A flange nut is a hexagon-shaped nuts with a circular locking flange at the bottom that is larger than the top hex section. Such design allows the pressure of the nut to be distributed on the part being secured, reducing the possibility of damage to the part. It also enables secured tightening thanks to the uneven fastening surface. Flange nuts are normally made of hardened steel coated with zinc.
Flange nuts are sometime serrated (i.e., serrated flange nut) to ensure secure locking. The serrations are also angled so that the nut will not rotate toward the direction to which the nut will loosen. And because of the serration, flange nuts cannot be used on surfaces that need to be scratched. The serration also prevents the vibration of the nut from moving the fastener, thereby ensuring optimal retention of the nut.
There are two common types of flange nut available: the flange lock nuts and the serrated flange nut as we described above:
● Flange Lock Nut:
This type of nut is an all-metal prevailing torque hex flange nuts. As an all-metal nut, it is restricted to chemical and temperature limitations of non-metallic insert type lock nuts (e.g., nylon). The increased nut’s bearing surface enables flange lock nuts to fit irregularly shaped and oversized holes. The nuts are widely used in both industrial and commercial settings, ranging from gardening equipment to truck manufacturing.
Despite being called the “lock nut”, this type of nut is not actually permanently locked in place in order to allow certain degree of adjustment after installation. The “locking” feature however does not prevent loosening unless the nut is completely seated. This is because flange lock nuts are sometimes used so that they can function as a stop nut or spacer.
Following the above, flange lock nuts need to be incorporated with the screw (or bolt) threads for the locking feature to prevail. Generally speaking, bolts and screws should be long enough to extend beyond the nut face upon fastening to ascertain full thread engagement. Likewise, the head side of the flange nut should also have two full threads to make sure that the nut can be securely fastened. One disadvantage of flange lock nut is that it is highly consumable as the prevailing torque declines after each us.
● Serrated Flange Nuts:
Serrated flange nuts, as mentioned above, have serrated bearing surface. The serrated flange nuts can rotate freely until the serrations contact material on the mating surface while the nut is fastened. The locking and gripping nature of the serrations also enables less torque needed for installation because of the vibration resistant feature.
Be mindful when applying a serrated flange nuts on a painted or plated mating surface because corrosion can take place if the surface treatment is removed due to the nut’s wiping action. Just like flange lock nuts, bearing surface of the nut is increased so that serrated flange nuts can be used with irregular or oversized holes. They are also widely used for both industrial and commercial application.
Flange nuts are suitable for irregular shaped and oversized holes as mentioned earlier, since the serrations cover the entire bearing surface as the flange covers the discrepancies. Also, flange nuts are generally durable and can be reused without much limitations. It is still advised that you check with your manufacturers with regard to the torque value and applicable lubricants.
Flanged nuts can also save a lot of time and money on your applications since the flange extends the bearing surface. As aforementioned, less torque is also required when installing a flange nut on a surface, saving you a lot of valuable time during construction or assembly.
Flange nuts are also compatible with particular surface treatment, including those coated with zinc. They are very corrosion resistant as well, as most are made from hardened stainless steel in order to provide optimal protection against corrosion.
In a nut shell, flange nuts are extremely versatile and will work on all projects and constructions that require simple locking solution. You only need to decide whether a flange lock nut or a flanged serrated nut is the more suitable option for your line of work, given that both provide exceptional strength and resistance.
Flange nuts are the type of locknuts that utilize displacement and distortion to provide a tight fit. As a matter of fact, distortion can increase the likeliness of corrosion given a painted or coated surface. If moisture happens to be a concerning factor in your application, it is highly recommended that you opt for another type of locknut that will not cause corrosion on the surface due to displacement or distortion.
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