Very soon after finishing my previous project I realized a need for this device.
What was happening was the front (and only) sight on the rifle was a bit lower than where my head is when firing the rifle so when I looked at it there was a subtle angle between where I was looking and where the actual barrel was pointing. At extreme short range this was not much of a problem but if I moved about 15-20 feet back (still quite short given the range of the rifle) I would have to aim the rifle about 8 inches lower than where I wanted my projectile to hit. (In my video on the other project I shoot at a section of palm tree with spraypaint. I hit the center with no issues but I had to point the sight at the bottom of the outside circle to hit the center)
Obviously I needed to do something about this since moving forward or backwards would affect the aim and while this is fine for archery, a rifle ought to be more consistent.
What I decided to do was to bounce my line of sight off of two mirrors so that in the end, I had, in effect, a horizontal line from the sight to my eye instead of the angled one.
This is all good and well but there's still the issue of looks . . .I couldn't simply slap a couple of mirrors on and call it quits so after getting the basics designed I made sure to do a couple of things to keep with the steampunk theme.
If you like this please rate and comment! If not, please let me know what you think I ought to do differently so that I can improve in future endeavors!''
Come with me now and I will show you how I made this and how you can use it to develop your own!
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Background and Theory
Before we jump right in I felt that some of you may benefit from some theory regarding mirrors since we'll be dealing so closely with them. If this is all old news to you then just skip this step.
Everyone knows what a mirror is and how it works and indeed it's common knowledge when it comes to a single flat pane of reflective glass. . .but when working with two mirrors and needing precision, a bit of physics will help immensely with design.
Our eyes work by receiving light and transmitting the information to our brains which interpret it. duh! The cool thing is that we can bounce this light off of certain types of surfaces and shiny or reflective ones work the best (again duh).
With flat mirrors perpendicular to a light source, the light reacts in an intuitive way: if comes in, bounces off the reflective surface and exits all in a straight line. At an angle, the light comes in and bounces out slightly differently, rather than exiting the way it came in it exits at an opposing angle (much like a ball bouncing on a flat court if we had no gravity). The convenient thing is that if we draw a line perpendicular to the mirror coming out of the point of impact (sounds cooler in my opinion) we can measure the angle between our line and the light's line. this angle is the same for the incoming and outgoing light! (see diagram). What's even better is, you can have light coming in and exiting at an infinite number of angles and following this rule all simultaneously.
This is why we're able to perceive objects as if they reside within the mirror.
The last convenient property we'll take advantage of is the fact that the reduction in intensity due to passing through the glass of the mirror and the imperfections of the reflective substrate is negligible. So we can bounce that light around as much as we want until the cows come home without worrying about dimming it.
So without further ado hop on over to the next step where we'll be using these properties to angle and place two mirrors.
*NOTE* the images for this step were lifted off of google since I lost my drawings and didn't have the heart to re-do them . . .
Step 2: Design and Drafting
Okay, for this part all you need is a 2D scale drawing of the rifle (or whatever), a ruler, a triangle, a protractor(optional if you aren't that concerned) and a pencil with a good eraser.
The first thing you'll want to do is make a couple of copies of the base drawing so that if one gets too fouled up you can scrap it and start again.
Now draw a line parallel to the barrel of the rifle at the height of the top of the sight all the way back to where you want your aiming device. This will serve as your desired line of sight.
Draw another line parallel to the barrel but in line with where your eye is when firing the gun. This line was higher than the first one in my drawing. now we need to bounce these two lines using mirrors so that they connect perfectly.
I started with the lower one and worked back to my eye. If you don't mind having a vertical sight device then your job is easy. Draw 2 mirrors(short lines) at 45 degree angles and you're done. If you're like me and nature and you abhor right angles then it will be a bit trickier though certainly not impossible.
In this case, draw your brackets first and then connect the lines of sight along the axis of the bracket. now using the law of reflection draw lines representing your mirrors so that the line of sight is reflected properly. The trick is to get mirrors the right size and height so that we get a decent square picture. My designs are included below. If you'd like you can also jot down some ideas for embellishments but it may be best to do those later . . .you know, AFTER, we get this thing working! No matter how good you are at drawing you'll need some adjustments to make it ideal. The point of doing this step is to make the requirement of those adjustments minimal and doable simply by rotating the mirrors or the bracket.
