Concave MF Locknuts

Used in conjunction with a regular square nut, the concave MF Locknut spins freely from either side into place with the fingers.  When the MF Locknut touches the nut, an additional one-half to three-quarters of a turn with a wrench locks it securely. The additional turns deflect the nut threads from their true helix and causing them to firmly grip the bolt threads; vibration cannot shake it loose.  No special wrench is required.