PDA

View Full Version : technical drawing of a lens barrel with Waterhouse stop slot...anyone got one?



pjd
25-Aug-2016, 23:12
I recently bought orphaned lens cells from a 15 1/2 inch series ii Velostigmat. The glass isn't in good condition, but I'm going to see if I can get a barrel made by a local machinist.

The machinist does work to spec, but isn't a photographic expert so he'll not know about lens flanges or a waterhouse slot. He also doesn't speak English, so I think it'll be good if I can take a diagram with specifications. I've been given some measurements to work with (thanks Mark), does anyone have a diagram of a lens barrel that I could adapt a bit? I don't think scale is important, I can add my own measurements and let it be known that it's not to scale. Drawing a barrel isn't so hard, but a diagram of a flange looks tricky to draw by hand without drafting equipment.

I have googled a bit without finding anything usable. Sorry if I've missed an obvious source.

Before someone suggests SK Grimes, I'm in another continent and the lens cells aren't in good enough condition to warrant that level of cost.

Thanks for reading!

Steven Tribe
26-Aug-2016, 03:28
CCHarrison's website has an extended section on Petzvals and shows a real photo of Alex's "1/2" lens. This is a lens cut down the middle exposing a cross section of lenses and brass. This gives a very good impression of the brass machining which is necessary to install the internal baffle/guide for Waterhouse stops.

Nodda Duma
26-Aug-2016, 06:01
Careful about providing a machinist napkin sketches. You may get lucky and get what you want, but you likely won't.

The machinist would expect a dimensional drawing rendered from a CAD model, with tolerances and finish information. If the machinist runs a CNC, he'd also prefer the CAD file. I'm guessing he machines by hand, tho.

If you have a buddy who's a mechanical engineer, he/she could do that fairly quick (like over a weekend) in Solidworks. But you'd want to give them something for their time.

Regarding finish: you'll want to blacken the inside of the barrel to mitigate stray light, so recommend you request aluminum (Type 6061) and black anodize finish, or brass with blackened interior finish.

Dan Fromm
26-Aug-2016, 07:32
Hmm. A black anodized smooth surface is quite shiny. One way to reduce reflections from the inside of the tube is to put baffles in. Another is to cut grooves in the tube's inner wall, then anodize. And another is to line the tube with flocking paper as is sold by Edmund Optics.

Bob Salomon
26-Aug-2016, 08:08
Hmm. A black anodized smooth surface is quite shiny. One way to reduce reflections from the inside of the tube is to put baffles in. Another is to cut grooves in the tube's inner wall, then anodize. And another is to line the tube with flocking paper as is sold by Edmund Optics.

What about this then? One is a 210 Apo Sironar N one is a 65 4.5 Grandagon N and the little one is a Rodagon.

154331

Dan Fromm
26-Aug-2016, 10:03
Its hard to tell, Bob, but the barrels' interiors seem to be a matte black. Smooth black anodized isn't matte black.

Bob Salomon
26-Aug-2016, 11:31
Its hard to tell, Bob, but the barrels' interiors seem to be a matte black. Smooth black anodized isn't matte black.

They are shiny metal where they are cut and you can't see what they are like inside the lens, but all visible interior parts visible are matte black.

Jac@stafford.net
26-Aug-2016, 11:43
Black flocking paper works perfectly well. It is entirely non-reflective dead-black. If it gets dusty in time, just pat it with the sticky side of masking tape to lift off the dust.

Regarding the guides for the Waterhouse stop: The machinist can cut two short lengths from the barrel work piece, then cut off a section in each so they clear the width of the Waterhouse slot. Then push them inside into place, one on each side of the slot. They will gently conform to the inside of the barrel. Good to go. Solder them in place if you like. An alternative is to just cut one length from the barrel workpiece, cut it so it will just slide into the barrel, then cut the Waterhouse stop through the barrel and the cut piece.

(The Waterhouse stop should be cut to about half the diameter of the barrel, and the stops should look like these (http://static.photo.net/attachments/classifieds/141/1415170-208301.jpg).) Credit: Wollaston (http://www.re-inventedphotoequip.com/Home.html)

Steven Tribe
26-Aug-2016, 12:18
Black flocking paper works perfectly well. It is entirely non-reflective dead-black. If it gets dusty in time, just pat it with the sticky side of masking tape to lift off the dust.

Regarding the guides for the Waterhouse stop: The machinist can cut two short lengths from the barrel work piece, then cut off a section in each so they clear the width of the Waterhouse slot. Then push them inside into place, one on each side of the slot. They will gently conform to the inside of the barrel. Good to go. Solder them in place if you like. An alternative is to just cut one length from the barrel workpiece, cut it so it will just slide into the barrel, then cut the Waterhouse stop through the barrel and the cut piece.

