Is there a way to measure the tightening torque?
The problem is that there is no practical way to measure the clamping force in normal production situations. Consequently the value of the clamping force is usually referred to as the tightening torque.
When do you need to audit a torque joint?
Once a torque specification is determined, the joint should be audited to verify the product has been fastened to the specified torque. It is important to audit the joint for accuracy and to ensure your product’s quality, safety and…
What should the torque be on a torque table?
Torque specifications are shown either as an exact figure, or a specific range. Follow any special instructions or multi-step directions carefully to assure correct final torque. There may be different specifications for different size bolts, bolts in different positions, tightening bolts in several stages, or a cold engine vs. a warm engine.
How does lubrication affect the tightening of a screw?
EFFECT OF LUBRICATION If a screw is lubricated, the friction in the threads and under the head is decreased and the relation between tightening torque and clamping force is changed. If the same torque is applied as before lubrication, a lot more torque will be trans- formed into clamping force.
What do you need to know about torque tightening?
Torque is the measurement of rotational force being applied to an object. In simple terms, you need torque to create tension in a bolt. You use torque to turn a nut onto a bolt and then to stretch the bolt, making it a solid spring that then clamps the two materials together.
How to determine the torque of a bolt?
The wrong way, asserts Archer, is to pick a number off a standard engineering table or to rely solely on the classic equation, T = KDP, in which T is the target tightening torque; K is the coefficient of friction, or nut factor; D is the nominal diameter of the bolt; and P is the desired tensile load on the bolt.
Torque specifications are shown either as an exact figure, or a specific range. Follow any special instructions or multi-step directions carefully to assure correct final torque. There may be different specifications for different size bolts, bolts in different positions, tightening bolts in several stages, or a cold engine vs. a warm engine.
Why does a torque wrench have a k value?
The tightening torque specification is developed using a “K” value for dry threads. Lubricating with a high-pressure lubricant like anti-seize reduces the friction, resulting in a much greater preload than the nominal design value. In the extreme case the bolts stretch when tightened to the recommended torque.
The problem is that there is no practical way to measure the clamping force in normal production situations. Consequently the value of the clamping force is usually referred to as the tightening torque.
How much preload can a torque wrench cause?
Because of the many interrelated variables that directly or indirectly affect friction, such as surface texture, type or coating or finish, lubrication, speed of tightening, human error, etc., it is possible to experience as much as ±25% deviation in preload (clamp load) with the use of a torque wrench.
What’s the torque for grade 5 Hex Cap Screws?
Tightening Torque Guide for Grade 5 & 8 Hex Cap Screws This table is based on IFI 5th Edition Technical Data N-12/N-16, using Equation (1) and a torque coefficient, K=0.20 for non plated steel fasteners and K=0.15 for plated fasteners.
How is the tightening torque related to the clamping force?
Consequently the value of the clamping force is usually referred to as the tightening torque. As the clamping force is a linear function of both the turning angle of the screw and the pitch of the thread, there is a direct relation between the clamping force and the tightening torque within the elastic range of the screw elongation.