One of the most frustrating aspects of metalworking is spending hours meticulously tightening dozens of hard-to-access fasteners only to see one fall out afterward. Fortunately, there are methods to keep these metal bits from coming loose; you just need to choose the best one for your application.
Locking hardware, which is made to stay put once it has been tightened, is available in numerous sizes and configurations. And with standard hardware, you can employ various formulas of locking compound to prevent pieces from loosening. Either way, your screws, bolts and nuts will stay as tight as the day you installed them.
Washers and nuts
Locking hardware has been around for decades and is probably familiar to most people. These friction-based pieces can be classified into two main categories: lock washers and locknuts.
A lock washer is a metal ring similar to a standard washer that is placed between a fastener (such as a bolt or screw) and the work surface. However, whereas a standard washer is smooth, a lock washer uses friction to secure the fastener head to the attachment point and prevent the fastener from turning once it has been tightened.
Like lock washers, locknuts rely on friction to stay in place. But rather than bite into the fastener head, these nuts grab the fastener’s threads. Locknuts can be subdivided into two groups: metallic and nonmetallic.
Chemicals
There are many applications where the use of mechanical locking hardware such as a locknut or lock washer simply won’t work, and that’s where chemicals come into play. First developed in 1953 by American professor Vernon Krieble in his basement laboratory at Hartford, Connecticut’s Trinity College, anaerobic thread-locking adhesives (such as those offered by Loctite, the brand you’re most likely to find) remain inactive as long as they are exposed to air. But once you pour the chemical onto the threads of a fastener and screw it together, the sealant cures as the air is forced out of the spaces between the threads.
Depending upon what you’re working on, you may encounter a few other methods of securing a nut to a bolt, each specific to certain applications. A few common examples include; cotter pins, Keys and keyways and peening nuts.
The next time you’re tackling a metalworking project and you want to make sure that your hard work doesn’t come apart, grab a few locking washers or a couple of squirts of the appropriate thread-locking adhesive. Years later, you’ll be glad you employed these friction creators to keep your assembly as tight as the day you bolted it together.
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