Fitting a Cylinder Cam Lock: Drilling the 19 mm Hole for Wooden Drawers Accurately

October 6, 2025

A furniture cylinder lock generally requires a 19 mm hole through the furniture front to seat the cylinder core flush and anchor the locking mechanism securely in the carcass.

Retrofitting or installing a new lock on wooden drawers and cupboard doors is a classic task in furniture making. Whether in the workshop, office, or at home, a precisely fitted cylinder lock protects contents against unauthorised access. The practical challenge lies not in the complexity of the components, but in absolute dimensional accuracy. A drilled hole misplaced by just a few millimetres inevitably leads to a jammed bolt or a lock sitting crooked on the front.

This guide is aimed at installers and skilled DIYers. It covers determining the correct backset, drilling clean cylinder holes in engineered wood materials such as chipboard or MDF, and precisely aligning the striking plate.

Required Tools and Materials

Proper drilling and measuring tools are essential for the professional installation of a furniture lock. An untidy hole permanently ruins the front panel.

Cylinder lock (consisting of lock case, cylinder core, rosette, and keys)
Striking plate (angled plate or flat plate)
Cordless screwdriver or drill
Forstner bit with 19 mm diameter (centre point and rim cutters are strictly required)
Wood drill bit (2 mm or 3 mm diameter) for pre-drilling fixing screws
Marking tools: precision tape measure, try square, sharp pencil
Bradawl or centre punch for marking
Screwdriver (PZ or TX drive, matching the supplied wood screws)
A piece of scrap wood (backing board) and a G-clamp

Preparatory Dimensions: Understanding the Backset

Before drilling starts, the backset of the lock must be determined. The backset refers to the exact distance from the outer edge of the lock case (which rests flush against the top edge of the drawer) to the centre point of the cylinder core.

Standard commercial furniture locks typically feature a backset of 15 mm, 20 mm, 25 mm, or 30 mm. This dimension dictates the horizontal position of the 19 mm hole on the furniture front. An incorrect backset during marking out will result in the lock case either protruding over the edge of the wood or sitting too low in the material, preventing the bolt from engaging with the carcass profile.

Step-by-Step Guide: Fitting a Cylinder Lock

Installation requires systematic precision. Allow approximately 15 to 20 minutes per drawer.

Step 1: Mark the Position on the Front

Determine the vertical centre of the drawer front. If the drawer is 600 mm wide, for example, the centre is at exactly 300 mm. Mark this line lightly with a pencil on the inside of the front panel. Now measure downwards from the top edge of the drawer front by the specific backset of your lock. Mark the intersecting point precisely. This point is the centre for the 19 mm hole.

Step 2: Punch the Centre Point

Wood drill bits and Forstner bits tend to wander slightly on smooth melamine coatings or dense wood fibres. Indent the marked centre point using a bradawl or punch to a depth of about 1 mm to 2 mm. This indentation guides the centre point of the drill bit securely in the next step.

Step 3: Drill the 19 mm Hole

Drilling the front is like a surgical operation on wood – tear-out on the visible face must strictly be avoided. There are two established methods for this:

Method A: Using a Backing Board Clamp a piece of smooth scrap wood firmly with a G-clamp against the outside (visible face) of the drawer front, directly over the drilling spot. Place the 19 mm Forstner bit on the inside and drill completely through the front into the backing board at medium speed and light pressure. The backing board prevents wood fibres from tearing out as the bit exits.

Method B: Drilling from Both Sides Drill from the inside of the front until the fine centre point of the Forstner bit is just barely visible or felt on the outside face. Stop immediately. Switch to the outside of the front, insert the centre point into the tiny hole, and drill the remainder from the outside inwards. This method guarantees perfectly clean edges on both sides.

Technical note: Similar to installing a desk cable grommet where large diameters are drilled, keeping the drill bit at an exact 90° angle to the workpiece is crucial. A slanted hole causes the cylinder to bind.

Step 4: Insert and Screw the Lock Case

Slide the cylinder core from the inside through the finished hole. The lock case must now be aligned completely parallel to the top edge of the drawer. Use a try square for this. Mark the positions for the fixing screws. Remove the lock again and pre-drill the markings using a 2 mm wood drill bit to a depth of roughly 10 mm. Pre-drilling prevents the chipboard from splitting and ensures the screws drive straight. Reinsert the lock and secure it with the wood screws.

Step 5: Attach the Rosette

On the outside of the front, push or lightly press the cylinder rosette onto the protruding core. It covers the cut edge of the hole and ensures a clean finished look.

Step 6: Mount the Striking Plate to the Carcass

When locked, the bolt must engage into an anchor point. On drawers, the striking plate is mounted beneath the rail or the worktop above inside the carcass. Extend the bolt with the drawer open. Measure the exact distance from the bolt to the front edge of the carcass and transfer this dimension to the inside of the furniture unit. If necessary, use a wood chisel to cut a shallow rebate so that the striking plate sits flush with the surface of the wood. Secure the plate with screws after pre-drilling here as well.

Specific Application Areas in Cabinetry

Locks are not only used in standard office pedestals. Those wishing to childproof a TV sideboard or lowboard to protect expensive electronics or cables use the same technique.

Internal drawers in a wardrobe for two are also frequently fitted with a separate locking mechanism to keep personal documents or valuables private. Always consider internal clearances during planning. Internal hardware, such as a dish rack for wall cupboards in kitchen furniture, must not collide with the path of the lock bolt.

Particular care is required with flap stays. On upward-opening fronts fitted with heavy-duty gas struts, the closed flap is often under slight tension. Here, the striking plate must be adjusted so accurately that the bolt does not rub against the plate under pressure when turning the key, which would otherwise quickly wear out the lock cylinder.

Common Installation Mistakes

Tear-out on the face: Occurs when drilling straight through with too much pressure without a backing board or without drilling from both sides. The laminate coating chips off extensively.
Lock binds after installation: Usually the result of a 19 mm hole that is not drilled precisely square. The cylinder twists in the wood.
Bolt fails to lock: The striking plate was mounted too high or too low. The bolt hits wood or metal instead of sliding into the cutout.
Incorrect cylinder length: The length of the cylinder core must match the board thickness. For a 16 mm thick front, a 22 mm cylinder is standard (including room for the lock case). If the cylinder is too short, the rosette cannot be fitted.

Frequently Asked Questions

Can I use a standard twist drill bit instead of a Forstner bit? No. Standard 19 mm twist drill bits tear out the wood fibres on the surface severely and leave ragged edges. A Forstner bit cuts the outer fibres first with its rim spurs and then cleanly planes out the waste material.

How do I find the exact position for the striking plate when it cannot be seen with the door closed? A tried-and-tested workshop trick: apply some chalk, lipstick, or a dab of thick paint to the face of the lock bolt. Close the door or drawer and turn the key until the bolt presses against the carcass. The paint marks the exact point of contact on the timber. Position the recess for the striking plate precisely there.

Are locks available for thicker fronts, such as solid wood? Yes, cylinder locks are available in various cylinder lengths. While standard dimensions are 22 mm (suitable for 16 mm to 19 mm material thickness), versions with cylinder lengths of 32 mm or even 40 mm are available for thick solid timber fronts.

What is the difference between keyed alike and keyed to differ? In keyed alike systems, multiple installed cylinder locks (for example, on a mobile pedestal with three drawers) can be opened with one single key. In keyed to differ locks, each lock has a unique keying profile and requires its own specific key.