How to Fix the Lock on a Filing Cabinet

What You'll Need
Lock kit and keys

Even though it’s not rocket science, few of us actually know how to fix or replace the lock on a filing cabinet. However, generic filing cabinet locks are relatively simple devices that are very easy to replace so it’s hardly worth trying to repair them. Only a handful of tools and materials are required for this job and the task takes only a few minutes.

Step 1: Safety First

Before getting started, think about your personal safety. It is advisable to wear protective goggles and gloves when replacing or fixing components. Although this is a quick and simple process, there is a definite risk of swarf flying around when dealing with metal so protection for your eyes and hands is vital.

Step 2: Remove the Old Lock

First, take the entire lockable drawer out of the filing cabinet. If the drawer is locked in position, you may need to unscrew the top of the cabinet to access the inside. Now, you should be able to locate the hexagonal nut that holds the old locking mechanism on place. This is usually found at the rear central position of the filing cabinet. Look for an oval indentation in the hexagonal nut. The indent is the point at which you should position the tip of your punch. Using the punch and hammer, you will need to tap the hexagonal nut firmly to loosen it. You may have to do this quite a few times until the old lock works itself free. Don’t hit the nut too hard but try to exert a moderate amount of force.

Step 3: Insert the New Lock

New lock kits always come supplied with keys. Insert a key into your new lock mechanism. Turn the key until the locking tag at the other end of the mechanism faces in an upward direction. This is an important step because if the bolt is in the wrong position, you won’t be able to fit the new lock into the hole of the cabinet.

With the bolt in the correct position, insert the replacement mechanism into the knocked out hole. Now that the mechanism is in place, turn the key in a clockwise direction for a ¼ turn to establish a "normally open" position.

Step 4: Fix Hexagonal Nut

Your lock kit will have come with a new hexagonal nut. Slide this over the thread of the barrel to the rear of the cabinet door and screw into place until it is finger tight. The locking tag should still be facing in either an easterly or westerly direction.

Step 5: Finish Up

Ensure that the new hexagonal nut is screwed into position tightly on the barrel of the new locking mechanism to finish. This can be achieved by using the punch and hammer on the oval indentation. A few light taps should secure the nut into place. The drawer can be slid back into place and your filing cabinet should have a fully functioning lock. If you had to remove the cabinet top, screw it back on before putting the filing cabinet back into position.