[oxidized]

Hey guys,

So today I decided was the day to relube my 50mm Takumar. I was able to disassemble it all the way down to the housing, however I was unable to detach the helicoid in order to fully clean it up. Ended up just fully extending it, wiping, retract, repeat until no grease was coming out. Then I applied lube to the threads. I noticed a lot of the lub had migrated into the inner compartment of the lens so I tried to clean that as best I could.

My question is, how do you fully detach the helicoid? There were 3 screws which were hidden underneath the aperture ring, I was able to remove 2 of them however the third seemed to be permanently suck on there and could not move it. I felt like taking it off wouldnt have released the helicoid though. Any ideas would be extremely helpful!

[vladimiroltean]

Do you have a proper screwdriver? JIS #00 is required, I think. Apply pressure on the screw and only then torque, or else you will strip the screw head.

[jatrax]

Like kcobain says you need a JIS screwdriver and be really careful to not strip the head. One thing that has worked for me is a ratchet with driver bit if you can find a set with JIS in it. You can apply a lot more torque while pressing into the head.

Also, be very careful to mark the helicoid as to where it threads together, it is easy to miss align when putting it back and you have to trial and error it to get it back to the right place.

[oxidized]

Well, the screw is actually a flat head type. There were no JIS screws anywhere on the lens. I didnt have problem removing the other two screws. The third one just seems completely stuck. Almost like it is glued. Anyways, I just saw this article:

Pentax 50mm f/1.4 strip-down instructions

The screw I am referring to is seen in the 5th picture as you start from the top and below it reads:

"There are three bright slotted screw-heads now visible in the picture above right, remove these and the main lens tube can be lifted from the lens mount."

So I am guessing this is not what I am looking for then, since I am trying to get to the helicoid not release the lens tube.

There is another screw (also a flathead) which is just by itself. I think it is the screw that stops the helicoid when infinity is achieved. Could that be the one that needs to be removed in order to free the helicoid?

[vladimiroltean]

Yes, sorry, Super Takumars had flat-head screws, while the SMC 50/1.4 had JIS.
You have to remove that screw in order to remove the helicoid. Then it's held by 2 tabs. Although not the same lens, here's what you should get:

Be careful to mark your position of the helicoid somehow, because it will be a pain when reassembling it.

[oxidized]

First, thanks for the quick reply! Mine looks a lot different. I completely removed the optical components and they had no threads on them at all.
This video shows what I have at about 0:35:

You Tube

You Tube

I was just left with the outer shell and an inner shell with mechanical complents / aperture. And the helicoid was somehow inbetween the two.

[vladimiroltean]

Oh... I think you might be looking at the wrong stuff, first of all
I don't know exactly what you did there, but I suppose you unscrewed the optical part from the helicoid part, which you shouldn't.
And because I'm bad at teaching stuff, I took some very quick and dirty pictures of the disassembly process, on my junker 50/1.4. Sorry for the horrible pictures, but I'm sure you can understand.

1. First remove the name plate. You already did that.


2. Unscrew the 3 small screws, and remove the filter ring.


3. Unscrew the 3 small screws with washers, and remove the focusing ring.


4. Unscrew the 3 small set screws from the side of the lens, and remove the DOF scale ring.

5. Remove the aperture ring by pulling it, careful at the ball bearing.

This is how the lens should look by now (please ignore the camera). I think you can see one of the 3 screws that need to be removed (the one closest to the Auto/Manual switch). Leave that screw in the middle in place, it'll be a PITA to put it back, and it doesn't affect anything but the focusing ring.


6. Unscrew the 3 screws, pull the lens assembly away from the mount.


7. Looking at the rear of the assembly, you will notice 1. the aperture coupler, which you will have to match to the F shaped lever, and 2. the two tabs I was talking about.


Here starts your madness. Once you remove these tabs, the helicoid will no longer be kept on the track when turning it. Be careful from now on, so you won't mess the focus altogether.

[oxidized]

Wow. Thank you so much for the detailed pictures. I think this may have answered my question. I just put it all back together a few hours ago. I will take it apart again tomorrow and take a look. I more or less followed these steps in the exact order. Picture #4, the screw which is right where the orange diamond is supposed to be is the one which was stuck. That screw needs to come off and I shouldnt touch the focus ring stopper screw?

How did you mange to take off the helicoid out together with the optical elements if you already removed the three screws which are holding them together in picture #3? I feel like once I remove those, the lens elements are pretty much ready fall out on their own.

So, once I remove that last screw and I take out that the whole contraption (for lack of a better word) I then should see the brackets at the back? Once I remove those I will be able to completely unscrew the helicoid I guess.

Last question, how (or where) do you suggest I mark the two parts so that later when I re-assemble I will able to put them back together the right way?

Again, thank you soo much for the help and the pictures!!!

Bogdan

[vladimiroltean]

Picture #4, the screw which is right where the orange diamond is supposed to be is the one which was stuck. That screw needs to come off and I shouldnt touch the focus ring stopper screw?
As far as I can see, only the focus ring stopper is right under the orange diamond. The 3 screws you should undo are the ones under the aperture ring.

How did you mange to take off the helicoid out together with the optical elements if you already removed the three screws which are holding them together in picture #3? I feel like once I remove those, the lens elements are pretty much ready fall out on their own.
The 3 screws with washers do not hold the helicoid together with the elements. They press the focusing ring against the brass part of the helicoid, so they turn at the same time. The lens elements are secured by retaining rings, which have 2 diametrically opposed slots. No need to worry about them falling. You have to remove the focusing ring, to make way for the DOF scale and aperture ring to come off.

So, once I remove that last screw and I take out that the whole contraption (for lack of a better word) I then should see the brackets at the back? Once I remove those I will be able to completely unscrew the helicoid I guess.
Yes, but the screws are the ones under the aperture ring, as I hope you already understood.

Last question, how (or where) do you suggest I mark the two parts so that later when I re-assemble I will able to put them back together the right way?
Sorry, I have absolutely no idea, I decided not to mark anything, but I tell you it's going to be a mess reassembling it.

[oxidized]

Sounds good. Thanks again for all the help!