Step 3: Cutting Out the Pieces
- Two mirrors
- Two flat metal brackets
- Three threaded rods
- 12 flat washers
- Six wing nuts
- Mirrored glass (I bought this at a craft store but if you want fancy mirrors visit a glass store)
- Flat sheet metal (I used the outer casing of the cdrom drive I took apart for the last project)
- 1ft of brass threaded rod (I used 6-32 from Ace Hardware)
- Jeweler's Saw (or any other saw with a very fine blade)
- Glass cutter
- Bench Grinder
- Permanent Marker (I used sharpie since they're alcohol soluble)
- Tin snips
- Anvil(or heavy duty hunk of metal)
- Hammer the heavier the better . . .a 1 pounder is pretty nice
- Drill (either press or hand)
I wanted my mirrors to be able to swivel within the brackets(which is immensely useful by the way) so I cut my mirror into squares the same width as my rifle at the point where they will attach. The reasons for this will be explained later.
Use the calipers to get an accurate measurement of your rifle's thickness and use the ruler to draw squares onto the mirror with your marker. A super fine tipped marker is essential.
Now lay the glass on a smooth flat surface and place the ruler along the line so that when the glass cutter is used the "blade" is directly on your line. Grab the cutter and press it onto the glass firmly but not extremely hard and run it along the ruler. This will make a faint crunching/grinding sound as it scores the glass along the line. What we're doing here is setting ourselves up for a very controlled break. Mirror is especially finicky so make sure you get a proper score. Now would be a good time to wear some gloves and safety glasses are not optional here. The cutter has rectangular sections cut out of the backside (sort of like a medieval sword breaker).
Insert the glass into one and then carefully flex the glass until it breaks. Let the tool do all of the work since any extra stresses will make the glass break in a way that you don't want.
Score along your other lines and repeat.
If you're unwilling to go through the trouble of cutting your glass that's fine but make sure you buy mirror that's exactly the right size.
Now go to your bench grinder (now gloves are also required) and carefully round out the corners and smooth any unevenness away. There's a serious risk of breakage here so you could skip this step but I'd recommend it as it makes the mirrors look much better. Obviously you'll want a fine stone not a coarse one.
Clean off your glass and set it aside.
Cutting the brackets
Now take your sheet metal (or cd-rom casing as it were) and draw rectangles onto it. I split mine up into 4 long rectangles and decided they were too wide so I used one of them cut in two.
Whip out the tin snips and gloves and cut along your lines. The snips will bend your sheet a bit but that can be fixed easily. Avoid closing the snips completely as you'll get funny little twists along your cut every so often. Be extra careful here since your cuts will result in sharp edges. Make them way longer than you need since you can always cut them down later!
Draw a rounded (or whatever you'd like) bottom and put a dot for where we'll drill the first hole later. Next pound the brackets flat using an anvil and a hammer. Don't aimlessly whail on it though . . . just hit it hard enough to make it flat. If your hammer has been used a lot (like mine has) it will have a very uneven face. This is great as each time you hit the bracket, designs are left behind imprinted into the metal!
Now that they're flat stack your brackets together and clamp them. Go over to the grinder again with your glasses and grind the shape into the bottom of the brackets and make them even and the same size.
Keeping them clamped, take a bolt or a nail set and hold it over the dot you made earlier and whack it once with the hammer. This creates a little divot so the hole may be drilled without worrying about slipping. Get a bit slightly larger than your rod and drill the hole through both brackets using a drill press(recommended) or a hand drill in either case, use a piece of scrap wood to back them up so they don't flex in the process.
Drilling through thin sheet will leave burrs behind. use a screw driver in the holes to press the burrs outward away from the hole and then give the bracket a good whack to flatten the burrs outside the hole. Grind the sharp edges away and your brackets are ready for initial placement and measuring.
