Which ring magnet do you choose?
Ring magnets with or without countersunk holes: which one is suitable for screw mounting, closures, or the workshop? Sizes, holding force, north and south poles, and safe use.
A ring magnet is a neodymium magnet with a hole in the center. You make your choice based on two things: how you will mount the magnet (with a bolt or shaft through the hole, or with a screw in a countersunk hole) and how much holding power you need. If you want help choosing the size for a specific application, use the Magnet Advisor.
Quick selection by application
| Application | Example | Holding power (approx.) |
|---|---|---|
| Model building, displays, light fastenings with a screw | Ø10 x Ø4 x 5 mm | 1.6 kg |
| Doors and hatches with a countersunk screw | Ø20 x Ø9.8 x 5 mm with countersink | 2.1 kg |
| Mounting on a bolt or rod, small clamping applications | Ø20 x Ø10 x 10 mm | 6.6 kg |
| Workshop and heavier parts | Ø30 x Ø12 x 20 mm | 18 kg |
| Heavy clamping applications | Ø40 x Ø8 x 20 mm | 26 kg |
All sizes can be found in the ring magnets collection.
Straight hole or countersunk hole?
- Straight hole (without countersink): for mounting on a bolt, rod, or shaft, for suspension, and in sensors.
- Countersunk hole: for screw mounting. The screw head sits flush in the hole, allowing the magnet to lie flat against wood, plastic, or metal. Do not overtighten the screw: neodymium is brittle and can crack.
North pole or south pole?
Ring magnets with a countersunk hole come in both north pole and south pole versions. Using one of each allows two magnets to attract each other, for example, for a closure between a door and a cabinet. Using two of the same version causes them to repel each other.
What to pay attention to
- Holding power: the values stated are measured under ideal conditions on a flat steel plate. Read how holding power is determined.
- Grade: the sizes with a countersink are N35, the sizes without a countersink are N45 to N50. A higher grade provides more holding power for the same dimensions.
- Temperature: the ring magnets are specified for use up to 80 °C.
- Safety: strong magnets can snap together or against metal with force; keep your fingers clear and keep magnets away from pacemakers, electronics, and bank cards.
