An essential skill for any locksmith, shimming can allow you to quickly gain access to a lock when it matters most. No matter whether you are a novice, want to refine your approach, or you just want a few pointers – it’s always helpful to get a refresher on the process. So, what exactly is shimming and how do you carry it out with minimum effort and maximum efficiency.
What is shimming?
Shimming is a lock bypassing procedure that uses a tool to gain access to an otherwise secure lock. The approach involves the use of – and points if you guessed it – a shim. This is commonly a slim piece of metal that is inserted into the device that releases the shackle element on a lock. While many modern locks will use technology or design approaches that make shimming impossible, it can be used on a range of standard devices or locks with significant design flaws. If a device uses a spring-loaded catch, there will often be a way to deploy a shim to gain access. If practiced enough, shimming can become almost effortless and help provide a simple solution to a range of security problems.
How is it done?
While looking for a ‘how to’ shim a lock video can help give practical guidance on how to deploy a shim in almost every environment, it can be important to understand the fundamentals involved well in advance. Any conventional lock that can be accessed with a shim will involve a variation on the approach listed below-
1. Obtain your shim: While a shim can be purchased at any reputable retailer, all of us will have the elements required in our home. The most common type of shim is constructed from an aluminium can. To make one, wash out the can well with warm soapy water and cut the top and bottom from the object. Once rolled out flat, draw a line lengthways on the metal and divide it into quarters, before halving each quarter and cut an ‘M’ shape into the metal – crimping the bottom of your shim to make a handle that will not cut your fingers.
2. Assess your lock: Shimming is most commonly carried out with a padlock and, in order for your attempt to be successful, take some time to assess the lock. The first thing to assess is if the padlock is single or double shackle – does it lock on one side with the internal mechanism or on both sides? If it is the latter, this will require two shims to be deployed simultaneously to open.
3. Start Shimming: Once you have determined your access route to the locking mechanism, insert your shim between the padlock body and the shackle. This should be opposite the locking groove; the indentation in the metal that is used to secure the bolt. Once inserted, gently but firmly turn the shim while moving the shackle element up and down. If successful, this bypasses the mechanism and causes the lock to open. If you are trying to bypass a double shackle lock, simply insert a second shim and repeat the process simultaneously. Thanks to CLK Supplies for consulting