This is a small rear-view mirror, meant to mount on your bike helmet (or glasses, or baseball hat...) so you can see behind you with just a little turn of the head. It's made from a bottle cap, a bike spoke and nipple, acrylic mirror, and glue.
Materials for one mirror:
Bottle cap (pick a good one!)
Acrylic mirror (TAP plastics has scraps for real cheap)
Bicycle spoke (free from local bike shop, ask when they cut up a wheel)
Spoke nipple (should come with the spoke)
Glue (I like "E 6000" from TAP plastics)
1 1/8" Hole saw (sans arbor)
Access to a Drill press
Dremel tool (not needed, but nice)
Step 1: Cutting the mirror
I'm making a bunch, but if you're just making one that's cool.
Take the arbor out of the hole saw. (That's the drill bit in the middle of it, that helps center your hole. Since that would put a hole in the middle of the mirror, we don't want it there.)
Mount the hole saw and mirror on your drill press. Have a punch-out tool (I use a blunt stick) ready. If your mirror piece has the protective film on it, leave it on! It will help keep the mirror surface good throughout the process.
Cut the mirror out, and then swiftly punch it out of the hole saw before the acrylic gets too solidified. If you're doing lots, do one at a time! Filling up the hole saw with stuck-together mirror bits is bad.