The mechanical iris has always been a fascination of mine, there is just something about the movement of the aperture...
This one is embedded within a more complex structure!
Where better to hide your most private secrets than a Stargate!!!...
This is a simple privacy vault that opens when the symbol ring is turned counterclockwise and closes on clockwise rotation. The infinitely more complex mechanism of a unique 7 symbol address with locking chevrons is not within the scope of this project... yet...
I will walk you through how to create the templates for this one since I built this on the fly as I was constructing it.
Step 1: No computer needed... yet
I wanted something unique and a little different so I decided to go old school and create the iris design using basic tools. I also chose to make this one open counterclockwise!
To to begin with you will require:
A compass, pencil, ruler, paper and Elmer's rubber cement.
The size of my mechanical iris was decided by the maximum size of my compass and the width of paper that I chose.
Ultimately you will also end up needing:
3 - 4X10 brass sheets
1 - 4X10 copper sheet
8-32 0.5 inch fasteners (countersink)
Drill and bits
1/8 inch thick aluminum
Buffing wheel and polish
2 inch aluminum angle
1.5 inch aluminum angle
Paint and primer
Step 2: Outer leaves
There are 6 outer leaves to construct. I will use my dimensions for simplicity but they are completely arbitrary and easily changed to suit your specific needs.
The simplest is the outer leaf...
Begin by making a circle of 8 inches in diameter.
Adjust your compass to a radius of 3.75 inches and place the needle in the center of the circle.
Draw a circle inside of the first one making a diameter of 7.5 inches.
Do not adjust your compass!
Select a point on the circle that you just made and draw an arc from the center to about a half an inch outside of the circle in a counterclockwise manner as shown.
Place the needle of your compass on the point where the arc crosses the circle and draw another are similar to the first.
Continue this process until you have divided the circle into 6 segments.
Number the pieces as shown
Step 3: Inner leaves
The inner leaves are the support structure which prevents the outer leaves from being pushed inward, plus this looks awesome when the iris is in motion.
Again, draw 2 outer circles of 8 inches and 7.5 inches.
Set to divide the circle into 6 segments as before, only this time only draw a short arc which crosses the 2 circles.
Set your compass to draw a 0.5 inch diameter circle and place the needle on the point where the arc crosses the inner(7.5 inch) circle.
Draw 6 circles in this manner as shown.
Set your compass back to 3.75 inch radius and place the needle on the point where the arc crosses the outer circle, not where the half inch circle meets.
The arc you are about to draw will be short of the center point and must extend from near the center to about a half an inch past the outer circle as shown.
Continue this process until you have divided the circle into 6 segments. You will have a small hexagonal shape in the center of the circle.
Again set your compass to a radius of 4 inches.
Place the needle of the compass on one point of the center hexagon.
The pencil of the compass will meet the outer 8 inch diameter circle one segment counterclockwise from the point of the hexagon where the needle is.
Draw an arc from the point where the pencil meets the outer circle to the the segment dividing arc immediately clockwise to where you started drawing.
Complete the process for all 6 segments
Number the circles in a similar manner as in the previous step.
Step 4: Cut the leaves
You will need to cut out the leaves for visualization purposes and to use a templates later.
You can cut the ones that you just drew. I chose to draw and cut from different coloured paper so it is easier for you to see how they fit together.
Step 5: The control ring
You need to find the minimum open diameter of the leaves in order to have the control ring work properly.
Fasten the two sections of leaves together. this is done with Elmer's rubber cement. The reason for this is that this is a non permanent bond which allows the pieces to be taken apart without damage. You will need the separate pieces for templates later.
Choose two leaf sections which are adjacent to one another.
place them on a 7.5 inch circle in the closed position. Pivot them open to the maximum point as shown.
Measure the distance from tip to tip. I show just over 13.25. I chose an inner circle diameter of 13.5 and an outer of 14.5.
If you are making a one piece continuous circle then you will have to draw it out do get the template.
I chose to make this one in 6 segments.