(The Waterhouse stop should be cut to about half the diameter of the barrel, and the stops should look like these (http://static.photo.net/attachments/classifieds/141/1415170-208301.jpg).) Credit: Wollaston (http://www.re-inventedphotoequip.com/Home.html)

This system (using barrel brass pieces) will only work if you are prepared to cut a Waterhouse slot almost half way through the barrel to allow full width entry of the WH stops. Cut the slot before you try and install one or a pair of baffles.

Nodda Duma
26-Aug-2016, 13:18
Hmm. A black anodized smooth surface is quite shiny. One way to reduce reflections from the inside of the tube is to put baffles in. Another is to cut grooves in the tube's inner wall, then anodize. And another is to line the tube with flocking paper as is sold by Edmund Optics.

Sorry, incorrect. A black anodized surface is as shiny as the finish callout allows it to be.

There's various ways to call it out but the specific callout I'm using on a recent lens barrel which received a satisfactorily flat black anodize finish is:

Finish: Hard Anodize per MIL-A-8625. Type III, Class 2, Color: Matte Black (or Lusterless Black)

But your comment does highlight that it's very easy to not get what you want if you don't think of the details.

Jac@stafford.net
26-Aug-2016, 13:32
This system (using barrel brass pieces) will only work if you are prepared to cut a Waterhouse slot almost half way through the barrel to allow full width entry of the WH stops. Cut the slot before you try and install one or a pair of baffles.

That is what I wrote. Make the stops as shown and baffles aren't necessary. The guides do the baffling.

pjd
26-Aug-2016, 19:08
I was thinking of flocking paper, whenever I get that far with it - Dan, thanks for mentioning Edmund Optics.

I'm still trying to get the beauty ring off the front cell to remove the limiting grub screw (for the diffusion control), as detailed in a post here by Mark Sawyer some while ago. Or rather, my brother in law is trying, he has access to a workshop and a lot more tools than I do.

I imagined I'd get it made with a flange at the back of the tube so it can be flush mounted on a 6x6 2D board - I have a packard mounted inside the front standard of my 2D. I now realize weight might be a problem mounted at the back of the tube. I'll think it over and will post back, I do appreciate the comments and information shared so far. Jac's suggestion for guides for the Waterhouse stop sounds simple and effective, I had been wondering how large a slot should be cut for stops.

Nodda Duma, the guys I've seen work out of small shops (I'm in Seoul). I was in a machine shop a month or two back, that machinist was doing lathe work manually but had a milling machine hooked up to a computer. I have no idea about CNC and CAD, don't think it will be viable. I'm still looking for my micrometer to try to figure out the threads!

To give a bit more context, the front cell is badly scratched, and the cells cost $25 with a Kodak no. 33 Anastigmat into the bargain. Shipping cost more than the bid - so I'm trying to do this on the cheap! On the other hand, I have a suspicion that even big scratches might not be such a disaster on such large cells - specially when a bit of fuzz focus is aimed at. Time will tell. I did mount the cells in a plastic pipe and held it in front of my camera. Looked ok, allowing for circumstances. Maybe I should paint that PVC tube black inside, bolt an arca swiss plate to the "barrel" and mount it on a little tripod ahead of the camera for a trial.

Dan Fromm
27-Aug-2016, 06:14
If you fill the scratches with india ink you'll lose a tiny bit of transmitted light and lose the flare they'd otherwise cause.

Jac@stafford.net
27-Aug-2016, 07:37
[...] the guys I've seen work out of small shops (I'm in Seoul). I was in a machine shop a month or two back, that machinist was doing lathe work manually but had a milling machine hooked up to a computer. I have no idea about CNC and CAD, don't think it will be viable. I'm still looking for my micrometer to try to figure out the threads!

Old school machinists are hard to find here (Minnesota, USA). They are usually far more resourceful than CAD/CAM machine operators who call themselves machinists today.

Forget the micrometer. Google "thread gauge", and choose a modestly priced one. It will last a life-time.

Best of luck,
Jac

LabRat
27-Aug-2016, 08:19
If you just want to test jig these cells out, and even sometimes have a OK working lens barrel, go to your local plumbing supply house and see if they have any brass/copper/ABS/PVC fittings or pipe that is close to size for a barrel... Sometimes you can find an O-ring or rubber coupler that will allow a friction fit of cells to tube, or form threads using epoxy + thread release on the cells, or have someone cut the threads, etc... You might get lucky... And coupling flanges could hold the cells, or for the lensboard mounting... Plastics wouldn't be too hard to cut/slot at home, and you will have a chance to decide if this lens is worth following through on...

For the stops, get a compass cutter from a good art store, and cut circles out of film, foil, beer cans, sheet stock, paper, card stock, whatever, and insert into slot on barrel...

Would be fun for DIY...

Steve K

Jac@stafford.net
27-Aug-2016, 08:22
[... snip good stuff ...]

