Fasteners are often the lower priority, class C afterthought components in sourcing, yet they can drive product complexity, inventory waste, and late program cost increases if not managed properly. Fasteners are used in nearly every industrial application; quite literally they are the pieces holding everything together. Without them, our cars, homes, cell phones, and even the chairs we sit in would fall apart.
Knowing a few key characteristics about the fasteners you are sourcing will expedite and improve sourcing results. Below are five things you need to know when sourcing fasteners.
Choosing the right material for fasteners is not only important when considering cost, but even more so when considering factors like strength, brittleness, and corrosion resistance.
Steel and stainless steel are the most common materials used and account for approximately 90% of all fasteners manufactured. Steel continues to gain popularity because of its tensile strength, durability, and high degree of formability.
Silicon bronze (bronze) is primarily used in marine settings. This alloy makes it superior to stainless fasteners for marine engineering due to its high corrosion resistance and superior to brass due to its strength. Bronze, however, can be extremely expensive, which explains its limited application.
Brass and aluminium fasteners are also commonly used. Both materials are highly corrosion resistant, however they are softer than the ones previously mentioned.
Coatings are commonly used for one of two purposes: to add or increase corrosion resistance or for decorative and appearance purposes. Zinc, hot dip galvanizing, and chrome are among the most common fastener coatings.
Zinc plating provides better corrosion resistance in most environments, though it is prone to rust if the coating is damaged or if it is exposed to prolonged water submersion and humidity.
Galvanizing coats the fastener in a thick layer of zinc. This creates greater corrosion resistance, however galvanized bolts are not compatible with other nuts due to the thickness of the coating.
Chrome plating is used for corrosion resistance and as a decorative feature for certain applications. Chrome plating provides similar corrosion resistance to zinc, but offers a quality polished finish. Typically it is used where a polished finish is necessary due to its high cost.
There are endless different types of fasteners, but the most common are bolts, screws, nuts, washers, clips, and pins.
Within each of these categories are several more variations and each application could require a new fastener to be engineered. When sourcing screws, for example, it is important to know the type of head that is needed (flat head, pan head, truss head, etc.). Each type has its own distinct purpose.
Within each of these different fastener commodities you have the option of designing your product utilizing standard off-the-shelf components, or engineering your own unique fastener to best fit your purpose.
Size is another differentiator that will determine where you can source your fastener from. It is common for fastener manufacturers to develop capabilities in certain size ranges, like M6 or larger and M5 or smaller. This is due to the equipment required for the different size ranges.
Fasteners, unlike many other components, may be sourced through multiple channels instead of going directly through a manufacturer. The latter can be highly beneficial if you have very high volume and low diversity in parts. However, if you are in search of a greater variety of fastener types and sizes, in the mid- or low-volume range, a distributor may provide greater value for you, as many manufacturers will decline to quote lower volume packages directly to a customer.