It’s based off of the heaviest piece you are lifting, right? That certainly is one key component but there are many others to consider. Material surface condition, alloy content, material thickness and contact area are also major factors in determining the proper magnet selection. Use the following information as a starting point for your selection of the proper lifting magnet for your application.

Safe Working Load

Safe Working Load values include at least a 2:1 Safety Factor on typical hot rolled surface mild steel plates of 1” thickness or greater with 100% magnet contact. The recommended application capacity on thinner material is reduced due to the inability of the material to handle the full magnetic output of the magnet and the additional airgap caused by the bending of the material. When considering a lifting magnet as a below the hook device, please consult Permadur for a detailed capacity rating and a maximum plate size for thinner Magnet material.

Most Realistic Actual Conditions

Permadur feels that this Safe Working Load approach based on typical hot rolled surface conditions represents the most realistic view of actual field load surface conditions. Better quality load surface conditions can result in a higher maximum recommended capacity. The above information not only is important for individual lifting magnets, but also for plate handling magnets, sheet handling magnets and multiple part handling magnet systems. Permadur’s experienced engineering staff is always available to review your applications and confirm your selection of the proper lifting magnet.