If you use an offset extension on your Torque Wrench, unless you apply a conversion formula, you are over-torqueing.
A torque wrench is a tool used to apply an accurately known torsional or twisting movement about the axis of rotation.
The twisting force applied through the tool should be as close as possible to a right angle with respect to the axis of the twisting motion. Continue applying the force while looking at the dial until the desired value is reached. You can damage your torque wrench if the maximum dial value is exceeded. Ideally, the torque value you need should be 'Center of Scale' on the torque wrench you use. That way maximum accuracy is archived. Most types of measuring devices (dials, gauges, torque wrenches ect.) are the LEAST accurate at either end of the scale.
In my toolbox, I have four or five torque wrench's. Each has it's own scale and uses.
A 'clicky' type 0-150 ft/lbs. scale
A 'dial' type 0-150 ft/lbs. scale
A 'dial' type 0-50 ft/lbs. scale
A 'dial' type 0-400 in/lbs. scale
A 'dial' type 0-150 in/lbs. scale
I use each depending on the amount of torque needed to be applied.
Never, Never use your Torque Wrench to tighten or loosen your work. Thats what other tools are for.
The twisting force applied through the tool should be as close as possible to a right angle with respect to the axis of the twisting motion. Continue applying the force while looking at the dial until the desired value is reached. You can damage your torque wrench if the maximum dial value is exceeded. Ideally, the torque value you need should be 'Center of Scale' on the torque wrench you use. That way maximum accuracy is archived. Most types of measuring devices (dials, gauges, torque wrenches ect.) are the LEAST accurate at either end of the scale.
In my toolbox, I have four or five torque wrench's. Each has it's own scale and uses.
A 'clicky' type 0-150 ft/lbs. scale
A 'dial' type 0-150 ft/lbs. scale
A 'dial' type 0-50 ft/lbs. scale
A 'dial' type 0-400 in/lbs. scale
A 'dial' type 0-150 in/lbs. scale
I use each depending on the amount of torque needed to be applied.
Never, Never use your Torque Wrench to tighten or loosen your work. Thats what other tools are for.
If you must use an adapter, this adapter adds length to the fulcrum which adds FORCE. By using an adapter, you are adding more torque than indicated. This also applies to 'Clicky' type torque wrenches.
Use the following formula to calculate what the dial should read to apply the proper torque.
Use the following formula to calculate what the dial should read to apply the proper torque.
DR = Dial reading of the torque wrench
A = Distance from the center of the square drive (mounting point of socket or extension) of the torque wrench to the center of the handle grip
B = Length of adapter from center of the square drive to the center of the nut or bolt. Use only the length which is parallel to the handle
T = Torque Desired. This is the torque needed to be applied to the fastener. The torque spec...
So, if you need a torque of 30ft/lbs, use a 2" extension and have a torque wrench length of 12", then the formula says that the dial should read 25.7ft/lbs to apply a real torque value of 30ft/lbs.
Torque Wrench's
DR =
25.7 ft/lbs
A x T
=
A + B
12 x 30
12 + 2
360
14
=
=
A = 12
B = 2
T = 30ft/lbs