Wrenches Safety Tips
Applying excessive torque will strip or damage threads, so quality wrenches are designed to keep leverage and intended load in safe balance.
Users should not put extension handles or “cheaters” on wrench handles to increase leverage. Instead, the proper size wrench should be used.
When possible, a wrench should be pulled, not pushed. Also be sure to brace your stance in case of sudden release or slippage of the fastener.
Never place sockets designed for a hand tool on a power tool or impact wrench.
When breaking loose frozen fasteners, always use a box wrench with a striking face or a heavy-duty socket wrench and a sledge hammer of the appropriate size.
Always make sure the wrench is completely seated on the nut or bolt being fastened—never tilt the wrench at an angle.
When using an adjustable wrench, pull so that the force is on the fixed side of the jaw.
Never use a torque wrench as a conventional wrench.
Open-end Wrench

Provides gripping power on two sides of the head with another side open so the wrench can be placed on a nut, which might not be accessible to a closed or box wrench.
Has different size openings on each end and should fit the nut exactly to prevent mutilating the nut edges.
Some models, called gear wrenches, have ratcheting capabilities.
Other varieties, called flare nut wrenches, are flared to fit hex fittings and flare nuts.
Generally available in sets.
Box (Box-End) Wrench
Has enclosed head and provides more leverage by completely enclosing the nut.
Some are offset to provide knuckle room and clearance over obstructions.
Ranges in size from 4" to 16" long and is available with either 6- or 12-point rings.
Some models have ratcheting capabilities.
Combination Wrench

Has a box and an open end on opposite sides of the same wrench. Both ends are usually the same size.
Used for working on machinery and is the most popular of all fixed-end wrench styles.
Also available is a reversible ratcheting combination wrench that allows the user to quickly tighten nuts and bolts without lifting the wrench off and repositioning it after each rotation
Adjustable Wrench

Comes in two styles: locking and non-locking.
Non-locking styles feature 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 a nut or bolt, it will not slip.
Pipe (Stillson) Wrench

Screws 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 mar the finish.
Socket (Hinge Handle) Wrench

Combines an offset handle with a male drive piece that has a spring-loaded bearing to lock on various size sockets. They can be used at almost any angle since handles may be attached to the head by a jointed hinge device.
The most common type is the detachable socket wrench, with square drive for hand use. Common square drive sizes are 1/4", 3/8" and 1/2", and these are normally used in conjunction with a ratchet wrench.
Sockets are available with 6-, 8- and 12-point gripping ends, in a full range of inch and metric sizes.
Hex-Key Wrench

Hex-key wrenches are short, L-shaped tools designed to turn bolts or screws with hexagonal heads.
They generally come in sets of different sized wrenches
Ratchet (Socket) Wrench

Available in a variety of handle shapes and lengths and used with sockets to make turning nuts and bolts easier than with a conventional wrench.
Available in 1/4", 3/8" and 1/2" drive sizes and are used with socket wrenches.
Available with a round or teardrop-shaped head and contains a reversing mechanism to facilitate tightening or loosening a fastener.
Popular accessories include flex handles, speeder handles, T-handles, extensions of various lengths and universal joints to work on fasteners in hard-to-reach locations.
Locking Wrench

Through a locking action, jaws can be locked in a holding position with pressure up to 1 ton.
Can also be used as hand vises, holding clamps, pipe wrenches and hand vise pliers.
Available with both curved and straight jaws
Torque Wrench

Designed to permit an operator to determine applied torque on bolts, nuts and other fasteners.
Torque value (generally measured in foot pounds) is set to a micrometer scale on the handle or preset by an adjusting screw in the handle.
Typically has square drives to use standard detachable 3/8” and 3/4” sockets.
Available with audible signal (clicking sound) or visual display.
Many torque wrenches are available with dual scales for conventional and metric measurements.
Chain Wrench
A Pipe wrench used for tightening and loosening odd-shaped objects, such as pipes and square objects.
Has an adjustable chain that wraps around the object, with ends that connect teeth of chain to engage and turn the object.
Some models feature a locking mechanism with ratcheting action for turning in either direction.
Courtesy of NRHA.org