Drill driver or combi drill — which one do I actually need?

These two sit next to each other on the shelf, look identical and differ by one internal mechanism. The marketing makes the choice sound like a question of how serious you are. It is not. It is a question of whether you will ever put a hole in brick, and in most British housing the answer is yes within the first month of owning the tool.

Step by step

1. Understand what a drill driver is.A motor, a gearbox, a torque clutch and a chuck. It turns a bit, and the clutch lets it drive screws without wrecking them. That is the whole tool, and for wood, plasterboard, flat-pack and metal it is completely sufficient.
2. Understand what the combi adds.Two ridged discs behind the chuck that click over one another as it turns, vibrating the whole drill forwards several thousand times a minute. That percussion is what lets a carbide-tipped bit chip its way into brick instead of polishing it.
3. Check what your walls are.Solid brick, blockwork behind plaster, a concrete floor, an external wall for a hose reel or a satellite bracket — all need hammer action. A stud partition or a plasterboard ceiling does not.
4. Note that the hammer switches off.A combi is a drill driver with an extra position on the collar. There is no penalty to owning the capability and leaving it unused, which is why the decision is asymmetric — the wrong choice only hurts in one direction.
5. Weigh the real costs of the combi.It is a little longer front to back, a little heavier, and on a cheap tool the hammer mechanism is the first thing to rattle. Length matters if you work inside kitchen carcasses; otherwise it does not.
6. Do not expect a combi to be an SDS.The blow energy from clicking discs is small and comes from you leaning on the tool. In dense concrete or engineering brick a combi will make a shallow hole and a lot of noise. Beyond about 10mm diameter, or a hard aggregate, this is the wrong machine.
7. Decide by the worst job you will realistically do.Not the best one. If the honest answer includes fixing anything to an external wall, buy the combi and stop thinking about it.

Tips

• A twelve-volt combi exists and is genuinely useful — small, light, and enough hammer for a wall plug in soft brick. It is not enough for a long hole in blockwork.
• If you already own a drill driver and hit one masonry job, hiring an SDS for a day is cheaper and far more effective than replacing the drill with a combi.
• Hammer action must be switched off for every material except masonry. In tile it cracks the tile, in wood it tears the hole and in metal it does nothing but damage the bit.

Common mistakes

• Buying a drill driver to save money and buying a combi six weeks later — The combi premium is a fraction of the price of a second drill, and you end up owning a tool you no longer use.
• Leaving the hammer engaged after a masonry hole — The next hole is in something else, and the percussion will chip tile, split plastic and ruin a brad point bit before you notice the noise.

Questions people ask