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 middle. Your choice depends on two things: how you attach the magnet (with a bolt or shaft through the hole, or with a screw in a countersunk hole) and how much holding force you need. If you want the size selected for a specific application, use the Magnet Advisor.
Quick selection by application
| Application | Example | Holding force (approx.) |
|---|---|---|
| Model making, displays, light closures | Ø10 x Ø4 x 5 mm | 3 kg |
| Doors and flaps with countersunk screw | Ø20 x Ø9.8 x 5 mm with countersunk hole | 2.1 kg |
| Mounting on a bolt or rod, light clamping | Ø20 x Ø10 x 10 mm | 11 kg |
| Workshop and heavier parts | Ø30 x Ø12 x 20 mm | 30 kg |
| Heavy clamping | Ø40 x Ø8 x 20 mm | 50 kg |
All sizes are available in the ring magnets collection.
Hole or countersunk hole?
- Straight hole (without countersink): for mounting on a bolt, rod, or shaft, for suspension, and in sensors.
- Drilled/countersunk hole: for screw mounting. The screw head disappears into the hole, so the magnet lies flat on wood, plastic, or metal. Do not overtighten the screw: neodymium is brittle and can crack.
Magnet against magnet or magnet against steel?
For a closure with ring magnets with a countersunk hole, you have two options:
- Magnet against magnet: ring magnets with a countersunk hole are available in north-pole and south-pole variants. Screw one of each facing each other, for example in the door and in the cabinet. This provides the most force. With two identical variants, they will repel each other.
- Magnet against steel: screw one ring magnet into the door and a steel ring with a countersunk hole as a counterplate in the cabinet. Cheaper and you do not have to pay attention to the poles; the force is slightly lower than with two magnets.
| Ring magnet with countersunk hole | Opposite pole | Steel counter ring |
|---|---|---|
| Ø8 x Ø6 x 3 mm | north / south | steel ring Ø8 |
| Ø10 x Ø7.1 x 3.5 mm | north / south | steel ring Ø10 |
| Ø12 x Ø8.1 x 4 mm | north / south | steel ring Ø12 |
| Ø14, Ø15 and Ø16 x Ø8.1 mm | Ø16 north / Ø16 south | steel ring Ø16 |
| Ø20 x Ø9.8 x 5 mm | north / south | steel ring Ø20 |
| Ø42 x Ø9.5 x 4 mm | north / south | steel ring Ø40 |
What to pay attention to
- Holding force: the stated values are measured under ideal conditions on a flat steel plate. Read how holding force is determined.
- Quality: the sizes with a countersunk hole are N35, the sizes without a countersunk hole are N45 to N50. A higher quality provides more holding force at the same dimensions.
- Temperature: the ring magnets are specified up to 80 °C.
- Safety: strong magnets can bang hard against each other or against metal; keep your fingers away and keep magnets away from pacemakers, electronics, and bank cards.
