Re-assemble aperture blades back to Helicoid body

After you have cleaned the aperture blades with IPA, now is time to re-assemble the aperture blades back to the fixed part then to the moving part. These installation is simple and straight forward. The more critical part is on the later part where you need to install the aperture parts back to the helicoid body where you really need some practice and knowledge on tuning the aperture.

Let get started. Let re-assemble aperture blades back to the fixed part, moving part and the helicoid.

Here is the holes in the fixed pin(FP) where you place the individual aperture blades on it. There are 7 hole for 7 individual aperture blades.

Use the twizzle to clip on the moving pin(MP) and place the fixed pin(FP) in the first hole. As you can seen, there are 5 more hole, but there are 6 more aperture blades, why? Well , one of the pin is being cover by the first blade. During the last pc installation, push the first blade MP inward , so that the 7th pin being show for apertures blades installation.

For the installation of the moving part to the moving pins, do follow below steps

1) push all the 7 moving PIN slightly inward

2) Use finger and push the aperture blade outward toward the edge of the inner ring of the fixed part as shown as above picture

After you have completed previous step , you should able to see the aperture blades being installed overlap each other as shown in the yellow and red arrow.

The white line is the marker that we mark previously (Kind of hard to take the marker picture there), Align the moving part’s rod to the white line, the moving part should able to sit properly on top of all moving pin as shown in below picture.

After the moving part sit on top of the moving pin, It should look as above picture.

Turn the moving part anti-clock wise, the aperture blades will close and the moving pin will change location (red Arrow). Installing the moving part to moving pin may take some practice, do try more and this is where the marker on the fixed part come into the place to function during the re-assemble process.

The concept of re-assemble is stick to maximum opening of the aperture blades. We know where is the maximum rod should align to the fixed part and how is the aperture blades should look like.

After you have assemble the Aperture blades part together , now is the time to place the entire system back to the helicoid. Look for the holder that has similar size to the aperture moving part circle. place it on top of the holder. In above picture , the holder is just a simple pil bottle from the fridge. You can found some other bottle like Vitagen bottle or medicine bottle.

Remember the first mark that we make in previously? Now , you will need to align the aperture rod to the original mark.

After align the rod to the helicoid maximum aperture mark, Insert the helicoid vertically down as shown above.

Use the holder to support the aperture system while rotating the helicoid 180’ for U-ring installation

Before you install the U-Ring, you will need to make sure the fix part is perfectly sit on the helicoid holder. Second item that you need to check is to do some fine adjustment by turning the the fixed part either left or right to align the marker (yellow arrow) align to the helicoid body’s marker. This will ensure proper aperture setting after re-assemble.

Before you install the u-ring, turn the aperture to check if the aperture rod can control the aperture blades.

Remember to place some force on the moving part before turning the aperture rod, else the entire aperture blades system will be loosen as the U-Ring is not in place yet.

Install the U-Ring back to the helicoid

Press the U-ring back to it position by using the secret weapon. After you have install the u-ring, turn the aperture rod to check if it can control the aperture blades close and open.

Clean off the marker using IPA. Clean the optic as well before moving forward to next process.

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Any precaution step needed ?

• please make sure the marker is not being removed during the cleaning process
• Clean off the marker after the re-assemble process.
• Each of the above process is very critical , please follow the step to re-assemble the aperture blades back to the fixed part and the moving parts.
• Please make sure the aperture blades, fixed part, moving parts, U-Ring, Helicoid and your fingers were oil free before re-assemble
• Please do not repair in oily environment. I remember I have repaired 3 Minolta in the dining table while my maid is doing some deep fried work at the kitchen which is just 3 meter distance away. Even thought all my stuff is oil free, but the environment is oily. I found out that 3 of my lens is having oily aperture blades after 3 days it being cleaned. The minor oil in the air has contaminated the aperture blades.

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What happen if the marker has been wipe off during the cleaning process?

Well, this is not the end of the day. Get the second lens advise that you have prepared, disassemble it until you can see the fixed part inside the helicoid. Both of the lens should have similar installation location.

The maximum aperture concept is still the same , the only different is the reference location is different.

New reference mark, By reference to the new pin, you should able to find where is the aperture rod of the moving part is located during maximum aperture setting.

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My personal experience

I have cleaned off the marker’s mark accidently on nearly each repair work. Well, I want all the parts to be oil free and don’t remember about the marking was there. This cost me a lot of time during the re-assemble process.

Overall re-assemble time is ~ half an hour after you get used to it. You may not able to re-assemble if you do not know the working principal behind.

I still remember my first repair experience. It took me 30 mins to dis-assemble and 4 hours for re-assemble. After the learning, it shorten to around 45mins to 1 hours for the entire process.