Why tighten the nut not the bolt?

Last Update: April 20, 2022

This is a question our experts keep getting from time to time. Now, we have got the complete detailed explanation and answer for everyone, who is interested!

Asked by: Kiara Swift
Score: 5/5 (9 votes)

The torsion in the shank of the bolt depends upon the thread friction torque. For a given finish condition, the thread friction has some scatter associated with it, but will not depend on whether the nut or the bolt head is tightened. ... The reason is that each face will have a different friction coefficient.

What happens if you under tighten a bolt?

Typically, an under torqued bolt will deform and be unable to provide as much clamping force as needed. An over torqued bolt will break.

Why is it important to tighten nuts and bolts in the correct order?

Installed in a moving machine or a housing that contains moving parts or simply on a surface that holds two or more weighty loads, proper nut and bolt tightening practices ensure a secure structural lock. Correct locking torque, as used in the fastener industry, goes far beyond what can be felt by touch.

Why is it important to tighten a locknut?

It helps to achieve high preloads as it minimizes the influence of friction between two mating surfaces.

Should the nut be stronger than the bolt?

Nuts are usually stronger than the bolts they are on, which is to say that the bolt will usually break before the nut strips. It is often said that two threads must be exposed above a nut. The reason for this is that the first two threads of a bolt are often poorly formed, and may not engage the nut properly.

A Screw That Can Be Tightened In Either Direction

32 related questions found

How do I choose a bolt nut?

Consider the “job” that you require the nuts and bolts to do; this will determine the particular type of bolt and nut you need to purchase. Nut and bolt variations include the type of material used and the thickness and length of the bolt. The quality of nuts and bolts varies from manufacturer to manufacturer.

What is ASTM A563 Grade A?

The ASTM A563 specification covers the chemical and mechanical requirements for carbon and alloy steel nuts used on bolts, studs, and externally threaded fasteners. ... Various nut styles exist and to some degree are determined by their grade. These styles include hex, heavy hex, square, jam, coupling, and sleeve.

How do you remove a bolt that keeps spinning?

7 Answers. Best way: put a wrench on the nut and the proper driver or socket into or over the head of the bolt, and turn one while keeping the other stationary. Second best way: put a wrench on the nut, and a pair of locking pliers on the shank of the bolt.

What tool do you use to tighten nuts?

Wrenches are used to tighten and loosen fasteners, mainly nuts and bolts. Wrenches are generally made from a chrome-plated steel alloy. The material makes wrenches both durable and simple to clean.

Will anti seize cause bolts to loosen?

Using anti-seize without reducing the required torque value can strip the threads or stretch the bolt in extreme situations.

Is there a tightening pattern when tightening the lug nuts?

Tightening them in a cross pattern reduces the likelihood of things shifting and flexing, which means that your lugs will stay tight after you torque them. Using the above diagram, tighten your lug nuts in the correct order that corresponds with the number of lug bolts your wheel has.

What is a bolt or nut tightening sequence?

Bolt tightening sequence, or torque sequence, is defined in the torque tightening procedure. Flange joints are torqued tight with the help of a torque wrench (manual or hydraulic). ... Torque bolts and nuts in a “CRISS-CROSS” sequence using a minimum of three torquing passes and the maximum bolt stress as defined.

How many times can a bolt be torqued?

Plain ASTM A325 bolts, however, possess sufficient ductility to undergo more than one pretensioned installation as suggested in the Guide (Kulak et al., 1987). As a simple rule of thumb, a plain ASTM A325 bolt is suitable for reuse if the nut can be run up the threads by hand.”

How can you tell if a bolt is tight?

Make sure you've tightened the bolts to snug-tight condition using an impact machine before checking the bolts with torque. Snug-tight refers to the condition where tightness is achieved with an impact wrench or by hand with a worker using an ordinary wrench.

How do you stop a bolt from tightening?

Nylon or metal inserts inside a nut (sometimes called a “lock nut”) can add extra friction to prevent loosening. A related idea is to fit a spring inside the nut, which firmly grasps the bolt threads and is designed to move in the opposite direction of the nut if vibration or other forces cause it to unwind.

What can I use instead of a nut?

Replace nuts with:
  • Seeds - a nut-free source of roasted pumpkin seeds (pepitas) or sunflower seeds makes a great replacement for nuts in granola bars, breads, and "butters". ...
  • Beans - specifically roasted soy beans, peas or chickpeas (garbanzo beans). ...
  • Pretzels - Yes, pretzels.

Can I use pliers instead of a wrench?

Although pliers can be used to tighten and loosen nuts, this is a task better suited to the wrench. Pliers tend to damage the surfaces of fasteners and are usually more difficult to use than a properly-sized wrench.

How do you tighten a Nylock?

When tightening screws into Nyloc Nuts the force required to tighten the screws will double, when the screw reaches the Nylon in the nut. You must keep on tightening and you will see the end of the screw come through the end of the nut. Tighten with your full strength.

What grade is ASTM A574?

Socket Head Cap Screws made from alloy steel are typically manufactured to a higher strength than SAE Grade 8: 180 ksi tensile strength for fasteners up to 1/2 inch, 170 ksi for larger sizes (ASTM A574, p. G-34).

What is ASTM A194?

Download. Carbon, alloy and stainless steel nuts used in high pressure and high temperature service. Scope – This specification covers carbon, alloy and stainless steel nuts intended for use in high-pressure and/or high-temperature service. Unless otherwise specified, heavy hex nuts (ANSI B 18.2.

What grade is a A325 bolt?

Type 3 grade A325 bolts shall be marked "A325" to distinguish them from standard grade A325s. Grade A490 bolts are available in diameters from 1/2 to 1-1/2 inch diameters with a minimum tensile strength of 150,000 PSI for all diameters, and are offered in two types.