"Combo Breaker is a motorized, battery powered, 3D printed, Arduino-based combination lock cracking device. It is portable, open source, 3D models provided, and exploits a new technique I've discovered for cracking combination locks in 8 attempts or less, but in an even more exciting, automated fashion."
This is getting close to optimal for an HN post. Too bad it wasn't programmed with Erlang. :)
https://www.youtube.com/watch?v=qkolWO6pAL8&feature=iv&src_v...
He exploits the fact that the last dial impinges on the shackle collar to reduce it to 8 attempts. A small manufacturing change could raise it back to the higher number of attempts.
Even 80 attempts isn't a tall barrier when you're cracking in an automated fashion.
The face of the lock implies 64000 combinations. Knowledge of the internals reduces that by 99.875%. That's almost 3 whole orders of magnitude, and reduces the absolute worst case scenario for opening the lock to about 45 minutes. The attack need not take place all at the same time, either, and once completed, the lock can be opened in the same amount of time an authorized opener takes.
Don't use this type of lock to protect anything valuable, kids. It deters snoops and casual thieves only. Use it to secure your bike, and both may be gone when you return.