For the stops, get a compass cutter from a good art store, and cut circles out of film, foil, beer cans, sheet stock, paper, card stock, whatever, and insert into slot on barrel...

He could also experiment with placing the stop in front or behind the lens.

Fr. Mark
27-Aug-2016, 08:35
Depending on the sizes of the pieces, I've found that used up gift cards painted flat black make good waterhouse stops, those I drilled an extra hole in and threaded a piece of string through them. I've even made conversion charts to use the same stops on several focal length lenses. Likewise non-corrugated cardboard painted black can work, but most any flat material you can cut holes in will work. I've made mine to go in front of both meniscus lenses and also a cooke triplet so I did not need to machine a slot in a huge lens barrel. I took some sheet cardboard (sort of like comes in the middle of dress shirts bought new in the US) made it into a cylinder that slips over the lens barrel (about 5" dia. in my case), made inserts for that cylinder out of foam core that I painted black, though in the US you can buy it black to start with, but that would've meant a trip to the store.... Three layers of foam core: two outer ones are ring shaped and give f8 (down from f3.6) the middle one coincides with the slot and is U shaped to hold the waterhouse stop. The stops are more of the cardboard painted flat black and give f11, 16, 22, 32, 45, and 64---that's three pieces of cardboard---they are double ended so I have fewer pieces to keep track of. I also made one with no holes to function as a "shutter" it is a little longer so I can grab it and not the stop when I want to open the aperture. None of this is as precise as what can be done in a machine shop, no, not even close, but it will give more control over images and can be made with glue/gaff tape/and an x-acto knife for almost no money into it.

el french
27-Aug-2016, 12:17
Protostar flocking works well: http://www.fpi-protostar.com/hitack.htm

Steven Tribe
28-Aug-2016, 03:26
Depending on the sizes of the pieces, I've found that used up gift cards painted flat black make good waterhouse stops, those I drilled an extra hole in and threaded a piece of string through them. I've even made conversion charts to use the same stops on several focal length lenses. Likewise non-corrugated cardboard painted black can work, but most any flat material you can cut holes in will work. I've made mine to go in front of both meniscus lenses and also a cooke triplet so I did not need to machine a slot in a huge lens barrel. I took some sheet cardboard (sort of like comes in the middle of dress shirts bought new in the US) made it into a cylinder that slips over the lens barrel (about 5" dia. in my case), made inserts for that cylinder out of foam core that I painted black, though in the US you can buy it black to start with, but that would've meant a trip to the store.... Three layers of foam core: two outer ones are ring shaped and give f8 (down from f3.6) the middle one coincides with the slot and is U shaped to hold the waterhouse stop. The stops are more of the cardboard painted flat black and give f11, 16, 22, 32, 45, and 64---that's three pieces of cardboard---they are double ended so I have fewer pieces to keep track of. I also made one with no holes to function as a "shutter" it is a little longer so I can grab it and not the stop when I want to open the aperture. None of this is as precise as what can be done in a machine shop, no, not even close, but it will give more control over images and can be made with glue/gaff tape/and an x-acto knife for almost no money into it.

Super advice!
I have made countless sets of brass Waterhouse stops. I gave up making these when I purchased a Euryskop where the owner had the original brass set, but had made a duplicate set in quality black card for everyday use! Since then I have stuck to card WHS manufacture. Black card is very a standard and cheap item in almost all hobby shops.
Machine working of brass presents far more safety issues than a sharp knife.

pjd
28-Aug-2016, 05:25
Indian ink...looking it up I realize I've probably got the right thing at home in inkstick form, used for making Chinese characters with a brush. I'll give it a go!

The tip from Jac about cutting a section from the barrel, shortening it and using it to make guides for Waterhouse stops sounds good. I had to cut a section off to get the correct barrel length, that section was useful to centre the rear cell in the barrel. The tube I got is a bit larger than would be ideal, the next size smaller was too small. I've fixed the rear cell in place and have mounted the tube on a board using L brackets from an ironmonger store (same place I got the tube). Quite fortunately the bolts through the barrel holding it to the L brackets also hold the cell in place. I should take a photo. I need to get a bit more tube to cut down for waterhouse stop guides / baffles, maybe tomorrow if I get chance.

About Waterhouse stops, that's probably the bit I'm most confident with - I recently made some paper stops to fit in the front of an Imagon (bought with no tea strainers). I bought an adjustable paper circle cutter, a bit fiddly but it works well.

I've received the front cell back, with the beauty ring removed - at the cost of a couple of big scratches, right through the Wollensak lettering! It's now an ugly ring, matching the front cell. I have no idea what tool was used to do that...maybe better not to know some things. It doesn't look like there are any new scratches in the front cell at least. Removing the limiting screw was easy, so the diffusion control now goes from zero to extremely diffuse like in the old thread by Mark Sawyer here.

