Screw on the back of the shutter interfering with lensboard

**Craig Tuffin** · 24-Aug-2009, 02:24

I'm trying to mount two lenses 1. Schneider APO SYMMAR f5.5 120mm (Copal 0) and a Schneider SUPER-ANGULON f5.6 65mm (Copal 0) on my new Chamonix lens boards. However, there is a small screw on the back of the shutter that interferes with the lensboard so it doesn't sit flush with the back of the shutter. It's not one of the three screws that fixes the barrel in the shutter.

Both these lenses had been fixed in helical focusing mounts...perhaps it's a locator screw for the mount?!

Can anyone tell me what this screw is for? Can I remove it so the lens board sits flat?

I don't want to touch it until I know what I'm breaking

I vaguely remember reading something about this a couple of years ago but I can't find anything on it at the moment.

**mikec** · 24-Aug-2009, 03:09

Yes, it's for orienting the shutter and can be safely removed. I could not find any doc on the Copal site, but it is mentioned in the archives here ( use lock pin for a key). SKgrimes also has a note at http://www.skgrimes.com/lensmount/shutmt/index.htm if you prefer to drill a hole to accomodate it.

**RichardRitter** · 24-Aug-2009, 04:18

Its called a dog screw and it is to keep the lens from turning. You can remove this screw.

**Craig Tuffin** · 24-Aug-2009, 04:24

Thanks guys!

Removed, lenses mounted...ready to go.

Cheers

**Steven Barall** · 24-Aug-2009, 12:04

What an incredible resource this site is to the whole wide world of large format photography. Every day I am amazed.

**Ernest Purdum** · 24-Aug-2009, 13:09

I realize the question has been answered, and the originator satisfied, but for what it's worth, rather than removing the screw, or drilling a hole. I like to use needle files to make a little slot for the screw. The screw does serve a useful function even if it is only a back-up in most situations.

It's a lot easier to correctly locate the slot than a dilled hole.