Neodymium Countersunk Magnets

Ι What Are Neodymium Countersunk Magnets?

Neodymium countersunk magnets are permanent magnets made from a Neodymium–Iron–Boron (Nd-Fe-B) alloy, often called “Neo magnets” or “NdFeB magnets.” What makes Neodymium countersunk magnets different is the built-in countersunk hole, which allows them to be mounted with matching countersunk screws so the screw head sits flush with the magnet surface.

Although countersunk holes are common in Neodymium ring magnets, they are not limited to round shapes. Neodymium countersunk magnets can also be rectangular or arc-shaped, and the countersink may be designed on one side or on both sides of the hole. The countersunk feature is defined by the major (countersunk) diameter, the primary hole diameter, and the countersink angle, which is typically 90°. Most Neodymium countersunk magnets are magnetized along the hole direction, helping deliver strong holding force around the mounting area.

Neodymium magnets are difficult to form into precise shapes and tight tolerances during pressing, because the powder is compacted under an external magnetic field. This means the pressed parts cannot meet most real application dimensions directly. After sintering, the blank must be machined to achieve the final size and geometry.

For Neodymium countersunk magnets, machining is usually done in two stages: making the primary hole first, then forming the countersink. The primary hole is produced by drilling or trepanning, depending on its diameter and depth. After that, the countersunk section is cut based on the size and position of the primary hole, ensuring the screw head fits properly and sits flush.