A Sidebar About Stainless Steel

The Encyclopedia Metallurgica will tell you that stainless steel is non-magnetic, but a visit to the local hardware store with a strong magnet in your pocket will convince you otherwise. Although stainless steel contains iron, its magnetic properties are ostensibly nulled when nickel is added to the alloy. But poor distribution throughout the part, or even the cold-forming of the material into nuts, bolts, and especially washers, can lend some level of magnetism to it. Not an admirable quality for hardware intended to mount, you know, a navigation compass!

In the course of my extensive field research and empirical scientific sampling of off-the-shelf SS hardware (ahem), I found that about 80% of the contents of the little bin of bolts at my neighborhood True-Value had a discernible measure of magnetism, and I was able to drag them around on a flat plastic surface with my alnico magnet. These I returned to the bin while carefully setting aside the non-magnetic examples. I was able to apply the same methodical process to the nylock nuts and washers before staff threatened to call security.

Certain grades of SS such as those found at marine suppliers may have lower magnetic qualities, but check them before using. I also learned that a metal part can be de-magnetised by laying it on a block of wood, oriented in an east-to-west fashion, and striking it with a hammer 50 times. Considering that I needed four bolts, four nuts, and four washers (and a few spares), I determined that my time was better spent working on my offside roll, so I just bought the non-magnetic hardware.