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Originally posted by Andy4639
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http://www.circletrack.com/techartic...s/viewall.html
If you’re using a mechanical click-type wrench, this one turns out to be absolutely true. A click-type torque wrench presses a ball into a detent that’s held in place by a spring. The wrench is normally adjusted by twisting the handle on the wrench. Twisting it in compresses the spring and requires more torque to pop the ball out of the detent. This is how it measures torque.
But if the spring is stored with the wrench “loaded” or set for a high torque rating, the pressure on the spring can cause it to weaken over time. To protect the wrench it should always be returned to the lowest setting before storing it back into your toolbox. For big wrenches (measuring in ft-lbs increments) the lowest setting is usually 20 ft-lbs. If, for some reason, you have a click-type torque wrench that goes all the way down to zero, leave the wrench set to 10 or 20 pounds. You always want to keep a minimum amount of pressure on the spring so that the ball can’t fall all the way out of the detent.
For other styles of torque wrenches, this isn’t an issue. The newest digital torque wrenches use an electronic strain gauge to measure torque, so when the wrench is not in use the only thing you may need to do is remove the batteries so that there is no chance of corrosion ruining your expensive digital wrench.
A torque wrench can’t measure... read full caption
A torque wrench can’t measure friction. For most fasteners the final torque will depend on the type of lubricant used. Motor oil, for example, has a different friction coefficient than moly lube or ARP’s new Ultra Torque lubricant. Make sure your torque number takes into account the lubricant being used. You can get this type of information from fastener manufacturers like ARP.
Read more: http://www.circletrack.com/techartic...#ixzz2JgLLGkWn
If you’re using a mechanical click-type wrench, this one turns out to be absolutely true. A click-type torque wrench presses a ball into a detent that’s held in place by a spring. The wrench is normally adjusted by twisting the handle on the wrench. Twisting it in compresses the spring and requires more torque to pop the ball out of the detent. This is how it measures torque.
But if the spring is stored with the wrench “loaded” or set for a high torque rating, the pressure on the spring can cause it to weaken over time. To protect the wrench it should always be returned to the lowest setting before storing it back into your toolbox. For big wrenches (measuring in ft-lbs increments) the lowest setting is usually 20 ft-lbs. If, for some reason, you have a click-type torque wrench that goes all the way down to zero, leave the wrench set to 10 or 20 pounds. You always want to keep a minimum amount of pressure on the spring so that the ball can’t fall all the way out of the detent.
For other styles of torque wrenches, this isn’t an issue. The newest digital torque wrenches use an electronic strain gauge to measure torque, so when the wrench is not in use the only thing you may need to do is remove the batteries so that there is no chance of corrosion ruining your expensive digital wrench.
A torque wrench can’t measure... read full caption
A torque wrench can’t measure friction. For most fasteners the final torque will depend on the type of lubricant used. Motor oil, for example, has a different friction coefficient than moly lube or ARP’s new Ultra Torque lubricant. Make sure your torque number takes into account the lubricant being used. You can get this type of information from fastener manufacturers like ARP.
Read more: http://www.circletrack.com/techartic...#ixzz2JgLLGkWn
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