Why torque is applied to a bolt?
Torque is used to create tension. Bolts are used to affix two components so that they can resist tensile (pulling apart) and shearing (sliding apart) forces. After the nut has been turned onto the bolt, additional torque causes the nut to turn and stretch the bolt.
How do you determine torque for tightening bolts?
The basic formula T = K x D x P stated earlier takes these factors into account and provides users with a starting point for establishing an initial target tightening torque.
How is bolt torque required?
DETERMINING TORQUE The general equation for bolt load based on applied torque is T = KFiDb where K = torque coefficient. K is a function of the coefficients of friction and collar friction in the joint, and these are based on variables such as surface finish, coatings, and so on.
Is torque normally applied to the nut or the bolt?
In many situations you can apply torque to either the nut or the bolt head. Both will result in a tight connection and neither will avoid breakage more often (that occurrence can be avoided through other means). In certain circumstances, however, you will need to torque one and not the other.
What happens if you torque a bolt too much?
One of the most damaging ways to do that is by over-tightening, or over torquing the fastener. This can result in stripping screws, snapping screw heads and damaging pre-tapped threading.
How do I know how much torque I need?
Torque is defined the length of the lever arm multiplied by the force applied. For instance, if you have a two-foot long bar and you hang a 10-pound weight from it, you have 20 foot/pounds of torque.
What does K mean in torque?
nut factor
where T is the torque measurement, K is the nut factor, F is the tension and D is the bolt diameter. With this equation, if you know K, F and D, you can multiply them to get the torque needed to tighten the bolt so that it has the right amount of tension.
When do you apply torque to a bolt?
Torque is only the amount of energy is takes to spin (think twisting force) the nut along the threads of a bolt. Torque must be applied to tension a bolt. Bolt torque is usually greater affected by lube, thread condition and exposure to weather. Tension is what we’re actually after here.
What’s the best way to lubed a torque table?
Lubricate all contact areas of the bolts and washers. Lubricating the bolts is the suggested method. Lubed means cleaned, dry bolts, lubricated with standard medium viscosity machine oil. Lubricate all contact areas of the bolts and washers. Lubricating the bolts is the suggested method. Nom Dia-Pitch Nom Size x Pitch INCH BOLT TORQUE TABLE
Can a lubricant affect a torque reading on a car?
So, torque isn’t the true measure of bolt tightness—it’s tension. But lubrication on the bolt threads—and a whole host of other factors—can cause fluctuation in torque readings. So once you add a lubricant of any kind to the threads, all bets are off as to whether the same torque setting will truly secure the bolt.
What is the correct torque for a SAE J429 bolt?
SAE J429 governs imperial sizes, while ISO 898 governs metric-size bolts. 1/4 to 3/4in. >3/4 to 1 1/2in. For imperial bolts, grades 5 and 8 are most common. SAE J429 conforming bolts will have radial markings machined on the head of the bolt that indicate bolt grade.