Top quality wrenches are forged from fine-grade tool steel, machined to close tolerances, hardened and tempered for long service life.
Because most imported products are made to metric specifications a set of metric wrenches has become a must in many home workshops
Types include torque wrench, open-end, box- end, combination box/open end, adjustable, socket and locking grip styles.

A wrench's main function is to hold and turn nuts, bolts, caps, screws, plugs and various threaded parts. Applying excessive torque will strip or damage those threads, so quality wrenches are designed to keep leverage and intended load in safe balance. Users should not put "cheaters" on wrenches to increase leverage.

A torque wrench is a wrench used to precisely set the torque of a fastening such as a nut or bolt. It is usually in the form of a socket wrench with special internal mechanisms. A torque wrench is used where the tightness of screws and bolts is crucial. It allows the operator to measure the torque applied to the bolt so it can be matched to the specifications. This permits proper tension and loading of all parts. A torque wrench indirectly measures bolt tension. The technique suffers from inaccuracy due to inconsistent friction between the fastener and its mating hole. Measuring bolt tension (bolt stretch) is more accurate but most often torque is the only means of measurement possible.

Click type torque wrenches are more precise when properly calibrated - however the more complex mechanism can result in them losing calibration far quicker than the beam type, where there is little to malfunction.
For the click type, when not in use, the force acting on the spring should be removed by setting the scale to zero in order to maintain the springs strength. In the case of the beam type, the is no strain on the component that provides the reference force except when it is in use.
Metric measure torque wrenches are available in Newton meters (N.m), meter kilograms (mkg) and centimeter kilograms (cmkg) with N.m becoming the more modern, universally accepted calibration. Many torque wrenches are available with dual scales for conventional and metric measurements.

Open-end wrench with a U-shaped opening that grips two opposite faces of the bolt or nut. This wrench is often double ended, with a different sized opening at each end. The ends are generally oriented at an angle of around 30 degrees to the longitudinal axis of the handle. This allows a greater fit the nut exactly to prevent mutilating the nut edges.

Box-end wrench is an enclosed opening that grips the faces of the bolt or nut. The recess is generally a six-point or twelve-point opening for use with nuts or bolt heads with a hexagonal shape. The twelve-point fits onto the fastening at twice as many angles, an advantage where swing is limited. Eight-point wrenches are also made for square shaped nuts and bolt heads. Box-ends are also often double-ended. Box wrenches provide more leverage by completely enclosing the nut.

Pipe wrenches screw pipes into elbows or other threaded devices. Jaws actually bite into the surface to hold it for turning. They should never be used on plated pipe installations because they will badly scar the finish.
Aluminum pipe wrenches are popular among professionals because of their lighter weight, but they are more expensive.

Combination wrenches are a box and an open end on opposite sides of the same wrench. Both ends generally fit the same size bolt. These are the most popular of all wrench styles.

Adjustable wrenches are open-ended wrench with adjustable smooth jaws, also sometimes called crescent wrench. They come in two styles, locking and non-locking. Non-locking style features an adjustable end opening with little provision made for slippage.
The locking style also has an adjustable head, but uses a locking mechanism to secure jaws in desired position, eliminating the need for constant readjustment. When properly adjusted to nut or bolt, it will not slip.

Crowfoot socket wrench: a type of socket designed to fit some of the same drive handles as the regular socket but non-cylindrical in shape. The ends are the same as those found on the open-end, box-end, or the flare-nut wrenches. These sockets use for use where space restrictions preclude the use of a regular socket. Their principle use is with torque wrenches.

Flare-nut wrench used for gripping the nuts on the ends of tubes. The design is similar to a box-end wrench but with an opening to allow the wrench to fit over the tube.

Chain wrenches are designed for easy use in extra-close quarters-on round, square or irregular shapes. Also self-tightening wrench with an either a chain or strap of metal, leather, or rubber attached to a handle, used to grip and turn smooth cylindrical objects.

Socket wrench: a hollow cylinder that fits over one end of a nut or bolt head-may include a handle but usually used with various drive tools. It generally has either a 6 or 12point recess, may be shallow or deep, and may have a built-in universal joint. In addition, face driving sockets are available. These are more durable still, and have the ability to drive a range of hexagonal head sizes, with less risk of damaging the nut or bolt head than traditional "corner" drivers. The drive handles generally used are:

Check your state and local codes before starting any project. Follow all safety precautions. Every effort has been made to ensure accuracy and safety.

Author: Carl Robinson
Toolprice
http://www.toolprice.com