The Lowdown on Wrenches

The most basic homeowner’s toolbox consists of a hammer, a couple of screwdrivers and a pair of pliers. Unless, however, you’re wealthy enough to pay a handyman for even the simplest household chores, like hanging a picture or changing a light bulb, eventually you’re going to accumulate tools. When you do, you’ll soon figure out that pliers may be a workhorse tool, but they’re not very useful in some circumstances – working with screws, nuts and bolts is much, much easier when you use a wrench.

There are many different wrenches. I’ve already addressed the socket wrench system, so let’s look at some other style. For now, we’ll stick to the wrenches workers use for nuts and bolts with a hexagonal (sometimes square) shape.


Open-End Wrenches

Offset on open-end wrench

Offset on open-end wrench

The first type to discuss is the open-end wrench. An open-end wrench is a handle with a precision-machined U shape at the end. The open end of the U fits precisely over a hexagonal or square bolt or nut. If you look closely at an open-end wrench, you’ll notice that the open end of the U is set at an angle to the handle. This offset allows a user to flip the wrench to get a slightly different angle on a nut.

Well-made wrenches have a thickened handle for reinforcement, with the size plainly marked near the end. Most open-end wrenches have two different, closely-spaced sizes on opposite ends instead of there being a single wrench for each size. Like most mechanics’ tools, open-end wrenches are available in both English (also known as SAE) and metric sizes, and are frequently sold in sets.

Open-End Wrench Sets

Open-end wrenches

Open-end wrenches

Buy at Amazon.com


Box-End Wrenches

Box-end wrenches are forged with an opening on the end, which fits snugly on the hex nut or bolt of the assigned size. The opening may be either six-point, which fits the nut exactly in six positions, or twelve-point, which fits in twelve positions. Because of this, twelve-point box wrenches are easier to place on a hex nut. A twelve-point box is slightly more “delicate” than a six-point wrench, mainly because the walls of the “box” are thinned at more points.

Offset on box-end wrench

Offset on box-end wrench

Like the open-end wrench, a good box wrench has a robust handle and the size is marked near the end. The “box” is also set at an angle to the handle, though in this case it’s as if the handle is slightly bent. This offset prevents the user from banging his or her knuckles on flat surfaces while using the wrench. Like open-end wrenches, box wrenches have different sizes at opposite ends, and come in sets of either SAE or metric sizes.

Box-End Wrench Sets

Box-end wrench set

Box-end wrench set

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The Ratcheting Wrench

In recent years, several manufacturers have combined the precise fit of a box-end wrench with the ratcheting action of a socket wrench driver. When using these ratcheting wrenches, you need not remove them from the nut to reposition them. Like a ratchet handle in a socket set, they engage in one direction and turn loosely in the other. To change directions, you simply turn the wrench over. The downside is that in order to facilitate this capability, the “box” must be oriented in line with the handle instead of offset at an angle. This can make the wrench hard to use on nuts or bolts on flat surfaces.

Reverse switch

Reverse switch

To combat this problem, tool manufacturers started adding little reversing thumb switches to their ratcheting box wrenches, similar to those found on modern ratchet handles. This allows a user to change directions without flipping the wrench over. It has the added advantage of allowing the wrench to be forged with the head canted at the standard 15° offset angle from the line of the handle.

Ratcheting Wrench Sets

 

Ratcheting wrench set

Ratcheting wrench set

 

Buy at Amazon.com


Combination Wrenches

Combination wrenches are pretty much what the name suggests: the wrench has an U-shaped open end, complete with the requisite angle, and a box (usually 12-point) of the same size on the other end. The open end tends to be better for breaking loose a nut, since the sides fully enclose the nut, while the box end is generally easier to get onto a nut. Most mechanics use whichever end they can get on the nut at the time.

Once again, combination wrenches come in sets of either SAE or metric sizes. Since each wrench is a single size, the sets are often twice as large as sets of either type alone.

Combination Wrench Sets

Combination wrench set

Combination wrench set

Buy at Amazon.com


Adjustable Wrenches

Adjustable wrenches are a favorite mechanic’s tool precisely because they’re adjustable. It’s essentially an open-end wrench in which one side of the U is fixed and the other slides to open and close the gap. Adjustable wrenches come in several different sizes, from relatively small ones to tools as big as a baseball bat. They’re sometimes sold in sets of different sizes. Obviously, there is no differentiation between metric and SAE sizes, since the wrench opening is infinitely adjustable.

An adjustable wrench’s chief advantage is that it can fit any nut or bolt within a range of sizes. The disadvantage is that the tool’s head is much bulkier than an ordinary open-end wrench, which can make it hard to reach into tight spaces.

Adjustable Wrench

Adjustable wrenches

Adjustable wrenches

Buy at Amazon.com


Pipe Wrenches

Pipe wrenches are specially designed for round stock like, well, pipes. Like an adjustable wrench, these wrenches, which are also known as Stilson or monkey wrenches, fit a range of sizes. They also come in several sizes, classified by their overall length. A pipe wrench also has a fixed jaw and a moveable jaw, though they are arranged vertically. The jaws are toothed to allow a better grip on a smooth-surfaced round pipe.

A pipe wrench fits the pipe or other round fitting loosely, but because the moveable jaw is slightly angled pressure in one direction tightens its grip. This means that you must reverse the wrench’s position on the pipe depending on whether you’re tightening or loosening it. Pipe wrenches aren’t particularly useful on a hex nut or bolt, but will come in handy if the corners have been rounded off a hex head.

Pipe Wrench

Pipe wrenches

Pipe wrenches

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Choosing Wrenches

Mechanics and serious DIYers know that a wrench is a purchase intended to last a lifetime, though many uses. Consequently, the quality of the manufacture is critical in choosing these tools. When deciding between brands, pay close attention to the quality of the materials used and to the design of the tool itself. A hand tool should be comfortable and well-balanced in the hand, with reinforcement in areas that will be subjected to heavy force.

Many well-made tools have a bright chrome or chrome-vanadium finish, although absence of this finish is not necessarily indicative of poor quality, nor is its presence a guarantee of high quality. Look for details such as the printing of the sizes: sizes etched on the surface or printed in raised lettering don’t weaken the metal, while printing incised or stamped in the metal is often a sign of cheap manufacture. More important, perhaps, is the warranty: manufacturers such as Snap-On and Craftsman warrant hand tools for life, no questions asked. This may mean the tools are more important, but it also means you’ll never have to pay for a replacement.

 All images from Amazon.com


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