Core Drills

A hammer drill works with a hammer-and-rotation action using a carbide bit, fine for mounting holes up to about 16–20 mm, but at larger sizes it causes vibration, dust and rough edges. A concrete core drill works purely by rotation, with a water-cooled diamond bit — cutting smooth, round holes from about 20 mm to over 300 mm, even in reinforced concrete, with practically no vibration or dust. For ordinary mounting anchors, a hammer drill remains more convenient.

A hand-held core drill is a motor held by hand, with the operator guiding the drilling axis — it suits holes up to about 130–150 mm and hard-to-reach places. A stand-mounted core drill sets the motor in a carriage on a column with adjustable feed, drilling perpendicular holes from a dozen millimeters up to over 300–400 mm, without side wobble or arm fatigue. It is sold separately or as a ready-made set with the motor.

A complete set includes four elements: a motor (a 230V or 400V drive with adjustable speed), a stand with a guide column, a core bit — a diamond drill bit with a mounting thread usually 1 1/4" UNC — and a water supply that cools the bit and flushes slurry when drilling wet. Each element can also be bought separately, if mounting parameters and column stroke match.

Choosing a motor starts with the power supply and planned bit diameter. Single-phase 230V motors rated 1.8–3.5 kW suit bits up to about 200–250 mm on a standard site socket. For larger diameters and continuous work, a three-phase 400V motor rated 4–5.5 kW and up, with speed steps of roughly 200–1500 rpm, works better — the larger the bit, the lower the speed needed to cut.

The core drill motor is also sold on its own, without a stand — for companies that already own a column and are expanding their fleet. Buying separately means matching the motor's mounting diameter, usually about 60 mm, and the chuck thread, typically 1 1/4" UNC, to the stand. A column stroke of 500–1000 mm covers bits up to about 250 mm; larger diameters need an extended column, up to 1600 mm.

At NORWIT.PL, core drills, stands and motors are supplied primarily by Dr. Schulze, Tyrolit and Husqvarna Construction — manufacturers of professional core drilling equipment for construction sites and installation companies. These are complemented by hand-held core drills and accessories from Toolsa, and complete sets from Norton Clipper. Husqvarna Construction also has a dedicated model line in its own category.

Core drilling accessories include core bits (diamond drill bits) in various diameters, threaded 1 1/4" UNC extension rods, seals and clamping rings for mounting the motor, and water supply components that cool the bit during wet drilling. Without these, a motor and stand cannot cut a hole — the core bit wears fastest and is usually replaced after a few dozen to a few hundred holes, depending on concrete hardness.

Professional diamond core drills from Dr. Schulze, Tyrolit and Husqvarna Construction cut through reinforced concrete when fitted with a bit that has a universal segment bond, designed to cut rebar usually up to about 12–16 mm without changing the tool. Drilling through reinforcement needs lower speed, constant water cooling and higher feed pressure, so a stand-mounted core drill works better than a hand-held one. If the reinforcement layout is unknown, locate the bars with a detector first.