Saunderson Security Home Visit New Website
 
View Cart
Items:
View Shopping Cart
Call Mon-Fri: 8am-5pm
0800 204 563
|

Catalog >Help > 

Door Lock Information

Looking for a lock? Try our lock help section to identify and find the right lock.
How do I determine door handing?How do I determine door handing?
On some products it's important to know the handing of the lock..
Q: How do you measure a sashlock?
KEY
A - Case Depth
B - Backset
C - Case Height
D - Centres
E - Forend length
F - Forend Width
Q: How do you measure a sashlock?
Q: How do you measure a deadlock?
KEY
A - Case Depth
B - Backset
C - Case Height
D - Forend Length
E - Forend Width
Q: How do you measure a deadlock?
Q: How do you measure a latch?
KEY
A - Case Depth
B - Backset
C - Case Height
D - Forend length
E - Forend Width
Q: How do you measure a latch?
Q: How do you measure a Horizontal Lock?
KEY
A - Case Depth
B - Backset (Follower)
C - Backset (Keyhole)
D - Case Height
E - Forend Length
F - Forend Width
Q: How do you measure a Horizontal Lock?
Q: What is Lock Bumping?
A: Many locks contain a cylinder with a pin tumbler mechanism. These cylinders have a set of pins, often five or six in a row. Each set of pins actually contains three parts: a lower pin, an upper pin, and a little spring. The lower pins have different lengths and sit in the barrel part of the cylinder (the plug) and make contact with the key. The upper pins sit above these and run from the plug into the cylinder body and prevent the plug from turning. When the correct key is inserted into the lock each pin is pushed up exactly the correct distance so that the join between each lower pin and upper pin lines up along the sheer line between the cylinder plug and body. This enables the plug to turn and activates the lock.

Lock bumping exploits a fundamental weakness in the design of the pin tumbler locking mechanism. Physics dictate that if you apply enough kinetic energy to the lower pin this will be transferred to the upper pin which will push up on the spring and create a gap between the two pins for a split second. If this gap falls across the sheer line between the plug and cylinder body in each pin chamber, the plug will turn. This is the theory behind lock bumping, but how do you achieve this pin separation effect?

The technique is startlingly simple. All you need is a special key called a bump key and a hitting tool like the handle of a screwdriver. A bump key is a key which has been cut down to the deepest cut at each pin position. Any key that will fit into the lock can be filed down to create a bump key:
Bump Key Image
The bump key is inserted into the lock and withdrawn a bit. Turning pressure is placed on the bump key with one hand and hit into the lock with the back of a screwdriver (or similar object) with the other. Sometimes a few hits are required until the pins are correctly "bumped", the pins separate for a split second, the plug turns, and the lock opens.
Bumping Image
This describes basic lock bumping. There are other techniques and tools available but the principle remains the same. Please also see our Range of Bump Resistant Cylinders.
Q: Am I at risk from lock bumping?
A: Many homes, offices and business in the South Africa are at risk from lock bumping.

Lock bumping is technique whereby certain locks can be opened with a specially prepared "bump" key and any suitable hitting tool. This technique has been around for some years but started receiving more peoples attention through the internet and media reports from 2005.

Lock bumping is a real risk to physical security that needs to be addressed for several reasons:

  • Media / internet exposure of lock bumping: If your reading this article you've heard of lock bumping. There is now lots of information on the internet and articles on how to make a bump key and techniques for bumping a lock. The information is free and easy to find. It is very simple for any criminally minded individual to add bump keys to his tool kit.

  • Cheap and easy: A bump key can be created for the cost of a key blank and a file and you can even use the back of the file as your hitting tool. The technique can be easily self taught and does not require any special skills. Compared to lock picking and other methods of bypassing locks, bumping is not technically challenging and much quicker to master.

  • Little evidence of intrusion: The lock should not be damaged when bumped, so it is very difficult to prove the lock has been bypassed. Some insurers require evidence of a break-in or some use of force to gain entrance to the property in the advent of a burglary, so insurance claims may be rejected.

    Please see our Range of Bump Resistant Cylinders.
  • Q Can I buy a bump proof lock?
    A: Yes. Lock bumping is technique whereby certain locks can be opened with a specially prepared "bump" key and a suitable hitting tool. Only certain locks can be bumped. Most locks that rely only on a pin tumbler mechanism can be bumped. Many cylinders in rim locks and uPVC doors have pin tumblers. Fortunately it is quite easy to protect yourself from bumping.

    The easiest way to protect yourself is to use a lock that does not use a pin tumbler. Most mortice locks use levers and do not use pins on springs so are bump proof by design. When choosing a cylinder ensure it has abump resistant element such Cisa G40D Cylinders with BKP.

    Product Sections