There is a weird little screw on my Schneider SA XL 5,6/58

[Kornscharfsteller]

There is a weird little screw on my Schneider Super Angulon XL 5,6/58 lens that protruded from the back just enough so that I can’t properly mount the lens, that it is really level and flat on my Chamonix 4x5 lensboard wich is perfectly flat on the side pointing away from the ground glas.

It doesn’t look like this is because of dirt or anything it looks like the screw is exactly designed for that purpose and can’t be screed in further.

What is this and what should I do about it? Should I completely remove that screw? It doesn’t look like it is holding anything.
Am I doing something wrong?

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[paulbarden]

That is the locating pin. Its meant to fit into a hole in the correct board to prevent the shutter from rotating.
Assuming I'm correct (corroboration?), it can be removed, as this is its only purpose.

[Conrad . Marvin]

Either drill a small hole in the correct place on the board or take it off and put it in a zip lock bag for future use or not. That is all that it’s there for.

[Tracy Storer]

As pointed out by others, that is an "anti rotation" screw, to prevent the shutter spinning on lensboards if the retaining ring becomes loose, more of an issue on wooden boards with humidity changes. There would be a corresponding notch or hole in the bore of the board to accept it.
You may remove that screw without worry to get the shutter to sit flat on the board.

[John Layton]

My Crown Graphic lens boards each have a little divot to accept those locating screws...but yeah - you can just remove that screw and save it for whatever (or maybe there's a Crown or Speed Graphic in your future?).

You would not want to drill holes into your existing lens boards to accept this screw because...then you'd have extra holes in your lens boards!

Or...you could get fancy, drill blind holes in your lens boards, tap these with a flat bottomed tap, and there you go! But you'd need to be very careful and precise.

Actually, there are those times when a lens begins to come loose while in the field...and if I'm without my lens wrench I'll usually unscrew the offending lens' rear glass, hold the retaining nut by hand, and screw the lens in by grasping the shutter in front prior to replacing the rear glass. Not always a great option if its raining/snowing/blowing sand.

The thing about those positioning screws is that they're really there to help position a lens as the retaining ring is tightened...and not so much to depend upon to keep a lens positioned if its retaining screw comes loose - although it does help in this way temporarily.

[Paul Ron]

That is the locating pin. Its meant to fit into a hole in the correct board to prevent the shutter from rotating.
Assuming I'm correct (corroboration?), it can be removed, as this is its only purpose.

yes thats to prevent the shutter from rotating on the lens board. it fits in a tiny hole or notch. it can be removed.

[Kornscharfsteller]

Thank you all for the info. I have seen two or three different different unscrewed lensboards so far, none of them contained such a hole for it and my other lenses don't have such a produding screw. So is this this generally not such a common standard? Where does this come from? What lenses/boards usually have this?

[Greg]

Either drill a small hole in the correct place on the board or take it off and put it in a zip lock bag for future use or not. That is all that it’s there for.

Immediately pit that very tiny threaded pin in a zip lock bag and label the bag. I once removed a threaded pin and set it on the counter, only to accidentally hit it and send it flying on to the floor... never found that pin and the floor was painted concrete and not a rug which would have certainly ate it up. Does any one have a simple method of determining where to exactly drill the hole in the lens board to accept the pin? On all my lenses I place a dab of glue from a hot glue gun on the back of the retaining ring or flange. As a backup it secures the retaining ring or flange from rotating and is very easy to remove.

[Bob Salomon]

Immediately pit that very tiny threaded pin in a zip lock bag and label the bag. I once removed a threaded pin and set it on the counter, only to accidentally hit it and send it flying on to the floor... never found that pin and the floor was painted concrete and not a rug which would have certainly ate it up. Does any one have a simple method of determining where to exactly drill the hole in the lens board to accept the pin? On all my lenses I place a dab of glue from a hot glue gun on the back of the retaining ring or flange. As a backup it secures the retaining ring or flange from rotating and is very easy to remove.

Get a rubber stamp pad. Rub the pad over the screw head. Put the shutter in the lens board hole and press down. You will have a mark where to drill or file out.

[Rod Klukas]

It will do no harm to remove it. Use a knife such as a steak knife to get it started, if you do not have a jewelers screwdriver.

Linhof especially pushed this, as they had a lens board with a quick connect for a cable release, that required a shutter be correctly positioned for it to work consistently. As someone mentioned, Graflex also went with a screw to set shutter position correctly for flash trigger on lens board.

It should not be removed on a #3 shutter, however, as the brass screw in back is a stop to prevent damage to the aperture blades in a #3 shutter.

Rod

[Alan Klein]

I used a special spanner tool to tighten the lens to the board after removing this screw. The lens has to be tight to prevent slippage. The tool helps. The tool works on a number of shutter types and sizes.
https://www.bhphotovideo.com/c/product/61131-REG/Toyo_View_180_625_Lens_Mounting_Wrench.html

[Bob Salomon]

I used a special spanner tool to tighten the lens to the board after removing this screw. The lens has to be tight to prevent slippage. The tool helps. The tool works on a number of shutter types and sizes.
https://www.bhphotovideo.com/c/product/61131-REG/Toyo_View_180_625_Lens_Mounting_Wrench.html
But if you had gotten the Rodenstock one it would also work with 3 size shutters. This one doesn’t.

[Alan Klein]

But if you had gotten the Rodenstock one it would also work with 3 size shutters. This one doesn’t.

I didn't need the No. 3. I also didn't like the little nibs that tighten the lens. They look like they'll break or bend compared to the Toyo I bought. Maybe someone can comment on the strength of the Rodenstock. The Toyo I used seemed pretty strong.

Toyo https://www.bhphotovideo.com/c/product/61131-REG/Toyo_View_180_625_Lens_Mounting_Wrench.html
Rodenstock https://www.ebay.com/itm/133872020620

[Bob Salomon]

I didn't need the No. 3. I also didn't like the little nibs that tighten the lens. They look like they'll break or bend compared to the Toyo I bought. Maybe someone can comment on the strength of the Rodenstock. The Toyo I used seemed pretty strong.

Toyo https://www.bhphotovideo.com/c/product/61131-REG/Toyo_View_180_625_Lens_Mounting_Wrench.html
Rodenstock https://www.ebay.com/itm/133872020620

The reason there is a Rodenstock lens wrench available to users is because we saw the factory technicians and engineers using them and asked the factory to make it a product. Same time we asked them to make their microfiber lens cleaning cloths a product.
There is no way you can break those prongs on that stainless steel lens wrench.