How to Remove a Lock from a Metal Filing Cabinet

Introduction

Metal filing cabinets are a common fixture in many offices and homes. They provide secure storage for important documents and valuables. However, over time the original keys can be lost or damaged. When this happens, you may need to remove the existing lock to replace it with a new one. Removing a lock from a metal filing cabinet is not overly complicated, but does require some specific tools and techniques to do it properly.

In this comprehensive guide, we will walk through the entire process step-by-step. We will cover:

• Assessing the lock and cabinet style
• Gathering the proper tools
• Drilling out the lock
• Removing the lock cylinder and mechanism
• Patching holes and preparing for a new lock
• Installing a new lock

With the right approach and tools, you can remove the old damaged lock from your filing cabinet and install a replacement quickly and efficiently. Let’s get started!

Assessing the Lock and Cabinet Style

Before you can remove and replace a metal filing cabinet lock, you need to assess the specifics of your lock and cabinet. This will determine the proper tools and techniques. Here is what to look for:

Examine the Visible Lock Mechanism

First, look closely at the portion of the lock visible on the outside of the filing cabinet. Note the keyhole shape, size, placement, and any identifying markings from the manufacturer. This will help determine what style the internal lock mechanism is.

Common lock styles include:

• Standard pin and tumbler – Most common, these have a simple keyhole and slotted screw heads on the exterior.
• Tubular – Identified by a round, hollow keyhole. May be found on lighter duty or lateral cabinets.
• Disc – Uses a keyhole with a rectangular opening and no visible screw heads.
• Wafer – Similar to disc but a different internal design. Keyhole is rounded at one end.

Check for Access Panels

See if there are any small access panels on the side, back, bottom, or top of the cabinet. These may cover up lock mechanisms and save you from drilling if removable.

Note Cabinet Construction

Is the cabinet made of thin sheet metal or thick steel? Thicker steel will require more powerful drilling tools. Also note if there are reinforcements around the lock area.

Try Original Keys

Before drilling, see if any original keys still work. If so, you may be able to disassemble from the inside by unlocking the cabinet first.

Consider Calling a Locksmith

For complicated or high security locks, calling a professional locksmith to remove and replace may be the wisest and most cost effective option.

Gather Proper Tools

With the cabinet assessment complete, gather up the proper tools to safely and effectively remove the damaged lock. Here are the must-have tool options:

• Variable speed drill – A powerful drill with clutch settings will allow you to carefully drill the lock out. A 1/2″ chuck size is best.
• Metal drill bits – Cobalt steel or titanium bits designed for metal cutting are required. Various sizes from 1/8″ to 1/2″ are ideal.
• Center punch – Allows you to mark the precise drilling location and keeps the bit from wandering.
• Hammer – A small ball peen hammer helps drive the punch into the lock casing.
• Screwdrivers – Standard and Phillips head screwdrivers will aid disassembly.
• Locksmith’s tools – These specialty tools for extracting and disassembling locks are very helpful.
• Utility knife – Helps pry apart lock components and access screws.
• Pliers – Locking pliers hold components in place while disassembling.
• Eye protection – Safety glasses protect your eyes from metal fragments.
• Work light – A bright light aids visibility within the cabinet.
• Sandpaper – Used to smooth drill holes and rough edges for the new lock.
• Replacement lock – Match this as closely as possible to the original.

Drilling Out the Damaged Lock

With the right gear on hand, it’s time to start drilling out the old lock. Take it slowly and carefully. Here are the step-by-step instructions:

Mark Drill Location

Use the center punch tool to mark the precise spot to drill. This is usually at the intersection of the keyhole and first screw. Applying firm pressure, tap the punch with the hammer to imprint the drill location.

Start Small

Attach a small 1/8″ metal drill bit to your variable speed drill. Set the clutch at low torque. Starting with a smaller bit prevents the drill from wandering. Gently drill the pilot hole at your punch mark.

Increase Size

Now switch to progressively larger bits – 5/32″, 3/16″, 1/4″ – until the screw head and lock cylinder are exposed. Take it slowly to avoid breaking a bit. Spray inside the hole with WD40 to clear out metal shavings.

Drill Through Screws

Once the screw head is visible inside the larger hole, you can drill directly through the screw to loosen it. Apply firm pressure but don’t force the drill.

Remove Screws

Use a screwdriver to back out and fully remove the screws holding the lock cylinder and mechanism in place. Having drilled through them first makes this much easier.

Drill Cylinder Holes

If needed, go up to a 1/2″ bit size to expose and drill out the pins around the cylinder. This allows the core to detach from the outer housing.

Extract Lock Parts

You can now remove all remaining components of the lock mechanism using your pliers, screwdrivers, and locksmith tools. Carefully extract any small parts left behind.

Removing Lock Cylinder and Mechanism

With the screws out and cylinder drilled, removing the entire lock mechanism takes some dexterity. Have patience and go slowly to avoid damaging the cabinet body itself.

Wiggle Cylinder Free

Using your utility knife and flathead screwdriver, carefully pry and rock the lock cylinder back and forth to detach it from the outer casing. The precise technique depends on the lock style.

Disconnect Linkages

The cylinder will have linkages, clips, rods or cams connecting to the latch mechanism. Carefully disconnect these from the back of the cylinder. Note how they are oriented for re-installation.

Access Interior Mechanism

You now have access to the latch mechanism inside the cabinet. Remove any remaining screws or fasteners to fully detach the entire lock mechanism from the cabinet body.

