Normally it will not matter whether the bolt head or the nut is torqued. This assumes that the bolt head and nut face are of the same diameter and the the contact surfaces are the same (giving the same coefficient of friction). If they are not then it does matter. Say the nut was flanged and the bolt head was not.
How is a bolt head measured?
For fasteners where the head usually sits above the surface, the measurement is from directly under the head to the end of the fastener. For fasteners that are designed to be countersunk, the measurement is made from the point on the head where the surface of the material is, to the end of the fastener.
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.
Does it matter if you torque the nut or bolt?
So in general, when using torque control, tightening the bolt by rotating the bolt head or the nut can matter. It is good practice to specify which part should be tightened so that the bolt preload variation is minimised.
Does thread pitch affect torque?
Thread pitch tends to be more independent of nominal diameter than the other variables. Increasing just thread pitch by 40% cuts tension 5% for a given torque. However, the reaction-torque term containing the thread pitch, P — P/2 π — does not contain a friction coefficient.
How do I choose a bolt size?
A typical rule of thumb . . . Use a bolt diameter that is 1.5 – 2.5 times (up to three times) the thickness of the thinner material you are bolting together. So, for 1/8″ material, a 1/4″ diameter is often a good bolt choice. For 1/4″ thick material, perhaps a 3/8″ or 1/2″ bolt.
How do I choose a screw size?
The general rule of thumb is that the screw should enter at least half the thickness of the bottom material, e.g. 3/4″ into a 2 x 4. The other factor is the screw’s diameter, or gauge. Screws come in gauges 2 through 16. Most of the time you’ll want to go with a #8 screw.
Are longer bolts better?
that longer bolts are more resistant to fatigue even when tightened to a same preload, or torque, of the shorter bolts.
Is a longer bolt stronger?
The longer the bolt length acting within the joint affects it’s stiffeners IE longer = more deflection and obviously shorter = less deflection of the bolt.
What is the purpose of bolt tightening?
Tightening the bolt puts the shank in tension, counteracted by compressive forces on the contact surfaces of the head and the nut, transferred from the parts.
How tight should a nut and bolt be?
In general, you should make the bolt tight enough so that the items it is holding together stay together, but not so tight that you damage the bolt’s threads. You should tighten bolts properly so that the bolt performs properly.
Does washer go with nut or bolt?
The washer helps prevent damage to the surface of the object being fastened. In most cases where the bolt is easier to turn, the bolt has a round head that will cause less damage anyway. For the same reason, lock washers always go on the nut side to stop the nut moving.
What is stronger fine or coarse thread?
Size for size, a fine thread is stronger than a coarse thread. This is both in tension (because of the larger stress area) and shear (because of their larger minor diameter). Because of the smaller pitch, they allow finer adjustments in applications that need such a feature.
What are the advantages of coarse threads?
Coarse threading allows for more material to sit between these threads as they are installed. Due to this, it is harder for coarse threaded fasteners to strip or cross thread. Their extra tolerance allows for nicks or marring to occur on the edges of the threading without inhibiting the ability to fasten them.
What does K mean in tightening torque?
T = K×F×D. 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.