When you have guests over for the holidays, don't cast pearls before swine. Make a 3D-printed bottle lock for the craft beers, and let your friends and family drink the cheap ones. Bah Humbug!
Step 1: Design
The first step in the design is to measure the bottle. The shapes of bottles vary pretty widely, but the caps seem to be totally standard. Because of that I decided to make the lock clamp onto the bottle cap, and left some wiggle room for the size of the neck.
I made the rough shape of the bottle, then designed the lock to be a clamp with a single 4-40 screw as the hinge part. The other end of the clamp has a hole that fits an off-the-shelf luggage padlock I found in a 6-pack at a hardware store.
I used Fusion 360 for the design because it's a great solid modeling tool. It has mechanical assembly functions that let me test out the motion and figure out if it would easily come on and off of the bottle. Fusion 360 is FREE indefinitely with a "startup" license option after the 30 day free trial.keep.stl
Step 2: 3D Printing
I used a Makerbot Replicator 2, but this model would work with practically any 3D printer. When you model Fusion 360 properly, there is no cleanup whatsoever when you prep it for 3D printing. Just bring it into the Makerbot app, position it, and off you go.
This is not a simple monolithic object. There are "overhangs" because the hinge parts interlock and there are holes. So whatever printer you're using, make sure you use supports. The group of 6 took about 6 hours to print.
Step 3: Assembly
I designed it to use a 3/4" long 4-40 machine screw, washer, and nut to be embedded into the bottom of the print. The fit was so tight that the screw ended up threading into the plastic. The nut was totally unnecessary, and in fact it cracked the plastic when I hammered it in, so you could probably leave that out.
Step 4: Keep the Good Stuff to Yourself
You're already spending a fortune on friends and family over the holidays, so save some good stuff for yourself.