Experience with making Waterhouse Stops

Apart from re-doing balsam achromats, this is by far what I spend most of my renovation time with in the summer! 19th Century lenses loose their WHS even more often than their brass flanges. A complete set is very rare.

In general, I am a believer in black card replacements for the needlessly heavy duty brass stops - except for the larger apertures - say, F.4.5 on a F.3 Petzval. The card width is a bit narrow (fragile) in these cases. Of course, blank brass stops do have a sort of "age" - even when then were made yesterday!

Basically, my system is very basic! Keep the brass you are working on as large as possible for as long as possible - to maximise safety control. Cut the sides before doing holes. Form the base curve before holes. Mark with a pencil circle the maximum aperture without stops. Do the usual focal length, known F value, and diameter at maximum aperture measurements. The equation will not go up completely as the real aperture is influenced by the front lens. It is then a simple calculation to work out the necessary hole diameter to achieve, for example F.4.5 etc.

The hole borers I have attempted to use have never been reliable. Poor cutters for brass sheet, perhaps, more likely poor operations from my side! I have reverted to drilling a hole large enough to take the blade of a stick saw and then remove the brass inside the marked circle as close as possible. Final work is with a curved file.

I have never understood why Waterhouse stops traditionally have tabs which stick out of the slot. I have always left quite a section of the stop sticking out which gives plenty of space for lens information. It must also provide a better light seal, especialy when the slot in the barrel is unnecessarily wide as is sometimes the case with early lenses/projection lenses which have been modified for WHS.

I include some examples of this week's effort. Note I have a double stop using the same principle as wheel/rotary stops - not so difficult a geometric calculation, but it saves a bit on brass plate. The observant reader will note that I have given up the system of cutting out a central square out of the bottom of brass stops which fits over focussing track. Cutting this requires precision and I prefer filling up this gap with either electrical tape or black silicon.

Your experiences are also needed.

Not sure this helps, but this would be my approach to get the holes the size one wishes. The router bit has a pilot bearing on top and all you need is some sort of small router to run it. The hole (in piece of wood) should be the size of the actual opening desired....this can be done with large drill, jig saw + files. If one makes a mistake and cuts slightly too much, there is always a piece of tape to compensate (rescue ?) for that 0.001" :>). Anyway, the brass should be placed under the wood....and could be pre-drilled some to make this operation easier. I'd chisel out a thin piece to make sure the brass rests appropriately and does not rotate under the wood. I'd sandwitch all this with some type of clamps and make sure the whole contraption is tighten to something.

Les
Attachment 179187

Get a compass circle cutter from a good art supply store, and cut the circles into b/w sheet film... Then mount the pieces into plastic, card, thin metal etc frames that will slide into the lens slot... The circles you can cut can be very precise, the film stock is thin, and can be made without major tools (on your kitchen table)...

Have fun!!!

Steve K

Try rules dies with hammer or arbor press. I worked most of my life in a large gasket factory. We made holes in everything. Big and small. I tested the holes.

We had boxes of round inner or outer dies from 1/16" to 6" and made anything bigger from flat stock. I kept a set for retirement. Very handy. They would have discarded them as used.

http://www.wagnerdiesupply.com/Wagne...ngPunches.html

Tracy Storer of http://www.mammothcamera.com/ also makes custom WH stops.

Randy, thank for the link. Very helpful.

I make mine out of aluminum sheeting. I get the stuff for free from my day job (I work at a print shop). Then I go to my computer and use Adobe Illustrator to design the shape of the waterhouse stop to precision (which is really easy to do). Then I print that, and spray glue it (with 3M Super 77) to my aluminum sheet. From there I'll cut the outside dimensions out with tin snips, and sand down any sharp edges. Next I drill out the hole. For that I like to clamp the aluminum to a piece of scrap wood. Even better if you can sandwich it in between two pieces of scrap wood, but harder to position the drill to precisely align with your planned spot for the hole. Though, if you have a drill press and take the time to set it all up, it's pretty doable, and you get a very nice and clean hole. If you're doing a hole size that doesn't correspond with a drill bit, you just drill it with a slightly smaller drill bit than the size hole you want, and sand it down with a Dremel by hand. It's not hard to do because you have the template still glued to it. Just sand until the edge touches the printed line. Then, remove the paper, clean it up with some acetone, and spray paint it with some black paint (usually a primer that will adhere to metals) and when the paint dries, write the f-number on the tab that sticks out the top in white. With the exception of the paint drying, I can do a whole set in about two hours. Or make two sets in about three hours and have a backup set incase something happens to the first. I like to keep them in an empty case for a filter, which I have plenty of, because I use filter stacks now.