Next I've used one of these fat and hard (not bendable) aluminium things.
The round shape at the end and the sidewalk source make obvious the previous use of the thing : LASER lab high grade stuff.
It's going to be that one, 8 mm thick nearly 50 mm wide and... long enough.
So nice chips, drilling 7,5 mm holes as I don't have the 7,7 mm needed for the 3/8 " threads.
Taping en place, just after drilling, with the help of the drill press tu be sure of the perpendicularity of the taraud (taping tool).
I must use a small enough tourne à gauche (tap wrench) to be able to turn without touching the drill press's column.
Those 3 holes have been very hard to tap, the tool is nearly new and a very good quality one, but I figured out afterwards that the 7,5 mm drill bit used was in fact a 7,1 mm bit ! If 2 mm isn't a lot because aluminium, even the harder one, is a soft metal, 6 mm less...
There are 3 holes because after trying to insert the screws in the first 2 holes, I realized that they where too close : the nut on the photographic screws, which is in charge of the final tightening, is very big, to give fingers a good grip.
Drilling 2,3 mm holes for M 3 screws en place : there are 5 holes that need to be perfectly aligned, It's close to the edge both parts. It's clamped on the other side.
Taping M 3 threads, for small diameter like that, I prefer use a smaller tourne à gauche (tap wrench) : it has less torque and the taping tools are hard, but sometimes, they tend to brake when too much torque is applied, and a broken tool is not very useful, and when it's broken, the remaining part in the hole is impossible to take away : if it broke, it's stuck inside !
That's a broken M 3 brass screw, the ten holes where nearly perfectly aligned, nearly.
It was easy to take away, and enlarge the hole with a very small round file also, but I coud have done it before : faut pas forcer (do not force), never !
The Sinar bench tube fits alright.
I need 2 pieces of 3 mm thick PVC of the same size, to block the Sinar bench tube in place.
Starting the cutting with an lathe tool, finishing with a metal saw.
Bonded with strong double sided adhesive tape, It fits perfectly, with some little strength needed at inserting.
It's that stainless steel rod on the Sinar bench tube that's tightly held in between the 2 PVC parts.
Drilling to have no more possible movement, with 3 screws on each side.
That's the Sinar tightening system I'm trying to reproduce, It's an injection molded very strong plastic.
The bench steel rod fits tightly into the central groove (just like in my project), and the closing and tightening mechanism is very simple, elegant and efficient, but too difficult to exactly and simply replicate.
Same thing closed, the small screw on the left tights perfectly the bench with a very intuitive and simple action.
I first wanted to use some aluminium to do the job, but searching for an appropriate shape in all the drawers, I found those very funky scaffold attaching parts. They have the right shape and size and it'll be much faster than aluminium cutting, drilling, taping, screwing...
It'll give a kind of touche rustique (rustic touch) to the project.
Rustic, OK, but rust, NO.
I had to remake the M8 threads, clogged with rust and green paint, and there's not enough space tu use the die holding tool,
I've used a pince-étau (vise-grip) instead.
Drilling and taping the M 6 tightening screw threads.
That aluminium tube is exactly the same diameter as the Sinar bench tube, it'l be used as a mold to shape 3 mm thick PVC.
It's not hot enough to bend easily so I've also used a hot air gun, with the set up on the V, and leather gloves not to burn my hands.
Very satisfied with the molding, the edge is a little wavy, but the part fits perfectly.
In fact I didn't need to bend so much material as the final part is small.
That was the last time for this very nice 2 mm drill bit, as it broke afterwards.
Taping M 2,5 threads, last time also for that taping tool as it broke also, some days, there are troubles.
And once again, very happy to find those M 2,5 stainless steel screws I thought I'd never need.
The V has a good weight to be used for gluing
The 2 final parts.
In position.
It works perfectly, the Sinar bench tube is perfectly tightly held.
Some plastic tubing, recovered in an abandoned warehouse, very hard and not easy to cut or flatten : beer pump tubing system.
In position, with the additional 600 mm bench (that's how its going to be used).
Rear view. The thing must be under the camera holding plate of the tripod's head to enable vertical movements of the Sinar system. The lever is very important and it needs a tripod to be positioned under the bench to hold the weight, but it's going to much more convenient than the entire Sinar camera on a tripod and the lens on another one like in the first test. And it makes a perfect alignment of the lens with the back very simple.
