Waterhouse Stop Source

[Richard K.]

Is there anyone out there that's manufacturing repacement Waterhouse stops/wheels? Quite often you see lenses that are in great shape but missing the stops. Seems like a possible nice little cottage industry? I realize that there's more to it than punching a bunch of round holes into brass stock.:rolleyes: The particular geometry, physical dimensions and lens focal lengths would have to be known. Is there enough known to remanufacture these important parts? It would be a great resource! I beg your indulgence if this has been covered previously...:o

[Tracy Storer]

SKGrimes makes them, EddieG and I have both used Laser cutting to make them, If you search posts for calculating f-stops(there are numerous posts covering fstops) you can make some yourself out of black card stock with a papercutter and an adjustable craft-store circle cutter.
I recently had a set made for a med-large lens, the Laser cutter charged me about $200 including materials and shipping for an 11 piece set.

[Steven Tribe]

This is very much a home workshop/kitchen table top activity. I personally need about 5 sets (some with, and some without, a survivor stop) and will try and get started myself when the outside temperature gets up to +5 degrees C! Originally, waterhouse stops were turned on a lathe which made the provision of bevels easy. If there is interest, I could try document my attempts with as little and as cheap technology as possible? Card is necessay as a check for checking centrality and fit, including thickness. Will be using scrap brass plate and will try the ancient system of blackening the brass stops using chemicals.

[goamules]

I haven't tried wheelstops, but I've made waterhouse out of black annodized aluminum. You can cut it with a paper cutter to size too. I have a lot of alum because that's what I make my wetplates on.

[Steven Tribe]

The pitman manual "Lens work for Amateurs" by Henry Orford has a lucid description and illustrations of wheel diaphram work. Remember wheel stops need a precise click stop system otherwise they drift away from central postions in use.

[Ramiro Elena]

I imagine sets of waterhouse stops are dedicated so each lens will fit its own set?
If not, it would be cool to have traced stops or diagrams from which to make your own. Maybe someone in the forum would be willing to trace their own?

I'll have my wife try and make some, she's a jeweler and works with brass eventually.

[Steven Tribe]

I guessed you might come in here as the "This lens in my parents closet" needs/deserves a nice set of waterhouse! I think your wife (Elena?) would be impressed if you made a mock-up of what you want first. You have to measure the focal length very precisely. Detailed comparison with the standard 150mm you have would be a good idea. Image is perhaps 2.7% smaller than the standard 150mm, for instance. Thus the effective focal length is 97.3/100 x 150mm, that is 146mm approx.

Then you have to "get inside" the barrel and measure the diameter inside part of the mounting where the stops fit. Use a piece of cardboard which you gradually cut down until it just bridges the diameter. If this is 42mm then the starting point is 146/42 which F4.5 approximately. You can then fix the diameters of the holes needed to provide you with the range of F values you need (5.6, 8, 11, 16 etc). How many and which values you can use with a Petzval must come from someone with more experience than I!

Enough for now. I enclose a photo of two different style waterhouse stops. The early models were usually backened but later producers (with good reputations) gave up this process. The larger has a thickness of 1mm whilst the smaller are about 0.74mm.

[Steven Tribe]

Here is the image!

[Ramiro Elena]

Aha! You're right once again :) In fact my wife won't start until I tell her exactly what needs to be done.
The inner diameter of the barrel is 33m, so yes, f4.5 is the widest in this lens.
My first concern is if I need to make the part where the stop sits on the lens, straight or slightly rounded. A test with a straight 1mm aluminum piece seems to work and sit well.

Roughly, a 27mm hole will give me f5.5 (plus softening the edge with a file), a 19mm hole f7,8... etc?

I dig the wide aperture mode but I suspect it will limit my chances. A photo out the window this morning called for a 1/30 exposure and the Jim Galli shutter ended up overexposing by 2 stops!

[Steven Tribe]

Do I understand you correctly? There is no internal circular slot within the barrel, reducing the effective barrel diameter, directly under the waterhouse slot? If this is the case, does the slot cut in the barrel cover the whole barrel diameter?

[Ramiro Elena]

Yes, there is.
http://farm5.static.flickr.com/4017/4306808976_340fe7f486.jpg
Barrel=60mm, inside it 33mm.
From your picture, I guess they could be made to have a small angle in both edges.

[Steven Tribe]

Good good photo! They have restricted the aperture quite a lot. So you need to cut strips of thick paper the same width as the opening - or rather 2mm less, to allow a little play. Trim the bottom corners in a curve - like the posted photo. This should be a little sharper curve the the external curve on the barrel. Pop in the paper and check that there is no light leak. Mark the top of the paper (pencil) where it just reaches the top of the barrel. Take a little more of the curve of at the bottom to see if it comes further down next time. Trim until it doesn't drop further. If the card doesn't sink further down at the first - make a duplicate card which adds a bit on the end - and repeat the process.
More later. I am in the middle of a rebalsam job!

[eddie]

http://www.largeformatphotography.info/forum/showthread.php?t=43380&highlight=waterhouse

i will be sending my own stuff off soon.

i need a template or a stop so i can make them. calculating the hole is fine. draw the wide open opening on card stock. then you divide by the square root of 2 for the right sizes.

the thickness of the stop is critical as well.

they are made from carbon steel as brass will melt under the laser.

eddie

[Steven Tribe]

OK, back with non-sticky fingers and after an evening meal! As you see from the pictures there is a tab which sticks up from the end. Mine are about 17mm proud of the edge. Note that the whole top curve sticks out about 5mm above the barrel edge. I assume this is theoretical precaution to reduce light intrusion. So the top of the tab is 17 + 5 = 23mm above the top of the barrel.

When you have got a dummy papir/cardboard stop made and it always goes in and sits correctly then you find the central point. I think it is easiest to trace the outer circle with a long pencil. An alternative could be give a single "blast" with a mat black spray paint! Find the centre of this circle and make a template which shows the precise outline of the stops on a stable material. Make a mark on this template through the centre of the "coming" hole. This, and other Stops, must be centralised around this central point. So you need to bore a 1mm hole to mark the centre and be hole you can bore up through into the many rough made stops to fix the optical centre.