Is the north pole of a countersunk magnet on the large hole face?

During magnet application and selection, some customers inquire whether the large hole in countersunk magnets is the north pole during magnetization. Many rely on experience to determine polarity, but this understanding isn't entirely accurate. Below, Xiao Fu will explain this issue.

Countersunk magnets typically refer to magnets featuring a tapered or flared opening in the center, available in various shapes. The countersunk design facilitates screw insertion into the magnet's interior, enabling flush surface mounting. This structure serves solely as a mechanical mounting method and does not inherently determine the magnet's magnetization direction or pole distribution.

Is the side with the large hole always the N pole?

Not necessarily. After magnetization, the side with the large hole can be either the N pole or the S pole, depending entirely on the magnetization direction. Taking common axial magnetization as an example, simply adjusting the magnet's orientation when placed in a fixed magnetizing head can change the pole direction. A small number of customers may request specific poles for particular surfaces.

Round counterbored magnet

Why do many people assume the large hole is the N pole?

This stems primarily from industry conventions and application preferences. In certain assembly scenarios, manufacturers may consistently designate the large hole side as the N pole for uniform identification or to facilitate iron component attachment. Over time, this practice has become a “default assumption.”

As explained above, you should now understand that magnetic poles are determined by the magnetization method, not by the countersink structure. Specific pole assignments (N or S on particular faces) can be discussed directly with the magnet manufacturer.

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Neodymium Countersunk Magnets