Healey Journal
Wrenches- Mundane they may be, but its impossible to do any work on any car without them. A brief survey of the different types and their merits and applications.
- Basic
- Special
At the top: a box-end wrench (ring spanner). In the middle: a combination wrench. At the bottom: an open-ended wrench. |
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I've found the standard open-ended wrenches to be just about the most useful and effective tools. Easy to use and essential to any mechanical work. The advantage of the open-ended wrench is that it may be easily fit to any bolt or nut, and it works well in loosening or tightening them. Such wrenches have a different size at each end and may be considered two wrenches in one. This makes the tools extremely versatile since a single tool can deal with the most commonly found sizes. For the Austin Healey a 1/2 x 9/16 wrench can be used for the largest number of nuts and bolts found.
Caveat: the wrench may be relatively short, thus unfastening and tightening may sometimes be hard work. A tightly fastened bolt or nut may be susceptible to be rounded off if too much effort is applied. In those cases a box-end wrench, or preferably, a six-point socket may be more effective.
The box-end wrench is also shown in the photo above. These are particularly useful for nuts and bolts that are tightly fastened. They provide more contact with the surface of the fastener, and because they encircle it, they are less prone to slip off under pressure. The wrenches shown are "twelve point" (sometimes called double-hex) and allow the wrench to be easily fit to the fastener with little movement around it. The alternative is a "six point" wrench (single hex) which has only six sides to exactly fit to the fastener. This gives a stronger grip, but it is less convenient to use since more movement (i.e., clearance) is needed to fit it to the fastener.
The combination wrench provides both an open-ended and box-end wrench in a single tool.
Standards: the three types of wrenches mention above should be considered an essential and standard part of any mechanic's tool kit. Of the three I find the open-ended wrenches to be most useful (because a single tool can cope with two different size fasteners). If you're starting out and have to prioritize your acquisitions I'd rank them in the order they're discussed: open, box, combination. I've found it necessary to have both the open and box sets for there are times when both the nut and the bolt's head must be held to tighten or loosen it. In those cases a single set of wrenches cannot cope.
Specialty Wrenches
At the top: a tappet wrench.In the upper middle: a ratcheting wrench. In the lower middle: a Metrinch wrench. At the bottom: a stubby wrench.
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Tappet: This is simply a long open-ended wrench, with narrower heads. Its useful for long reaches, as well as for adjusting tappets. While this might seem useful for uncooperative fasteners the thinner head means there's less contact and more chance of rounding off corners. Not good....
An OLD-style (from the early 1970s) ratcheting wrench with ratchet mechanisms for each end. Bulky and unwieldy in needing to be turned over to switch from tightening to loosening. New ones are smaller and MUCH improved!
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Ratcheting: The ratcheting wrench shown is a combination wrench in which the open end is shaped with a machined cutout and shortening of one side of its jaws so that it will grip the nut or bolt when moved in one direction only, reversing movement then allows the wrench head to slide back over the fastener. Some ratcheting wrenches have a true ratcheting mechanism in one of the wrench's heads (then necessarily box shaped)- these are larger and more complex, and expensive. The wrenches shown are probably a little more fiddly to use, but will fit places the others may not. The ratcheting mechanism type wrenches are useful when there isn't room for using a ratchet, otherwise I see no great appeal to them- and the type of wrench shown is even more useable in those situations. It is useful in places where there isn't much room for maneuvering a wrench (and no room at all for a ratchet). It takes a little getting used to for the wrench has to be held steady as its being "ratcheted" so that it stays in position on the fastener. The wrench also feels a little looser than standard open end wrenches, and not so much force can be applied using these. Once a fastener is loosened they work well and can be quicker than other wrenches.
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Metrinch: The Metrinch (brand name) wrench is one that tries to satisfy both metric and imperial measures in a single wrench. Thus, the 1/2 inch wrench is designed to also fit a 12 mm fastener. The idea is that someone with needs for both types of wrench (with both a modern and a classic car) needs only have the one set of tools. I must confess that I was rather skeptical about the whole idea. But after several months of light usage I'm inclined to think that they're worthwhile for most people in such a situation. They feel a little looser than standard wrenches, but that is due to their working on the sides of the fasteners rather than the edges as is usual. I doubt that the open end can exert as much force as a comparable standard open end, but that is compensated for with the box end, which is six pointed rather than twelve. This allows more force to be exerted than with the standard twelve point box end, though the wrench loses some freedom of movement as a result (i.e., it can only fit at six positions on a fastener rather than twelve).
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Stubby: The stubby wrench is exactly that: a short version of the combination wrench. It is useful for areas where standard sized wrenches are too long. I also find it useful when installing or removing studs to hold one nut stopped tight against another which has a large wrench used to provide the turning force. Another large wrench then would be harder to hold or manipulate.
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The flare wrench has a thicker and more "full" six-point head that encircles roughly 5/6's of the fastener. It is designed so that it holds the fastener more securely- both due to the six-point design and because the wrench head is thicker to make more contact with the fastener. These are used for automotive hydraulic systems- the fasteners may be of soft metal (brass) and the hydraulic lines make it impossible to use standard box wrenches on such fitting. A full set is seldom necessary, and virtually all requirements may be met with a pair of 3/8 x 7/16 and 1/2 x 9/16 wrenches. That said, I've found these usually live undisturbed in the tool box amongst all the other clever specialist tools, and the careful use of a standard open end wrench is perfectly workable. But, if I do hit a particularly uncooperative fitting, I know I've got these for insurance.
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The Crescent wrench is adjustable and allows the jaws to be exactly matched to the width of some fastener. These are particularly useful for square shafts, or for odd-sized nuts and bolts that may be encountered. These provide flexibility though at the cost of grip. Because of the adjusting screw there is a natural tendency for these to loosen slightly in use. This slackness can make it a little more difficult to do the job, and corroded nuts and bolts may be more prone to being rounded off when these are used.
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The obstruction wrench is like a box-end wrench that someone's stepped upon and bent the middle. It is used to reach around obstructions and fit otherwise inaccessible fasteners- virtually always manifold nuts. When the only way at it is by curving around something, this then is exactly the tool to use. One 1/2 x 9/16 wrench seems more than adequate. Note too that you may take a cheap box wrench and a welding torch to make one of these yourself, though the heat needed to bend it would seem to make it less reliable.
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These are sockets with ends that fit to wrenches (or to other sockets, but that seems unnecessary). This allows a ratcheting wrench to be used as a socket driver to. This allows for a little more clearence- if there's a lip around the fastener that doesn't allow straight-on access for a wrench and/or little clearance above that would make a full socket-ratchet head too large.
Copyright© 2005, 2008 James M. Wilson All rights reserved.