Case Hardening Your Hex Nut Fasteners

The hex nut, sometimes spelled hex nut, is a unique shaped hexagonal nut which is used primarily as the female threads (and occasionally male threads) to attach two sheets of metal to each other. Often the threads will be bent into distinct shapes for decorative purposes. More commonly they are used to attach thin sheet metals that are too heavy to be readily formed into normal bar stock or even pressed into work pieces. This can be due to a lower tolerance to higher stress, such as an alloy with a low tensile strength, or due to the design of the bar itself being unsuitable for use with thinner materials. They are available in a range of different sizes, which may also be bent into shapes. They are frequently used in applications where strength and/or thickness are an important factor, such as in the design of tubes and pipes, and where robustness is essential for aesthetic and mechanical purposes.

Hex nuts are made using a variety of different processes, including forging, press cast, pressing, and electrocast. A forged hex nut is one in which the face is machined from a solid piece of steel, while press cast nuts are pressed directly from steel sheet in a similar way to pressing or hammering. Electrocast hex nuts have a liner that goes into the steel hex face and are therefore more flexible than their forge counterparts. While they do not offer the same toughness and strength as their forged counterpart, they are much more suited to use in applications where a strong, yet light weight, hex nut is needed.

As indicated above, hex nuts are classified according to the way in which they are pressed into use. This classification can be broadly divided into two: flanged and flat. A flat hex nut has the outside, flat surface flanged to the end, while a flanged one does not. Flanged nuts are commonly used for electrical connections, though they are also found in fastener situations in which a flat nut would clearly not be suitable.

The third classification, flat hex nuts, are made with the flat end flanged to the left or right. They are the most widely used variety of hex weld nuts and are often seen in use for plumbing applications as well. Many times they will be used to provide friction or shear resistance for threaded fasteners such as pipe fittings, water pipes, bolts, and nuts. The shearing action that these nuts provide makes them particularly useful in situations where the bolt or joint requires a tight fit. This means that they need to be made with added strength, and as such are usually quite expensive.

The last classification, m6 hex nuts, have six faces, six sides, and six ends; a six sided hex nut, like its name indicates, is six sided. Like a regular hex nut, it can be used to provide friction or shear resistance when fastened to a metal surface. The six sided nature of the nut means that they can be manufactured into any shape, providing a versatile option. They are also relatively inexpensive when compared to other types of fasteners.

A few years ago I had a question about using a stainless steel hex nut on a yellow zinc finish case hardened rod. My question was: how would you identify if the two were compatible? My assumption was that the only way would be to take the two to a local jeweler who would be able to tell me the difference. After all, a stainless steel case hardened rod is not easy to tell apart from a yellow zinc case hardened rod. The person I dealt with however, did tell me that there was no difference, and that the only way the two would be similar was if both were in the same shape. To further complicate matters, he did inform me that I would need to do a couple more of these case hardening experiments to verify my assumption.

In order to get the case hardened rod to accept the stainless steel hex nut, I used a serrated flange nut Din6923 m6. I measured the distance between the center of one of the ends of the bolt and the fob price of the rod. I then drew a line across this distance to determine the maximum distance that the nut could be taken without the fob falling off the end. This gave me my maximum fob price, and once I had found the fob price at least I knew that I would have enough cash on hand for the nuts to be sent out.

The next step in the process was to heat the steel bolts. I placed two pieces of aluminum foil on either end of the long, threaded bolt. I then placed a can of spray paint on the flat surface of both the long and short bolts. I made sure to spray the bolts with the same color on each end so they would clearly see each other. After spraying the bolts with the primer coat, I took my time to carefully look over the flat surface of the bolts. After ensuring that there were no cracks or denats in the surface of the flange nuts, I gently rubbed the bolts with my finger until the paint started to run off.