Introduction: Steampunk Goggles With Mechanical Iris

If anyone remembers, I posted an instructable here  showing the basic method of constructing goggles out of brass or copper (or whatever).

I was encouraged to finish them and thought it would be fun to work in a mechanical shutter.

http://www.etsy.com/shop/CivilianArtificer

With the exception of a few screws and nuts, a poly-carbonate lens, and a spring, everything here is fabricated from sheet, rod, or square stock. Or leather (eww).

The straps are adjustable and their is a spring mechanism on the back of the strap to take up the slack and keep a firm but gental grip on your face.

The Iris shutter is admittedly not a diaphragm iris and I have been scolded endlessly for this and the slight gaps where the leaves come together. To this I must ask what practical necessity, fulfilled by an aperture diaphragm, is not suitably filled by this design?

I think in any steampunk build the end result is an aesthetic pursuit.  To that end, this iris is pretty slick (if I do say so) and far more robust than the diaphragm designs I tried.  I'm not griefing other styles, it's just odd how much opinion I get on this subject.

Like a lot of my work, this piece has an ugliness to it. Part of that is by design, part is the result of these being a working prototype.  The majority of this piece was kept thoughout several design changes, re-engineerings, partial rebuilds, shop explosions, etc. Waste not want not. As I solved problems the work was redone with the final result showing the trauma.

Even so, these goggles are incredibly robust. Hard solder was used throughout as well as hand-formed rivets whenever possible. On the iris' driver ring, for instance, the ring is a strip of scrap copper with the ends brazed to form the ring. For each leaf there is a pivot point that connects the ring to the leaf's connecting rod. That pivot point engages the ring in a journal made from a small length of copper tube (to make the bearing) which is brazed to the inside of an inch long brass strap, which is held to the driving ring with two hand-formed rivets.

So, while it looks beat up it's actually very sturdy.

 

Comments

author
Thrombis made it! (author)2015-10-10

What is hard and soft solder? I hear you mention it a lot in your instructables.

author
Ardumedes made it! (author)2014-02-21

I love the look of your iris! I will probably make this type for my steampunk safety goggles!

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gogglerman made it! (author)2012-02-09

This is a good development of the theme. Congratulations.

author
Lectric Wizard made it! (author)2012-02-08

I like the iris !!!! Can you give us a better look at it or how you built it. Cheers!

author
ArtificerMade made it! (author)ArtificerMade2012-02-08

Yes sure... I didn't take pics as I was building but I can do some close ups on the details and walk you in the right direction.

First I went to Columbus Idea Foundry. They have a project page here that directs to their forums where you will find the cad files for this style of mechanical iris. Don't grab the first set of files someone offers you, get to like page 11 or 10 as they refine the shape a bit.

The cad files are intended for a CNC router. The original was made out of wood and others using that file have been made with plexiglass or acrylic. I didn't see any out of metal.

Then I threw that out. I needed my template to be for all of the leaves in their closed position. Then I scaled it to size and printed it, cut it out and rubber cemented it to my copper sheet.

This let me punch the holes for each leaf's pivot point while the leaves were all still one piece. Then I laid the piece down on the copper disk (what I call the fixture) and punch the holes for each pivot point through the holes in the actual leaves. This seems finicky but tiny variations in where those holes are placed add up to huge kinks and binds. Doing it this way ensures that all the leaves will play nice with each other. number each leaf and number its space on the fixture. I use a scratch awl.

Then get the jeweler's saw frame and a nice fine blade and cut each leaf out.

After that I picked up leaf #1 and punched a hole where I want the connecting rod to pivot. The rod and its hardware cannot spill over the dimension of the leaf itself at any point in the travel as the leaf opens or closes. So round the end of the connecting rod and keep it and the screw that holds it  within the leaf.

Once I have #1 punched I used it to align the punch (one at a time) with the rest of the leaves. Once the leaves are all punched I tapped these holes with a 4-40 threads.

