Lock Nuts, Locking Nuts or Jam Nuts come in various forms as shown below, other types include Prevailing Torque Nut and All Metal Locking Nut. Traditionally a Lock Nut is a DIN 439 Half Nut which are used in pairs to create a locking mechanism, but today we have many other options. Lock Nuts containing a nylon collar which elastically deforms when a threaded fastener is inserted, causing a frictional locking action, are very popular. Referred to as Nyloc nuts we have several variants in Metric and Imperial sizes. Also stocked are All Metal Locking Nuts where again a collared section, this time made of metal but slightly smaller in diameter to the rest of the nut, deforms as the nut is tightened. Where vibration to the bolted connection is likely to cause loosening, a lock nut is the simplest and most effective solution.