Figure 1. Basic wrenches include adjustable, open-end, box-end and combination.

Figure 2. A basic socket wrench set includes sockets, a ratchet handle and one or more extensions.

Figure 3. Specialized wrenches include hex (Allen) wrenches, left, and Torx wrenches, right.

The most basic tools needed for working on lawn and garden equipment are wrenches. You can sometimes get by on other little fix-it jobs around the house with pliers, screwdrivers, etc., but almost anything you try to do on grounds maintenance equipment will require the use of wrenches. There are many types of wrenches available. As your skill and level of jobs that you tackle increase, you will need to add to your collection of wrenches.

Adjustable Wrenches
The most basic wrench is an adjustable wrench (often referred to as a “Crescent” wrench, although that term is properly the trademark of one brand). These wrenches work on a range of sizes of fasteners, but the large heads of these wrenches limit where they can be used, and they have a tendency to round off the corners of bolts/nuts if they are not kept fully tightened.

Open-end Wrenches
Open-end wrenches are simple tools designed to fit a single size of nut or bolt. They will have one size on each end of the wrench. They fit on the nut or bolt head easily but can slip and round the corners if not sized perfectly. This is more of a problem with cheap wrenches (or cheap nuts and bolts). They are relatively fast to operate but are limited to operating in the plane of the nut or bolt head.

Box-end Wrenches
Box-end wrenches are a step up from open-end wrenches. They have a circular head that fully encloses the nut or bolt head. Most box-end wrenches have 12 points, thus allowing them to fit on hexagonal nuts and bolt heads in 30 degree increments, although some have only 6 points. The 6-point wrenches are less likely to round off the corners of the nut or bolt head, but operate in 60 degree increments. Most box-end wrenches are offset to allow the wrench handle (and your hand) to be above the plane of the nut or bolt head. They will have one size on each end of the wrench.

Combination Wrenches
Combination wrenches have one open end and one box end (of the same size). This gives you the flexibility to use whichever head is best suited to a particular job but requires twice as many wrenches for a given range of sizes.

Ratcheting Box-end Wrenches
A more-recent development is the ratcheting box end wrench. These wrenches fit like a box-end wrench with a large head and allow you to swing the wrench back and forth without removing it. They may be combination wrenches with one open end, or they may have two box ends of different sizes. Some allow reversing the ratchet; others require turning the wrench over to reverse it. Some have a flex head that allows raising the wrench handle.

Socket Wrenches
Socket wrenches completely encircle the nut or bolt head in a cylinder that has a square drive hole at the opposite end. The drive sizes are standardized to ¼-, 3/8-, ½-, ¾- and 1-inch drives. For walk-behind and hand-held grounds maintenance equipment, you will normally need only 3/8-inch drive tools, although ¼-inch can be helpful. For larger riding mowers and tractors, you may need ½-inch tools. Larger ¾-inch drive sockets are handy for compact and larger tractors. Sockets are available in 6-point, 8-point and 12-point. The 6-point sockets are generally best since they will not round off the corners of the nut or bolt head. Since most sockets are used with ratchet drivers, you will not normally need the flexibility afforded by 12-point sockets. The 8-point sockets are far less common and are used on square-headed nuts and bolts. Sockets can be regular or deep. The deep sockets allow use on nuts when the bolt is protruding above the nut. The basic drive tool needed is a ratchet. You may also need extensions in various lengths to allow reaching difficult fasteners. A flex-head “breaker bar” will allow you to put more torque on stubborn bolts but will not ratchet (although flex-head ratchets are available). Many other socket accessories are available if needed. For instance, special spark-plug sockets are deep and contain foam padding. Special slotted deep sockets are available for automotive sensor applications (e.g. oxygen sensors). Special heavy-wall sockets are available for use with impact wrenches.

Special Wrenches
A wide variety of special wrenches are available for less-common fasteners. Torx wrenches can be internal or external and have a rounded 6-pointed-star shape. They are used on some hand-held lawn equipment. Hex wrenches (sometimes called Allen wrenches) are merely hexagonal bars bent into an “L” shape that fit into internal hex openings in set screws and bolts. Nut drivers are just socket heads affixed to a screwdriver handle and body. You can buy a handle to allow you to put a ¼-inch drive socket on the tool and make a nutdriver. Many other specialized wrenches are available for automotive and industrial applications, but you will seldom need them for minor maintenance on lawn and garden equipment.

Metric Wrenches
All of these wrench types (except Torx) are available in metric dimensions as well as inch dimensions. Since lawn and garden equipment is made with either (sometimes both) type of fasteners, depending on the manufacturer, you may need duplicate sets of tools. The trend is toward more metric fasteners, but many lawnmowers, for instance, still use inch dimensions. You will not need to duplicate socket drive components; metric sockets fit on standard inch drive tools.

Wrench Quality
There is a tremendous difference in price – and quality – among wrenches. You can buy sets of wrenches and sockets very cheaply or you can pay a very high premium price. You do get better wrenches when you pay more – up to a point. If you only plan to use your wrenches for very occasional and very light tasks, inexpensive wrenches may be adequate. If, on the other hand, you want your wrenches to hold up under heavier use, you should buy some of the better wrenches that carry a lifetime warranty.

A related article on tools for maintaining lawn and garden equipment provides recommendations on which tools are needed.