Question. What is the purpose of this?

[mrdan]

I am looking at a kwikset cylinder that is part of the locksmithing course I am taking at PCDI. I notice these kind of holes that are at about 1 o'clock looking at the front of the cylinder and they don't go through they are about an 1/8" or so deep. what are they?

[Octillion]

Those are for construction keying. Ball bearings are temporarily placed in the pin stack, and a contractor’s key will operate the lock, cut shallow at whatever pin stacks the ball bearings are (such that operating the construction key will have the ball bearings below the sheer line). When the owner uses their key for the first time, the ball bearings will fall into those holes (as their key pushes the ball bearings above the sheer line), rendering the construction key unusable.

[mrdan]

Oh! Okay. Cool

Thanks!

[Krypos]

dude. i have seen threads that needed an entire 3 pages to explain construction keys.

/applause

nice work.