How to Make a 12 Leaves Mechanical Irirs





1 - bicycle chain......yes a bicycle chain, you'll seee what's for.
1 - copper sheet
1 - 15mm MDF board (20 x 20 cm will do)
1 - 3mm MDF board (20 x 20 cm will do) ( not on the pics)
1 CD tube case
And also some tools such as:

Bicicle chain tool
4 mm drillbit
130 mm Holesaw
75 mm Holesaw
Table saw or router table, or router, or dremel.
A blowtorch
Soldering wire and paste
A visegrip (recommended)
A Vise

You will also need a template file wich you can download from here, is a dwg (Autocad) file, you have to print it on a 1:1 scale.

Step 1: Getting Some Pins

Ok, so what the heck is the bicycle chain for? well, every iris leaf, has two pins, one of them is  a pivot pin, and the other is a travell pin, wich runs in a slot.
So, in this project we will use the bicycle chain pins, ;)

Now,what you need to do is to take your bicycle chain, and dissasembly it several times, in order to get 24 pins, as the images show.

I put my chain tool in the vise to have a better handling.

Every chain link is componed by two pins, two little rings, and two little flat pieces, we will only use the pins, but save the other little pieces, cause they can be very usefull, and you never know when you gonna need them.

Once you get the 24 pins, clean them up very well (i use alcohol), to get all the oil and grease out, and we are ready for the next step

Step 2: Cutting the Leaves

Now let's make some leaves!

Ok, first print the leaf template, and glue it to the copper sheet.
Now cut the leaves!

Regular scissor will do the job (Remember, this copper sheet is 0,1 mm thick)

Once you get them all cut, remove the paper, and we are ready for the next step!

Step 3: Soldering the Pins

Ok, now comes the fun part, we will solder two pins in every leaf, you must be carefull of where you place the pin, you have to guide yourself using the leaf template

I had no time to make a jig to precicely position the pin in every leaf, so i did it "by eye", anyway, we dont need surgical precision for this one.

Now, in case you're wondering ¿how do i solder those little things? i'll show you how i do it.

-First, i fix my visegrip on the vise
-Then i fix the leaf with the pin in position, in the visegrip
-Then you have to apply some soldering paste (flux), be generous.
-Heat it with the torch, just enough to get the paste melted
-Then, cut a piece of soldering wire, about 15 mm long, and twist it in a "U" like shape
-Then, wrap the wire around the pin base.
-And finally, heat everything untill the solder gets melted, use a soft flame, there's no need for exesive heat.
Do all that, and 20 minutes later you will have your 12 copper leaves set, ready to go!

Step 4: Making the Rings

Now lets make the two rings.

First, print the rings template, and glue them in to the mdf boards.

-The ring with the runners, is for the 15 mm MDF borad, and the ring with the 12 holes, is for the 3 mm MDF.

-Then cut them with the holesaw

-Sand all the edges

-Drill the holes ( 4 mm holes)

-Cut the runners in the table saw (or router table, or with a dremmel, etc) i set the cut depth to 10 mm.

And that's all, now lets go to the assembly part!

Step 5: Assembly It!

Ok! so now we have our 12 copper leaves set, and two mdf rings, let´s put them all together.

First, take the cd tube case.
Then put the 15 mm MDF ring on it
Then put the first leaf, with the tracking pin in a slot (the tracking pin is the one tha's a little offset, the other one is the pivot pin)
Then put the second leaf under the first one
Put the 3rd leaf under the 2nd......and so, untill you get the 12 leaves set up.

the put the 3 mm mdf ring on top, make all the pins fit with their respective hole (you can use some stick, or screwdriver to help) and YOU ARE READY TO GO!

Lets see a video of the iris in action! i must said this one works like a charm, opens and close very smooth.

2 People Made This Project!


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117 Discussions


Question 11 months ago on Introduction

Thank you uploading such a wonderful informative article.
I want to make the project similar to iris bowl with petel like opening on outer side.
Please suggest.



1 year ago

Will this work if the pin is glued to the Leaves with some Super Glue???

1 reply

Reply 1 year ago

With experience in other projects, super glue will make a fairly strong chemical bond, but cannot be relied upon for durability as the soldering makes a very solid mechanical connection.


2 years ago

is it possible to use pieces of heavy wire instead of bike chain pins?

1 reply

Reply 1 year ago

Yes, except that, in other projects I have done, lifetime of the device will probably be shortened as the pins are hardened.


Question 1 year ago on Introduction


How do you compute the position of the 2 pivots on the blades and how the shape of the blades are related to the size of the iris? Thank for your very nice work.


Question 1 year ago

I don't have autocad and the online viewer isn't great. Any chance you'd post a pdf of the schematic?

Great work on this by the way!


1 year ago

Im checking your dwg files. The exterior circle is supposed to be 130mm, but I see 123mm. The inner circle is correct with 75mm.

Any idea about this?


2 years ago

How do I scale this up for a 2ft windows?


2 years ago

Hi kommodore, I was wondering how long it took you to make it and how difficult you found it. I was planning on making one that can be ran with a motor. Thanks!

1 reply

Reply 2 years ago

Hi MauricioP49. It may seems difficult, but you will notice by yourself that is not! I really enjoyed building it and it took me just 2 hour and a half (you could build that in less time if you don't spend a lot of time like me checking and rechecking everything in order to make it as perfect as possible ahaha).


3 years ago

Is there a trick to make the iris reach a fully closed position. I have been looking at several different designs and most of them seem to leave a tiny opening when closed. This one does not seem to have that issue. Any explanation?

1 reply

Reply 3 years ago

Hi, it will depend on the thickness of the leaves, when closing the iris, the leaves overlap with each other. In this case, the thickness of each leaf is 0,1 mm. When fully closed, the 12 leaves sum 1,2mm thick in the center. This causes the leaves to bend inward a little bit. So the thicker the blades, more force will be needed to bend the leaves in order to overlap with each other, sometimes making it impossible to fully close after some point.



3 years ago

This is great! Have a few questions, how can you be reached ?


3 years ago

Do the leaves reinforce each other? Would it be like bending 12 layers of the copper or does it feel rather flimsy when shut?

I'm playing with scaling your design up to about ~8-10"

It looks like the leaves are should cover 180 arc but how do you determine the width/thickness of the leaves?


4 years ago on Introduction

Thanks for this great tutorial. I love building things out of wood.

I am building the iris right now and let you know when I finished it.
A step by step documentation will be done as well on my Website:
I created a PDF file which has both files included (leaves and rings), with the same measurement.

I decided to make it a little bid smaller, because I can cut it with scrollsaw or bandsaw.
Maybe this PDF is usefull for somebody else. For me it was great because I have no AutoCAD and no knowledge about it.

Outer Diameter of my rings is 11,7 cm and Inner Diameter 7,1 cm.

greetings LNINO


7 years ago on Introduction

This is very well done! Excellent detail! I'm going to try to make it from tempered hardboard and large enough to walk through.
The only change I would like to see is that you post the iris.dwg file (presumably that contains the templates you mentioned) in a compatible file format. Very few of us are likely to have autocad.

2 replies

Reply 7 years ago on Introduction

You can also download this free dwg viewer from Autodesk.


Reply 7 years ago on Introduction

Viewer does not allow modification; Not even scaling, as far as I can tell.

But I'm sure a quick search would provide someone else's example in a friendlier format that you could start from for your larger, wooden version. There are lots of iris examples out there.

I'm sure you won't need to start from scratch, Marsh; When i eventually get around to making my own variation I'll be looking for YOUR work as my starting point, so don't forget to use an open format and post!

Great work though, Kommodore! Elegant & inspirational.