Types of Wrenches and Their Uses

Wrenches: Definition And Origin

“The determined soul will do more with a monkey wrench than a loafer will accomplish with all the tools in a machine shop.”

– Robert Hughes

Whether you’re a weekend grease monkey who spends hours in the garage or an apartment owner who just wants their taps to stop leaking, at some point or another you will need to familiarize yourself with the wonderful tool that is a wrench. There are various types of wrenches for your needs.

Several countries still use the term “spanner” which is a slightly narrower term, with “wrenches” only being associated with plumbing, heating and the like.

The common wrench has been in use for several centuries, dating back to the beginning of the Industrial Revolution, but a formal patent was only registered in 1835 to a Solomon Merrick. The basic “household” wrench is often of a fixed gauge and diameter but there are several variants that include an adjustable prong that can fit varying sizes of nuts and bolts. Further models have adjustable grips, stocks, and foldable stems or scope for different attachments depending on the nature of bolts and nuts used.

The types of wrenches today however, number in the thousands given the abundant and varied uses for them. They are often classified by their origin, torque and operation (whether they be manual or powered), etc., with powered wrenches being more commonly known as “impact wrenches”.

Types Of Impact Wrenches

The functioning of an impact wrench is theoretically the same as a manual one but with the manual force being substituted by hydraulic power, electricity, etc. It creates torque through the motorized “hammer” to fix a bolt into its desired place through rotational motion from the motor. Even a (relatively) low-powered Impact wrench of 12v far exceeds the amount of torque and effort a human being could apply at an exponentially faster rate and with a remarkable degree of precision.

A notable feature of most impact wrenches today is that their axis of rotation is reversible, meaning they can be just as easily used to unscrew nuts and bolts (some would in fact say it is easier), a familiar example being that of the pit crew of a Formula One racing team changing tires in between laps. And the fact that the tires that they bolt on in less than three seconds have to rotate at over 6000 rpm and at speeds of over 300 kmph without falling apart is a testament to the precision and quality of impact wrenches (not to mention the skill of the pit crew).

Below are the various types of impact wrenches most commonly used, based on their power source.

Types of Impact Wrenches That Work on Electricity

Electrical wrenches are by far the most commonly seen type of (powered) wrench in domestic households due to their relatively low price, size and ease of use. They can be used without any kind of special training or competency and are generally hazard-free (barring electric shocks, etc. if improperly used or wired).

The commercially available variants range from 12v or 18v with 20v being the highest sold for non-industrial purposes, and come in both cordless (battery powered) and corded models.

Cordless Impact Wrenches

Most common with first time users or individuals who do not have much experience with such appliances, the cordless wrench is a battery-powered tool that eliminates the need for the often cumbersome power cord. Due to this same reason, however, it tends to be heavier, bulkier and generally a little awkward to use as compared to other types of corded wrenches.

Where the cordless wrench really excels, though, is the sheer mobility it provides, meaning that users are not limited to working in areas where they have to drag out huge lengths of cable which may encumber movement or cause a safety hazard. (Tripped over any wires recently?)

For this very reason, it is preferred by many contractors, on-call road mechanics, and most households. Its torque and yield is comparable to most corded wrenches and it is usually marginally more expensive.

Corded Impact Wrenches

The corded variant of the impact wrench is among the most widely used type of wrench today, being extremely popular and most commonly seen in mechanics’ garages, assembly yards and construction sites. Since the power source is separated from the actual wrench body, it tends to be lighter and easier to use than its cordless counterparts, making it ideal for precision work.

The obvious disadvantage, as the name suggests, is that fact that it needs to be constantly connected to a power source which is problematic for outdoor work, work in remote areas, or simply working during a power cut.

Types of Impact Wrenches That Work on Hydraulics

These are most commonly used for heavy industrial work where massive amounts of torque are required in factories and shipyards for heavy-duty precision work. That being said, it is not unheard of for individual enthusiasts or households to have a hydraulic wrench, as it far exceeds the amount of torque provided by other types of wrenches. There are still commercially available variants but they are far more expensive.

Their price, bulk and technical difficulty make hydraulic wrenches less common than their counterparts, but it is indispensable in the industries it serves for its torque and precision. Indeed, our bridges, ships, and vehicles depend upon those very qualities. Hydraulic wrenches are also found on tow-trucks and heavy-lifters.

Types of Impact Wrenches That Work on Compressed Air

Probably the most popular type of wrench after electric wrenches, you would most likely find a compressed air wrench at a mechanic’s. Using quantities of super-compressed air to create torque and pressure, its output lies between electrical and hydraulic wrenches, making it an ideal choice for medium-intensity work such as removing/fitting tires, unscrewing heavy furniture bolts and building grilles, landings or supports for a building.

Compressed air wrenches tend to be lightweight and easy to use and manipulate though they are dependent on a source of compressed air for their functioning which aspiring users will need to have on hand.


Powered wrenches were an industry-exclusive tool till not so long ago, making the presence of them in a household a rare sight. However, with the amount of “do it yourself” jobs being done today, the rising number of machine enthusiasts and engineers, and the ease of use/replacement/maintenance have made wrenches an almost indispensable power tool in any context.

Author: John Clax

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