Stupid Question - Removing Lens

[dmb]

Got some additional photos, showing the rear element on and detached.



Had another look at it based on what all had said, and it's still baffling me. There doesn't appear to be anything that can be unscrewed any further than the ring with the rivets out of it, but it unscrews to a point then is faulted by the outer ring...

Thanks all

[Leigh]

The ring at the rear, still attached to the shutter, is an adapter or spacer.
It's a separate item that must be removed to permit unscrewing the retaining ring (the one with the slots).

It should unscrew counter-clockwise, just like the rear cell that you already removed.

One common trick in the repair industry is to put a thin rubber sheet on the workbench, then place the open end of the spacer/adapter on it. Apply pressure from above and try to rotate the shutter assembly in the proper direction.

If that doesn't work, there's another trick that must be done carefully...

Holding the lensboard with the shutter pointed up, apply one or more ice cube(s) to the outside of the adapter ring close to but not touching the retainer ring or the shutter itself. This may shrink the adapter enough to loosen it.
Be very careful that you don't get any water in the shutter. Thoroughly dry the area before you turn it right side up.

This works really well with dry ice. Don't try that unless you know how to handle it, and have appropriate gloves and tools.

A suggestion to avoid problems...

Engage the preview lever to open the shutter blades, and open the aperture to maximum.
This will prevent damage to the blades in the event of a mishap (tool slip or whatever).


- Leigh

[dmb]

...cut...

- Leigh

Just to confirm Leigh, you're referring to this ring here in red:

That needs to come off to allow the retaining ring to be removed?

If so, it's going to take a mighty amount of elbow grease!

Thanks for the extensive response though!

[Leigh]

Yes. The ring that turned red is the culprit.

It might have been installed with some type of thread locking agent (Loctite or similar).
That would be very poor practice, but nothing's impossible.

I would suggest removing the front cell before you proceed.
It's not involved in the effort, and you run the risk of damaging it while you're working on the rear.

- Leigh

[sumo]

Yeah it looks like you just have to give it some work.
The strap wrench idea is probably the safest but it requires a strap wrench.

[dmb]

Argh... The frustration grows... I used more force than I thought it would have needed and thought I had it when something released, however that was just the front part of elements unscrewing... Now it appears I have the shutter stuck in the lens board?

[Leigh]

The Copal #0 and #1 shutters have anti-rotation screws designed to prevent them from rotating in the lensboard,
which can cause the retaining ring to come loose.

Many people remove them, or fail to install them, so there's about a 50/50 chance of one being on your shutter.

If it's installed, the shutter will not rotate relative to the lensboard unless you apply enough force to sheer the screw.

- Leigh

[dmb]

The whole shutter definitely rotates in relation to the lens board, quite freely at the moment...

May have to take this to a repair place and have them pry it apart!

[sumo]

Do you have a vise or something?
Hold the shutter body secure and then grab the rear ring and turn. Alternatively hold the rear ring and turn the shutter. If you have 2 strap wrenches you should be able to get it off pretty easily...
Whatever you do don't get impatient and rush things. That usually ends in a bad way I find

[Leigh]

That adapter ring is way too thin for a vise.
It would get crushed or distorted if you applied enough force to prevent it from rotating.

The only commonly-available tool that might work is a strap wrench, as mentioned above.

The other option would be a custom-made collet with a threaded plug inserted in the adapter.

- Leigh