A magnet recess that is half a millimetre too deep can turn a crisp cupboard catch into a weak, frustrating closure. A recess that is too shallow leaves the magnet proud of the surface, where it can chip or stop a door from sitting properly. Knowing how to drill magnet recesses accurately is what makes compact, super-strong neodymium magnets work as intended.

The aim is simple: create a clean, flat-bottomed pocket that matches the magnet diameter and depth, then bond the magnet in place with its face flush or very slightly below the surface. The best method depends on the material, the magnet format and whether the finished part will be visible.

Start with the magnet, not the drill bit

Measure the actual magnet before machining the workpiece. Nominal sizes are useful for selecting a product, but a recess needs enough clearance for adhesive and easy fitting. For example, a 10 mm diameter disc magnet should not be forced into a precisely drilled 10 mm hole. In timber, a 10.5 mm or 11 mm recess usually gives sensible room for glue. Test the fit on an offcut first.

Depth matters just as much. For a 3 mm thick disc magnet, drill to around 3.1-3.3 mm if the magnet needs to finish flush. That small allowance accommodates adhesive without leaving the magnet sitting high. If you want the magnetic face concealed under a thin timber veneer or plastic skin, reduce the drilled depth accordingly, but remember that every extra layer between two magnets or between a magnet and steel reduces holding force.

Choose the magnet with the job in mind. A wide, shallow disc gives a larger contact area and is often ideal for cabinet doors and timber closures. A block magnet can suit a routed channel or a non-visible installation. Countersunk magnets are designed for mechanical fixing with a suitable screw, rather than a plain glued recess.

Mark the centre accurately

For repeated cabinet work, make a simple drilling jig from scrap hardwood or MDF. Drill the guide hole in the jig on a pillar drill, then clamp it at each fixing point. This keeps every recess aligned and prevents a handheld drill bit from wandering across the surface.

For one-off jobs, mark the centre with a sharp pencil or marking knife and use an awl to make a light starter mark. On painted, veneered or laminated boards, apply low-tack masking tape before marking. It improves visibility and can help reduce surface chipping.

Before drilling, check the mating component. A door magnet must meet its counterpart squarely when closed. If the door has hinges with play, or the frame is slightly out of true, position the magnet where it will make full contact rather than relying on a measurement alone. Dry-clamping the parts in their final position is time well spent.

Choose the right bit for a clean recess

A Forstner bit is the usual choice for drilling magnet recesses in solid timber, plywood, MDF and many laminates. It cuts a flat-bottomed hole, produces a crisp edge and can start close to an existing edge where a standard wood bit may struggle. Use a sharp, good-quality bit at a controlled speed.

A brad-point bit can work for small disc magnets, especially where a shallow recess is needed, but its pointed centre leaves a small dimple in the base. That is rarely a problem when bonding with adhesive, although a Forstner bit gives a more consistent result for larger diameters.

For plastic, use a sharp twist drill or a purpose-made plastic bit at low speed. Too much speed generates heat, which can melt the edge of the recess or pull the bit into the material. Back the workpiece with scrap timber to support it and reduce breakout.

Metal is a different job. A standard neodymium disc magnet should not be drilled after purchase: neodymium material is brittle, coated and can crack, overheat or shed hazardous sharp fragments. If you need a magnet fixed to steel or aluminium, drill the metal with the correct metalworking bit and use a pre-countersunk magnet, a magnetic catch or an appropriate mounting arrangement.

Set the depth before you drill

The easiest way to spoil an otherwise tidy installation is drilling through the face of a cabinet door or thin panel. Set a depth stop on a pillar drill whenever possible. For a handheld drill, wrap tape around the bit at the required depth, but treat the tape as a visual guide rather than an exact stop.

A better handheld solution is a drill depth-stop collar. Set it after measuring from the cutting rim of the bit, not from the tip of a centre point. Make a trial recess in an offcut of the same material and check it using the actual magnet.

Drill in short, controlled passes. Clear dust from the hole regularly, particularly in MDF, where packed fibres can make the bit cut hot and leave a rough base. Keep the drill upright. A magnet installed at an angle can be visibly uneven and may not meet its steel plate or opposing magnet correctly.

A practical method for timber and MDF

Clamp the workpiece firmly on a flat bench. Position the bit on the marked centre, bring it up to speed, then lower it steadily without forcing the cut. Let the rim of a Forstner bit establish the edge before applying more pressure. Stop just short of final depth, clear the dust, and test with the magnet.

The magnet should drop into the recess without being forced. If it binds, widen the hole very slightly rather than pressing it in. Neodymium magnets can fracture under point pressure, and a cracked magnet loses its clean finish as well as its strength.

If the recess is a fraction too deep, do not fill it with a thick pool of adhesive and hope for the best. Add a flat shim at the bottom, such as a thin plastic disc or carefully cut veneer, then fit the magnet on top. This preserves the correct face position and gives a more reliable closure.

Check polarity before using adhesive

Polarity errors are common when fitting pairs of magnets into doors, boxes and removable panels. Two magnets that should attract can repel if one is installed the wrong way round. Once bonded into a tight recess, correcting the mistake can damage the workpiece.

Before opening the adhesive, stack or pair the magnets in their intended orientation. Mark the outward-facing side of each magnet with a small piece of tape or a non-permanent marker. Keep that mark visible until the magnet is fitted. If you are using a steel strike plate, polarity does not matter, but the contact position still does.

Keep powerful magnets apart while you work. Larger N52 magnets can snap together unexpectedly, trapping fingers or chipping their protective coating. Store spare magnets with their supplied spacers until the installation is complete.

Bond the magnet securely

For most timber, MDF and plastic installations, a quality two-part epoxy provides a strong, gap-filling bond. Cyanoacrylate adhesive can be convenient for small magnets in a very close-fitting recess, but it is less forgiving of gaps and can become brittle in a high-use fitting. Construction adhesive is usually too thick for a neat, shallow magnet pocket.

Clean the recess of dust and wipe the magnet dry before fitting. Apply a small amount of adhesive to the base and sidewall of the recess, rather than coating the entire magnet face. Press the magnet in squarely using a non-magnetic tool, wood offcut or plastic push block. Avoid using another loose magnet to push it home, as it may jump onto the installed magnet and disturb the bond.

Wipe away squeeze-out immediately, especially if the magnet must sit flush. Hold or clamp the workpiece so the magnet cannot creep upwards while the adhesive cures. Follow the adhesive curing time rather than testing the closure after a few minutes.

Avoid the common causes of weak performance

A high-strength magnet cannot compensate for poor alignment or excessive spacing. Recesses on a door and frame need to meet face-to-face. A 1-2 mm gap caused by a proud magnet, thick paint layer or misaligned installation can noticeably reduce usable pull performance.

Do not assume the strongest available magnet is automatically the right answer. On a lightweight cupboard door, an oversized magnet can make opening awkward or pull a poorly secured strike plate loose. Select enough holding force for the door weight, handle position and expected use, then install it with a clean, close contact surface.

For visible joinery, make the recess slightly deeper and cover the magnet with a thin timber plug only if the reduced magnetic gap is acceptable. For concealed catches, a flush-fitted disc magnet paired with a steel plate is often the more practical choice.

A careful trial on an offcut is the quickest route to a professional result. Once the bit size, depth and adhesive are proven, the final recesses become repeatable – and the powerful, compact magnetic closure will feel as reliable as the rest of the build.