I need a board at the rear end of the thing, to hold a digital camera so I can try to calibrate the speed of the shutter.
It's bigger than the Sinar board, because it must fit the below size
Cutting with the jig saw.
This completely worn lens will give an important mechanical part.
Very happy to have the exact 46 mm hole saw, no filing needed, it'll be clean.
Drilling the 2 mm holes, the original screws are too short, hopefully I had some nice 10 mm long M 2 stainless steel screws, and the head fits perfectly in the baïonette's holes.
Nearly ready.
That beautiful purple bungee is quite strong and will have to stand important stress, so il must be firmly held in position, those M 6 pythons are going to be perfect.
Using 5 mm thick Dibond, the same material as the blade, it's going to be the same thickness and that what's needed.
Here's the second cutting cession with a metal lathe tool with sharp flat edge.
Searching for a thin strong metal around the shop, this is a very good material, a 35 mm film canister is very smooth, super easy to shape and does not wear, and it's mat black painted on the opposite side, which'll be perfect for the task.
I need it flat, so bending on an edge makes it easier to flatten with the proper soft and light hammer.
The back of the flap is mat black and to avoid light leaks, it's much better than anything.
I needed two film canisters to have the good length.
It's bonded with strong double sided tape.
And a small piece of mat black aluminium tape that's used for lightening to seal the two film cans in the middle.
Getting ready to drill the 2 holes. The film can's so soft that it's imperative to have a good mark, otherwise, the drill bit slips on the surface, scratching all around without drilling.
Been very careful to have perfect alignment without any movement of the parts by clamping.
And it's good, but not perfect at all for the alignment, and the nut takes too much space.
Now the nut will no more bother, as it will have enough place to hide.
Much better.
Some other pieces of that fantastic Epson yellow (T6364) cartridge spring are cut.
Now the flap must be adjusted not to obstruct the path of light in front of the lens. Tracing with the compas and cut with scissors.
That 15 mm more or less square PMMA will be easier to drill than the 6 mm one, it slips well on the polished sides and has the thickness needed.
One more horrible lace curtain 3 x 12 x 600 mm brass rod and a piece of 1,5 mm thick brass plate are the next materials.
It's easy to cut if the thing you want to cut is strongly held in position, the valet and a piece of worn sandpaper to prevent slipping, a soft wood martyr to have enough angle and avoid to cut the edge of the bench.
Filling in the small vise... Hey, I know that guy !
Tapping the rod.
Cutting some other brass plate, fond a small box full of those at a vide grenier (garage sale), some with a central hole : some door ornament.
I was tired, it was the end of the day, and the screw that goes thru the the brass support and the PMMA, on the right, wouldn't pass thru the rear part of the brass.
It had been drilled en place, to avoid that exact trouble, the first one on the left got through easily but le left one didn't wanted.
After maybe ten minutes of unsuccessful tries, I finally decided to drill again, and... holding firmly the part in place with the left hand and drilling with the right one, I successfully managed to insert the drill bit, a 3 mm metal kind, under a nail of my left hand, I have good reflexes as I stopped drilling immediately, hopefully, it wasn't a 3 points wood drill, but a "softer" metal one.
So when tired, a good option is to stop, have a drink, and relax.
Drilling en place to be sure the holes will be at the same position up and down.
The screw on top left holds the blade, but it's a little too much down, too close from the flap.
Same thing from another viewing angle.
Drilling and taping to ad a little piece of aluminium to have the right length, just a few millimeters.
Those two holes are the worst accurate job until now, the piece of aluminium isn't strait at all, never mind, it's ugly, but it should work.
Ugly, but it works.
Now I have to do something with the flap holding screws, the threads are acting like a file when moving thru the holes, it's noisy and not very even, it doesn't slip well and I want a good glide.
So the drill press is going to be used as a metal lathe : the screw is held in the mandrel and the head is maintained down in the vise in a rotating position with the help of a small bearing with the nut tightly screwed.
With the help of a lathe tool, a file and sand paper, the screw is no more threaded between both ends, it takes time and its tiering to hold the tool by hand, vibrations are important.
Of course, the top threads must be passed thru the appropriate fillière (die) to repair the little damages made by the tight closing of the mandrel.
Perfect !
