Is there a loss of torque when extensions are applied to the socket end of a torque wrench?
I work on power plant turbines for a living and have heard many arguments about not using extensions or Universal joints on torque wrenches when torquing bolts. I was wondering if there is hard evidence that agrees with or denies this claim.
If this is true, where can I find a table/ chart with the foot lbs. lost by extension?
You know, occasionally, I've heard claims such as these as well. But, when you need to use an extension to torque a bolt you have to use it. Anyway, I've thought about it and the only loss that I could see would be the torsional flexing of the extension taking a portion of the torque you intended for the fastener.
Since the rotational deflection of a shaft (i.e. the extension) is directly proportional to the length of the shaft, then I would recommend using the shortest extension possible. Also, since the rotational deflection of a shaft is inversely proportional to the shaft diameter raised to the fourth power (i.e. large stiffness change for a small increase in diameter), then I would recommend always using extensions with a diameter greater than the bolt diameter.
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US $215.99
