The use of an extension has a v ery negligible effect on the torque accuracy - the WAY you use an extension does have an effect.
Extensions should be supported with an open palm, perpendicular to the work area. Gripping the extension results in drag, which in turn results in inaccuracies.
To calculate the effect of lengthening a torque wrench with a crows foot for example, follow this link;
Torque Wrench Extension Calculator, Calculate Torque, Norbar
Torque has become a serious business. Motors, transmissions, and almost everything else mechanical have evolved to the point where very tight tolerances are the norm. Notice how your car engine can easily run to 200,000 miles? With these tight fits and high precision the correct recommended assembly guidelines have to be followed...ever see what happens when someone installs a timing belt on the Volkswagen and does not torque the bolts correctly? It is not pretty and it is not cheap to fix it.
Extensions should be supported with an open palm, perpendicular to the work area. Gripping the extension results in drag, which in turn results in inaccuracies.
To calculate the effect of lengthening a torque wrench with a crows foot for example, follow this link;
Torque Wrench Extension Calculator, Calculate Torque, Norbar
Torque has become a serious business. Motors, transmissions, and almost everything else mechanical have evolved to the point where very tight tolerances are the norm. Notice how your car engine can easily run to 200,000 miles? With these tight fits and high precision the correct recommended assembly guidelines have to be followed...ever see what happens when someone installs a timing belt on the Volkswagen and does not torque the bolts correctly? It is not pretty and it is not cheap to fix it.