It'll slip easily, fast and even after giving the second screw the same treatment.
Those 40 mm long M 3 screw , and a few of these 1,5 mm thick small brass things just behind are going to be involved in the next step.
Some washers, to adjust the height and springs to hold the little brass part in place.
The small brass plates are held down with the springs, the brass is an auto lubricant material so I'm hopeful for a good glide.
These little brass parts could have been some electrical parts, the thing on the top right, a curtain slider ,is finally not going to be used this time.
The washers where only for testing the height, now I know I need a 6 mm square shape. A first try with PMMA gave a very good idea of the brittleness of that material in such a small size, a drop from woodfloor oak has exactly the right size and is going to be stronger and durable.
Very good !
The hole on these small brass part is at the exact place to prevent it from turning around the screws.
A little fine grain sanding, and some paraffin will help the sliding.
Fantastic glide, you can't see it on a still picture, but it slips quite well.
I really didn't need to cut that side all the length, but I've liked the way of doing it for the previous cut and that aluminium is less thick and very easy to work with.
Only 4 parts to hold the rolling mechanism that will (I hope so) guide the blade in a smooth and regular motion in front of the lens.
Some more of the 2 mm thick 3 cm square tube are cut.
The roller must be exactly at the right place to be able to guide the H profile.
Adjustment was first though to be made with some washers. But the 6 mm diameter are too big for the place where I'd like to put them.
And in one of the spring boxes I found those very nice long springs, recovered from Epson yellow ink cartridges (when the printer, a big one, says it's empty, you can still hear the liquid remaining so I decided to recover all the ink I could from "finished" cartridges so the students could use them as paint, or whatever), and they have some kind of a problem with the yellow because only that cartridge has that very long spring inside.
They're very good quality springs as Epson belongs to Seiko that have a long story with springs.
Easy to cut, they fit perfectly on both sides of the roller to keep it straight in line (even if the hole isn't perfectly aligned on both sides, it works all right.
It looks like that from the low side of the system, the big spring gives just the good tension to have a smooth and regular glide of the blade.
Closer view, some more springs have been used, up and down the black screw, to finalize the alignment.
The final touch : a homemade goupille (pin ?), it's been very hard to make with 1 mm (I don't want to try to know what gauge it is) piano string, but it won't fail.
Now the blade must be cut, with a 90 ° angle from that first cut.
Continuing with a small file. I wanted to cut all the aluminium on the right, but only the top part of the left.
The Araldite epoxy didn't adhere at all on the PVC, it was quite easy to take away.
It was also not too hard to rip it off the metal, but the bond was here.
Here is the beginning of the building of a flap that will prevent light leaks from under the blade. I discovered very recently on HAD (https://hackaday.com/2022/03/11/making-a-locket-from-a-coin/) that these compas are made to not only trace a circle, but could help you do a lot of other markings, the metal is very hard and it's super sharpened : the tips are very pointy.
It's going to be 5 mm thick Dibond, a drop from picture laminating, 600 x 190 mm, its lighter than metal, rigid and flat. The size of the lens has been traced but it'll have a square opening.
Very easy to cut with a 2 mm tool, but not at a too fast speed, I don't want to have the smell of burned PVC in my workshop.
Doesn't go straight very easily, needs clamping.
I really love using those metal parallel jaws clamps, they're very strong, not always very fast to adjust ((when you have the screws on top of the left one, it takes time to go down !), but very strong.
Ok, it fits perfectly, but the 1 centimeter left on each sides of the opening are not enough to make it strong and flat for a long time : it must be reinforced.
That complicated double H aluminium profile will be perfect when cleaned of that strong double sided adhesive tape (it had been used behind some pictures, laminated on Dibond, to strengthen the flatness... and it's going to have exactly the same purpose, on the same material, when recycled.
And please stop crying and screaming, this wood chisel has been found in the street, just out the door, and the blade was quite worn, and I have another one which has the same width and a good Swedish blade, so after a little sharpening, it's very useful for that kind of heavy duty work.
But first, a small sliding rig must be build.
so it can be cut in two halves, in the middle.
Same 2 mm tool, the fastest possible speed on the drill (around 2500 RPM only), and patience, but patience is a skill a photographer must excel at, we're experts in time.
Nearly finished ! It took some time though.
