31.03.2022 | Category : spectrum

What types of spanners are there?

A brief introduction to the world of spanners


In all likelihood, everyone has held a spanner in their hand at some time. But not all spanners are the same – there are many types for a wide range of different applications. Below we would like to explain what you need to know to make sense of the topic.

What types of spanners are there?

Classic spanners are designed for a fixed spanner width ("width across flats") which is given as an embossed figure on the handle. In addition, there are adjustable spanners that can be used to grip fasteners (nuts and bolt heads) of different widths. All in all, a distinction is made between seven widely used types of spanner-like tools:

  • Open-ended and double-ended spanners
  • Sockets and nut spinners
  • Ratchet ring spanners
  • Monkey wrench, English model
  • Monkey wrench, French model
  • Pliers wrenches
  • Box spanners  

Since in European countries the metric system prevails, the drive size of the fastener head and the width across flats of the spanner are given in millimetres. In the USA and a few other Anglo-Saxon countries, the imperial system is used; here, spanner sizes are measured in inches. STAHLWILLE offers both metric and imperial spanners.

Combination spanners

The open-ended spanner is probably the most common type of spanner. It is available in versions for hexagonal and square headed fasteners. The jaws of a spanner are angled at about 15° on most models, and the handle, or shaft, is slim or flat.          

  • Advantage: open-ended and double-ended spanners allow work in confined spaces and are also suitable for union nuts and fasteners that are difficult to access. Work in confined spaces is possible.
  • Drawback: the open jaw always involves a certain risk of slipping and injury.

Ring spanners

While open-ended spanners, monkey wrenches and adjustable spanners only grip the fastener on two of its flats, ring spanners grip the entire fastener head. The ring can be ergonomically designed, for example angled, offset or deeply offset.

  • Advantage: ring spanners can transmit significantly higher torques – especially on hexagon and double hexagon head fasteners. In addition, slipping off the fastener head is much less likely with this tool than with open-jaw spanners.
  • Drawback: ring spanners are less suitable for cramped conditions, fasteners that are difficult to access or union nuts and line connections. Exceptions: there are open ring spanners (brake line spanners), which have a cut-out, and crescent ring spanners which were developed for working in confined spaces.

Ratchet ring spanners

Ratchet ring spanners are ring spanners that have an integrated ratchet, which enables them to be moved back in the opposite direction without removing them from the fastener head.

  • Advantage: refitting and repeated application of the tool is unnecessary. The fastener can be tightened quickly and efficiently in the same way as with a ratchet without interruption. In the case of angled ratchet ring spanners with a reversible ratchet, this works for both clockwise and anti-clockwise action.
  • Drawback: like all ring spanners, the conventional ratchet ring spanner is not suitable for cramped conditions or union nuts and pipe connections. Exception: a ratchet ring spanner that can be opened up. It is extremely thin-walled and can grip union nuts even in confined working spaces.

 

Adjustable open-jaw spanners

A distinction is made between two adjustable open-ended spanners: there is the "English" and the "French" type. Both are very similar and are not designed for one particular size of fastener. Instead, the spanner width can be infinitely adjusted. They are named after their respective regions of origin.

The "English" type

With this tool, the distance between the two clamping jaws can be infinitely adjusted.

  • The benefit for users is that this spanner can be used for fasteners of many sizes and independent of the metric and imperial system. It is also suitable to a certain extent for tight installation spaces and for gripping flat workpieces.
  • Drawback: a really snug fit is almost impossible to achieve with this tool. If used incorrectly, deformation and damage to the jaws will occur quickly. That is why this model is particularly suitable for counter-tightening and for connections that only require low torques. It is important that the moveable jaw always points in the direction of rotation.

The "French" type

In contrast to the English type, the French type has two jaws and a finer thread.

  • The benefit for users is that the French type can also be used universally, where the fine thread allows a much more precise clamping action. Furthermore, when applying high torques, a nut of identical size can be clamped into the opposite jaw. This ensures that the jaws remain parallel to each other even when strong forces are applied because no bending moment acts on the tool.
  • Drawback: due to its design, the French type is less suitable for use in confined installation spaces.

Pliers wrenches

The pliers wrench is a kind of self-grip spanner. The jaws of the pliers wrench are aligned approximately parallel to ensure a secure grip on the fastener head.

  • Advantage: the pliers wrench combines the features of an adjustable spanner with gripping pliers, which makes it suitable for many different spanner sizes.
  • Drawback: the pliers wrench is not suitable for the application of high torques.

Box spanners

Box spanners are made from metal tubing. They usually have two profiles, one at each end. They are referred to in DIN 896 as "tubular double head tee wrenches, type B". One hexagonal end is placed over the nut or bolt head. The rotary momentum is applied with the help of a tommy bar inserted through the spanner perpendicular to the axis.

  • Advantage: box spanners are available in many versions: from light to solid and heavy, from cheap to very expensive. The hexagon ensures a good fit and encloses the entire fastener head. The amount of torque applied can be varied by adjusting the length of the tommy bar or lever arm.
  • Drawback: box spanners are only suitable for fastener heads that are accessible from above.

 

Other types of spanners:

Hook spanners

The hook spanner is a special tool for tightening or loosening slotted locknuts. The size of the tool depends on the outer diameter of the locknut. These spanners are available in various sub-versions and as articulated hook spanners.

 

Pin spanners

Pin spanners are often also called flange spanners and are used when tightening two-hole nuts. Their pins can be firmly fitted to the nut so that it can be effectively loosened or tightened.