Set your compass to a radius of 6.75 inches and draw a long arc. Using the same pivot point draw another at radius of 7.25. then a third at radius 7.
Using the radius 7 select a point on the middle arc and draw a cross arc. You now have the mid points of one of 6 segments. Draw a small circle at each of these end points. these are your drill points. make a template of this.
Cut and drill 1/8 bit. You will make 6 of these from aluminum.
Step 6: Control arms
The leaf actuating arms are to be the same length at the leaves are wide this is pivot point to pivot point. They are also to be of the same radius as the control ring.
Again you will need 6 of these from aluminum. Cut drill and tap both ends for an 8-32 fastener.
Step 7: Lets make it real...
I chose to shop at a local scrap yard since Aluminum is only $1 per pound. You have to take what you get. I found a long section of extruded aluminum box 6 inches by 2 inches total price $3.
Downside is that it is anodized and will have to be stripped for the outer leaves.
Begin by using the cut pieces from the previous steps as templates. mark the metal with a permanent marker, making sure to get as close to the cut lines of the template as possible.
You can choose to cut as you go or mark all then cut at once. I do it as I go to give myself a break.
Wear safety glasses and gloves as I am going to prescribe a massive amount of hacksaw abuse here... Note that the cheaper the blade the more success you will have. I am using dollar store blades at 24 TPI. You can twist the hacksaw to create an arc cut. These blades allowed me to create a radius cut of 3.5 inches for the leaf support ring halves. Note: name brand blades typically break when trying this. I broke 3 in a row on the first piece then changed to cheap... I completed ALL the remaining cuts for the project with just this one blade.
Cut as close to the drawn line as possible as you will be needing to remove the additional material with a file.
Turns out that my half round bastard was my best friend here... Complete the rough out with all of the metal parts as shown...
This is also a good time to drill the pivot holes with a 1/8 inch bit.
Step 8: Assemble the rings
Since the support rings are in pieces you will need to attach them together. I used JB-Weld for this.
Wherever a joint is being made, scrape or grind to the bare metal for a better bond.
The inner leaf support ring was in 2 pieces, so I joined them then covered the joint with a scrap piece of aluminum.
The control ring was in 6 pieces, having a template off cut from previous, I was able to fashion a gluing template by even spacing 3 of the sections than overlapping the remaining 3 at the drill points.
I used scrap metal and heavy sockets for weight at the joining points.
wait 24 hours...
The outer control ring needs to be re-drilled at the the existing holes, 11/64 then countersink the holes.
Step 9: Leaf Support ring and adjustments
Dry fit the base pieces together and file material to adjust fit and movement
Using your leaf support ring divided into 6 and hand file the segments until you get a friction free close fit.
Drill 11/64 and countersink the pivot points.
Insert screws from the wrong side of the support ring and place the leaves on the corresponding points.
Hand file until you have a smooth movement between the pieces.
Once satisfied, correctly fasten the leaves to the ring and using a divider, mark a point for the control arm attachment.
Step 10: Cover leaves
Fit and adjust
I fastened these to the inner ring then adjusted the fit with a hand file and sand paper.
I had to remove the anodized coating to get the look and finish that I wanted... The leaves went from dull grey to brushed aluminum to shiny polish ad I moved from sand paper to buffing.
Again, hand file for a close, friction free fit...
Once you are satisfied with the fit, attach the outer leaves to the inner as shown, using adhesive.
Step 11: Cosmetic rings
The visible parts other than the outer leaves are 3 rings, designed to mesh within one another. The inner ring is stationary, the outer ring is also stationary and the middle ring moves in both directions and has the engraved symbols on it.
The base is a single piece of hardboard 0.25 inches thick.
Beginning with the inner ring the diameter of the opening in the center is 7 inches the outer diameter of this ring is 9 inches.
The movable ring for the engraved symbols has an inner diameter of 9 inches and an outer diameter of 12 inches.
The chevron support or outer ring has an inner diameter of 12 inches and an outer diameter of15.5 inches.
The inner circle diameters had to be adjusted for a smooth friction free fit by hand sanding.
