Axially or diametrically magnetised: what is the difference?
Short answer: on an axially magnetised disc or rod magnet, the north and south poles are on the two flat faces (the ends). That is the standard. On a diametrically magnetised magnet, the poles are on the curved side, opposite each other: one half of the circumference is north, the other south. Diametrical magnets are used when the magnet has to rotate or attract sideways, such as in rotating closures, sensors and small motors.
The difference at a glance
| Axial | Diametrical | |
|---|---|---|
| Poles | on the flat faces | on the curved side |
| Stacking | flat on top of each other into a rod | side by side |
| On steel | stays upright | lies down and can roll |
| Typical use | closures, fixing, holders | rotary knobs, hinges, angle sensors, small motors, magnetic stirrers |
| Availability | almost all sizes | limited number of sizes |
How do you recognise a diametrical magnet?
- Place it on a steel plate: an axial rod stays upright, a diametrical one lies down.
- Place two magnets side by side: diametrical magnets turn so that their sides attract.
- With magnetic viewing film you see two halves for diametrical, one face for axial.
What are diametrical magnets used for?
- Rotating closures and hinges: a small rod in a shaft that attracts or repels as it turns.
- Angle and rotation sensors: a Hall sensor measures the rotation of the magnet.
- Model building and 3D prints: moving parts, turrets, wheels.
- Small motors and stirrers.
Diametrical magnets in our range
- Rod magnet Ø3 x 6 mm N52 diametrical, also in gunmetal, black epoxy and rosé
- Rod magnet Ø8.9 x 50 mm N48 diametrical
- Rod magnet Ø10 x 50 mm N52 diametrical
- Filter magnets (diametrical, in a stainless steel tube)
More selection help in which rod magnet should you choose?
Frequently asked questions
Is a diametrical magnet as strong as an axial one?
The material is equally strong, but the holding power on a flat plate is lower, because a curved side only touches the plate along a line.
Can I have an axial magnet magnetised diametrically?
No. The preferred direction is fixed during pressing at the factory. See how are neodymium magnets made?
How are block magnets magnetised?
Usually through the thickness (the smallest dimension), so the poles are on the large faces. See which block magnet should you choose?
