In addition to earbuds, I have a tendency to lose padlocks. As a result, I tend to go through more of them than I should. Note to locker designers: place the loop on the inside frame instead of on the outside of the door so that after I open the door, I have somewhere to hang the lock where I won’t forget it.

Cheap combo locks have never been that secure, but since things have gone from bad to worse, I figured I’d try a new lock. Enter the Master Lock Speed Dial.

Instead of numbers, the combination is a sequence of cardinal directions. The packaging promises I can pick any combination of any length, though I doubt they have really invented an infinite data storage device. The default sequence length is only four inputs, which is far too short for my comfort and they should recommend at least eight. 4^8 combinations just tops the 40^3 of a very precisely machined 40 digit combo lock (to say nothing of less precise models). Despite the length, with very little practice it’s easy to enter the combo quickly and accurately. Trying to spin a dial too fast I would frequently over rotate and have to start again. The speed dial can be consistently unlocked one handed in about five seconds.

Programming the lock is a little weird and error prone. The sequence of unlocking, resetting, and locking must be performed in exactly the correct order or you get a lock with the wrong combo. Or no combo! Fortunately, this video explains two common mistakes, which I definitely experienced first hand.

For a look at the insides of the lock, this video reveals a little more about how it works. Also a toool.nl PDF.

Initially, the lock was very stiff to open. I couldn’t tell if I’d done the combination right or not (pretty important right after purchasing), but after some use it pulls open much more readily. On the downside, the casing is rather large and won’t fit everywhere that a smaller lock is expected to.