How do you tighten a 12 lug pattern?
- First time around just snug the nuts with a hand wrench.
- Second time around tighten the nuts firmly with the same wrench.
- Third time around apply approximately 25% recommended torque.
- Fourth time apply approximately 75% of recommended torque.
- Fifth time around, apply 100% of recommended torque.
Why do we torque in a star pattern?
Here’s the secret: The simple reason behind the star pattern of torquing your lug nuts is to reduce wheel flexing and shifting. You see when you tighten a single nut, it keeps getting tighter and tighter till the point the wheel mounting face (what you’re tightening against) gets stuck to the hub.
How are bolts numbered when using a star pattern?
Before they are tightened, bolts can be numbered sequentially (1,2,3,4 etc) in a clockwise direction around the flange (fig 1 below). Or they can be numbered by the order of tightening (fig 2 below).
What is the importance of torque sequence?
Because the joint surfaces compress, tightening one bolt in the vicinity of another will affect the preload generated by the first bolt tightened. A good tightening sequence ensures that an even preload distribution is achieved in the joint (See Dia. A).
Why is it important to torque the fasteners in the proper sequence?
Position Control torque arms are designed to reduce the risk of improperly fastened screws, ensuring that every screw is in the correctly tightened in the correct sequence. An encoded torque arm is perfect because it guides the operator’s sequence and provides feedback if done incorrectly.
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.
Does it matter what order you tighten lug nuts?
Tightening your lug nuts or wheel bolts in the right order is actually kind of important to get them all tight, and keep them that way. Tightening lug nuts may not seem like a complex job, but as you know, a technician can make even the simplest job complicated.
Why are some bolts tightened in a sequence?
A good tightening sequence ensures that an even preload distribution is achieved in the joint. Since joints containing conventional gaskets have a comparatively low compressive stiffness, bolt preloads in such joints are particularly sensitive to the tightening sequence.
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 is bolt torque calculated?
How is bolt preload calculated?
- • Bolt preload ensures that the mating. parts stay connected during the operation of the machine.
- • Calculate bolt preload as. =
- − where;
- External load. on the flanges.
- F+P. P.
- Total load on. the bolt.
- • Calculate the torque corresponding the bolt preload as. = × ×
- Type of bolt.
Why is it important to torque lug nuts in a star pattern?
Should you torque 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 is the maximum bolt torque?
Bolt Size TPI Tension (lbs) Tightening Torque Range (ft lbs) (Min – Max) Min Max Plain Lubricated; 1 ⁄ 2: 13: 15,000: 18,000: 125 – 150: 63 – 75: 5 ⁄ 8: 11: 24,000: 29,000: 250 – 302: 125 – 151: 3 ⁄ 4: 10: 35,000: 42,000: 438 – 525: 219 – 263: 7 ⁄ 8: 9: 49,000: 59,000: 715 – 860: 357 – 430: 1: 8: 64,000: 77,000: 1,067 – 1,283: 533 – 642: 1 1 ⁄ 8: 7: 80,000: 96,000: 1,500 – 1,800: 750 – 900: 1 1 ⁄ 4: 7: 102,000: 122,000: 2,125 – 2,542
What is the cylinder head bolt torque and sequence?
You must adhere to this. Torque sequence refers ro the pattern in which you tighten the bolts. The overall goal is to spread the torque evenly as you are tightening the bolts. Usually, you start at one bolt, and you work your way around in a circular pattern. Doing so ensures that your head won’t be warped during the tightening sequence.
How to calculate torque to tighten bolts?
– T Target tighten torque (the result of this formula is in inch pounds, dividing by 12 yields foot pounds – K Coefficient of friction (nut factor), always an estimation in this formula – D Bolts nominal diameter in inches – P
How to determine a torque specification?
Define the Formula The formula T = K x U x D x P must be used.