Drew Bedo
28-Aug-2016, 05:32
Wasn't there a modern production run of a Petzval design a couple of years ago?

Would there be anything relevant to this project from that?

Jac@stafford.net
28-Aug-2016, 13:19
Not really, Drew. The Lomo Petvals (three or four models) uses a complex CNC configuration. All that is needed for the project here is simplicity.

Bob Salomon
28-Aug-2016, 14:43
Wasn't there a modern production run of a Petzval design a couple of years ago?

Would there be anything relevant to this project from that?
Stills, from Lomo, I have one and I believe that they may have introduced a second focal length.

pjd
31-Aug-2016, 08:36
Having asked for help and advice, and having received, it's only fair to give up update on far I've gone - or how bad it looks!

154460

Here's an image of the worst part of the scratches to the front cell - haven't yet tried the Indian ink yet.

154461

The prototype barrel as it is so far (I painted the outside of the barrel black as my wife laughed when she saw it, the pipe was made by Hyundai group). The L brackets work well even though they look clumsy.

154462

The circle cutter I use for Imagon barrel stops and now Waterhouse stops. It's easy to use as a smaller circle can be cut perfectly aligned within a larger one - just lift the cutter after making the larger circle cut and adjust the arm length.

154463

Inside the barrel with front cell removed.

pjd
31-Aug-2016, 08:54
154464

Back of the lens board. The rear cell is firm against the board centred in the middle of the barrel, so that should be fairly well aligned. The front cell is more difficult. Right now that's just shoved into the barrel and held in place by friction. It's difficult to fix that front cell securely in place partly because I need to leave the variable diffusion ring free to rotate (clamping it at the front to prevent the risk of it falling out would otherwise be tempting).

Jac's suggestion about cutting a section of barrel off, splitting it and fitting it internally for Waterhouse guides was a good one. So good that I took it a stage further, and fitted an extra section internally. The barrel is twice as thick in some parts because of that, and the Waterhouse slot didn't need to be cut 50% of the diameter of the outer bit of pipe as a result.

The pros and cons of this as I see it so far:

Pros
It's been very cheap indeed.
It's light (in weight)
It works, so far as I've tested it (it hasn't left the basement yet)
It might be useful to show to a machinist to give them a better idea of what I want made

Cons
A machinist might well take one look and dismiss me as a passing idiot
Still not quite sure how to fix that front cell in place
Cell alignment must be a bit out
My wife was at first suspicious of why I was spending so much time in the basement; having seen the results, she's now just amused.

Not having tried the lens with film (or even outdoors on gg) yet, I'm not sure how much of a problem poor cell alignment will be. I'm not expecting to use it as a sharp lens, so it might not be a big problem. Writing this it occurs to me that it might be worth trying the lens with the front cell deliberately fitted a little off centre just to see how it goes.

With diffusion ring turned out it gets very fuzzy indeed. Focal length is reduced that way.

Another thing I didn't decide is whether to leave the barrel fairly open or to add a permanent stop (baffle?) replicating the wide open aperture of the factory produced lens. Without a stop this barrel is about 100mm in diameter, the original aperture would have been about 87mm wide open.

Thanks for all comments and suggestions so far.

pjd
31-Aug-2016, 08:57
Also, thanks to Mark Sawyer for very patiently and helpfully sharing information by PM - he's helped create a monster of sorts!

Fr. Mark
31-Aug-2016, 18:05
I have a fondness for this sort of monster. Keep going!

Steven Tribe
1-Sep-2016, 01:04
This is the exactly similarly procedure applied to orphaned lens cells from a "front turn" Dallmeyer 3B - just in Brass. Using the same barrel brass as guide for the WHS meant that the maximum speed was noticeably higher when compared with another 3B. This is even more the case with this version of the 3B which had a bulky iris. The WH slot went almost halfway through the barrel.

pjd
1-Sep-2016, 04:36
This is the exactly similarly procedure applied to orphaned lens cells from a "front turn" Dallmeyer 3B - just in Brass. Using the same barrel brass as guide for the WHS meant that the maximum speed was noticeably higher when compared with another 3B. This is even more the case with this version of the 3B which had a bulky iris. The WH slot went almost halfway through the barrel.

The same procedure with rather more handsome results ;)

Maybe I'll just leave the barrel a bit wider open than original and see how it goes.

Steven Tribe
5-Sep-2016, 01:15
Here is photo of the first system used to hold WH stops in the barrel. It is more visable on this lens than usual as it is a convertible Petzval where the barrel can be split in two exactly there where the WH slot is.
THere is a circular piece with 2 extra straight-edged pieces to guide the brass stops down. The extra pieces has tiny rivets to hold them in place. The edges have a narrow rebate (2mm) to catch the brass stops. This is from a late 1850's Hermagis, but was continued for many Petzvals for a long period.