How Does A Ratchet Work [Hands-On]

If you’ve ever done any kind of maintenance or repair, then chances are good you’ve used a ratchet before. They’re ubiquitous, and the go-to tool for installing or removing fasteners of various shapes and sizes. Being a car guy, myself, I use one almost daily.

But just because you use a ratchet doesn’t necessarily mean you know how it works. Which, makes sense. It’s a tool, after all, with a job to do, and as long as it’s functioning there’s not much reason, beyond regular maintenance, to crack it open and peek at its inner workings.

Still, you may be curious, or, perhaps, you find yourself in the unenviable position of breaking a ratchet and need to know how it works in order to fix it.

As luck would have it, I have a ratchet in need of cleaning. Since I need to open it up anyway, I think it’s a great time to take some pictures and explain what’s going on in there. Use this guide to find out exactly how a ratchet works, so you can satisfy your curiosity or complete all necessary maintenance tasks.

What Is A Ratchet?

A ratchet is a simple hand tool used to install or remove fasteners. It uses interchangeable sockets that correspond to the fastener size. While typical sockets are made for hexagonal nuts and bolts, they can be made to fit a number of other shapes. This includes 12-point and E-Torx among many others. Sockets can also be made with bits, like hex or Torx.

A ratchet gets its name from its ratcheting action. When you turn the ratchet it will spin freely in one direction and lock-up in the other. The direction can be changed with a selector switch on the back of the ratchet. This action let’s you quickly install or remove fasteners without removing the ratchet from the fastener.

The ratchet I’m opening up here is a 3/8″ drive. There are, however, two more common sizes available: 1/4″, 1/2″. Other sizes like 3/4″ and 1″ are available, but are not common unless you’re working on large equipment and machinery. This ratchet is also commonly referred to as a pear-head or teardrop ratchet due to the shape of its head. Round-head ratchets are also very popular, and I’ll talk more about them later.

How Does A Ratchet Work?

The ratcheting mechanism inside a ratchet utilizes a gear and pawl to allows the ratchet to rotate freely in one direction but not the other. Depending on how the pawl is oriented, the direction of rotation can be changed. This action lets you drive a fastener clockwise or counterclockwise and return to the starting position without removing the ratchet from the fastener.

1. The selector switch is moved right or left to dictate the direction of rotation.
2. Inside the ratchet, a small hole is drilled into the selector switch. Inside the hole is a small spring and detent. When you actuate the selector switch, the spring and detent push against one side of the pawl.
3. The pawl engages the gear on one side and disengages the other.
4. When turned, the gear spins freely in the direction that the pawl is disengaged. When turned the opposite direction, the pawl presses against the gear and wedges itself against the side of the ratchet head, preventing the gear from moving in that direction.

Ratchet Variations

The ratchet, as a tool, has been around for more then 160 years, giving it a lot of time to evolve. As a result, there are a number of variations available today – the most common of which is the round head rartchet.

Even among ratchets of the same type, you are likely to find some small differences. For example, a ratchet may use a ball bearing instead of a detent or have two pawls instead of one.

Despite the variability, you’ll find that most ratchets work in a very similar way. That means if you know how a ratchet works based on what was described above, then understanding how the different variations work will be easy.

Round Head Ratchet

Standard teardrop ratchets, as described above, use a central gear and a spring loaded, but largely stationary pawl. With a round head ratchet, the gear is broached into the head of the ratchet itself and the pawl is integrated into core mechanism, which turns.

A selector switch, also a part of the core mechanism, is turned clockwise or counterclockwise and engages one side of the pawl with the gear. Depending on how the pawl is oriented, the ratchet will spin freely in one direction and lock up in the other.

Pass-Through Ratchet

A pass-through ratchet is designed for use on extra long fasteners where a standard ratchet, even with deep sockets, won’t fit. Instead of a combined anvil and gear, it uses a gear ring and special sockets that allow fasteners to pass right through the head – hence the name.

Though it may look a bit different, a pass-through ratchet works just like a common teardrop ratchet. The selector switch is actuated, a detent inside the ratchet pushes on one side of the pawl, the pawl engages with the gear, when the ratchet is turned, it will spin freely in one direction and lock-up in the other.

One thing to note is that pass-through ratchets are not generally user-serviceable. Instead of using a backplate to enclose the ratchet, the ring gear is pressed into the ratchet read. As a result the internals are not accessible without potential damage to the ratchet.

Ratcheting Wrenches

While not exactly a ratchet, a ratcheting wrench is a common tool used for the same purpose – to install or remove fasteners. As such, I think some might want to know how they work.

A common wrench differs from a ratchet in that it is made from a single piece of steel and has no moving parts. It does not use interchangeable sockets. Nor does it have a ratcheting mechanism, so when placed on a fastener, it can be turned both clockwise and counterclockwise. This means the wrench has to be removed from the fastener before returning it to the starting position. Otherwise you would reverse your progress.

This is, perhaps, the biggest downside of wrenches. They’re slow and inefficient when compared to a ratchet in many cases. The big upside of wrenches, though, is that they can access fasteners in very tight spaces.

A Ratcheting wrench offers the benefits of a ratchet and a wrench. Like regular wrenches, they’re compact and can fit in tight spaces. The box end, however, is replaced by a ratcheting end. This ratcheting end uses a ring gear similar to a pass-through ratchet that is sized specifically for a fastener.

Like both a pass-through and teardrop ratchet, the mechanism inside a ratcheting wrench works the same way. A small pawl inside the ratchet is actuated by a selector switch, the pawl engages the gear and stops it from spinning in one direction.

Note that some ratcheting wrenches do not use a selector switch and can only spin in one direction. These wrenches have to be flipped over to spin a fastener in the opposite direction. Also note that like most pass-through ratchets, ratcheting wrenches are generally not user serviceable.

Wrapping Things Up

As we’ve seen, a ratchet is a simple hand tool and how it works is pretty straightforward. In general, they use a gear and pawl that allows the ratchet to spin in one direction but lock up in the other. Even most variations will operate in a similar manor.

What do you find interesting about how a ratchet works? Let me know in the comments below. And if you’d like to learn more about ratchets, check out our Ratchets And Sockets Category.