Removing lens elements from shutter

[Ulophot]

My 4x5 lens is a Komura Commercial 210mm f/6.3 in a Copal 3. At some point, I will need to send the shutter out for CLA; the aperture lubricants have gotten gummy over years. I know that the front and rear lens groups unscrew, but is this something I should do, or should I leave it to the technician? In other words, what about remounting? Is an optical bench needed to ensure proper distances?
And, since I am asking about removing elements:
In the case that it's okay for me to (very carefully) remove the elements, is this a lens design that allows using either the front or rear element group alone, for, perhaps, a longer focal length, as some lenses allow?
I bought this lens in the late '70s on advice from the dealer, who mounted it in the shutter and lens board for me, and have always been very pleased with it. I have found all of about four mentions of it in searches. #212115, if that's any help to anyone.

Thanks.

[Dan Fromm]

The lens is a tessar type. If you don't want to send the cells to the shop -- there's no reason to -- unscrew them, send the shutter, and when the shutter comes back screw the cells back in.

Tessars are not convertible. Double anastigmats (there are many types) are convertible.

Don't worry so much.

[Ulophot]

The lens is a tessar type. If you don't want to send the cells to the shop -- there's no reason to -- unscrew them, send the shutter, and when the shutter comes back screw the cells back in.

Tessars are not convertible. Double anastigmats (there are many types) are convertible.

Don't worry so much.

Thanks for your reply; good to know that removing the cells is a simple matter.

[Liquid Artist]

the general rule of thumb seems to be if there are spacers between the elements and shutter put them back in the same place.
Although I've never had spacers in my lenses I understand that they may be used to make up for variances in the manufactoring.

[IanG]

I'd be very surprised if the Komura Commercial 210mm f/6.3 is in fact in a Copal 3# which is quite a large bulky shutter. It's a small light lens and shouldn't be much different to my Congo/Osaka Commercial 210mm f6.3 which is definitely in a Copal #1 shutter. Even the larger 210mm f5.6 Symmar S and similar are in Copal #1 shutters.

Ian

[EdSawyer]

I even have a Congo 240/6.3 (tessar) that is in a #1 shutter.

[Dan Fromm]

Guys, I just did a quick search. All of the 210/6.3 Komura Commercials Google found are reported to be in #1 shutters. Fine, wonderful. But what does that have to do with the OP's question of how to extract cells from a shutter?

[IanG]

Guys, I just did a quick search. All of the 210/6.3 Komura Commercials Google found are reported to be in #1 shutters. Fine, wonderful. But what does that have to do with the OP's question of how to extract cells from a shutter?

Copal #1 shutters or even Compur #1 shutters are quite easy to come by second hand so that's another option, Copal #3 shutters are much rarer and tend to be very much more expensive as a consequence, parts are harder to find for repair shops as well.

The OP should be able to just remove the cells and store them carefully. I've never seen spacers with Tessar & type lenses. However having a Linhof CZ 150mm Tessar that's un-sharp stopped down it's just possible this one does have a missing spacer, but I've only seen spacers with WA lenses were cell spacing is very much more critical.

Ian

[Ulophot]

Copal #1 shutters or even Compur #1 shutters are quite easy to come by second hand so that's another option, Copal #3 shutters are much rarer and tend to be very much more expensive as a consequence, parts are harder to find for repair shops as well.

The OP should be able to just remove the cells and store them carefully. I've never seen spacers with Tessar & type lenses. However having a Linhof CZ 150mm Tessar that's un-sharp stopped down it's just possible this one does have a missing spacer, but I've only seen spacers with WA lenses were cell spacing is very much more critical.

Ian

It is quite possible that I have a Copal 1. I will look tonight and let you all know. I apologize for any confusion.

[Michael E]

Removing the cells from the shutter is a 30 second job. Leave it to the mechanic or do it yourself, if you don't want to send the glass by mail. It's not complicated and doesn't require special equipment to remount the cells.

[Ulophot]

Apologies for the confusion -- mine. My Komura is indeed mounted in a garden-variety Copal #1; nothing exotic or rare.
Thanks again to all.

[Leigh]

If you remove the cells, carefully protect the shutter.

The diaphragm blades and shutter blades are quite delicate.
If anything hard hits them, they'll likely be bent and damaged to the point that they must be replaced.

Open the diaphragm fully, and open the shutter using the preview lever. Cover the front and rear openings of the lens with rigid plastic or similar material to keep junque from hitting the blades.

- Leigh

[hiend61]

I have one lens that I want to remove from a Compur 1 shutter. I had no problem with rear element, but I can´t remove front element. I´m in a hurry and can´t send the lens to a repair facility. (The nearest is 135 miles away). Do you gentlemen know any trick I can use?. Thank you.