When they first arrived on the market years ago, impact drivers were all the rage in Japan but it took a while for Americans to understand what a terrific advantage impact drivers have over an electric drill when it comes to driving long screws into planks, especially decking. American companies like Porter Cable grasped the idea and Makita started competing with impact drivers offered by overseas companies. The idea of impact drivers was begun long ago with the inventions of (1) the impact wrench, used in every automotive garage, and (2) the hammer drill used to power masonry bits into concrete and other extremely hard materials.
The technology that allows them to do this is sometimes referred to as “hammer and anvil” meaning that, unlike the simple twisting action of an electric drill, the impact driver literally thumps the screwdriver bit around as if being repeatedly being smacked by a hammer. This action gives these woodworking tools remarkable power that simply would not be feasible if the exact same screwdriver bit were chucked up in an electric drill with the same size motor and battery. An additional plus is that there are hex shank drill bits available so that your impact driver can stand-in as a quick-change cordless drill thus becoming one of your most multi-purpose woodworking tools.
The first time I picked up an impact driver, a 12-volt Makita, I thought it appeared to be a toy. I then tried it out by driving a 3-inch deck screw into a 4 x 4 piece of fir. I was astounded as I watched (and felt) the tiny machine effortlessly drive the screw home, sinking the head beneath the face of the timber. I had to remember to keep a lot of hand pressure against the tool so that the screw driver bit did not fly out of the screw head and strip it. From that moment forward, I have never been without one of these amazing tools in my presence
In the last few years, these drivers have been enhanced to the point of near perfection and this includes the batteries that power them. Battery voltage has grown from 9.6 volts to 18 volts and more. More than that, battery resilience has been greatly extended from what it was with the introduction of Lithium Ion technology and subsequent improvements on that. In fact, a substantial part of the actual cost of any impact driver, whether it comes from Makita Tools, Bosch or Dewalt is the battery or batteries that are packaged with it.
You may have seen that most designers of cordless woodworking tools have started featuring so-called “bare tool bodies” meaning that they come with no battery or charger included and a greatly reduced price tag. The reason for this is that most designers (but not all) have found out that if they make all their tools run on the identical18-volt Lithium Ion battery, they can sell more bare tool bodies while locking in their customer to their brand. Loyal users love this because they do not have to keep laying out hard-earned income for shelves full of different batteries and chargers but, instead, can just buy the bare devices that share the same battery.