I made the connecting rods out of 3/32" bronze brazing rod, annealed then hammered flat and punched. Connecting rods were attached to the fixture with brass 4-40 screws. The threads that stick out the end were clipped and files smooth then a touch of silver solder added to make them permanent. Take care not to solder the connecting rod to the leaf at this point.

The holes in the fixture are similarly threaded and each leaf is attached with a screw. My fixture was a little thin so I added a hex-nut to the back as well and locked the nut onto the screw with a small bit of silver soft-solder (stay-brite). This is optional or you can use thread-lok or superglue. I wanted to keep plastic out of this build where I could.

For each connecting rod I created a small pitman arm. This arm fits over the outer end of the connecting rod and set into the linkage points on the outer ring. I made this out of a quarter inch of  3/32" copper tube (this is a nominal size not the actual dimension) and an inch of 3/32" bronze brazing rod. I drilled a hole in the side of each tube and brazed the rod in so it wouldn't obstruct the hole. I then threaded the rod ... 4-40 I think but it's not crucial. I cut slices of 5/16" brass square stock and drilled a 3/32" hole in each. I didn't thread these holes.

The outer ring, what I call the driving ring, is probably my 3rd or 4th version. A lot of trial and error went into that. My frustration came from trying to find an easier simpler solution for what had to happen.  That's generally a good practice, simplification, but in a fit of frustration I decided to take a whole day and just do it up righteous.

The driving ring is a strip of copper with the ends cramped and brazed (see my instructables for cramping).  

Where each connecting rod will be attached I created a simple journal bearing. I took a quarter inch of 3/32" copper tube and wrapped it in a small length of brass sheet then folded back the ends to make a sort of pillow-block. I brazed each copper bearing into the brass strap then punched a hole at each end of the strap. Divide the outer ring into 5 equal parts and center the bearings on those points. mark and punch holes in the outer ring to correspond to the holes on the brass strap.

To join the bearings to the outer ring I cut 10 1 inch lengths of 3/32" copper wire. Holding them in tongs I heated them up, one by one, with a hand torch until the bottom end of the wire melted and pulled up into a nice round ball at the end of the wire. This is a great technique for forming rivets as it keeps the new rivet from just sliding through the hold until you get it properly set and it forms a nice starting point for a decorative rivet head if that is your goal.

Poke the rivet up from the bottom of the joint, clip it a little less than an 1/8" inch from the top of the joint, file it flat, then set your rivet. Because of the close proximity of the journal bearing, I needed to use transfer punches to hammer the rivet head. I also used a center-punch a fair bit because that does a great (if a little ugly) job of spreading a rivet without much risk of bending the rivet.

Repeat this process until all 5 connection bearings are attached.

By now the outer ring is bent all to hell and back. That's fine, this is copper not glass. lay it on its side and tap tap tap the high points until  its flat and then pull it to shape (circle).

Almost done. Put the driving ring over the eye cup. Put the pitman arms over the connecting rods. set the threaded rods from each pitman arm into a journal bearing then I cranked one of those slices of brass square stock onto it.  It will force thread on and work fairly well that way, but I set each nut with a touch of silver soft solder. I left the nut off the point closest the nose because of clearance.

Now close the leaves of the iris up tight and position the driver ring so  the connecting rods are at a fairly acute angle.  Then braze the connecting rods to the pitman arm and clip them flush.

There you are. Simple.

Actually I would try very hard to find a different way to do most of that. Many of my design choices were limited by the materials available and tools available. As with the goggles themselves this iris was made predominantly from scrap.


author
ArtificerMade made it! (author)ArtificerMade2012-02-09

Next time I build a mechanical iris I will take photos.

This one was a nightmare. The final product went together fairly well but it was like my 3rd or 4th revision.

Version 1 and 2 went into the scrap heap and that always makes me cranky.

author
Lectric Wizard made it! (author)2012-02-09

Wow, great detail, thanks! You could make an Instructable just with that ! Cheers!

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