For example, a grade 12.9 bolt will begin to stretch when the load on the bolt is 90% of the breaking load. Similarly a grade 9.8 bolt will begin to stretch at 80% of its breaking load.

Size | Pitch (std) | Pitch (fine) |
---|---|---|

M8 | 1.25 | 1.0 |

M10 | 1.5 | 1.0 or 1.25 |

M12 | 1.75 | 1.5 |

M16 | 2.0 |
1.5 |

5

Why does it take more force to tighten a bolt?

- Several factors affect
**how much**tension occurs when**a**given amount of tightening**torque**is applied. The first factor is the**bolt**‘s diameter. It takes more force to tighten**a**3/4-10**bolt**than to tighten**a**318-16**bolt**because it is larger in diameter. The second factor is the**bolt**‘s grade.

Contents

- 1 Do bolts stretch when tightened?
- 2 How do you calculate tension torque on a bolt?
- 3 What is Max locking torque?
- 4 How much do bolts stretch?
- 5 How do you tell if a bolt is a stretch bolt?
- 6 When the bolts are stronger than the plate tension?
- 7 Is tension equal to torque?
- 8 How do you calculate max torque on a bolt?
- 9 Does bolt length affect torque?

## Do bolts stretch when tightened?

Even though bolts may seem perfectly rigid, steel is an elastic material. This means that when they are tightened in a bolted joint, they actually stretch a tiny amount.

## How do you calculate tension torque on a bolt?

The Torque/Tension Equation is a method used to estimate the torque/tension relationship in an assembly. T = (K D P)/12 can be used to developt a torque value that will achieve a certain tension or clamp load.

## What is Max locking torque?

So, the maximum locking (prevailing) torque going into the bolt is measured, as is the minimum torque required to remove the bolt. Semantically speaking, the torque value table measures the maximum torque for installation, and the minimum torque for removal.

## How much do bolts stretch?

The head is thought to stretch about half as much as the same volume of body would stretch. In order to use stretch control one must initially determine the amount of stretch each separate portion of the bolt contributes to the total stretch.

## How do you tell if a bolt is a stretch bolt?

Like the others have saidif it gives you that “1/4 turn” line, it’s a stretch bolt. For example, the brake caliper bolts are listed as “always replace” in the Bentlybut it’s just a regular bolt with the threadlocker stuff on it.

## When the bolts are stronger than the plate tension?

The tensile stress in the plate at the net cross-section may exceed the working tensile stress. Tearing failure occurs when bolts are stronger than the plates. Bolts may have been placed at a lesser edge distance than required causing the plates to splitor shear out.

## Is tension equal to torque?

“Torque” is simply a measurement of the twisting force required to spin the nut up along the threads of a bolt, whereas “Tension” is the stretch or elongation of a bolt that provides the clamping force of a joint. Torque wrenches provide this tension by the amount of rotational force they apply to the bolt.

## How do you calculate max torque on a bolt?

You may determine the maximum, or max, torque for a screw with the mathematical formula T = K x D x P. The formula’s “T” is the targeted torque for the screw measured in inch pounds.

## Does bolt length affect torque?

Tightening torque is not influenced by the bolt length so easy to standardize. The Bolt efficiency will be low due to wide tolerance of the tension.