Back Home / Fasteners / Nuts / KEP NUT UNC STAINLESS #4-40 KEP NUT UNC STAINLESS #4-40 SKU: XKN440SS Categories: Fasteners, Nuts Keps nuts, also known as K lock nuts. A hex nut pre-assembled with a free spinning external tooth lock washer. The locking action is achieved when the nut is tightened against a bearing surface as the teeth of the lock washer dig into it. The most popular type of locknut because of its versatility, cost and ease of installation. Stainless Steel. Case Quantity: 100 Log In For Pricing