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How to make an iris diaphragm? Answered

Hey there!
I've been scouring the internet, and I still can't fin anything to help me, so I'm hoping someone here will have the knowledge to give me some assistance.
I would like to build an iris diaphragm. Yes, those things inside cameras. But bigger.
But I can figure out the size thing on my own.
What I'm hoping is that someone will understand the mechanics of it.

I've included a basic picture of one. Google image search might reveal other examples.
Basically, I'll need to be able to slide the leaves with some sort of handle so that they form a larger hole and then can close up again.
Here is a link to the entirety of the useful information I could find.

I would be incredibly grateful! As would, I'm sure, several other people on the internet that are apparently also trying to figure out how to do this.

Hopefully thanks in advance!


go to Sur La Table at your local mall and buy this $7 item (or get one online):


this is sold as a spaghetti measuring device, but it's really a diaphragm iris

take it apart (break the ultrasonic welds holding it together), you can see how such a thing can be simply and ruggedly built. Also interesting to note how friction is not a problem when using self-lubricating materials like nylon, and when the notches and pivots are placed with advantageous angles and leverage.

Awesome dude!!

Thanks for saving me from buying an expensive one or manufacturing one.


3 years ago

Does anyone know how to design the leaves from scratch (other than trial and error)? I see lots of references to "miscalculations" in making an iris, but where do you find the basis for making those calculations? I've been hunting for a while now, and while I can easily make a pattern that works okay, I can't seem to learn how people make them "just-so", without simply copying another device.

Search this awesome instructables site and:
Both have really helped me understand how to make an iris diaphragm. Plus a lot of Googling!
Hopefully this comment is of help to someone still...

OK, this is totaly late but if ever someone still is searching for good info, I also found this. It helps figure out whats going on with movement....
Hope this helps. I'm also trying to figure this out for a huge round window I have at home. I'd like to make this as a way to shut the window for privacy...



9 years ago

The above 3D Studio Max illustration gives you a rough idea of the assembly, although the extra notches in the leaves are unnecessary. The above illustration also lacks an actuator plate, the part which is going to make the leaves open or close. This is a little more helpful, this guy used a laser cutter and pegboard. As you've noticed well enough yourself, you can use two different styles of leaf. One being easier to prototype then the other when it comes to hand tools and basic materials. I got onto this similar path after seeing these today. Good luck.

My search began with the exact same pair of goggles

As did mine! Too bad titanium is too expensive or I'd make a pair now!

I think the extra notches are for the next two clockwise pins, so the iris/aperture can open further.


patent in 2003 what has been in use for decades, even centuries?
truly bogus dude!
this is why i can't take seriously anything that site posts, really.
but hanks for letting us know about it.


Very nice.  I attempted to make one to be a dust shield for a autonomous 16 inch Meade telescope.  It was a failed attempt, but maybe someone can learn from my failure :-)

I used 30 blades (although 5 blades are missing when I took these pictures.

The large number of blades and the wooden/metal slip surfaces simply took too much force to open and close the device.  I'm going with a clam-shell approach instead.

I hope the pictures are self-explanatory.

Best Wishes


thanks i was needing this to make my Stargate model :)

Nice work.

How did you fabricate the blades ?

Why so many blades ? You'd be magifying thefriction massively.


Hey Steve,

I had a large roll of steel flashing from which I cut the blades using tin snips. The number of blades was dictated by the design goal of having the ring very thin.  Thirty blades is way too much friction.  Also, the design is poor, the slots in the blades tend to cut into the spokes and also to bend and thus make more friction as the bent edges drag on the rings.

So I'm abandoning this design and trying a clam shell instead. 

Best Wishes.

I've got a design for a clam-shell enclosure I keep meaning to build a prototype of. It completely folds off the scope, and keeps the scope cold during the day


hay i have found a site ull have to download a pdf on it though.

Its been a while since this was discussed. Does anybody know if this ever was made. Planning of making an iris diaphragm in aluminium, but need some detailed drawings...


9 years ago

I found another version that has the pivot pin, and driver (? for lack of a better word) pin on opposite ends of the leaf.

Seems like this would result in a greater rotation of the driver ring between open and closed, and a more consistent leaf motion over that rotation.

I think this is the way I'd go if I were to make one. I might give it a go once I get some metal (soda cans)

Hey Scruffy I am interested on how your Iris valve turned out? I am interested in the valve for my industry except with a few adjustments.


9 years ago

I made something similar for my class, but none of the parts overlap, so I made irises out of plywood and acrylic and cardboard. Here is where I've documented the process. I'll put pictures of the big plywood model up later. Now, I'm trying to figure out the best way to drive this with a motor.



I am in the same boat as ScruffyRasputin... I have been searching for days on a decent clear show me of the workings and the motion of the blades... I found pretty much the same thing as he... I have the Idea of what needs to be done.. i guess there will be a bit of trial and error... I hope to make one and post the step by step. I will be huge however... basically a window shade for a steampunk room...

you should totaly post that...when you make it.

you should post an instructable on this. i so want to make one but i cant find out how to make one ... not even on instructables.

I can't explain it out loud, but I think I get it. I'm going to try and build a paper model.

Would you let me know how it goes when you get to it? I think I may try a cardboard one when I get the time, before springing for some metal. We can share notes.

It's gone pretty well, considering. I need to hurry up and eat some canned food so I have some spare metal bits to try with. Attaching posts to paper has proven problematic.

Searching for apertures might give you better results.

The mechanics?

Look at the single leaf on top. See the pin on the left near the top? That's a pivot, picture that leaf by itself swinging on it. All pivots are on the outside, looks like all leaves are mounted to a ring. Now see the slot next to the pivot? There's a pin in it from underneath. All the pins appear mounted on a ring that's inside of the pivot ring. Turn that inside ring, see the change in distance between the pin and the pivot, visualize where that would make the leaf pivot to. That may be difficult. The center of the arc is not the pivot, but close to it, mechanically it's not that great but then apertures are often stiff. However the difference is there, as the pin moves and slides in the slot the leaf will move. There is a detail I've noticed on a few quality photographic ones I've played with, each leaf had a spring to keep the leaf in position under tension. I can just make out what I think are the springs in that pic you provided, those circles under the leaf around the pin, small coils which would have one arm against the pivot and another on the leaf.

Found a different version that's simpler to understand, and build. See what you think about it.

That explanation helped out a ton. Thank you. - I couldn't figure out what parts would move and how. But now I might be able to get it. The link was also good, but I think I'll try the traditional leaf iris diaphragm first, as it fits the purpose better...maybe. Anyway, thanks a load! I really appreciate the explanation.