Can a 6 pin cylinder/lock be keyed to match a 5 pin cylinder/lock?
The Kwikset 6 pin keyblank has offset shoulders whereby the key will stop at the first shoulder along the top of the key in a 5 pin lock but will stop at the second shoulder along the bottom of the key in a 6 pin lock. This allows the key blank to be used for both 5 pin and 6 pin locks and this is even documented in the smartkey documentation that a 6 pin key could be used in the 5 pin smartkey but a 5 pin key could not be used in a 6 pin lock. This means that you can pin a 5 pin lock to be opened by a 6 pin key but you can not pin a 6 pin lock to be opened by a 5 pin key . In theory you may still be able to key a 6 pin lock to a 5 pin key by removing both lower and upper pins from the sixth position (the furthest into the lock) as the 5 pin key would not reach it anyways. This means that you can have an interesting scenario where a 6 pin key acts as a master key opening both 6 pin and 5 pin locks but a 5 pin key will only open the 5 pin lock. Using this scheme to master key your locks has the advantage of not having multiple shear lines which make lock picking easier and more 6 pin locks can be keyed to keys that can open the 5 pin lock but not the other 6 pin locks. Note this is only possible with the Kwikset locks because of the offset shoulders on their 6 pin key blanks.
