Wrenches are designed to tighten and loosen nuts, bolts, screws and other treaded items. Typically wrenches are well suited for tight areas where a lot of torque is needed. There are a number of different types of wrenches, each with special uses. When shopping for wrenches, the best ones are made of forged carbon alloy steel and often time bear the marking of “Cr-V” which stands for the alloying materials of Chromium for corrosion resistance and Vanadium for added strength. Additionally many wrenches will also have chrome-nickel plating to give greater corrosion resistance. Good wrenches will be clearly and permanently labeled with the measurement. Usually the best way to purchase wrenches is in sets. Make sure that you have both metric and standard (SAE) measurement wrenches in the kit you buy since there is no telling what kind of fasteners you will encounter. The increments of the measurements are usually in millimeters for metric and in 1/16 of an inch for the standard (SAE). When using wrenches, make sure that they fit snuggly on the fastener. If you are not sure of the exact size of the fastener, try several wrenches until you find the one that fits the tightest. The reason you want to have a snug fits is because it is easy to round off the edges of the fastener if the wrench is loose or too big. Most wrenches fall into a few major categories.

The Open Ended Wrench is the most basic type of wrench. With openings on the ends that are U-shaped, the two opposite faces of the opening are what grip the fastener. Some variations of these wrenches will have different sized open end wrenches on each end of the handle or they might have the same size open end and box end style wrench on the same handle. 

Box Ended Wrench is another very common type of wrench. The name box end wrench come from the fact the fastener is “boxed” in by the end of the wrench since the entire fastener is surrounded by the tool. The box end wrench normally has 6 or 12 corners or points. The 6 point is the most stable and effective for high torque applications because an equal amount of force is applied to all edges of the fastener. A 12 point box end wrench is handy because it doubles the amount of position that you can fit the wrench end on the fastener. This can be especially helpful in very tight spaces where there is a limited amount of space to swing the wrench. The trouble with using a 12 point box end for high torque applications is there is a possibility of round over or stripping the head of the fastener. More recently ratcheting box wrenches have become popular. These types of wrenches operate much like a ratchet and socket combo and make it handy to not have to reposition the box end of the wrench at the end of a turn.

Tube or Flare Wrenches are a variety of wrenches that serve a special purpose. A flare wrench looks much like a 6 point box end wrench except for a section of the ring is missing. This missing section is slipped over the tubing which then makes it possible for the wrench to be placed over the fastener. Typically the nuts used to secure tubing are some what delicate or made of soft materials like brass or plastic. The use of a regular open end wrench can lead to rounding off the corners of the nut since it does not contact all sides of the softer material. These types of wrenches are handy when working on car brake line systems or compression fittings on copper piping for things like dishwashers or ice machines.

The Adjustable Wrench functions just like an open ended wrench. With a mechanism to adjust the parallel distance between the jaws, just about any size nut or bolt can be fit. This is a great tool to use if you don’t have the right size wrench or you don’t need to apply a lot of torque to the fastener. The only negative side to this type of wrench is as you use the wrench, the jaws will move slightly which can cause you to slip off and round off the edges of the fastener. When using, you have to keep checking that the adjustment stays set so there is a snug on the fastener.  These kinds of wrenches are available in various sizes to better accommodate the different sizes of fasteners encountered. Many times these are improperly called Crescent Wrenches, which is actually a trade marked brand name for one company’s version of this type of tool.

Another common, yet specialized type of adjustable wrench is the Pipe Wrench. These heavy duty wrenches have a fixed upper jaw and a movable lower jaw. The jaws are heavily serrated so that they can bite into the pipe they are turning and they jaws are usually pinned into place so they can be replaced when they wear out. Smooth jaws are also available so they don’t damage the surface that is being turned for certain applications. The handles are usually made of steel but there are some lightweight aluminum handle models available at a much higher price.

Ratchet and Sockets are a great substitute to regular wrenches. The advantage is that a ratchet can be fitted with numerous sockets that will fit varying sizes of nuts and bolts.  Ratchets work on the same principle as wrenches in that they have a long handle that allow you to put a lot of torque on the fastener, with the main difference being the head of the ratchet moves and will only provide movement in one direction. This facilitates quicker fastener turning since you do not have to remove and reset the head position every time you make a turn as with a wrench. The most common drive sizes for ratchets are 1/4”, 3/8”, and 1/2”, but 3/4" and 1” sizes are available for certain industrial uses. Ratchets work with both metric and standard (SAE) sockets as long as the drive of the socket matches the drive of the ratchet.

Sockets are cylinder looking with one end that has a square hole that matches one of the common ratchet sizes. The other end of the socket is sized to fit the fasteners, usually with either a 6 or 12 point configuration. The size of the socket is usually permanently stamped into the side of the socket for quick identification.

Conclusion

The best value in starting your collection of wrenches, ratchets and sockets is to look for quality sets. The good thing is that the set sizes range greatly and the variety include also vary. There should be sets on the market for just about any budget. Some manufactures like Craftsman and Snap On offer lifetime warrantees that will replace broken tools as long as they were used in the way they were designed.