One of the simplest kinds of combination lock, is seen in simple bicycle locks,
uses several rotating discs that have notches into them.
The lock is secured with a pin with several teeth on it which hook into the rotating discs.
with the teeth on the pin When the notches in the discs align, the lock can be opened.
This type of lock is considered to be one of the least secure of combination lock.
. Opening one in this fashion depends on slight irregularities in the machining of the parts.
Unless the lock is aligned precisely, when the pin is pulled outward, one of the teeth will pull more strongly
than the others on its disc. This disc is then rotated to a slight click is heard,
telling us that the tooth has settled . The procedure is repeated for the remaining discs,
resulting in an opening lock, and a correct combination, in very little time.
Combination locks found on padlocks and may use a single dial which interacts with several parallel discs .
Customarily, locksmiths can open by rotating the dial clockwise to the first numeral, counterclockwise to the second,
and so on in an fashion until the last numeral is reached; the cams have an indentation or notch,
and when the correct combination is entered, the notches align
. Combination locks of this type are more secure than the type described above,
some of them do have weaknesses.
For example, some combination padlocks made by Master lock could be cracked by pulling off the shackle of the lock
and turning the dial until it stopped .
More recent models of Master padlock with a 40 positions dial wich have a mechanical weakness that can give away
the last numeral in the combination, and the first two numerals have a mathematical relationship with the last number.
This weakness reduces the number of possible combinations from 64,000 to a mere 100, which can be tried in a relatively short amount of time if it is an emergency.
Inexpensive padlocks are often susceptible to the use of a padlock shim, which can be used to release the shackle without entering a combination.
ive been a locksmith for 8 years. we own a locksmith service in southern california. most people are not aware of their home security, we try to change that.