Anyone have waterhouse stops for a Newer Dallmeyer 3B?

[bieber]

I've got a Dallmeyer 3B, what I believe is a newer model with a black barrel, photo attached. I'm wondering if anyone has a matching lens with a set of waterhouse stops that they wouldn't mind scanning and sending me images of. I've found a thickness of black plastic I can get laser cut which fits nicely into the waterhouse slot (also seems to work well as a partial dark slide), and I'm thinking I could probably just get a set of plastic stops made that would work in a pinch for a lot less than getting a set of metal ones machined.

184166

184167

[karl french]

Yup, that's a pretty late one. Not sure how much the stops changed over time. I think the slot on my 3B (1889) is 87mm wide. Yours?

[c.d.ewen]

Just a thought - you might check the plastic for opaqueness.

Charley

[Len Middleton]

I've found a thickness of black plastic I can get laser cut which fits nicely into the waterhouse slot (also seems to work well as a partial dark slide), and I'm thinking I could probably just get a set of plastic stops made that would work in a pinch for a lot less than getting a set of metal ones machined.


If you are going to farm out the laser cut, you could probably get metal ones cut via plasma, abrasive, or water jet, rather than machined. The difference is likely just the material costs.

It is something I have been thinking about, but not yet looked at it in detail myself.

[Steven Tribe]

The forum links at the bottom of this page will give you plenty of extra information. Especialy:-

http://www.largeformatphotography.info/forum/showthread.php?110388-Waterhouse-stops-Dallmeyer-3B

Making Waterhouse stops out of brass is easy when you have a lathe, but time consuming without!
There is really no reason why these these shouldn't be made with black card, scissors and a sharp blade. I have made dozens of brass and card sets and they work equally well! And card doesn't scratch the barrel around the Waterhouse slot.

[bieber]

Yup, that's a pretty late one. Not sure how much the stops changed over time. I think the slot on my 3B (1889) is 87mm wide. Yours?

It's hard to get my caliper in there precisely, but it looks like I'm within a few tenths of a millimeter of 87mm.


If you are going to farm out the laser cut, you could probably get metal ones cut via plasma, abrasive, or water jet, rather than machined. The difference is likely just the material costs.
.

I'd love to, do you know of a service that could do the cutting affordable? I can get plastic laser cut pretty cheap by Ponoko, but their metal cutting is up in the hundreds of dollars range.


The forum links at the bottom of this page will give you plenty of extra information. Especialy:-

http://www.largeformatphotography.info/forum/showthread.php?110388-Waterhouse-stops-Dallmeyer-3B

Making Waterhouse stops out of brass is easy when you have a lathe, but time consuming without!
There is really no reason why these these shouldn't be made with black card, scissors and a sharp blade. I have made dozens of brass and card sets and they work equally well! And card doesn't scratch the barrel around the Waterhouse slot.

Neat, thanks. I found a drawing on the collodion bastards group I can hopefully use as a basis as well. I guess my main concern, which I'd kind of hoped to sidestep by getting scans from a working set, is if cutting the correct hole sizes is really as simple as dividing the focal length (11.5", right?) by the f-number to get the diameter. Or are there other practical concerns to take into account when cutting stops for a real life lens rather than the theoretical version?

[Steven Tribe]

The link I gave included a post from me pointing out that there is some difference between the actual length of the WHS during the many decades of production! Eddie, who had a project some time ago with semi - commercial reproduction project brass stops for the beloved 3B (!!), found variation in size too!

The physical diameter of the stop holes is only an approximation of the real aperture size. The "seen" diameter - looking at the aperture through the front lens - is real dimension to be used in the magic equation.

There must be an equation to find the effective aperture based on the focal length of the front lens. That is, to produce a correction coefficient to convert physical diameter measurements to optical diameter.

I have seen a number of "original" Dallmeyer stop sets, which obviously didn't follow the usual stop sequence as diameter sizes fell by the same amount with reduced apertures.

[bieber]

Oh, fun. Maybe I should just forget calculations altogether, point it at a light and use a meter on the center of the ground glass to figure out when I've shaved a stop off of each successive size