Abstract: Two forms of load bearing or transmitting structures are disclosed wherein each uses magnetism to hold a key in one of two bodies to prevent movement therebetween. One embodiment is a clevis, wherein the clevis pin is instrumented as a load cell and a magnetic key resides in a slot in a portion of the clevis pin which protrudes outside of one of the clevis legs. In another embodiment, torque is transmitted between a shaft and a coupling by means of keys that are held in keyways by magnetism thereby to provide a torque coupling between the shaft and coupling members.