Introduction: Mechanical Iris V2.0

About: Teacher of Science and engineer

Before anything else, I would like to say that this Instructable is based on and inspired by carlbass and his Mechanical iris.


Inspired by his work I quickly put a piece of plywood in my desktop laser cutter and set it to work. Minutes later the promise appeared, and within moments I had pieced everything together in a fully functioning mechanical iris. Awesome!

However, after admiring the design I spotted few ways in which I felt it could be improved.

So here it is; my take on the Mechanical iris (v2.0).

Step 1: Improvements

- In the original Mechanical iris there were three layers. I felt this was excessive and so this new design offers only two (plus 1mm for the optional Perspex cover).

- The points at which the 'arms' attached to the blades relied on a shared pin to partially rotate about. This aspect seemed over complicated when the same effect could be achieved with clever cutting. This means that post cutting assembly time is reduced.

- The holes have been changed to fit 6mm dowel instead of 5mm which, for some reason I found stupidly difficult to obtain.

- Drawing pins have been used to cap the wooden dowel pins ensuring that the blades and outer ring do not wonder or come off. This design does not however ensure the arms are kept in place when holding the finished product upside down. This is where the optional 1mm Perspex cover comes in should you feel you need it.

- Although this last part is very crude in its current design, I have included a use for the offcuts. Stuck together they form a raised grip for the back of the iris enabling you to hold and manipulate it more easily. This will prove its worth when you come to 'working' the outer ring in for a couple of minutes.

Step 2: Materials

Wood glue
Drawing pins
Your choice in wood
6mm dowel
Scalpel / hobby knife

1mm colourless Perspex (optional)

Step 3: Laser Cutting Files

Below are a choice of files for you to use. I couldn't think of any other file type you might need, so if I'm missing a major one please message me and I'll see if I can sort something out.

P.s. The .dxf and .svg files are a slightly updated version -- there are two turning handles so the iris can be used in one hand now.

Edit: SVG files now uploaded (18/03/2022).

Step 4: Assembly

Assembly is very easy.

  1. Measure and cut a 6mm long length of your dowel.
  2. Use your knife to press down and cut as you roll the dowel back and forth.
  3. Repeat steps 1 and 2 a further nine times.
  4. Dab a small amount of glue in one of the base layer holes.
  5. Take one of the dowel 'lugs' and rotate/push into the glued hole.
  6. Ensure that the lug is flush with the back of your base layer.
  7. Wipe away any excess glue.
  8. Repeat steps 4-7 for the remaining 9 lugs.
  9. Glue the two semi circle off-cuts together and then glue to the back of the iris where you feel is most comfortable.
  10. Wait for the glue to dry.
  11. Place the outer ring over the glued lugs then spend a few minutes carefully working it in by repeatedly rotating it. You may need to shave minute amounts off the inside and outside of the lugs.
  12. Once the outer ring turns with minimal force add the blades and the arms linking everything up as you go.
  13. OPTIONAL - If you want to use a Perspex cover, this is where you would lay it over the top making sure that all holes align with the lugs underneath.
  14. Carefully push a drawing pin into the centre of each lug ensuring that the top of the drawing pin does not exert too much pressure on the piece reducing its mobility. Remember, these are merely a way of stopping the pieces falling off -- I left a fingernail's spacing under each one.

Step 5: Finished Product