I am not a expert in which are best but here is a quick and simple way to check your Torque Wrench for accuracy. Be aware, though, that this is not the best way to check it. That would be to send it to a company that specializes in calibrating test instruments. This will, however, let you know if the Torque Wrench is “close” to correct.

Stick an old socket on the wrench and clamp the socket in a vice. You want the wrench to rotate freely. Turn the handle to a horizontal position. Now, hang a known weight (You can use water for the weight by using a bucket and filling it using gallon water bottles. Every gallon of water you add weighs 8.3 lbs. You can factor in the weight of the bucket if you wish, but this is probably more accuracy than you really need. Remember; this is a “ball park” check.) on the wrench handle by using a loop of wire. Measure the distance between the wire and the pivot point of the wrench head, and divide by 12. Then multiply this by the weight applied. The result is the actual torque being applied to the wrench and can be compared with the reading on the Torque Wrench.

For example, if you hang a 60lb weight at 10 inches, your applied torque is:

60lbs. x 10inches/12inches per ft. = 49.9ft-lbs. If you have a click-type wrench, you would adjust the setting and see if it clicks when it's set near 50 ft-lbs.

A final word about the click-type wrenches. ALWAYS relieve the pressure on the springs by resetting the torque to zero when finished. The springs can take a “set” and lose ANY accuracy if you leave them under pressure.