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Spanners, wrenches and ratchets buying guide

Guide written by:
John, DIYer & IT developer, Brighton

John, DIYer & IT developer, Brighton

59 guides

Open-ended wrenches, ratchets, socket sets and Allen keys… It’s not so easy figuring out what you need as there are so many different types. Need a little help? Everything you need to know, and a little more, is right below.

Important features

  • Open-ended spanner
  • Socket Wrench
  • Combination Spanner
  • Ratchet spanner
  • Ring spanner (or box-ended)
  • Adjustable spanner
  • Torque wrench
  • Hex & Allen Key


from £1.00 to £2,484.00

What are the main types of spanners?


There are several types of spanners for various uses. The typical bolt goes from 4 to 10 mm in diameter for small mechanics, from 10 to 23 mm for the common job, and all sizes above are usually for heavy mechanics.

  • Open-end spanners usually have one or two U-shaped openings of different sizes. They are ideal for nuts and bolts that are difficult to access, and where another type of wrench wouldn’t be handy. They’re essential for plumbing or general mechanics.
  • Ring spanners place pressure and power on all sides of nuts and bolts. They often now also exist as ratchet spanners, meaning there is no need to detach the tool from the nut or bolt until the job is done. While a little more expensive, ratchet spanners are compact and are very convenient.  
  • Combination spanners have both an open end, and a box end. Pretty useful!
  • Adjustable spanners are single open-ended wrenches with a moveable lower jaw to adjust to any size of nut or bolt.
  • Socket wrenches usually have an L shape. They fit completely over a nut or bolt, and allow for tight fastening. The socket is often interchangeable, and these often come in sets.
  • Torque wrenches are a type of socket wrench. They provide a specific amount of torque (rotational force) for precise fastening. This helps to avoid over or under-tightening a bolt,in industries such as automobile

Allen and Torx keys : Allen Keys, also known as hex keys, have a male hexagonal end, and Torx keys have a star-shaped end. These are often used for small mechanics, and are also common in furnishment. Their L shape gives you access to deep or hidden screws and allows for tight fastening. Sizes usually range from 4 to 10 mm for Allen keys, and 10 to 50 for Torx keys.

Open-ended vs Ring spanner


Open-ended spanners have a U-shaped opening and only grip nuts and bolts on two sides. They can access from the side, but are more likely to slip and round the fitting.  

Ring spanners, as well as socket wrenches, grip all six faces of nuts and bolts. Pressure is maintained on the whole fitting, and it is less likely to slip and damage the nut or bolt.  Ring spanners are available with 6-point heads to apply more strength and tighten harder, but also in 12-point heads for quick repositioning.

Combination spanners combine both an open-end and a box-end, and prove to be very useful as they provide the advantages of both types.

What’s a ratchet?

The ratchet mechanism, on certain types of ring spanners and socket wrenches, speeds up the work while reducing hand fatigue. It allows you to fasten without having to disengage from the fitting, as the handle can swing freely in one direction, and engage the fitting in the other. 

Wrench, spanner, ratchet… what will loosen my nut?


It has been said a thousand times, but remember that you cannot use brute force or knock off a seized nut with a hammer! Professional brands work quite well, but a socket wrench would be better for the job! Also, a ratcheting wrench will not allow to you to work on inaccessible bolts. Luckily, numerous accessories are available to help you! Just like socket wrenches, you can find accessories that fix to a square connector and lock in place with a spring ball groove. The most common connector sizes, expressed in inches, are 1/4, 3/8 or 1/2. You can also find 3/4 or even 1” for XXL wrenches.

Accessory summary !

  • Socket extension: allows you to reach a nut in an orifice or to avoid any obstacles that would impede you from turning the key
  • Gimball: offers the possibility to work on a bolt whose screw axis is not strictly perpendicular to the plane on which you are using the key.
  • Adapter: to fix a small attachment socket to a larger one, or the other way around, for example 3/8 to 1/2. They are particularly handy to make different sets of sockets interchangeable.
  • Bit holder: to fix any screw bit with a hexagonal shank directly to a socket wrench or any of the accessories above.

If I have understood correctly, there is no ratchet for flat spanners?

Flat spanners do not really have a ratchet. Nonetheless, there are fast open-ended spanners. The spanner has two working positions. The first, at one end of the spanner, has a profile designed in such a way that the spanner can both exert a force on the bolt as well as turning around it freely. Once the screwing is nearly complete, you only have to put the bolt in contact with the inner part of the spanner for the final tightening.

And if I force it, will it hold out?


The forces exerted on spanners and bolts may be considerable. If you have to force a bolt strongly, you may consider buying tools made of solid metal (the hardness varies from 42 to 50 HRC on the Rockwell scale). Refer to the manufacturing norms that is marked on the tool (DIN, ISO, DIN ISO or BSI ISO) which define a set level of quality. The mention of Chromium-vanadium steel does not constitute to a sufficient guarantee of quality. The manufacturing quality is also found in the shape and the precision of the bore which will fit the hexagon. An adjusted bore and certain optimized shapes will transmit a maximum force whilst protecting the hexagon. Remember that the best distributers guarantee their wrenches for life: if broken, it will be replaced.

What is a torque wrench for?

In certain applications, the tightening force must be controlled. If it is not tight enough, the assembly risks falling apart with serious consequences. Think of a bike handlebar which comes off while you are on it. If it is too tight, you risk braking the screw or distorting the parts you are tightening. Their use is quite simple. Fit the right-sized socket, choose the setpoint torque expressed in Newton-metres, and wrench away! They are mainly used in precision mechanics.

Where should I get started?

You can buy your tools as and when you need them. The sets of spanners are cheaper than single units. If a certain spanner will be useful for regular jobs, invest! Otherwise, a socket wrench set and an adjustable spanner will fit most of your common needs. A set of open-ended spanners will also be useful!

Did you find this guide helpful? Yes
Guide written by:

John, DIYer & IT developer, Brighton 59 guides écrits

John, DIYer & IT developer, Brighton

Since I was a child, I was always interested in manual and technical works. Always fascinated by woodworking, I took advantage of my first flat as a playground. On the cards: electricity (of course, safety first!) and some partition walls; but also decorating with the help of the missus, made-to-measure furniture and little tricks to optimise the space, all the while remaining as original as possible. When the little one arrived, I started building bits and pieces for him!

Lacking space, I have not got a permanent workshop and certain tools I dream about but are not part of my collection. Not to worry, I already know a lot about DIY and I have a high-tech profile that I hope will guide you in your decisions!

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