Tag Archives: Tosei Koki

TKS … blades of glory.

Tosei Koki apparently made their own shutter for their cameras … the TKS. I have not found any information about repairing this type … so I just went for it, and now you get to know about it.

This shutter had a specific problem, when you cocked the shutter the leaf’s would open up then shut … well this poses a problem by exposing the film to light. Obviously something is not right … so I went deep deep deep undercover for this one.

It took me a while to figure out how the mechanisms are supposed to work … but I did figure it out after watching how all the parts moved and how correct it.

FYI: I later figured out that this is a Gauthier type shutter … hmm, Camera Repair Course?

First thing to do is to remove the shutter from body. Like most folding cameras the shutter is attached with a ring screw that can be accessed from the back. I find it easier to get the spanner wrench into the knotches by not having it completely folded closed.


Now the bellows will separate from the shutter.

Revolve the front and you will see the rear lens element and a large paper spacer thing.

Work the paper spacer/washer out without damaging it.


Not much to say about the back.

You can unscrew the rear element and clean it up.




DSC00765OK, now back to the front !!

There are some small grub screws that hold the focus ring to the first lens element … I could not budge them, so I worked around it.

Remove the focus ring stopping pin … pin vise, plastic tip pliers, or just wrap something around it to avoid tool marks.

Rotate lens slowly while lifting lightly … when lens releases mark its position as you will use that when you screw it back on.


Unscrew the middle lens element.





DSC00767Remove the focus stopping post.

Turn the locking dial until the flat end faces the inside

Rotate securing plate until you match the notches.



Noticed the speed cam.

Pull it off.






The mechanism at 7’oclock, stamped T.K., is the self timer.

Remove the long spring.

At top there is a brass arm that need to be pushed out of the way.

Position self timer priming arm curved notch.

With your three hands … convince it all to come out.

DSC00770 1The slow speed escapement is held on by two large round headed screws. The top-middle one can be accessed after cock the shutter to push some arms/gears out of the way.



DSC00748Here is a view of both components.

DSC00771 1






Mark the position of the flash sync port on the aluminum plate … this will help when putting the shutter back together.

Note the torsion spring that is held on by that screw.

This image shows what I figured out about the shutter problem … when the shutter is set, the blades would open then close. At the top you can see the setting arm and the leaf lever. The leaf lever was engaging the blade stud. This should not occur if the stud is in its left most position … in this case it was not. The torsion spring (at 5 o’clock) is the blade-operating-ring spring, this keeps the shutter blades from opening. I noted that it was slightly bent out of shape, but even correcting this the blades where not kept in the fully closed position. This meant there was resistance on the blades, which required me to get down there and clean up.

Remove the spring and the sync port parts.


The shutter cocking levers and things are almost all spring loaded.

Take a careful look at how the springs are positioned … you may even want to make a map.

Keep them together when removing them.

DSC00753There are three large headed screws.





Gently flip over and the shutter part will come out in your hand.

This was the first problem … the shutter blades were not moving freely without resistance.

These need to be cleaned … and try not to bend them.

Clean the surrounding metal it rides on.

DSC00755Unscrew the three screws with the metal washer underneath.

Clean up the ring that moves the blades.






I was not so bold as to take apart the 10 leaf aperture … good thing they were in good physical shape, clean, and moving freely.

When going backwards to put it together note any bent arms, springs, and things … make appropriate adjustments.

Now I leave it up to you !!!

Frankly my dear, I don’t give a damn.

Tōsei Kōki Y.K. … also known as Tosei Optical Instruments. They started out in Tokyo Japan in the early 1950’s, and appeared to ended only four years later. Not a lot of info … anyway … they made mostly folders that did not deviate much in design, though the last camera they did make was a TLR … and they made their own shutters (TKS).

The Frank Six seems to have been their primary camera … they made many variants of it, I think they made five sixes. The Six is a medium format folding camera.

The camera I have is the model I version made in 1952 (stamped on back) … that was a dual format 6×6/4.5×6, sadly my camera is missing the internal mask.

Tosei TKS shutter … 80mm f/3.5 Seriter Anastigmat lens