Which pot magnet do you choose? Based on mounting and holding force
A pot magnet is a neodymium magnet encased in a steel pot. The pot concentrates the magnetic force onto the flat front face, which makes the holding force on steel much higher than that of the same magnet without a pot. Which pot magnet you choose mainly depends on how you attach it and how much force you need. You can read more about the principle in Why are pot magnets so strong?
Step 1: choose the attachment
- Countersunk hole (drilled hole): you screw the magnet flush onto wood, plastic, or metal using a countersunk screw. Do not overtighten, as the magnet material is brittle.
- Threaded bushing (internal thread): you screw the magnet onto a bolt or threaded rod.
- Threaded stud: the thread protrudes from the pot; you screw it into a threaded hole or secure it with a nut.
- For bonding: you glue the back side. Use an adhesive suitable for metal and the base material.
- Rubber-coated pot magnet: the rubber casing protects the surface against which the magnet is placed and provides grip, preventing it from sliding easily.
Step 2: choose the holding force
The holding force in the table is measured under ideal conditions on a flat, thick steel plate. In practice, the actual holding force is lower due to rust, paint, an air gap, or a thin base material. Therefore, choose a size with a safety margin. Furthermore, the holding force is not a permitted working load: do not use a magnet as the sole support for heavy loads where a fall could cause injury. Read how holding force is determined.
Quick selection
| Size | Holding force (approx.) | Suitable for |
|---|---|---|
| Ø16 x 5 mm | 7.3 kg | Light objects, displays, lighting |
| Ø20 x 6 mm | 11 kg | Signs, displays, workshop |
| Ø25 x 7 and Ø25 x 8 mm | 15 to 18 kg | Workshop, molds, heavier objects |
| Ø32 x 7 and Ø32 x 8 mm | 17 to 21 kg | Workshop and assembly |
| Ø40 x 8 and Ø40 x 8.5 mm | 24 to 25 kg | Fixtures, assembly |
| Ø48 and Ø50 mm | 37 to 41 kg | Professional assembly, mechanical engineering |
| Ø60 x 15 mm | 73 kg | Heavy objects, fixtures |
| Ø75 x 18 mm | 107 kg | Very heavy applications |
| Rubber Ø31 and Ø43 mm | 13 to 14 kg | Where grip and surface protection count |
| Rubber Ø66 and Ø88 mm | 27 to 55 kg | Heavier objects with rubber grip |
Not every size is available in every attachment type. Please check the pot magnets for this.
Safe use
Magnets are not toys and should be kept out of reach of children. Keep strong magnets away from pacemakers, electronics, and bank cards. Large pot magnets snap against steel with force; keep your fingers clear.
Help with choosing
Are you in doubt between two sizes? Use the Magnet Advisor or contact us.
