Magnaflux Lead Contact PlateMagnaflux Lead Contact Plate The Magnaflux Contact Plates are installed on every magnetic particle bench unit sold. The purpose of a contact plate is to give good contact to the part and protect the surface of the head and tail stock. These plates need to be replaced when you start seeing holes and excessive wear marks on the surface. Note: Worn surfaces can lead to poor part contact, which could result in damage to the part. The Magnaflux Lead