Hello again. Hopefully you have read my other articles on tools if you are a novice do-it-yourself enthusiast and are looking to build yourself a great tool collection of your own on a reasonable budget. A critical part of your collection should be the combination wrench. When dealing with wrenches the most basic universal wrenches come in two styles - open end and box end.
We are all pretty familiar with the open ended wrench. When advertisers use a tool shape to symbolize the meaning of "Tool." they will often display a picture of an open ended wrench head. The open ended wrench was designed to allow you to slip a bolt into the head through an opening on the far end of the wrench. If it's a six point design, this allows the wrench to apply leverage on 5 out of the 6 points of the fastener. While good, this can be improved upon which is why there is a close ended or box end wrench design.
The box end wrench is designed to slip vertically over the fastener head to provide full engagement of the points of the fastener. Using this box end design typically will allow you to provide a greater extent of leverage on a fastener with less fear of rounding a point off. The drawback to this design is that since it must slip over the fastener vertically, you cannot get it onto a nut that only provides you with side-access.
A combination wrench as you may have already imagined is a combination of these two designs. It will feature an open end design on one side of the wrench while featured a box end design on the other end, and both end are typically meant for the same size fastener. These wrenches should make up the majority of your wrench collection. Typically I like to suggest that new tools buyers get both a long and short set of wrenches in both metric and SAE sizes. Typically you will want a set that has a completely uniform appearance and finish, as well as being completely smooth with no rough edges. That indicates that the manufacturer properly plated the tool and helps ensure that you are buying a quality wrench.