Torque wrenches are calibrated based on the length of the torque wrench. When you change the centerline distance between the handle of the torque wrench and the socket, the torque reading will no longer be accurate. A crowsfoot extends the centerline; therefore, you will need to either convert the torque setting of the torque wrench with a converting calculator or orientate the crowsfoot in a way that it does not change the centerline length of the torque wrench.
Place the torque wrench on the worktable, and measure the distance between the centre of the torque wrenches' handle and the centerline of the socket attachment located at the far end of the torque wrench.
Attach the crowsfoot to the socket attachment of the torque wrench at a 90-degree angle to the handle of the torque wrench.
Measure the distance between the centerline of the torque wrench handle and the centerline of the 90-degree mounted crowsfoot. The measurement should change slightly but the slight change will not affect the setting of the torque wrench.
Slide the crowsfoot over the fastener that you need to torque. If you cannot access the fastener with the crowsfoot turned at a 90-degree angle, rotate the crowsfoot parallel to the handle of the torque wrench, and use a torque converter to adjust the torque setting of the wrench.
Enter the required measurements into the torque converter, and adjust the setting on the torque wrench to the torque specified by the converter.