Which block magnet do you choose?
Which block magnet is right for your project? An overview by application, from model building and small fasteners to cabinet doors, workshops, and mechanical engineering, including explanations of countersunk holes, pole orientation, epoxy, and self-adhesive versions.
Choosing the right block magnet is based on the application and the holding power, not just the dimensions. Below you can read which version is suitable for each application, when a magnet is too small, and what you should pay attention to regarding countersunk holes, pole orientation, epoxy coating, and self-adhesive versions. All block magnets are made of neodymium. Do you want to calculate how much holding power you need? Use the calculation tool below or the Magnet Advisor.
Quick selection by application
| Application | Usually matches | Example |
|---|---|---|
| Model making, electronics, and small fasteners | Holding power up to approx. 1 kg | 6 x 4 x 2 mm |
| Cabinet doors, hatches, furniture construction, camper, and caravan | Holding power approx. 4 to 10 kg | 60 x 40 x 5 mm, 50 x 50 x 5 mm |
| Workshop, tools, molds, and heavier panels | Holding power approx. 10 to 25 kg | 40 x 40 x 10 mm, 25 x 25 x 10 mm |
| Industry, clamping, and machine construction | Holding power from approx. 25 kg | 60 x 60 x 30 mm, 85 x 30 x 12 mm with stainless steel handle |
| Screw-in mounting | Version with countersunk hole | 25.4 x 25.4 x 12.7 mm plastic with hole |
| Humid environment or steel doors | Epoxy version | 80 x 20 x 2 mm epoxy |
This is a guideline. Always test with one or two magnets before ordering or installing a large series.
Calculate how much holding power you need
Enter the weight, the number of block magnets, and the surface material. The calculation tool indicates the minimum holding power per magnet you need and shows suitable block magnets from our assortment. It is a guideline: always test with one or two magnets.
Why a block magnet?
A block magnet has a flat contact surface. This makes it convenient for installation in slots and against flat surfaces, and in elongated or flat designs along an edge. A disc magnet is round; if you prefer a round shape, read Which disc magnet to choose?.
Choose by holding power
- Below 1 kg: thin and light, for model making, electronics, and small parts.
- 1 to 4 kg: small fasteners and detachable parts, for example 10 x 5 x 4 mm: approx. 2.0 kg.
- 4 to 10 kg: cabinet doors, furniture construction, and campers, for example 60 x 40 x 5 mm: approx. 5.5 kg.
- 10 to 25 kg: workshop, tools, molds, and heavier doors, for example 40 x 40 x 10 mm: approx. 21 kg.
- From 25 kg: professional use. These magnets can snap together or against metal with force; keep your fingers away.
Countersunk hole and pole orientation
Block magnets with a countersunk hole can be fastened with a countersunk screw. For these versions, the product name or specifications indicate which pole is on the countersunk side: north pole or south pole. This is important if two magnets need to attract each other, for example, a magnet in a door and a magnet in the frame.
Two identical variants will repel each other. If two magnets need to attract each other, combine a north pole variant with a south pole variant. Sometimes you need one of each, such as with 30 x 13.5 x 5 mm north pole and south pole, or 13.5 x 13.5 x 5 mm north pole and south pole. A block magnet with a countersunk hole and a steel counter-surface always works; the pole choice only counts if you place two magnets opposite each other.
Self-adhesive versions have the same pole orientation: when sticking them on, pay attention to which side faces outward. Stick them onto a clean, dry, and flat surface. Are you unsure about the pole orientation? Contact us.
Epoxy and plastic coated
Standard block magnets have a NiCuNi coating (nickel-copper-nickel), suitable for dry indoor spaces. Epoxy versions and plastic-coated versions offer extra protection against moisture and wear. For steel doors, read Epoxy-coated magnets in steel doors.
What to pay attention to
- The holding power is a laboratory value. It is measured on a flat, thick steel plate. In practice, the actual force is lower, especially with a thin, uneven, or coated surface or if there is an air gap. Read how holding power is determined. Always test.
- Quality (N35, N48, and so on). A higher number means a stronger magnet of the same size. Read what N35, N42, N48, and N52 mean.
- Temperature. Our block magnets are suitable up to 80 °C. Above that temperature, the magnet can permanently lose strength.
- Jewelry. The NiCuNi layer contains nickel. Incorporate the magnet into the jewelry so that the skin does not come into contact with it.
- Safety. Magnets are not toys and should be kept out of reach of children. Keep strong magnets away from pacemakers, electronics, and bank cards.
