As you can see, it is best to know the thread type of the nut and then choose the spanner size that will then give the best fit. Once you know the thread type and size of the nut, then it is simple to look up the correct spanner size. C Spanners - Also known as hook spanners, these are high-quality tools designed to loosen retaining rings and adjust chains. View our range of C Spanners here. Who uses spanners?

What Size Spanner do I need ?” is a common question. Theimmediate answer is another question: “ What type of thread does your nut and/or bolt have?” Spanners are one of the most common hand tools found in any tool bag, box, or kit and are used for fastening and loosening nuts or bolt heads with a hexagonal shape. Spanner tools are also commonly called wrenches, particularly in American English. They are typically made from hardened chrome vanadium steel or beryllium copper. The most common types can consist of a ring-style spanner on one end and an open jaw spanner on the other (a combination spanner), or two open jaw ends (an open-ended spanner). Just to mix things up a little; for nuts and bolts with BSW or BSF threads, you will need a spanner marked with the diameter size of the thread e.g. a 1/4″BSW or BSF nut or bolt would require a spanner marked 1/4″BSW. METRIC Combination Spanners - A combination spanner will have the open jaw spanner on one end and the ring-style spanner on the other.A standard metric M6 nut will be 10 mm across the flats, a 1/4″ UNC is just under 11mm and a 1/4″ BSW just over 11mm. Attempting to use the incorrect (oversize) spanner could cause the spanner to slip, rounding off the edges of the hexagon. There are many types of threads available for nuts and bolts, Metric, Unified (UNF/UNC and British Standard (BSW/BSF) are just three that we deal with, and they all have different measurements depending on the international standard they are manufactured to. For example, a metric M6 nut and bolt are very close to an imperial 1/4″ UNC/UNF thread. Measuring the thread manually you could be mistaken for thinking they are the same. Also, a 1/4″ BSW/BSF nut may sound similar but is different again in size. You should also be aware that the size given to any nut or bolt is relevant to the thread type and size. A metric M6 nut for example means the measurement ‘d’ shown above is approx. 6mm and this ‘M6 – 6 mm’ measurement bears no resemblance to the distance across the flats, or the spanner size required. Spanners are available in a variety of metric (mm) and imperial (in) sizes to allow for greater functionality across a wider range of applications, though adjustable spanners (or shifting spanners) are often a preferred choice because users can increase or decrease the size with ease. Our range includes products from leading brands such as Bahco, Facom, Ega-Master, Stanley, Wera & RS PRO, and are available as individual pieces or as part of a larger spanner set. How do Spanners Work? Open-Ended Spanners - As the name suggests, these tools have an open jaw at each end, however, they often differ in size.

In engineering circles a Spanner is often called a wrench and is generally used to grip a nut or bolt while applying torque or put more simply to help you fasten and loosen nuts and bolts.