by quepid » 28 Sep 2017 11:37
I broke my only key unlocking my front door and decided to change the door knob lock as it was pretty dinged up. Afterwards I proceeded to rekey the deadbolt to match the new kwikset door knob lock.
What I noticed is that the door knob pins were not the standard kwikset lengths (both bottom pins and master pins). I've been trying to understand why the lock has such unusual pin lengths and how to derive what the bitting for the master key would be given only my charge key.
The pin lengths for the kwikset deadbolt:
Position 1 - top pin, mp (1.05mm), bp (6.03mm)
Position 2 - top pin, mp (1.73mm), bp (4.91mm)
Position 3 - top pin, bp (6.06mm)
Position 4 - top pin, mp (0.67mm), mp (1.73mm), bp (4.92mm)
Position 5 - top pin, mp (1.05mm), mp (1.06mm), bp (4.33mm)
The pin lengths for the pre-rekeyed kwikset knob lock:
Position 1 - top pin, mp (1.05mm), bp (6.03mm)
Position 2 - top pin, mp (1.73mm), bp (4.91mm)
Position 3 - top pin, mp (1.05mm), bp (6.06mm)
Position 4 - top pin, mp (1.73mm), bp (4.92mm)
Position 5 - top pin, mp (1.05mm), bp (4.33mm)
The broken charge key bitting is 4-2-4-2-3 (information obtained by inserting different pins into the cylinder along with key). When I use the key guide to determine bitting it shows 4-2-4-2-2 (apparently the tiny 1.05mm mp is needed to match sheer line of key).
When I put the charge key in the cylinder and insert the pins, that for position 5 the master pin also fits along with bottom pin.
I am curious about why one would have mastered a lock this way.
