How to choose an electric core drill: hand-held or stand-mounted?

To drill concrete and masonry with a diamond core bit you can choose between two families: the hand-held core drill, light and convenient for small holes and occasional jobs, and the stand-mounted core drill, more stable and suited to larger diameters and repeated holes. In the collection the power ratings range from about 1300 to 5000 W and complete machines weigh from about 5 to 25 kg; the motor and the stand of stand-mounted systems are weighed separately. Before deciding, establish the hole diameter, the power supply available and whether you will work wet or dry.

The types

• Hand-held core drill: held in the hands, with no stand. It is light and quick to set up, like the Milwaukee 2-speed dry core drill. It suits small-diameter holes.
• Stand-mounted core drill: the motor slides along a stand fixed to the wall or the floor (with an anchor, a vacuum base or a prop). More accurate and less tiring, it is the choice for large holes or many holes.
• Cordless core drill: the 54 V MX FUEL series, such as the MXF DCD150 or the MXF DCD350 for 350 mm, lets you work without an extension lead.
• Dry or wet core drill: for wet drilling the bit is cooled with water; for dry drilling you connect a vacuum cleaner. There are models that do both, like the 3-speed wet and dry core drill.
• Gearmotors and separate motors: single-phase 230 V, three-phase 400 V, hydraulic or pneumatic, to be mounted on a stand.
• Bits and supports: in the collection you will also find diamond core bits and fixing accessories.

How to choose by job

The features to look at

• Power (W): from about 1300 to 5000 W, with some models reaching 8300 W. Large holes in reinforced concrete need more power; small holes in masonry need less.
• Voltage (V): 230 V single-phase, 400 V three-phase or 54 V cordless. Check what you have on site before choosing.
• No-load speed: many machines have several gears (for example up to 3 or 4 speeds). Low gears for large bits, high gears for small bits.
• Connection and bit connection: the most common connections are 1 1/4" UNC, but 1/2" BSP and M16 are also found. The bit must have the same connection as the machine.
• Weight: from about 5 to 25 kg for the machine; for stand-mounted systems also look at the weight of the motor (from about 5 to 23 kg) and of the stand (from about 9 to 37 kg).
• Motor: single-phase electric, three-phase electric, hydraulic or pneumatic.

Common mistakes

• Not looking for reinforcing bars and services. Before drilling you must locate the reinforcement, pipes and cables in the wall.
• Using a hand-held machine for large holes. It tilts, the bit jams and it is hard on the wrists.
• Forgetting how the stand is fixed. The anchor, vacuum base or prop must be chosen according to the surface: a stand that moves ruins the hole.
• Forcing the feed. Work with steady pressure, without pushing: pushing too hard wears out the bit.
• Neglecting the protective equipment. You need an RCD, glasses, ear defenders and gloves.

Frequently asked questions

Is dry or wet better?

With wet drilling the bit is cooled and you can work for longer, but you have to manage the water. Dry drilling uses a vacuum cleaner and is cleaner for indoor work.

Can you drill without a stand?

Yes, with hand-held machines, for holes of limited diameter. For large holes the stand is much safer.

How do I know whether a bit is right for my machine?

Look at the connection: the machine and the bit must have the same one, for example 1 1/4" UNC.

Does a cordless core drill replace a corded one?

For many holes, yes, and you work without an extension lead. For long cycles and high power ratings a 230 or 400 V motor is still preferable.

You will find machines, stands and bits in the electric core drills collection: for a quote or help choosing diameter and power, contact the AMES technicians.