Clean Out Hole

Use your drill and a round file attachment to clean and smooth out the hole where the lock was removed. File down any burrs or sharp edges.

Remove Backplate

If there is a backplate from the lock cylinder on the inside of the cabinet, detach it now. This may require drilling out spot welds then prying it off.

Patching Holes and Preparing for New Lock

With the original lock fully removed, you will need to patch holes and prepare the area for installation of the replacement. Here are the steps:

Clean Surface

Use a wire brush attachment on your drill to vigorously scour the front surface around the lock hole. This removes any dirt or debris.

Sand Area

Use coarse grit sandpaper to smooth and level the surface. Then follow up with finer grit to polish it. Remove any burrs, dust, or grime.

Fill Holes

For small drill or screw holes not needed for the new lock, fill them with metal epoxy putty and allow to fully cure. Sand smooth when dry.

Drill New Holes

Mark and drill precise holes for the replacement lock screws based on the specific model. Use new sharp bits and take it slow.

Prime Bare Metal

Use spray primer to coat any bare metal or epoxy fill patches. This prevents rusting and aids paint adhesion. Allow primer to dry fully.

Repaint Cabinet

Finally, repaint the area around the lock hole using touch up paint to match your cabinet finish. Allow paint to cure before installing new lock.

Installing a New Lock

With fresh paint and holes ready, it’s time to install your new lock. Make sure you purchased the proper replacement style and size. Here is how to complete the install:

Insert Cylinder

Carefully insert the new lock cylinder into the hole in the cabinet front. Support it from the interior as you attach the exterior housing/shell.

Attach Cylinder

Using the provided fasteners, bolt the cylinder assembly into place. Don’t overtighten! If needed, drill new screw holes.

Reconnect Linkages

Attach the connecting bars, clips, rods and springs between the cylinder tailpiece and interior latch mechanism.

Confirm Smooth Operation

Test the lock function several times with the included keys. The latch should extend and retract smoothly when locked and unlocked.

Install New Handles

Most replacement locks do not include new exterior handles. Swap them over from the old lock or purchase new ones.

Weatherproof Exterior

Caulk or silicone seal around the new cylinder and handles to prevent water intrusion into the cabinet.

With some care and patience, your metal filing cabinet will now have a fully functional lock once again! Be sure to label the new keys and store them in a safe location.

Frequently Asked Questions About Removing Filing Cabinet Locks

Removing old, damaged locks from metal filing cabinets can be tricky. Here are answers to some of the most common questions on how to do it properly:

What tools do I need to remove a filing cabinet lock?

You will need a variable speed drill and assortment of small to medium metal drill bits, center punch, hammer, utility knife, screwdrivers, locking pliers, sandpaper, replacement lock, and eye protection.

How can I get the filing cabinet open if I lost the key?

Unfortunately without the proper key there is no way to open it without drilling out the lock. A professional locksmith may be able to pick or decode some locks to avoid drilling.

What if I can’t detach the cylinder from the casing?

With the screws removed, carefully use a flathead screwdriver and hammer to pry the cylinder free by tapping it alternately left and right. Spray lubricant into the cylinder hole to help.

What size drill bit should I use?

Start with a 1/8″ pilot hole on your center punch mark. Gradually increase the size up to 1/2″ diameter until the lock cylinder is accessible. Use bit sized needed to penetrate any lock screws.

How should I fill drilled holes I don’t need?

Use a metal epoxy filler, allow it to fully cure, then sand smooth. The filler should be rated for exterior use. Properly prime and paint to prevent corrosion.

What if I drill into the cabinet interior by accident?

You will need to patch larger holes with thin sheet metal plates pop-riveted over the hole. Use multiple plates if the hole is over 1″ wide. Fill gaps with epoxy filler before attaching plates.

Can I just replace the handles rather than the entire lock?

Unfortunately the lock cylinder and latch mechanism are usually damaged or corroded. The handles rarely fail. You will need to replace the entire locking mechanism for proper operation.

How do I find an exact replacement lock?

Check the manufacturer name and serial number stamped on the old cylinder. Search online using the brand and model number to find an exact replacement. If not available, bring the old unit to a locksmith.

What should I do if the cabinet has a high security lock?

Special high security locks require professional disassembly. Call a licensed locksmith to remove and replace high security locks to avoid damaging the cabinet or contents. Never try to drill these out on your own.

Carefully following the steps in this guide will allow you to successfully remove the old damaged lock from your metal filing cabinet and install a new replacement. Take it slowly, use the proper tools, and call a locksmith if needed for high security locks. Your cabinet will be back to providing secure storage in no time!

Conclusion

Removing old, worn out locks from metal filing cabinets and replacing them with new ones is a common DIY repair. With some preparation, assessing your cabinet style, gathering the right tools, and carefully drilling out the damaged lock, you can access and remove the entire locking mechanism.

Be sure to properly patch any leftover holes, prime, and paint the area before installing the replacement lock. Following the steps outlined above and working slowly with proper tools will result in success. Just take all safety precautions, wear eye protection, and consider calling a professional locksmith if you run into issues removing certain high security lock types or cylinders that won’t detach.

Your important documents and valuables stored in the filing cabinet will once again be protected and secure thanks to your diligent efforts removing and replacing the damaged lock. Just be sure to label the new keys and keep them in a safe spot for easy access when you need to lock up your cabinet.