Diamond Core Drill Bits – What They Are and the Types Explained

Wysłane przez   wrz 5, 2025          0Komentarze

A diamond core drill bit (core bit) is a steel tube with a diamond cutting rim. Instead of crushing material like a twist drill, it cuts a ring and leaves a core, which makes holes faster, cleaner and precisely sized.

Construction & how it works

  • Barrel – steel tube of a given diameter and length (e.g., 35–450 mm).
  • Cutting rim – diamond: sintered, segmented for concrete/RC, or electroplated (vacuum-brazed) for porcelain/stone.
  • Mount – M14 (angle grinders), 1/2" BSP or 1 1/4" UNC (core rigs). Adapters are available.
  • Cooling – wet (best life) or dry (short holes, mobile work).

Types by material

  • Concrete / reinforced concrete – use sintered, segmented cores. Harder bond for abrasive materials; softer bond for rebar so diamonds expose faster and avoid glazing.
  • Porcelain, ceramic, natural stone – electroplated (vacuum-brazed) or thin-wall segmented bits. They start cleanly with minimal chipping.
  • Asphalt / very abrasive media – wider gullets and a softer bond to clear swarf efficiently.

Types by tool

  • Core rigs – 1/2" BSP or 1 1/4" UNC, mostly wet drilling, larger diameters (68–300+ mm) for pass-throughs and sleeves.
  • Angle grinder (M14) – quick holes in porcelain/stone (6–35 mm) and light concrete duties (with cooling breaks).
  • Drill/driver – no hammer; with adapters you can run M14/BSP cores, but control RPM and maintain alignment.

Diameters & lengths

Small: 6–12 mm (fixings, anchors). Installation sizes: 32–132 mm (boxes, pipes). Large: 160–300+ mm (service penetrations). Common working lengths: 35–60 mm (tiles) and 300–450 mm (concrete).

Wet or dry?

  • Wet – superior cooling, faster cutting, longest tool life; needs water feed and slurry management.
  • Dry – handy on ladders/indoors; drill in short pecks and let the rim cool between passes.

How to choose in 5 steps

  1. Material: concrete/RC → segmented; porcelain/stone → electroplated.
  2. Diameter: match the fitting, allow +2–4 mm clearance.
  3. Mount: M14 / 1/2" BSP / 1 1/4" UNC (or adapter).
  4. Mode: wet (preferred for concrete) vs dry (short holes).
  5. Parameters: larger diameter → lower RPM; steady feed without bouncing.

Common mistakes

  • Too high RPM on large diameters → overheating and glazed bond.
  • Continuous dry drilling without cooling breaks.
  • Poor alignment or worn adapter → run-out and chipped edges.

Need help choosing? Message or call us — we’ll match diameter, mount and bit to your material. Free delivery in Poland from 200 PLN. In Warsaw we offer same-day express delivery.