took on a second National Graflex to repair. Looking at it I discovered what I was doing wrong on the first camera. Both cameras went back to their owners in usable condition.
I tore down the Prontor S and while putting it back together a very little spring tried to go into orbit. Most springs land within 2 feet of where it was when it popped into the void. I searched by hand, with a strong magnet, and finally the shop vac in the expanded area of 6 feet from the launch point but no spring to be found. 3 days passed with minor repeat searches with no luck. I moved all the boxes, chairs and such and went over that half of the room with the shop vac. I sat down with the magnet and started going through the debris in the bottom of the shop vac tank a small section at a time checking the magnet for the spring. I was 95% through the debris when a piece of wire stuck my finger when checking the magnet, it was the spring. This time the shutter went back together without problems and it works like new.
Perseverance will pay off.

 

[peter k.]

Oh that was great, thank you, and were still trying to persevere.

Update: Well as stated in post #five, cut some masking tape, and placed over the slot. Then took a toothpick tip of acrylic art color ultramarine blue acrylic pigment, and coated the pin.
Put the lens together, at f5.6, with lens lock all the way counter clockwise, aperture spring held in place externally by paper clip created finger, and mounted it together. Aligning the lens together, by using the screws holes, and slid it in place directly to them. No twist! It nailed the slot. So cleaned up, and tried again for keeps. More than once, four, seven or more times. Checking again, two more times, with masking tape and acrylic.Still nailed it.
Yet.. not functioning. Will not stay.. or what ever. With no screws in, you can twist the back barrel, and the spring pressure, will move the slot, and the aperture works! And it takes only the slightest twist!
At a loss.
So thought, maybe when the spring is released its causing the pin to jump out of the slot, as it puts pressure against it, cause the tension of the external pressure cannot be released slowly.
So got the caliper out again... just to be sure with all this fiddling around, ... nope.. It looks like the pin can goes far enough in. Not shallow. Sigh...

So then I got humorous, ... and crazy.
What the 'ell. Have nothing to lose can't get the dam thing to behave and if Dan Forman is reading, this is a WARNING.. you'll either never end up shacking your head about what were going to tell, or maybe die laughing.

Got out the rubber cement. Toothpick dot of cement on the pin, and a little on the edge of each side of it, so it will touch and contact the slot when put together. Then.. toothpick cement on the slot, a little on each side and dragged a slight thread across the opening of the slot.
Mated the lens together again.
Nope.. and yes, the cement contacted each other, thread across opening of slot gone and all of the cement on the slot, which was not much, and there is evidence of it on the pin.
Sooooooooooo... Go figure.. crazy!!!
Next... maybe forgetaboutit...
The 'ell mit de birds.. and der spring ding...
Go shoot me trusty MF and LF's... or dig out the old nikon and its 80-200mm..

Who knows... yaawwwwn... Use to be a perfectionist, but now senility is wining, and cannot think of what else to do.

 

[shutterfinger]

The actual aperture movement does not match the aperture scale. The aperture blades usually open beyond the edge of the lens barrel at the widest aperture and will close down further than the marked smallest aperture.
Put it together at scale setting f5.6 mating the pin to the slot then once seated turn the barrel to align the screw holes. All cameras I have worked with assemble the aperture wide open not stopped down.

 

[peter k.]

Hmmm... Some misunderstanding here. You understand, and have more familiarity with all this stuff than I do, but it may not be understood that the "Lever" (see image post #1) rests against the outside of brass ring. In this position when trying to put the lens together, it hits the brass ring on the slot part of the barrel. Stopping them from joining, no matter what angle the barrel is rotated at.
So we made a long L, with a short finger, 90* at the end, out of a paperclip. This could be inserted from the rear of the lens, and with this in place, (between the lever and the brass) and also at the same time, being pressed down, clockwise, in the image, toward the arm that the pin rotates on, the lever will clear the non-slotted flange that sits at four o'clock.
Thus the lens could then be put straight together, without rotating the barrel.

The actual aperture movement does not match the aperture scale.