Cutting the Threaded Rod
Take your threaded rod and mark it with sharpie in intervals at least 1/2 an inch bigger than the width of your gun and mirror. Take the jeweler's saw and carefully cut the sections . . . If you copy my design you'll need three rods. The jeweler's saw is needed since a larger saw will mar the threads and make it impossible or at least very difficult to thread the nuts on later. Work slowly and let the weight of the saw do all the work . . .if you press on the saw that tiny blade will just snap under the pressure and we wouldn't want that to happen . . .insane saw blades are not funny business since they don't have asylums for them.
Good job! now all the cutting is done!
Step 4: Preliminary Assembly and Measurements
- Sandpaper (80 grit)
Grab your mirrors and place them between the brackets at the angels you calculated and put dots on the brackets below the lower mirror and above the upper mirror making sure the mirrors will not interfere with each other. To hold the mirrors steady while you do this, simply squeeze the brackets together a little bit and they'll hold the mirror just fine.
Now that you've done everything up, take it all apart again! now you know 3 new things, first you know where the lower mirror's hole goes, second where the upper mirror's hole goes, and third how tall the brackets actually need to be. I decided to leave mine a bit long and do some fancy stuff with the ends.
Go and drill the new holes (again clamping the brackets together to make sure they line up and backig it with scrap wood) and grind in any fancy shapes that you want. Take some sand paper (I used 80 for this part) and make sure all burrs are gone and that you can't cut yourself on the brackets. Avoid sanding the faces too much or you'll get rid of the designs left by the hammer.
Step 5: Secondary Assembly
- A sharp knife
- 2 part plumber's Epoxy Putty
Place a wing nut and washer on the last rod and put it through the bottom hole of one bracket. Place another washer over the bottom hole on the inside of one bracket and thread the rod through it. Align this with the hole in the stock of the rifle and thread the rod up through the rifle. place one more washer on the rod and then thread it through the other bracket. Add the last washer and wing nut.
If * is a wing nut, | is a washer, 1 is the bracket, and S is your stock it will look like this:
In other words, each component in this entire assembly has a washer on either side of it with the exception of the wing nuts. The reason for this is twofold. This gives us a bit of spacing which makes it possible to swivel the mirrors or the brackets independently without loosening the entire bracket assembly and it protects the holes driven in the wood from damage and keeps them out of sight (okay so that's technically more than two . . .sue me).
Step 6: Lining It All Up!
We now need to line everything up so that your sights work!
- a laser pointer or bore sight
- a stable surface
Now tweak the mirror assembly until the laser beam rests just above the sight. Angles are important so hold your head where it will be when shooting!
If the beam lies off to the right or left, then the brackets aren't aligned. . .simply push one forward and pull the other back to align them.
Once everything is good then you can either use it as is or continue on and embellish the assembly to make it look really nice.
Step 7: Embellishments and Finishing
Tools and materials:
- your intuition and imagination
- Junk: namely gears, circuitboards, wires, tubes, pipes, anything that's been cast aside but looks cool
- rub n buff or other gilding solution
- 220 grit sandpaper
- metal polish
- some rags and paintbrushes would come in handy too
First, (I know you're going to kill me . . .) take it all apart again! Grab some 220 grit sand paper and sand the metal to get rid of any paint and whatnot. The hammer blows most likely have left little raised areas and indentations. The 220 is too fine to take these out so what it does is shines up the raised areas and leaves dust and grime in the lower ones which makes for a great design. If you don't like this then whip out the 80 grit and sand it smooth keeping the same direction all the time and if you want the brushed look to be less pronounced, work your way up to about 150-180. Get your polish and a rag and polish the metal but leave it a bit unfinished . . .mirror finishes won't work as well visually. If you left the hammer marks then these will take on a shiny appearance and the other spots will get grimier which is great for making it look aged. If you sanded smooth then the polish will still work but will give you more of a brushed look unless you went too fine with the paper.
I epoxied some circuitry to the backs of the mirrors and then rolled little coils of epoxy putty to embellish the faces of the mirrors. I gave many of the parts a quick flat black undercoat and then re assembled everything and realigned it. now I glued little bits and pieces everywhere to really steampunk it out and tie it into the rifle. Notice the "tubes" going from the mirror device to my "optically driven trajectory rectification apparatus" (see other ible for explanation). All that's left is to use a bit of that gilding stuff to give the black primed spots a bit of brassy goodness!