Core Drill Bits & Adaptors

About Core Drill Bits & Adaptors

Core drill bits and adaptors are essential components for creating large-diameter holes in demanding materials including concrete, brick, stone, and reinforced masonry. Unlike standard drill bits that remove all material, core bits cut an annular ring, leaving a solid core in the centre. This efficient method requires less power, generates less vibration, and produces cleaner holes—making core drilling the preferred choice for tradespeople installing pipes, cables, ventilation ducts, and mechanical services.

MyToolShed.co.uk stocks everything needed for professional core drilling applications, from diamond-tipped core drill bits in various diameters to essential arbors, adaptors, and extensions that connect bits to power tools. Our range includes wet and dry core bits suitable for handheld drills, dedicated core drilling rigs, and appropriate adaptors for 240v mains-powered equipment. Whether you're drilling shallow holes for electrical outlets or deep penetrations for plumbing installations, the right combination ensures efficient, accurate results.

Applications

Core drilling equipment is indispensable across numerous trades and industries:

• Electricians: Creating holes for conduit, cable runs, back boxes, and ventilation in domestic and commercial installations
• Plumbers and Heating Engineers: Drilling penetrations for waste pipes, water supply, central heating pipework, and boiler flues
• HVAC Specialists: Installing ventilation ducts, air conditioning lines, and extraction systems through structural elements
• General Builders: Creating openings for services, structural sampling, and installation requirements on construction sites
• Groundworkers: Core sampling, drainage installation, and drilling through concrete slabs and asphalt surfaces
• Fire and Security Installers: Drilling holes for cable routes, detector wiring, and sprinkler system pipework
• Maintenance Engineers: Retrofitting services in existing buildings and carrying out repairs requiring access through masonry

Choosing The Right Core Drill Bits & Adaptors

Material Compatibility: Match your core bit to the material you're drilling. Diamond core bits handle concrete, brick, stone, and masonry, whilst different segment specifications suit reinforced concrete versus softer materials.

Bit Diameter: Select diameter based on installation requirements, remembering larger bits require more powerful tools. Common sizes range from 25mm for small conduit holes up to 300mm for substantial pipe penetrations.

Arbor and Adaptor Compatibility: Verify thread connections match between bits and arbors. Check your arbor shank suits your power tool—common options include SDS-Plus, SDS-Max, hex shank, and 5/8" thread. Brands like Makita, DeWalt, and Milwaukee often have specific requirements.

Wet or Dry Drilling: Wet drilling with water cooling extends bit life significantly and complies with HSE dust suppression guidelines. Dry core bits offer convenience but generate substantial dust requiring appropriate extraction.

Power Tool Suitability: Ensure your drill has adequate power—typically 1,200W minimum for smaller bits, with 2,000W or more for larger diameters. MyToolShed.co.uk can advise on compatible equipment for your applications.

Safety Information

Dust Control: Drilling concrete and masonry generates respirable crystalline silica (RCS), a serious health hazard. HSE requires effective dust suppression—use wet drilling with water feed or high-efficiency extraction systems. Always wear minimum FFP3-rated respiratory protection.

Electrical Safety: When using mains-powered core drills, ensure 240v supply circuits are RCD-protected. Check cables and plugs before use, and consider 110v site transformers for construction site applications.

Structural Awareness: Before drilling, verify no hidden services occupy the drilling path. Never core drill through load-bearing steel reinforcement without structural engineer approval.

Frequently Asked Questions

What's the difference between core drill bits and standard drill bits?

Core drill bits cut only an annular ring around the hole's perimeter, leaving a solid core in the centre, whilst standard bits remove all material. This makes core drilling far more efficient for large-diameter holes (typically over 20mm), requiring less power and producing less vibration in hard materials like concrete.

Can I use core drill bits in a regular electric drill?

For small-diameter core bits (up to approximately 50mm), a powerful corded drill (minimum 1,200W) with appropriate arbor adaptor can work in softer materials. However, larger bits and harder materials demand dedicated core drilling machines or heavy-duty rotary hammers. Always check manufacturer power tool recommendations.

What thread size arbor do I need for my core drill bits?

UK core drill bits commonly feature 1/2" BSP thread (smaller bits) or 1 1/4" UNC thread (larger professional bits). Many European-manufactured bits use M14 or M16 metric threads. Always verify thread specifications before purchasing arbors—mixing incompatible threads creates dangerous situations.