What is the pull force of a magnet and how do I choose a magnet for my application based on its pull force?
Pull force is one of the methods used to determine the strength of a magnet. It is typically defined as the force that separates the magnet from a low carbon steel plate with direct contact and a direct pull, where the steel plate should be 20 mm thick. The steel plate surface should be smooth and clean. The force pulling the magnet away should be perpendicular to the surface.
Based on these factors, the pull force will be lower in each of the following situations,
- The magnetic surface is less magnetic than low carbon steel.
- The magnetic surface is thinner than 20 mm ("0.787")
- The magnetic surface is rough or not in direct contact. For example, the surface is painted or there is debris on the surface.
- The pull is not perpendicular to the surface. For example, when hanging an item on the refrigerator
- In most applications, the actual pull force is lower once these factors are taken into account.
Unlike gauss and maximum energy product, which are more scientific terms, pull force is more often used by hobbyists when choosing magnets. For example, when choosing a magnet for crafts, the office, the home and so on, where the actual pull force is the basic concern.
