A New Standard for Bump Testing

The ASTM, (American Society for Testing and Materials), organization has updated their standard F883 to a 09 version.  The revisions constitute a new test for bump resistance in pin tumbler cylinders.  Such a standard testing method has been needed for some time now.  Many manufacturers tell locksmiths that their products are bump resistant but there is little qualification of how much resistance is provided.

This standard will eliminate that problem as it gives locksmiths a standard way to measure bump resistance through some stringent testing.  The test requires each manufacturer to submit 5 samples of the cylinder to be tested and each cylinder must be supplied with 7 operating cut keys.  Why 5 cylinders?  To test the validity of a solution you need to demonstrate that it is successful repeatedly, in this case, 5 times.  Why 7 keys?  Many cylinders that claim bump resistance are patent protected to the point that blank keys aren't available to allow making a bump key.  If extra keys are supplied with the cylinder to be tested, some of them can be turned into bump keys.

Three locksmiths conduct the testing and each locksmith must be familiar with bumping techniques and have had good success in the past 2 years using the technique.  Each locksmith gets 2 of the operating keys supplied with each cylinder.

Each locksmith turns their operating keys into a bump key, actually two bump keys for their are two design types that must be tried in each lock called a Pull and a Push.

Once a locksmith has made his bump keys he can start testing.  The test for each cylinder must be completed at a rate of 10 impacts from each type of bump key every 2.5 minutes to a maximum of 60 impacts within 15 minutes.  Some pretty significant testing when you consider that the same test must be performed by each locksmith.

The chart below shows the various grade levels at which a cylinder can qualify.


There is of course one original operating key that isn't turned into a bump key.  That key is used at the end of the test to determine if the lock will still operate after this concentrated attack.  If it won't operate, the grade level isn't changed since rendering it inoperable by the attack is a good form of bump resistance.

Remember this testing when looking for a bump resistant lock and ask the Grade level where the lock qualifies.


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