Lock bumping is a technique that uses a specially cut key and a sharp tap to jolt the pins in a standard pin-tumbler lock, sometimes allowing the cylinder to turn. It has been widely publicised, which makes it worth understanding without overestimating.
Which locks are vulnerable
Basic pin-tumbler cylinders with standard pins can be vulnerable. Many modern residential locks include features that make bumping harder, and high-security cylinders are designed to resist it.
How to reduce the risk
- Security pins: spool or serrated pins in a rekeyed cylinder make bumping and picking harder.
- High-security cylinders: sidebars, rotating pins or disc mechanisms resist bumping.
- Alternative mechanisms: some residential designs do not use traditional pin stacks.
Keep perspective
Most burglars use force rather than technique. A bump-resistant cylinder on a door with a weak frame still leaves the easiest route open. Reinforce the strike and frame first, then upgrade the cylinder.
What bumping is
A bump key is a specially cut key used with a light strike to jar the pins into position. It works on many standard pin tumbler locks that lack protection.
Practical protection
Bump-resistant or high-security cylinders make it harder. Combined with a solid door and frame, they deter most attempts. Check for tampering marks and any change in how the key feels.
Where to focus
Bumping is only one method; forced entry is more common. Prioritize strong strikes, quality deadbolts and good lighting. See high-security locks.
How to tell if your cylinder is a candidate
Standard five- and six-pin cylinders from budget ranges are the usual targets. Look at the keyway: a wide, open profile with simple grooves is easier to attack than a restricted, complex profile. Ask a locksmith to identify the brand and grade, which is quicker than guessing. If the lock is old and the key is worn, replacing it may be sensible whatever the bumping risk.
For bump-resistant and high-security locks in Toronto, see high-security locks.