Depending on the size and mounting arrangement, they may have a single countersunk hole, multiple holes, or countersunk recesses on one or both sides.
The hole configuration should match the intended screw direction and installation method. Single-sided countersunk holes are used when screws are inserted from a defined face, while double-sided countersunk holes provide greater flexibility when either face may be used during assembly.
Countersunk hole dimensions should be matched to the selected screw rather than determined only by the overall magnet size. The through-hole diameter must allow the screw body to pass through, while the countersink diameter and angle should suit the screw head so that it seats properly without excessive protrusion or uneven contact.
Magnet thickness and the remaining material around the hole also need to be considered. If the countersink is too large or too deep, the area around the hole becomes thinner and more vulnerable to chipping or cracking during installation. Screw size, head geometry, tightening method, and required seating depth should therefore be confirmed before the magnet drawing is finalized.
Most round Neodymium countersunk magnets are magnetized through the thickness, with one pole on each flat face. The countersunk face may be either the north pole or the south pole, depending on the required assembly arrangement.
Polarity should be confirmed when two countersunk magnets are intended to attract each other or when multiple magnets need to be installed with a consistent pole orientation. For magnet-to-magnet assemblies, matched north- and south-facing versions may be required.
SDM supplies custom Neodymium countersunk magnets in different shapes, dimensions, material grades, and coatings. Options include single or multiple countersunk holes, recesses on one or both sides, and specified polarity on the countersunk face.
For project evaluation, please provide a drawing with the magnet dimensions and countersunk hole details, together with the screw specification, required grade or operating temperature, coating, quantity, and polarity requirements.
