The cordless drill-driver has been an integral part of enthusiastic DIY households and all professional workshops for many years. The gradual evolution of battery technology, coupled with ever more sophisticated electronics mean that today’s power tools are a far cry from those first models of a few decades ago. The introduction of wood screws specifically designed to be power driven has at the same time advanced the rapid development of drill-drivers, particularly relevant to trade requirements. Drill-drivers though, struggle in one important area and that’s when a hole needs to be drilled in brick, cement or concrete.
All models differ, but essentially a drill-driver has two, trigger controlled variable speeds, one approximately in the range 0-500 and the other 0-1700 rpm. The lower screw driving range has a number of torque settings, with the greatest torque at the highest numerical setting whilst the higher speed range is used purely for drilling. When a standard drill-driver is used with a tct masonry bit on very hard brick or blockwork it quite rapidly becomes ineffective as the bit tends to ‘skid’ on the material. The result is that it blunts very quickly and may become so hot that the carbide tip falls out.
The Advantage of a Combi Drill
Combi drills have an additional setting, which is usually a small ‘hammer’ logo. When this setting is selected for drilling into masonry, the bit is hammered many times a second as it rotates. These very rapid impacts on the bit enable it to drill far more effectively into brick and block work with the result that there’s none of the overheating and ‘skidding’ associated with an ordinary drill-driver.
Types of Combi Drill
The majority of the combi drills sold are professional quality, industrially rated tools. Brands vary, but there are usually different models within the range and this is reflected in the price. Drills at the lower end of the range may have a smaller drilling capacity, a less robust chuck and a battery with less power. Conversely, the more expensive combi drills will have larger, more powerful batteries, a metal gearbox and teeth, as well as increased drilling capacities in metal, steel and wood.
When there’s a necessity to drill a lot of holes in a variety of different materials, particularly on site or in the home, a combi drill is almost indispensable as it provides not only a means to drill metal or wood, but at the flip of a switch provides a very convenient way of drilling masonry and brickwork.