Good, but now it's too thick ! those 2 millimeters added to the Dibond where not in the program, and it will no more slide.
So the Dibond has been routed, to have the exact thickness needed for the blade to slide.
Gluing with Araldite epoxy and a heavy weight to hold in place.
And... it fits perfectly, tight, much too tight, it does not slip easily at all. The H profile has an 5 mm opening, the rack profile has a 5 mm thickness, and the adjustment is in a too high number on the tolerance scale, it won't work like that !
Trying to get some space with the help of fine grain sand paper.
A lot of dust but...
Too tight ! I have to find another solution for the still part of the mechanism as the blade is very satisfying.
Here nearly finished with the moving blind...
Once again too tight ! I had to use that little wood hammer to make it slide back... needs some sanding here too.
block all the light except where there will be the shutter mechanism opening
hold the shutter blade in shut position
liberate the shutter blade
stop the shutter blade in a shut position again
It will have round openings, the one touching the lens must fit precisely to avoid any light leaks, the front one must be bigger not to block any ray of light in the optical path.
I'm getting used to that, with a 6 mm tool and, for the first time, at fast speed (there are gears and a belt I can change in the drill), little more than 2500 RPM, not really a router, but it's good for me.
Once again, it's the limit of the size I can do without touching the drill's column with the corners when turning it.
Magnifique !
The frames are made in 9 mm thick Betonex plywood, they are going to be bond with two 220 mm long aluminium 2 mm thick square tubes. I'm going to use 2 of those gold anodized aluminium profiles (same sidewalk find), they have a V shape, but the outer angle is not sharp, it's rounded so I had a lot of troubles to drill them in position (to be sure the holes will be at the same place on both elements to assemble, I prefer this method when there is going to be more than 2 holes). It's some rack holding side bars, must be very expensive ! Drilling, and taping for M 3 screws . It fits perfectly and I must be very careful to mark the center of the two holes that will make the junction between the lens and the shutter. Same view from the front. Another autoportrait, the pink cast on the top right is radiosity, a reflection of the light on my pink shirt : don't take me as an assistant when taking photography, as I always wear very colored things that give an ignoble color cast at everything around me ;o).
The two holes perfectly drilled, but not thru the whole board : the blade of the shutter is going to slide on the other side and the surface must be perfect. The shutter will be locked in position with the help of those two things, nearly used here in their original purpose : parts of window or door closing system. They come with a plastic part (the black thing just in the center) that can be conveniently put inside the part to change the sliding path, and the sliding thing can be a rod or a flat bar.The height must be adjusted with some pieces of worn sandpaper : I don't want to have the 3,5 x 12 wood screw tip on the opposite side. Really happy to have big jaws on my wood bench !That flat brass bar fits perfectly in the slider.A small piece of drywall galvanized steel frame profile is easily shaped with appropriate pliers and the vise. From the side it's possible to see the inner plastic shape that's exactly th right size. Its an interesting part as it can be used in both directions (you can see the other whole at 90 °) and the plastic thing can also be used on both ways, with a choice of the type of thing sliding : I choose a flat bar, but could have used a cylindrical shape as there's a round entrance too.
But for the spring type action needed here, a flat bar is perfect.
Here complete with two 4 mm M 3 screws and two little springs for the tension.
Here in action for the first time, it fits perfectly and doesn't allow any movement.
Other view of under the lens.
I'm very satisfied every time I can use a spring in anything, and this particular mechanism needed exactly that : I don't want to have to use any tools when taking a picture, so everything must be easy to use, fast, and not too many parts I could loose or forget.
It fits perfectly well and it's firmly attached to the bottom of the lens, but I think my 60 cm long guillotine blade will have a serious speed (I hope so) and the shutter must be secured from the top too, so those 3 mm thick black anodized aluminium sheets (plates ?) are going to be perfect, attached to the top of shutter with the L 2 mm thick aluminium profile.
I first thought those plates could be bended to have the needed 90 ° angle, but after a small try, they're un-bendable, for only 3 mm thickness, I've never met such a hard aluminium (but I'm not in the aviation business).
It's going to be assembled with (cheap) steel hinges, so the thing is "foldable" and easier to transport and store.
Then I was very happy to have those awkward stainless steel small screws around (I once brought in a garage sale 2 full bags of those, in bulk, from M 2 , some M 2,5, some M 3, M4 and M5, in very various length and head shape, I took hours, days to sort them all, and when finishing, with the smallest ones, I was thinking that I'd never use those 4 mm long M 2,5 screws...).
