Top Features of Aviation Fasteners

The Boeing 747-400 is made up of 6 million parts— of those, half are fasteners. If you’ve never seen an aircraft up close and in person, you probably can’t imagine why of 6 million parts, 3 million are aviation fasteners. Well, that’s because fasteners are any piece of hardware used to mechanically join or affix two or more objects together. So, it makes sense that half of the 747’s part list is fasteners; what wouldn’t make sense is if all 3 million fasteners were of the same type.

Fasteners are actually a very broad category. They can be grouped based on the type of head, the threading, whether or not they use a nut or a washer, what kind of drive they have, whether they have points or not, etc. One example is the hex bolt, a bolt with a hexagonal head and threads for use with a nut or tapped hole, and its variation, the heavy hex head bolt.

Heavy hex bolts are bolts that have larger and thicker than head than the standard. They are available in different lengths and diameters or different threading, but they are all marked by their hex head and the fact they have larger than standard heads. They are also all designed to be used with hex nuts for a more secure fit. Typically made from metals such as stainless steel, hex bolts can be customized via zinc, cadmium, or hot-dip galvanized plating.

Like other fasteners, heavy hex bolts are made based on a number of different ASTM specifications. ASTM International, formerly known as the American Society for Testing and Materials, is an international standards organization that develops and publishes technical standards for a variety of materials, products, services, and systems. So, while heavy hex bolts can vary in size, material, and plating, they are manufactured in order to meet certain standards in regard to grades, mechanical properties, and chemical properties. For example, the A193 standard calls for heavy hex bolts and nuts that can withstand high heat conditions, A320 standard calls for heavy hex bolts and nuts that can withstand extremely low heat conditions, and A490 and A325 standards call for heavy hex bolts with shorter threads.

Thanks to their stronger durability, heavy hex bolts are typically used in a variety of industrial sectors. While they’re incredibly useful, you won’t find a heavy hex bolt among the 3 million fasteners on a Boeing 747-400— their characteristically larger and thicker than average hex heads make them less than ideal for applications where excess weight matters. Instead, common uses include steel fabrication, railroad system construction, pump and water treatment, modular building construction, and renewable and alternative energy.

At ASAP Aero Supplies, owned and operated by ASAP Semiconductor, we can help you find all the hex bolts and aircraft parts you need, new or obsolete. As a premier supplier of parts for the aerospace, aviation, and defense industries, we’re always available and ready to help you find all the parts and equipment you need, 24/7x365. For a quick and competitive quote, email us at sales@asapaerosupplies.com or call us at +1-708-387-7800.

1. gary anderson
2. Posted on February 26, 2019
aviation

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