Removing a Lens from a Lensboard

[Fotoguy20d]

Help please before I break anything. I have here in front of me a very nice 90mm Optar in a recessed Graphic View lensboard. It's held on by a proper retaining ring and not one of those nice big flanges. There's no room for me to grab the shutter and try to twist it off from the front. I could provide a picture or two but I'm sure you all know what it looks like. Anyway, help a newbie get this lens off the lensboard before he destroys it. I'd be happy to leave it alone but I can't get the rear element off since half of it is obscured by the ring, and the thing needs a hefty cleaning. Besides, I think it'll be very nice to use on my speed graphic if I can put it onto a lens board for that one.

Thanks,
Dan

 

[bdial]

The correct tool is a spanner such as;
http://www.skgrimes.com/span/index.htm
They are available from Micro-tools as well (www.micro-tools.com).
I've used one of these; http://www.parktool.com/products/detail.asp?cat=25&item=SPA-2 successfully, available at almost any bike shop.
Or you can use a small screwdriver against one of the flanges of the lock ring. You are almost guaranteed to make a scratch across the lensboard though. Some people advocate two jeweler's screwdrivers held in a vice.

 

[Fotoguy20d]

Figured I needed some sort of special spanner. The bottom bracket spanner is a neat idea - I have one of those floating around somewhere. I've never gotten the screwdriver to work - seems to be prone to slipping. Here's what worked great though - a pair of 4 3/4" bent nose pliers (in the set of 6 mini-pliers for something like $6 from Harbor Freight tools) that just happened to be sitting right here on my desk.

But, that rear element is sitting in there like it was crazy glued in place (hope that's not the case). I've tried a silicone rubber pad with a large pair of pliers to no avail. Will differential expansion help? Hot or cold? Any other thoughts?

Thanks,
Dan

 

[panastasia]

But, that rear element is sitting in there like it was crazy glued in place (hope that's not the case). I've tried a silicone rubber pad with a large pair of pliers to no avail. Will differential expansion help? Hot or cold? Any other thoughts?

Thanks,
Dan

Dan,
If the previous owner damaged the fine threads somehow, it's conceivable that glue was applied. Applying heat doesn't sound like a good idea.

I know this sounds like the wrong way to go, but it worked for me once:

Tighten it further ever so slightly to break the connection, and I mean slightly, watch closely, you only have to see (or feel) it move. Don't use that "large" pair of pliers or you'll apply too much torque. If it moves, then back it off - a little back and forth at first - carefully without crossing the threads. Try this if all else fails - a drop of penetrating oil allowed to soak in for awhile may do the trick. If this doesn't work the threads are probably crossed.

Good luck if you try this method - plumbers do it all the time. You have my blessing.