Question: What Is The Most Accurate Way Of Measuring Bolt Tension?

How do you measure torque on a tight bolt?

The marking check: After tightening the bolt, mark the bolt surface and that of the product or workpiece.

Then loosen the bolt.

Re-tighten it until the markings re-align.

The torque needed to return the bolt to its original position is the torque value of the bolt..

How do you tell if a bolt is stretched?

usually if the specs say when installing – “torque to xx ft pounds and then a 1/4 turn” thats a stretch bolt.

What happens if you reuse stretch bolts?

However, because the tightening procedure does permanently stretch the bolt, there is some risk of breakage if the bolt is reused. And since there is no way to tell how many times a bolt has been reused, it doesn’t make any sense to reused TTY bolts – the risk far outweighs the replacement cost of used bolts.

How tight should bolts 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.

Is torque check necessary?

Checking for loose lug nuts Torque is the unit of measurement for the twisting force that’s applied to a lug nut. Mechanics will ensure that each lug nut has been torqued to the vehicle manufacturer’s specifications when first fitting a wheel. But a second follow-up check is also necessary.

How do you determine tension?

The tension on an object is equal to the mass of the object x gravitational force plus/minus the mass x acceleration.

What is the most accurate way to measure bolt tension?

SPC4™ measures the stretch of the bolt (in other words, the bolt tension), directly from the fastener. Because stretch is the force that creates clamp load, this capability makes SPC4™ the most accurate method available to monitor the clamp load of critical joints.

Should you tighten the nut or the bolt?

The answer depends on your application and the condition of the materials being fastened. 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).

How do you check torque?

Mark the tightened fastener and surrounding application. In the tightening direction, begin to slowly apply force to the tool until the first movement in the fastener is noted. The reading recorded is a good indication of the original torque applied to the joint. This is the best way to determine residual torque.

How many times can a bolt be torqued?

Plain ASTM A325 bolts, however, possess sufficient ductility to undergo more than one pretensioned installation as suggested in the Guide (Kulak et al., 1987). As a simple rule of thumb, a plain ASTM A325 bolt is suitable for reuse if the nut can be run up the threads by hand.”

Is a bolt stronger in shear or tension?

A joint in tension is weaker than a joint in shear. Doesn’t matter (much) what type of fastener, pop rivets, welding, bolts, it is stronger in shear than in tension.

How do you calculate bolt tension?

Tensile strength is the maximum tension-applied load the fastener can support prior to fracture. The tensile load a fastener can withstand is determined by the formula P = St x As.

How much does a bolt stretch when torqued?

To appropriately answer this question, it helps to first consider that only approximately 10-15% of the input torque actually stretches the bolt; the remaining 85-90% of input torque is primarily used to overcome friction between the mating threads and friction under the bolt head or nut.

Why is bolt torquing needed?

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.

When bolts are tightened They are also stretched?

In a bolted joint, tightening the nut actually stretches the bolt a small amount, like pulling on a stiff spring. This stretching, or tension, results in an opposing clamp force that holds the two sections of the joint together. If the bolt comes loose, this clamp force weakens.

What happens if you dont torque head bolts?

If the head isn’t torqued down properly, then the most likely failure is of the head gasket, which could lead to loss of compression, the mixing of oil and coolant, exhaust gases getting into the oil ways or cooling channels, erosion of the cylinder head, overheating and warping of the cylinder head.

What happens if you over torque a bolt?

Everyone who has ever worked with fasteners has accidentally messed one up at some point. 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 run down torque calculated?

The proper procedure is to run the nut or bolt down to maybe half a turn to contact (washer still loose). Measure the torque required just to move the nut the last bit before the nut makes contact, and add that to the total.

What is bolt tension?

What is Bolt Tensioning. Tensioning is the direct axial stretching of the bolt to achieve preload. Inaccuracies created through friction are eliminated. Massive mechanical effort to create torque is replaced with simple hydraulic pressure. A uniform load can be applied by tensioning multiple studs simultaneously.