Yes your point made is good, but in this case it is not a concern.
What we did is set the scale to f5.6, (not stopped down), and with the masking tape test, paint on the pin, it nails the center of the slot, not only marking the slot with the paint, but also indenting the masking tape into the slot, by the pressure of the pin against it!
This was achieved, several times, when the two were pressed directly together, with no turning of the barrel, but done by aligning the barrel directly, straight, to the screw holes, by using the paper clip that is doing its two jobs. One, keeping the lever away from the brass, so the lens would go together, and also holding the tension of the lever spring away, so there was no interference is placing the lens straight in without rotating it. The lever would not hit the non-slotted flange! Trouble is, the pin is not staying in the slot! I guess after the lever spring tension is removed, somehow it is forcing it away.

What you seem to be implying, is place the lens together, not aligned to the screw holes, but get them joined and then rotate the barrel, and automatically the pin will find the slot.
Is this what your implying?
I tried that several times, with the paper clip "L' allowing the lens to be joined, and it didn't work, and I tried it just now again, three times and still no luck.

 

[shutterfinger]

I thought you were trying to mate it at f32.
If this is a T mount lens remove the T to Canon adapter and if a dual scale lens use the left 5.6 (orange) not the right side 5.6 (green).
No I'm not experienced with this type of lens but the aperture mechanics are not that complicated.
Did any stray parts suddenly appear around the work area?
Sharp well lit pictures looking straight into each mating end may help.

 

[peter k.]

View attachment 175829 I don't believe its a T mount lens.. as there is no orange or green 5.6 designation.
Yes it should not complicated, but somehow its turning out that way...
Nope ... no stray parts appeared around the work area.

Do you want them larger?

 

[Gerald C Koch]

When disassembling just about everything more complicated than a fly swatter it really helps to take detailed notes during disassembly. I learned this the hard way. Btw, an empty egg carton or muffin tin is useful to keep track of small parts. Professional camera repairers make scratch marks before disabling the helicoid cylinders. Remember there are usually 6 sets of threads. Get the wrong match and the lens will not focus correctly.

 

[peter k.]

Yes your absolutely correct, what we do is shoot images of each step, and instead of an egg carton we use thin tall empty yogurt cups and place the parts in them in order, and then place the next one on top of the bottom one, and when working, place and empty one in case ... ya know.. so the parts, screws ect, wouldn't fall out.
With this problem, it came apart, no big deal.. but getting it back together has become a mystery.
You can see the pin and the slot.. why won't it stay there, when put together?

 

[shutterfinger]

I use 35mm film cans, one for each camera section or shutter sub assembly, no mixing things up.

I see no reason for it not to mate properly. Is the tripod collar lock screw tightened or loose when you try to assemble the sections? Should be loosened.
Has the slot reseeded into the barrel from a misalignment attempt?
Set aperture to 5.6, loosen the tripod collar position knob, set together with pin and slot aligned, start all section screws and snug lightly then try the aperture.

 

[peter k.]

Yep.. i don't see a reason either,, Hmmm .. had to think a moment, no I had the collar lock screw tightened when I would assemble it, so it wouldn't move.
Ok.. I'll try it loosened.

Has the slot reseeded into the barrel from a misalignment attempt?

