Tool anatomy: The combination wrench

May 31, 2023

If you’ve worked on a car, a bicycle or basically anything that uses a hex fastener, you’ve grabbed one of these. Well, maybe not one of these, but you’ve reached for a combination wrench. You might have asked yourself what, exactly, a combination wrench combines, as it seems to simply turn hex fasteners -- and you wouldn't be the only one.

The combination wrench gets its name from combining an open-end wrench and a boxed end wrench. Pretty simple -- but there was a time when your wrench selection was stuffed full of open-end wrenches, with the occasional boxed end to supplement. There are so many types of wrenches (ignition wrenches, flare nut wrenches, strike wrench, etc.) that the particulars of what makes those wrenches special will be addressed later. Today we’re just going to explain the parts of a wrench and what makes a high-quality wrench worth the cost.

A combination wrench is essentially three parts: an open end, a beam and a boxed end. Despite only having three parts, there are a few different ways to shape them. On the open end side, it's pretty simple -- you can have standard jaws or a modified open end. There are other details like jaw shape, as seen in the difference of these Proto wrenches and Wright wrenches, but that matters less than the difference between a modified and standard open end.

Open end

The modified open end that you see in these Wright Wrightgrip wrenches has teeth broached into the jaws as well as a recess engineered into the jaw that allows the fastener to lock into the tool. While generally considered better for removing stubborn and rusty fasteners, most modified open ends will mar the fastener during removal. That means using one of these wrenches on a chrome or polished stainless-steel fastener isn't a good idea. The standard open end is, well, standard -- its two parallel faces grab the flats of a fastener. The reason that this is inferior to a modified open end is that the wrench's jaws can spread open enough to allow the fastener to roll over its corners, or strip. You’ve done this. We’ve all done this.

Boxed End

On the other end, it's more cut-and-dried. The boxed end will either come in six-point or 12-point and sometimes features some type of off-corner engagement method. High-end wrenches make sure to advertise this, as it moves the contact point on the fastener away from its corner, reducing your chance to strip it. Lower quality wrenches might not sport a system like this and could lead to you stripping fasteners. You should also note, the size difference between the Proto and the Wright wrenches. The Wright is narrower, which will make it more useful in tight places. There are also ratcheting combination wrenches, like the SK X-Frames we reviewed a while back.

The Beam

The beam might seem insignificant because it's just a piece of forged steel, but its one of the most important parts of how a wrench feels in your hand. It might sound cheesy, but how a tool feels in your hand will color your impression about how it performs. These two wrenches sport two different kinds of beams -- the Wright is squared off, while the Proto is rounded. Some wrench makers will make their wrenches even thinner, like Snap-On, but that can also dig into your ungloved hand and cause pain. Beams can also come with no offset for the box-end -- lifting your knuckles away from the workpiece -- or, more frequently, a 15-degree offset. There are exceptions, especially with specialty tools, but you’re probably going to see a 15-degree bend pressed into the beam.

Now that you know the pieces, the question is: Why you should drop the money on a quality wrench set? Well, there are a lot of reasons, including broach precision, jaw type, steel quality, feel and the intangible -- confidence. High quality doesn't always mean expensive -- I picked up this vintage Proto wrench set off Craigslist for a princely sum. The Wrights I bought from an internet tool-supply house. Both were less than half what a set of Snap-On, Mac or Matco wrenches go for, and both are made in America. Imported wrenches can be good, too, but they can lack features like modified open ends, off-corner engagement systems or polishing that won't hurt your hands. Cheap wrenches will likely sacrifice steel quality, and they'll try to make up for it with bulky open end jaws, colloquially called lobster claws or ultra-wide beams. You’ll want to avoid those.

A set of high-quality wrenches will outlast your interest in cars -- and probably your life. My Proto wrenches outdate me by almost a decade, and they'll still probably live beyond my wrench-spinning ambitions.

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