(Note: There's now a better, tapered version. I recommend that you print this instead: http://www.thingiverse.com/thing:12348)
I was ashamed Thingiverse. So ashamed. I presented the Mighty Bottle Opener as the pocket equivalent to Starno's Coin-Op. It wasn't. It isn't. I just wasn't able to find a reliable way to protect the plastic.
It works really well if printed in PLA, but for the vast majority of users it's an annoying chewed-up mess.
WELL NO MORE! After months of self recrimination, I went back to the drawing board, and have come back with a beefier "church key" design.
Two things that make me confident in this design:
1 - I've used it to open several bottles with ease. (Gasp!)
2 - I took the time to make the model fully parametric. If it's not strong enough for you, you can make it 10 inches thick! (not recommended)
Another benefit to the parametric model is that it can be adjusted to fit the coin of your choice. (See the attached image for some of what can be specified. When I say "fully parametric" I mean FULLY)
Mighty Opener: http://www.thingiverse.com/thing:9350
Starno's Coin-Op: http://www.thingiverse.com/thing:1842
UPDATE: I've added the ability to sexify the opener with a makerbot M. Just set the "UseBadge" flag in the scad. if you'd like to use an M in your own OpenSCAD part, I've broken out the module I used to draw my M into its own thing: http://www.thingiverse.com/thing:11105
UPDATE #2: These things make great gifts. With a little tweaking you can print a custom design instead of the M. I've detailed the process here: http://brettbeauregard.com/blog/2011/09/making-a-custom-bottle-opener/
There's really only one thing to watch out for with this design. Because the slot is parallel to the build platform there's a long gap that needs to get bridged by plastic
1- Rotate the part such that the first layer above the opening runs across from plastic to plastic
2- If you're getting sagging/drooping, see the discussion below regarding bridge settings
A note about fill: I set the fill ratio on my thingomatic to 0.9, which is essentially 100%. Because of the relative thinness of the part, this isn't the time to skimp on plastic.
Coin Insertion: It had not occurred to me that people might try to insert the coin by pausing mid-print. Apparently this works, but it's not what I do. After printing I slide the penny into the slot as far as I can. then using a pair of pliers (one jaw on the penny, the other on the short edge of the opener,) I squeeze the penny in the rest of the way.