Neodymium Donut Magnet

BMAG Neodymium Donut Magnets are characterized by their distinctive wide-center aperture and robust outer walls. Often referred to as “hole magnets,” these donut-shaped components are the ideal solution for designers who need to integrate high-strength magnetism with mechanical fasteners like bolts, screws, or shafts. The donut shape allows for a unique flux distribution that is particularly effective for “sandwich” style assemblies where the magnet is clamped between two steel plates.

Despite the removal of the central material, these magnets retain a high volume-to-strength ratio. We optimize the magnetic circuit by focusing on the “permeance coefficient” (Pc), ensuring that the donut geometry does not lead to self-demagnetization. Available in various thicknesses, these magnets can be customized with countersunk holes or straight bores.6 The smooth, chamfered edges prevent the brittle neodymium material from chipping during high-impact fastening, while the multi-layer plating ensures a low-friction surface for easier handling during the assembly process.

Neodymium Donut Magnet Dimension Diagram

Ring Magnet Magnetization Direction