You have selected the right magnetic material (Neodymium or Ferrite) and the correct grade (N42, N52). But which shape should you use in your industrial product design? Disc, block, and holed (ring/countersunk) magnets each have their own unique advantages.
1. Disc and Cylinder Magnets
Disc magnets are the most popular shape for cost and pull force optimization. The magnetic field lines are concentrated on the flat circular faces of the disc. They are the perfect shape for embedding into milled or turned circular cavities using epoxy adhesives.
2. Ring and Countersunk Magnets
If you need to mechanically fasten a magnet to a surface using a screw instead of adhesive, you must use a magnet with a hole or a countersink. However, boring a hole through a magnet (creating a ring form) reduces its total volume, thereby slightly decreasing its pull force compared to a solid flat disc magnet.
3. Steel-Cased Pot Magnets (Reinforced Structures)
If you are mounting with a screw, a bare ring neodymium magnet can easily shatter when you tighten the screw. To prevent this and to maximize pull force, Pot Magnets are preferred. Enclosed in a steel cup (pot), these devices redirect the magnetic field to a single open face (e.g., the bottom), amplifying the holding power by 3-4 times compared to a bare magnet. These reinforced architectures are heavily used in sensor mountings and as core connectors in mechanical systems like Magnetic Lifters.