How to use a single-ended spanner

A single-ended spanner is a wrench-like tool that can be used to tighten bolts and nuts. It is a versatile tool that can be used for various purposes, making it a staple in many toolboxes. This article will introduce the different uses, types, and applications of the single-ended spanner.

What is a single-ended spanner?

A single-ended spanner is a small tool for tightening bolts and nuts. Spanners can be distinguished from each other by calling those with a head (mouth) on only one side of the handle a single-ended spanner, and those with two types of heads on both ends of the handle a double-ended spanner. In this article, we will discuss the single-ended spanner with one head.


Uses of a single-ended spanner

Like ordinary wrenches and spanners, single-ended spanners are used to tighten and loosen hexagonal bolts, nuts, and square set screws. Since these bolts and nuts are used in an extremely wide range of applications, from light work such as furniture assembly to heavy equipment such as vehicles, engines, and various types of large equipment, it can be said that the single-ended spanner is a tool with a very wide range of uses. If you have one of these spanners in your tool box, it will be very useful.

Unlike double-ended spanners and combination wrenches, which have heads for different purposes on both ends of the handle, the single-ended spanner has a head only on one end of the handle and can be used only for bolts and nuts of a single standard. Although this may seem inconvenient, it is more suitable for line work where one process is performed repeatedly over a long period of time, or where the bolts and nuts to be handled are always of the same standard. In such cases, the use of a single-ended spanner is convenient because it eliminates the trouble to choose which head to use and allows work to be performed in a short time.

In addition, a hole may be provided at the end of the handle of a single-ended spanner to attach a strap to prevent the wrench from falling. It is advisable to select a product with such a function at sites where work is performed at heights, such as construction and machine maintenance.

How to use a single-ended spanner

The use of the single-ended spanner is basically the same as that of other spanners and wrenches, and is not difficult at all.

The single-ended spanner is used by inserting the head of the spanner parallel to the bolt or nut, and rotating it by applying force to the handle.

Basically, the single-ended spanner should be considered as a tool for quick-turning or temporary tightening. Since the spanner grips the bolt or nut on only two sides, when a large torque is applied, a large load is applied to only the two sides that are in contact with the bolt or nut, causing the corners to be worn out. On the other hand, a ring spanner is not suitable for fast turning, but it can hold a bolt or nut firmly with more surfaces and can withstand about twice as much torque as a single-ended spanner. Therefore, it is recommended that you use the single-ended spanner only for quick-turning and temporary tightening, and switch to a ring spanner or the like for tightening work that requires more torque, or when starting to turn for removal.

Precautions for use

What are the precautions for using the single-ended spanner? Be sure to understand the precautions and use the wrench safely.

Pay attention to the size compatibility

Use a single-ended spanner that matches the size of the bolt or nut to be tightened or loosened. If the size does not match, the tool may be damaged, the corner of the bolt or nut may be worn out, or the tool may fall out when force is applied, resulting in an unexpected accident. Select a tool that does not have any excess wobble when the bolt or nut is fitted.

Pay attention to the direction in which force is applied

A single-ended wrench should be inserted and turned parallel to the bolt or nut. If torque is applied with the head at an angle, the corner of the bolt or nut will be worn out easily.

Be careful around the work area

When turning with a large amount of force, for example, the tool may fall out the bolt or nut and slip. Use the tool with caution to ensure that there are no hazards or obstacles in the direction of the applied force.


The single-ended spanner is a tool with a simple role, yet it is indispensable for all kinds of on-site work. Use it properly with other tools as necessary, and use it for a wide range of work.