There are many different brands and types of 3/8 torque wrench. Which is best really depends on what the torque wrench is needed for. One of the main points for an excellent brand is the reliability of the torque wrench calibration. The best brands will have torque wrenches that rarely go out of calibration or only need to be calibrated sparingly. Additional ease of use may be more important for other users, and in this case a 3/8 digital torque wrench may be the best.
Using the Torque Wrench
Torque wrenches are used to tighten bolts and screws. A specific torque, or force per revolution, is needed for the bolt to function properly. If the bolt has too much torque then it can break or damage the mechanical device. If there is not enough torque then the bolt may become loose and cause damage because the equipment cannot function properly. If you are using a torque wrench frequently then it is best to ensure you have a high quality wrench from a top brand.
One of the best torque wrench brands for a motorcycle is from Precision Instruments. It has a ±0.4% accuracy from 20% to 100% of its scale, so the accuracy is constant from 20 ft-lbs to 100 ft-lbs. The micrometer or click type wrench can be used in either direction, clockwise or counterclockwise, and is virtually break proof. The feel and click is very clear and the only downfall is that a zero setting must be used each time the wrench is used. This company also offers excellent beam torque wrenches and a dial torque wrench with easy to read dial and some of the best accuracy at ±0.1%.
This is one of the most reliable and well known brands of torque wrenches. They offer many different types of wrenches, though the most popular is the beam style 3/8 wrench. It has both the Metric and English scale. There is line on line reading which helps to minimize and parallax error. It has a lifetime guarantee and can measure from 0 to 75 ft-lbs. It is very easy to use and is very affordable. The tool comes correctly calibrated right out of the box, so it's possible to start using it immediately.
Sunex torque wrenches are carbonized, heat treated, tempered and quenched to ensure that they last long and provide precise results at all times. These instruments do not need to be consistently recalibrated. They have an accuracy of ±0.3% and come with sandblasted nickel and chrome plating which reduces any metal fatigue. The drive for the 3/8 torque wrench is from 10 ft-lb to 80 ft-lb. It provides metric and SAE scales and has a 90-day warranty on the calibration and any manufacturing defects.
KD Tools offers a 3/8 drive micrometer torque wrench. It is very easy to use, fast and accurate. The range of the tool is 10 to 100 ft-lbs. It has a reversible ratchet head and the Metric and English measurements are color coded. In order to keep this wrench working well and to prolong the calibration and life of the tool, it uses a ball bearing which provides the necessary internal lubrication.