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Combi drill vs impact driver: which do you need first?

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In short

Buy a combi drill first if you only get one tool: it drills wood, metal and masonry and drives screws through its clutch. An impact driver is the better second tool, because its rotational blows drive long screws and coach bolts faster and with less wrist strain, but it cannot drill brick well and needs hex shank bits.

Details as stated in the Amazon listing or by the manufacturer. See the current price on Amazon.

Our verdict

Buy a combi drill such as the Bosch GSB 18V-45 first if you need one tool for holes and screws. Add an impact driver like the GDR 18V-215 on the same battery when you take on decking, framing or lots of long screws.

Combi drills and impact drivers look alike and often come together in a twin pack, so it is easy to assume they do the same job. They do not. A combi drill turns a chuck with a clutch and adds a hammer mode for masonry. An impact driver turns a quick release hex holder and adds sideways hammer blows that keep a screw turning when it gets tight. This article explains how each works, what each is good and bad at, and which to buy first.

How a combi drill works

A combi drill has a three jaw keyless chuck, usually 13 mm, that grips round, hex and many other bit shanks. A numbered clutch ring sets how much torque reaches the bit before the clutch slips, so you can drive a screw flush without stripping it. A two or three speed gearbox gives a slow, strong gear for driving and big bits, and a fast gear for small holes.

The third mode is hammer. Two ridged discs inside the gearbox ride over each other and push the chuck forward and back many thousands of times a minute. That small hammer action helps a masonry bit chip its way into brick and block. It is what makes it a combi drill rather than a drill driver. The drill clutch and speed settings guide covers the controls in detail.

gear 1 · 2chuck jaws

Drill

Bit spins. Wood, metal, plastic.

1 to 20gear 1 · 2chuck jaws

Driver

Clutch 1 to 20 slips at a set torque.

gear 1 · 2chuck jaws

Hammer

Spin plus forward pulses. Brick, block.

The three modes on a combi drill's collar, with the clutch ring and gear switch.

How an impact driver works

An impact driver has no clutch and no chuck jaws. It takes 6.35 mm (1/4 inch) hex shank bits in a spring loaded collet. When the screw resists, a spring loaded hammer inside the head disengages and strikes an anvil, giving the bit a series of sharp rotational blows. Those blows push the screw round in short bursts rather than through steady force.

Because the blows are around the axis rather than along it, very little twist comes back into your wrist, so long screws and coach bolts go in with less effort than with a drill. The hammer is rotational, not forward, so an impact driver is not a masonry tool. You can read more in what an impact driver is used for.

impacts turn the bit
hammer pushes into masonry
An impact driver's blows turn the bit; a combi drill's hammer pushes it forward.

Side by side: two typical 18 V tools

The table compares a compact combi drill and an impact driver from the same brand, using figures from their listings. The torque numbers are not directly comparable, because makers measure them differently for the two tools, but they show the gap in driving force.

Bosch GSB 18V-45 combi drillBosch GDR 18V-215 impact driver
Bit holder13 mm metal chuck1/4 inch hex holder
Max torque45 Nm215 Nm
Max speed1,900 rpm3,300 rpm
Hammer for masonryYesNo
Clutch or auto modesNot statedTwo Auto Driving Modes
Supplied asKit with 2 x 2.0 Ah, charger, caseTool and L-BOXX, no battery
Listing figures for two Bosch Professional 18 V tools

Compare drill and driver twin packs →

Which jobs suit each tool

For most homes the drill does more jobs. Shelves, curtain poles and TV brackets all start with a plug hole in masonry. Flat-pack, hinges and small screws need the fine control of a clutch. Hole saws, flat bits and augers in timber need a chuck and a low gear.

The impact driver wins on volume and length. Decking screws, 100 mm plus timber screws, coach bolts into joists and self drilling screws into steel go in faster with less fatigue. Trades who fix all day often use the driver far more than the drill.

  • Combi drill: holes in brick and block, wood and metal drilling, hole saws, mixing small batches of filler with a paddle, controlled screw driving.
  • Impact driver: decking, framing, long timber screws, coach bolts, roofing and cladding screws, repetitive fixing.
  • Either: everyday wood screws, though the driver can snap small screws if you are heavy on the trigger.

Which to buy first and why most people end up with both

If you can only buy one, buy the combi drill. It covers more jobs, and you can still drive long screws with a pilot hole and the low gear. Add an impact driver on the same battery platform when you start a big decking, studwork or fencing project.

That is why twin packs are popular: two tools, one set of batteries, often for less than buying separately. Look at the battery size and what charger is included, and think about whether you will add saws later. Our twin pack guide and impact driver guide list what each kit contains.

Note:Wear eye protection for drilling and driving, keep the hand that steadies the work away from the bit, and use impact rated bits in an impact driver. Follow the manual for both tools.

Frequently asked questions

Can an impact driver drill holes? Yes, in wood and thin metal, using hex shank drill bits. It is not suited to masonry because it has no forward hammer action, and it is less precise than a drill for large or accurate holes.

Can a combi drill do everything an impact driver does? It can drive most screws, but long screws and coach bolts take longer, need pilot holes and put more twist into your wrist. The drill's clutch may also slip before a large screw is fully home.

Is an impact driver too powerful for small screws? It can be. Use the lowest speed mode if your driver has one, feather the trigger and stop as soon as the head is flush. Some drivers, such as hydraulic or auto mode models, are easier to control.

Do I need different bits for an impact driver? Use impact rated hex shank bits. Standard bits can snap or round off under the hammer blows. See impact driver bits explained.

What you need

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