Magnet lifting capacity—what is it, and why is it important to pay attention to this parameter?

When choosing magnets, many customers pay attention to their size (length, width, and height), but when asked about a magnet’s load capacity, we often hear, “as strong as possible.” When choosing the right magnet for your needs, you should first determine what you’ll be using it for, what load it needs to hold, and under what conditions.. When planning where a magnet will be placed, we cannot assume that we have space for a cylindrical magnet—say, 10x5 mm—and expect that “the strength will somehow work out.” A magnet with specific dimensions will be limited to a certain lifting capacity, and the only way to increase this capacity is to install more magnets or replace it with a larger one..

This is a very important parameter because it determines the overall usability of a given magnet. If we choose a magnet based solely on, for example, the hole where we want to place it, we may end up with a magnet that doesn't serve its purpose at all.

What is a magnet's lifting capacity, and what does this term refer to??

In our store, each product lists the "Force (Max)" parameter. "Lifting Capacity," but what does that mean in practice?? This is the force required to lift a magnet off a steel surface under the following conditions:

• The direction in which the magnet is pulled away is perpendicular to the steel surface.
• The magnet adheres to the steel with its entire surface.
• The area is at least half magnet thickness.
• The surface is made of pure steel.

In most cases, these conditions are not met, and therefore the magnet's strength may be lower. In this article, you'll find a list of factors that can reduce a magnet's strength.

What affects the strength of a magnet??

1. There is a gap between the magnet and the metal surface.

If there is an air gap or a layer of nonmagnetic material (such as paint, plastic, or rubber) between the metal surface and the magnet, the magnetic force decreases. The greater the distance between the magnet and the metal surface, the weaker the attraction..

2. The magnet is not pulled away perpendicular to the surface.

The image above shows the difference between perpendicular peeling (on the left) and lateral peeling (on the right). Sliding a magnet along a metal surface requires much less force than lifting it off at a right angle. If the surface is very smooth (such as the paint on a refrigerator), the magnet's strength can decrease by as much as five times. There are surfaces that increase friction (e.g., rubber) and can make it easier for the magnet to detach than to slide off. In our store, you can purchase magnets in rubber casings, which work better when the force is applied laterally rather than perpendicular to the surface.

3. The magnet does not adhere across its entire surface.

If the metal surface is uneven and the magnet does not make contact with its entire surface, the magnetic force decreases in the same way as with an air gap.

4. The metal surface is not thick enough.

To achieve the maximum lifting capacity of a neodymium magnet, It must be attached to a surface that is sufficiently thick. For example, a magnetic roller measuring 20 × 10 mm achieves maximum force on sheet metal that is 5 mm thick or thicker. If we reduce the thickness of the sheet metal to 1 mm, the magnet's strength will be cut in half. When the sheet metal is 0.5 mm thick, the magnet's force drops to one-fourth.

5. The surface is not made of pure steel.

Our magnets were tested on a smooth, polished steel surface. If the sheet metal is made of a different magnetic material (such as an iron alloy with another metal) or if the surface is rusty, the magnet's strength may be reduced.

How to Choose the Right Magnet?

Because the magnet's lifting capacity It depends largely on the conditions of use; we recommend the following to our customers:

• Order samples of a few magnets and test them in practice.
• Allow for a margin of safety and use a stronger magnet.
• Try to minimize the factors described above (magnet slippage, air gap, surface irregularities, a surface that is too thin or of poor quality).

As we mentioned at the beginning of this blog post, before buying a magnet, we also need to determine its intended use. Magnets can have various uses, and some of them will depend on the magnet's construction.

Magnet with a lifting capacity of 590 kg

UM F400x2 + Mount - Neodymium Mount

This is a magnetic holder designed for prospecting. Double-sided, very strong, and equipped with two threaded holes for easy installation. These types of magnets are most often used to retrieve metal objects from hard-to-reach places, such as wells or ponds.

Screw the screws included with the magnet into the threaded holes, tie the rope to it, and the magnet is ready to use. Double-sided magnets are good for searching a larger area. Mounted using the hole in the metal clamp, you can use both sides of the magnet at the same time. These mounts are also available in a version with a single threaded hole and one open side, designed for spot exploration.

Magnet with a lifting capacity of 25 kg

C66 with handle - M8 - rubber-coated neodymium magnet - black

The rubber-coated neodymium magnet with a handle has a much lower lifting capacity than the magnet described above. However, it is used for tasks that do not require a great deal of power. A rubber grip has several advantages:

- It is waterproof (the rubber coating protects the magnet from rusting)

- It is safe for delicate surfaces (the rubber protects surfaces from scratches)

- It doesn't slip, even on very slippery surfaces (the casing increases friction, so the magnets don't slip under weight as easily)

These clamps are often used in printing shops to hold sheets of paper or film in place so they do not shift. Another way to use them is to attach something to your car; thanks to their rubber casing, these mounts won’t scratch the paint.

Magnet with a lifting capacity of 22 kg

D25 - UM 25 x 8 x M5 (internal). x 17 - neodymium magnet holder

The weakest of the products listed, but certainly not the worst. The neodymium magnet with a threaded sleeve is our most popular product. The threaded sleeve makes installation a breeze, making this magnet very versatile:

- You can screw a threaded rod into it and use it as a magnetic grabber to pull metal objects out of hard-to-reach places

- Just screw on the hook, and this holder becomes a hanger for clothes or small items

- It can be secured with a screw to a box that will hang from a metal surface, but it can be removed at any time

These are just a few examples of how our product can be used. Thanks to its steel housing, this neodymium magnet is impact-resistant and doesn't break easily.

Magnets must therefore be selected based on the appropriate size, application, and load they will be subjected to.. It seems difficult, but with careful thought, we can avoid making a mistake. If you're not sure which magnet to choose or have doubts about the choice you've made, we'd be happy to help you decide. You can always contact us by email or phone, and our experts will help you choose the right magnet.