Because to be able to completely close the hinges, the head of the M 3 screws are too big, so I needed some 4 mm long M 2,5 screws because their head is flatter than the M 3 (in fact they're all flat, but the conical part under the head, the counter sink, isn't the same diameter, so the smaller screw penetrates a little more in the hole).
So happy I was to have those M 2,5 screws in their small drawers, and even happier when I found I had the necessary M 2,5 taping tool !
M 3 screws on the right horizontal position, M 2,5 screws vertical, not at all the same thickness when closed.
Its good to have various sizes of tourne à gauche (taping tool), of course, the big one have a lot of torque, but it's for minimum M 4 threads, it can't hold the smaller tools, and also its a little too big to be used under the drill press (witch is the very best method to have perfect job : drill and tap without moving the part, and using the drill press to be perfectly perpendicular to the hole while giving strength to the tool).
The brass screws are fixed to the moving part (the black anodized things on top) and they enter in holes directly, without screwing, as the holes are just big enough : I don't want to need any tool when taking a picture.
The fixture isn't very strong as it's possible to take it easily, but it'll have a sturdier system.
First try of the guillotine with a black 5 mm cardboard that was exactly the right width : it slips perfectly !
I've always used a camera with a built-in shutter, analog 35 mm, 120 and 4 x 5 " cameras or lenses all have a system to close the optical path of the light, and to open it fast and to close it fast again.
Twenty first century films are photosensitive, very, it does not needs much light to have it overexposed, completely burned, this is why the minimal aperture of f/16 isn't much, so I need to have light coming to the film for a small amont of time.
Photographers are not so good at math, they use the second, and half of it, and again, again and again, half of the time, and when the next division is going to give a too complicated following, they round the number.
The common shutter speed scale goes like : 1 second, 1/2 s., and well, everybody knows it's a question of seconds, and fractions of a second, and there's not so much place to write on a camera or a lens, so it continues like : 1/4, 1/8, 1/15 (first rounding), 1/30, 1/60, 1/125 (second rounding) and continuing, but I will not need faster, and I'm sure the faster, the more difficult to achieve with my poor knowledges of mechanical engineering.
So I've asked internet about shutters and found that fantastic page :
In fact, I was thinking of a more complicated thing, a leaf shutter, just like the Copal/Sinar one, but Sara, a colleague, through that the elastic string system looked very convenient and simple to build, so it will be my first choice.
Of course, my first idea isn't abandoned, as soon as I find the .stl files for that kind of thing
another colleague, Christophe, has the printer and the will to try to print it, he likes experimenting things, and it's a good thing because he's in charge of the research lab ;o). We'll just have to make it big, as the rear element of the beast has a diameter of 129 mm !
Yep, I'm that kind of photographer, slides, color transparencies is my practice, sometime developed like this, in positive E-6 chemicals, and sometimes, more often, developed in C-41 chemicals, to get a weird color negative.
And what I was fearing has happened : the first 10 pictures, taken with too much light for the f/16 aperture, are completely overexposed and blurry.
I augmented the contrast when developing the raw file, but there's not much to see.
Blurry and overexposed.
I should be more careful with the below, but that picture points a suspected trouble : the inner color of the below isn't as black as the outside, It's bluish, dark, but not black, I need to paint it black (as some other things to avoid parasitic reflections).
Ok, the ones shot later are much better, still a trouble with the below, but the lens looks good, event if it's a little blurry due to the opening of the film holder blind, the exposure is good and the details look sharp.
A 100 % crop of the previous image (this is not a real digitalisation of the picture, just a handheld shot) gives me good feeling about the results, the lights are not too burned, and it seems to have a good micro contrast, looking at it with a good magnifier is not the same sensation than on screen, its more detailed.
Well, I can continue the experiment, it is not a « cul de bouteille » (French for very bad optic), but now, I need to build a shutter.
It's good to have an elevator to go to the fifth floor when so much things are needed to take a picture :
Two heavy duty tripods with solid heads (and therefore heavy), the lens, the big aluminium case for the camera, accessories and films, between 30 and 50 kilograms.