As shown the circled nest within on another.
I custom built a Dremel circle cutting jig for rough cuts then hand finished the inner edges. The tool is just a piece of aluminum slat with holes drilled into it.
I hand shaped the pieces using a divider to first draw the circles, then cut using a Dermel with a spiral bit. the inner circles were hand filed then sanded while the outer circles were sanded on an orbital hand sander then hand sanded.
Finally all the hard board is primed then painted flat black,
Step 12: 39 segments
Sooo I cheated a little here, and yes I used a computer to save time.
I used a drawing program to get my 39 segments in a circle 12 inches in diameter. I created a template and glued it to my brass sheet the cut as needed.
I then used online resources to get the symbols that I needed. Printed then glued to the segments.
I used an engraver to create 3D texture to the symbols. 39 TIMES!!!!
The 39 brass plates are glued to a cosmetic ring and weighed down, ideally these should have been done individually for a better fit but as this is a proof of concept for an all metal version, it will work for now..
I then polished the individual segments with a small buffing wheel and polishing compound.
Step 13: The base
The entire support structure relies in having a space behind the iris. This is the vault.
I used some 2 inch aluminum brackets, 1.5 inch aluminum brackets and .75 inch furniture brackets. The spacing is 1/3 of the circle.
The aluminum brackets were marked then drilled and tapped then finally glued to the hard board circle.
The idea here is to have any fasteners hidden from view yet still accessible. this was done by allowing for reaching the fasteners from the opening provided by the iris.
The inner support ring was fastened using 3 8/32 screws to 3, two inch aluminum angle brackets which were glued to the back piece on an 8 inch circle.
The inner cosmetic ring is also fastened in this same manner. The leaves of the iris are opened and brackets are placed a 3 openings that will not interfere with the movements. These brackets will later be glued to the inner cosmetic ring and will also support the movable symbol ring.
The outer control ring is assembled with the control arms and it is temporarily supported in position.
Finally brackets are glued in place to support and guide the outer control ring. As shown these go to the outer edge of the control ring, the control arms are not fastened to the leaves yet. again choose a position that will not interfere with the mechanical movement.
Secure an additional bracket to the outer bracket to support the outer cosmetic ring. this is height dependent on the other cosmetic rings.
Step 14: Securing the control ring
Since this is a hand built item you will have to be careful and mark each piece for assembly.
With all the pieces in their places , mark the control arm attachment to the leaves.
drill and countersink the leaves then use 8/32 countersink screws to fasten to the leaves..
Step 15: Assemble and test
Polish the metal leaves and assemble the internal working parts. Polishing is a long task using a Dremel and polishing compound. Mirror finish is ideal but will take many hours. Test the function before final assembly.
3 additional brackets are needed to support the outer cosmetic ring and guide the control ring. these are fastened to the control ring support brackets with a screw from the inside of the iris as shown.
There are 3 small arms that connect the symbol ring to the outer control ring. These are glued and fastened to each piece securely. Turning the symbol ring also turns the control ring.
Step 16: Chevrons
On this model, the chevrons are purely cosmetic. Future models will have them as key points in a 7 symbol combination to unlock the vault.
Begin with a hand drawn template and repeat it 9 times. I rough drew it then used a drawing program for repeatability and printed templates.
I used a backing plate made from 1/8 inch hardboard, hand shaped and painted black.
The individual pieces were cut from aluminum and copper sheet.
The copper is soldered to the aluminum after shaping then polished with a Dremel buffing wheel and compound
Again these are hand made and you will require 9 of them.
Cut and glue to the outer cosmetic ring as shown using a guide template of nine segments.
Step 17: Final assembly.!
The inner ring is glued to the inner ring supports.
From the back side the middle ring has brackets glued to it and it nests to the outer ring, not glued.
The outer ring is glued to the outer ring supports.
The symbol ring is fastened to the control ring to allow for opening and closing.
I also chose to create an inner pocket from craft foam as a measure to keep things from interfering with the workings of the iris. This is 7.5 inches in diameter and 2.25 inches deep.