noscriptSpanners | Adjustable, combination, ratcheting spanners | Cromwell Tools


One of the most well-used hand tools by professional tradesmen and DIY enthusiasts alike, the spanner is extremely useful in a wide range of industries. Made from durable materials like vanadium steel or titanium, these resilient tools are often plated to protect against corrosion and general wear and tear.

General-purpose applications often utilise open-ended or combination spanners, where a six- or twelve-point profile is common to give adequate grip. For this type of activity, spanner sets are ideal and are comprised of a handy range of sizes to suit the most common sized fittings.

Specialist application spanners include basin-tap and box spanners, which are used widely by plumbers and engineers to reach into tight spaces.

Available in metric, imperial, Whitworth and BA measurements, Cromwell stocks a wide selection of spanners from reputable brands, including Stanley®, Facom® and Bahco®.

What is a spanner?

Designed to tighten or loosen rotary fittings, spanners are extremely versatile by design. Fitting over or around the fixing, they apply maximum grip at the contact points. The shaft magnifies the force applied by the user and provides torque to loosen or tighten the fitting with minimum effort.

Why spanners?

Spanners are incredibly versatile, cost-effective and easy to use. They are also a crucial element in performing many jobs.

When are spanners used?

Used widely in plumbing, automotive and construction work, spanners are an essential tool when safely and reliably connecting components with a rotary fastener, like a nut or bolt.

Spanner types

There is a huge range of spanners available on the market, with designs suitable for every application you can think of. Here are just a few of the most commonly used:

• Open-ended   -  U-shaped heads with flat profiles to grip either side of the fastener

• Combination, non-ratcheting   -   One open-end and a closed ring end with a 12-point hexagon

• Double ended ring   -   Offset rings on both ends to get into tight spaces

• Basin tap   -   Used by plumbers to reach under sinks

• Ratchet combination   -   Comprised of an open-ended head and a ring head

• Short arm combination   -   Short shank and compact heads, with or without a ratchet

• Ratchet   -   system to take the effort out of turning the fixing

• Swivel end socket   -   12-point bi-hexagon sockets fit over the nut or bolt

• Box   -   Profiled ends fit into the fastener and is turned with a tommy bar

• Flare nut ring   -   Thick jaws fit over the nut to allow good contact

• Flex head ratchet combination   -   Used in confined spaces and turns at an angle up to 90°

• Flexi ring end socket   -   Swivels to allow access in tight conditions

• Crowfoot open-end   -   Used to secure tubing

Considerations when choosing a spanner

Profile - The shape of the spanner head will match with the fastener shape to ensure good grip. The greater the contact between the profile and the fastener, the stronger the grip for reduced slipping.

Material - The stronger the material, the stronger the tool. Good quality spanners are mostly made from vanadium steel or titanium.

Length - This affects the amount of torque generated to turn the fixing. More power will be generated by a long spanner for larger or stubborn fixings.

Spanner jargon buster

We want to make it easy for you, so here are some key terms that will help you understand the range and applications a little better

What does ISO 3318:2016 mean?

This standard refers to open-ended, box and combination spanners. It outlines the maximum head dimensions for these tools.

Let's break it down...

• ISO - The International Organisation for Standardisation defines global safety and quality standards

• 3318 - The identification number for this standard

• 2016 - The date this 5th edition of the standard was published


What's the difference between a spanner and a wrench?

The terms spanner and wrench are often interchangeable and can cause some confusion when searching for the right tool. In the USA, wrench is the name used for a spanner, and because the USA and European markets are connected, the term often filters through. In the UK, a wrench is similar to a spanner, but instead of turning fasteners like nuts or bolts, it turns and manipulates non-fastening components, like pipes.

How do you select a spanner size for bolts?

The first step in choosing a spanner for the job is to find out the head size on the fixing. These are usually marked on the fixing, but if this has been worn away, you can still identify it by measuring the width across the flat angles of the bolt head. This is the widest side of the fixing and shouldn't be confused with the shorter side.

What are SAE spanners?

SAE is an abbreviation of Society of Automotive Engineers. Primarily a sizing standard used in the United States, SAE tools are mostly used on cars and other automotive vehicles.