Ask the Fastener Distributor | How To Deal With Friction

By /
Larry Melone
by Larry Melone
President

[email protected]

  • Building Fasteners
  • Fastener Distributor
Friction can be advantageous in an application or it can present a challenge. Your fastener distributor understands that the occurrence of friction only presents a problem after the development of high thread tension. At that point friction will present an obstacle to rotation. And it’s also at that point that you need to deal with […]

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Friction can be advantageous in an application or it can present a challenge. Your fastener distributor understands that the occurrence of friction only presents a problem after the development of high thread tension. At that point friction will present an obstacle to rotation. And it’s also at that point that you need to deal with this condition in order to provide a secure and easily assembled joint.

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When friction is present between the bearing surface and the head, or within the mating threads, a majority of the torque applied is used to overcome resistance. That leaves only a minimal amount being applied to a tension increase, which is the ultimate purpose when applying torque. As you can see, this situation can be challenging and designers, contractors and assemblers need advice on how to effectively combat or avoid that friction and the conditions that result.

 

Possible Solutions

 In some ways friction is beneficial, since it can help to make a tighter, more reliable joint. Friction between mating threads will hold a bolt in place and locking fasteners often work on the basis of friction. But it’s important to understand that when friction is present the relationship between torque and tension is altered.

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Lubrication helps to combat friction. But when lubrication is present the torque values change. You will find that fasteners have various torque values stated, depending on whether they are dry or lubricated, plated or left untreated.

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Often slower driving speeds can help to reduce friction that occurs as a result of the heat and force being applied. This friction can result in galling and wear, and is easily avoiding by using consistent and controlled driver speeds.

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Friction Joints

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Structural engineers are familiar with friction joints. This type of joint occurs when loads are transferred via friction, as opposed to the bolt bearing the load. There is no risk of slipping or loosened fasteners in a friction joint. The structural members support the shear load.

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You may come across an issue involving friction that requires a solution in the form of method or material. Your fastener distributor can direct you to a lubricant or advise you on the proper assembly or installation method. And in the case of friction joints this condition provides a benefit that’s hard to miss.

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