Most of us probably have a selection of ratchet spanners lost amongst an existing set of combination, ring and open-ended spanners. They can certainly save time when undoing or tightening fastenings thanks to a clever and compact mechanism inside which, just like a ratchet screwdriver or socket driver, eliminates the need to remove the tool after each turn.
Ratchet mechanisms are nothing new and have been in use in those screwdrivers and socket drivers for well over half a century. Ratchet spanners are a little more complicated due to the limitations of size, however. Some of the oldest designs (which are still available) look quite chunky and cumbersome. The more modern ratchet spanners are slimmer though, some have a flexible head and they are easier to manoeuvre into tight spots, so they are easier to operate.
Teeth technology for ratchet spanners is another aspect that has evolved. This concerns the number of teeth the spanner has inside its ratchet mechanism. The figure, such as 72 teeth, helps to work out how many degrees the spanner needs to be wound back before the mechanism clicks and you can then turn the spanner again to tighten or loosen a fastening. It's often an essential factor when working in a confined space where there's limited movement of the spanner – if the spanner can't be turned enough to click the mechanism, you can't wind it back and continue to undo or tighten a