I think the day I'll go for a photographic ride on my recumbent bicycle, with all that stuff in the side luggages and in the trailer, I'll need some very good motivation, and legs...
The below is too long for infinite focus, it'll need some rods to hold it strait.
It's not easy at all to have an idea of where exactly the thing is aiming, an external simple viewfinder is necessary for the first adjustment of the frame, anyway, there's not so much room for those big tripods on the terrace, if I want to shoot in that direction (with the sun on my back), I won't have so many framing options : the two tripods must be perfectly in alignement to have the lens board and the film parallels so the pictures are in focus all around the frame.
I know this is not at all informative of what I was trying to shoot, but I think it's a nice autoportrait (I never take selfies ;o).
Anyway, this is analog photography, you can't see the result instantaneously, the sheet films must be processed in various toxic liquids at the right temperature, the good order and for a precise duration, and washed, and dried before being able to see something.
Photographers material is photon, a very weird thing, the more you know about photons, the more you know you know nothing, and our principal tool, to shape that very fast energy phenomenon is time : photographers are experts in time.
There was a lot of light and without any shutter, I wasn't sure to have anything on the sheet films more than a blurry too big amount of light, blurry because the exposure was done by removing the volet (blind ?) of the film holder, and putting it back in place is giving a little movement to the camera.
A little bit later, thru the kitchen window, there's less light, I can stop the exposure without movement with the help of a black coat, more shots, maybe a better chance to get an idea of what that lens can do.
It's not convenient at all in the workshop, those two big tripods have an enormous envergure, one is needed for the lens, the other one for the camera (the stripped below in the center).
So, can I see something on the Fresnel lens of the camera ?
After trying to focus on something I decided to open the window, not so clean, and...
Fantastic !
That's about 12 meters away from the film position.
Looks sharp, but with blur on the highlights, typical of an uncoated lens mid XX century, not really GOOD, but certainly interesting.
But, wait a minute, why is that image round ?
A big lens like that must have an image circle far bigger than the 4 x 5 inches of the camera fresnel viewfinder lens...
That's what I can see thru the window, and it's not round shaped.
Ok, there's a rond thing in the camera.
The marvelous Copal/Sinar shutter has a round opening of something between 8 and 9 centimeters, more than enough for the average large format lens, but quite too small for this one.
Yes, I like it like that ! (the viewing with a large format camera is upside down).
[zit] Olivier Gade
Very satisfied with the molding, the edge is a little wavy, but the part fits perfectly.
That was the last time for this very nice 2 mm drill bit, as it broke afterwards.
And once again, very happy to find those M 2,5 stainless steel screws I thought I'd never need.
The V has a good weight to be used for gluing
The 2 final parts.
In position.
It works perfectly, the Sinar bench tube is perfectly tightly held.
Some plastic tubing, recovered in an abandoned warehouse, very hard and not easy to cut or flatten : beer pump tubing system. 
In position, with the additional 600 mm bench (that's how its going to be used).
Rear view.
Those 40 mm long M 3 screw , and a few of these 1,5 mm thick small brass things just behind are going to be involved in the next step.
Only 4 parts to hold the rolling mechanism that will (I hope so) guide the blade in a smooth and regular motion in front of the lens.
It's going to be 5 mm thick Dibond, a drop from picture laminating, 600 x 190 mm, its lighter than metal, rigid and flat. The size of the lens has been traced but it'll have a square opening.
Drilling, and taping for M 3 screws .
It fits perfectly and I must be very careful to mark the center of the two holes that will make the junction between the lens and the shutter.
Same view from the front.
Another autoportrait, the pink cast on the top right is radiosity, a reflection of the light on my pink shirt : don't take me as an assistant when taking photography, as I always wear very colored things that give an ignoble color cast at everything around me ;o).
The height must be adjusted with some pieces of worn sandpaper : I don't want to have the 3,5 x 12 wood screw tip on the opposite side.
A small piece of drywall galvanized steel frame profile is easily shaped with appropriate pliers and the vise.
From the side it's possible to see the inner plastic shape that's exactly th right size. Its an interesting part as it can be used in both directions (you can see the other whole at 90 °) and the plastic thing can also be used on both ways, with a choice of the type of thing sliding : I choose a flat bar, but could have used a cylindrical shape as there's a round entrance too.
Here complete with two 4 mm M 3 screws and two little springs for the tension.
