Holding force, pulling force, and working load: what is the difference?
Short answer: the holding force (or pull force) in kg for a magnet is the force with which the magnet detaches from steel under ideal test conditions. It is not an allowable working load. Never use the stated value as the maximum weight for lifting or hanging something.
What is holding force?
Holding force is the force with which a magnet adheres to a steel surface, expressed in kilograms. You can read about how this is measured in how is the holding force of a magnet determined?
Why is the practical reality different from the stated value?
The stated holding force is measured under ideal conditions. In practice, the actual force may be lower, for example due to:
- a thicker or thinner surface;
- a surface that is not flat, clean, or dry;
- a layer between the magnet and the steel, such as paint, rubber, wood, or plastic (can magnets work through wood, glass, and plastic?);
- a force that is not acting perpendicularly, but at an angle or sideways;
- a higher temperature (what happens at high temperatures?).
Holding force is not a working load
A working load is the weight that a product can safely carry, including a safety margin. Holding force is not this. Therefore, do not use magnets as a lifting or hoisting tool based on the holding force. If a magnet detaches during a heavy application, it can be dangerous.
How to deal with it in practice
- Choose a magnet with significantly more holding force than you think you need.
- Test the combination of magnet and surface in a safe manner.
- Pay attention to the mounting and use: with a pot magnet, the design (threaded bushing, threaded stud, bore hole) is important.
- Keep fingers and hands away from strong magnets; they snap against steel with force.
Frequently asked questions
Is holding force the same as pull force?
For magnets, these terms are often used interchangeably to describe the force in kilograms with which the magnet detaches from steel. Always check how the value is intended for a specific product.
May I use the holding force as the maximum weight?
No. The holding force is not an allowable working load.
Are you unsure which magnet is suitable for your application? Ask the Magnet Specialist via the magnet advisor or contact.
