Locknuts are used where there is a significant probability that a nut will loosen over time because of vibration or frequent temperature changes.
When the danger of corrosion is not too severe and 18-8 or 316 Stainless is adequate for fastening we would offer nylon insert locknuts. These nuts feature a nylon ring that compresses against the bolt threads as the nut is tightened.
In instances where common stainless would not be adequate to withstand corrosion and a locknut would be required, we would recommend a top-lock nut. These nuts are produced by crimping the top thread of a standard hex nut. When top-lock nuts are assembled, they should spin freely until the lead thread of the bolt meets the distorted thread in the nut. The more the nut is torqued from this point, the greater the effort for disassembly becomes.
Nickel Systems stocks nylon insert locknuts in 18-8 and 316 Stainless. We stock some top-lock nuts in Hastelloy® C (Alloy C276) and Carpenter® 20 (Alloy 20). Within a reasonably short lead-time, we can provide top-lock nuts in Hastelloy® (Alloys C22, B2), Inconel® 600 (Alloy 600), AL6XN®, Duplex 2205, Nitronic® 60 (A194 8S – Finished Pattern) and 317L Stainless, as we stock standard hex nuts in these materials.