9 Flange Nut

There are several good reasons to use a flange nut, which comes with a built-in washer. First, is convenience. By eliminating the washer under the nut, you have one less part to lose or worry about. But second is tightness. When you use a nut with a washer, you create two bearing surfaces: one between the nut and the washer and one between the washer and the bolting surface. No big deal, right? Wrong. For mission-critical bolted assemblies, that extra bearing surface can be an opportunity of one metal surface to wear against the other, resulting in loosening of the nut. Use a flange nut, especially a high-quality one, and you cut the number of bearing surfaces in half and increase the odds that the nut stays tight. And the final case for using a flange nut is that the sturdy flange helps support the first couple of threads in the nut, creating a unified assembly as the nut is tightened. Again, this helps the nut stay put, which is exactly what you want.