No, the slot nor the pin can reseed when pushed. Although the pin is of thinner metal, it rests against the brass doohickey behind it.
The reversed 'C' piece of metal, rotates counterclockwise from f32 to f5.6, by the brass doohickey behind it. We check with the caliper, twice, to verify the pin and its depth. All seems to be well and it was not bent. I even took it off to make sure it was flat.
The brass doohickey, mentioned above, has a curve to it on the inside, that cannot be seen because it is covered by the lighter reversed 'C' piece. The brass doohickey, with the curve pushes against a pin on the reversed 'C", as the f settings are changed. This end can be seen at 2 o'clock, on the reversed 'C" part.
So as the f setting are changed, the curve of the brass doohickey, presses against and moves and rotates the reversed 'C' clockwise, viva this pin, as one goes from f32 to f5.6.
When changing setting from f5.6 to f32, the spring tension of the lever pushes the reverse 'C' against it, in a counter clockwise motion, and keeps it snug.
BTW the slot is solid on its ring. All it can do is be rotated, by the pin, when the f setting is changed. That of course is what is actually connected to the blades. and has no other free movements. The spring tension lever, on the pin side, @ 7'clock is what applies the pressure on the pin/slot area when there mated, to keep the blades in place.
That is the lever @ 7 o'clock that needs to be away from the brass ring that you see it resting on, in order for the lens to even advance together.
The paper clip tool is what we have used to do this, and at the same we compress the spring in the lever toward the right, clockwise, so not to put pressure on the slot ring, as it goes together, so the pin can mate with it.
When its doing its job, this pressure is applied against the non slotted flange, with the two holes in it at 4 o'clock on right side of the image, and of course this pressure moves the slot, as they both are on the same ring .

 

[shutterfinger]

Is there a slot just to the right of the slot bracket that the lever at 7 o'clock must be rotated to match to allow proper assembly? That pin likely only engages the slot by .010 to .015 inch. Screws may start/holes look aligned with a slight blockage but not seat properly and a slightly cocked barrel will cause the pin to jump from its slot.

 

[peter k.]

No.. there is no slot.. its wide open. See image.

slightly cocked barrel will cause the pin to jump from its slot

Hmmm,,, that's true, cause as you state there is not much give.. any suggestions..
Its to small to make a click... I've tried last week to insert it, not all the way and then slightly rotate it,to see if one could feel a 'drag' as it adjusted the blades, when it mated. But very difficult to keep it at a correct space away.
Hmmmm.. using the caliper, maybe a washer of a sort could be made out of cardboard to the right thickness. Then the lens could be inserted against that. Thus having something to gently push against and totally square it up, remove the cardboard, then gently closing the final distance.

 

[marcusBMG]

Resurrecting this thread because I am working on the same lens, OM mount, see here.
Can the OP tell me if they ever sorted their lens out? Also can they tell me if the separation of the lens at the tripod mount gives access to the rear optical group. I can see a light baffle with two slots in it for a lens spanner to remove but not if the optical elements are accessed from that end.
My best suggestion re the original problem - use a small fine file to take the edge off that pin. It really looks like it should just reassemble, and that this is how the lens goes together (and comes apart). certainly taking the mount off didn't help anything on mine. The mount end seems like a solid piece. I don't think I want to split my lens at the helicoid upon reflection, I have found helicoids with mechanics that don't rotate the front end of the lens problematical before (or it might be a double helicoid, even worse), and there are aperture mechanics/links involved too.

PS it's always a good idea to have a search friendly thread title ...

 

[HermannK]

Hello gentlemen,

I own 2 of these lenses and I am not sure of how to disassemble these. One of these has Olympus OM mount, while the other has M42 mount. My idea was to swap back parts with mounts between these lenses because OM version is worn out and therefore loose, has aperture changes when focusing, and has bad front lens, and M42 version is considerably better in these regards. However I do not know where are the screws that hold the lens in place - are thee under the rubber shell on the back part?

Also, I realized that putting everything back together is kinda risky and I may end up without being able to control aperture. is it worth taking a shot? My other idea in case it fails was to simply swap front lens - however, unluckily enough I cannot unscrew the ring on the M42 version. I tried hard with a caliper, but no dice. Do you gents have any suggestions ?

 

[marcusBMG]

Well PeterK, if you catch up with this you are going to hate me, but i finally set to with a PK mount example of this lens, disassembled the rear end, cleaned the rear optical group, eased it it all back to gether, wiggle, click ..what's the problem?! None in my case..

more info here:

https://www.pentaxforums.com/forums...notes-disassembling-vivitar-400mm-f5-6-a.html

 

[peter k.]

Oh my goodness... think we still have this somewhere. Going to have to dig it out where ever its hidden, and give it another try.
Thanks for the info, and BTW welcome aboard, especially as this is only your second post in two and half years. ;-)