Bits
Diamond Core Drill Bits UK
All UK sizes from 38mm to 200mm. Dry and wet diamond core bits for brick, block, concrete, and rebar, with full material compatibility guide.
View Bit GuideUK Trade Diamond Drilling Resource
Diamond Core Drill Bits, Machines & Trade Guides
Straight-talking buying guides, bit size references, and machine comparisons for UK plumbers, electricians, builders, and serious DIYers drilling concrete, brick, and masonry.
UK bit sizes from 38mm to 200mm
Trade-focused — plumbers, electricians, builders
Affiliate disclosure on every review page
UK Bit Size Quick Reference
107mm
Boiler flue — standard concentric
117mm
110mm soil stack & WC discharge
52mm
40mm waste pipe — basin, shower
38mm
Cable entry & EV charger install
Diamond core drilling is one of the most misunderstood areas of UK trade work. Plumbers reach for a 107mm bit for a condensing boiler flue. Electricians need a 52mm core through external render for a cable entry. HVAC engineers specify 117mm for a 110mm waste stack. Each of those jobs has a correct answer — and the wrong bit or wrong machine costs time, ruins the wall, or damages the equipment.
This site covers the specific questions UK tradespeople and advanced DIYers actually search for: which diamond core drill bit size for which application, when to use dry versus wet core bits, how to choose between SDS adaptor drilling and a dedicated core drill machine, and whether hiring or buying makes financial sense for your workload.
Every product recommendation includes an affiliate disclosure. We earn commission on purchases made through our links at no extra cost to you.
Equipment & Guides
Diamond Core Drill Resources
Guides covering every aspect of choosing, using, and maintaining diamond core drilling equipment for UK trade and advanced DIY.
Machines
Core Drill Machines
Trade buyer's guide to diamond core drill motors. Wet and dry rated, ½" BSP chuck, from DeWalt, Makita, Hilti, and Marcrist.
View Machine Guide
Accessories
Accessories & Adaptors
SDS Max and Plus adaptors, extension rods, pilot drills, and dust shrouds to complete your core drilling kit.
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Buying Guide
Best Diamond Core Drills UK 2025
Top picks for UK trade and DIY — tested for concrete, brick, and boiler flue drilling with clear pros, cons, and prices.
See Top Picks
How-To
How to Use a Diamond Core Drill
Step-by-step technique: pilot drill setup, correct RPM by diameter, cooling method, and extension rod use.
Read Guide
Reference
Core Drill Bit Sizes Explained
Which size for boiler flues, waste pipes, extractor fans, and cable entries? Full UK size chart from 38mm to 200mm.
View Size Chart
Why Use This Site
Built for UK Trade Professionals
A reference tool answering the questions UK tradespeople actually ask about diamond core drilling — not a product catalogue.
Boiler Flue & Waste Pipe Sizing
Find the right bit diameter instantly for any condensing boiler flue, twin-pipe system, 110mm soil stack, or 40mm basin waste.
Hire vs Buy Cost Breakdown
Know the break-even point between hiring at £20–£40/day versus owning a core drill from £150. Based on current UK hire rates.
Dry vs Wet — Explained Plainly
Which core bit type for brick, block, dense concrete, and rebar — without manufacturer marketing language or brand spin.
Trade-Focused Advice
Written for UK plumbers, electricians, and HVAC installers — not generic DIY content.
Full UK Size Coverage
Bit diameter references from 38mm cable entries to 200mm service ducts, with pipe compatibility data.
Honest Product Comparisons
Marcrist, DeWalt, Makita, and Hilti side by side — with clear affiliate disclosure on every recommendation.
UK Locations Covered
Regional guides for London, Birmingham, Manchester, Glasgow, Cardiff, Belfast, and 6 more UK cities.
Regional Guides
UK Location Guides
Diamond core drilling guides tailored to UK cities, covering local trade contacts, typical building materials, and common applications.
Common Questions
Diamond Core Drilling FAQ
What size core drill bit do I need for a boiler flue?
Most condensing boiler flues need a 107mm or 117mm diamond core bit. Check the flue manufacturer's spec — twin-pipe systems may need 125mm or 127mm. Drill from outside inwards where possible to avoid blow-out on internal render.
Can I use a diamond core drill without water?
Dry diamond core bits are designed for waterless use and suit brick, blockwork, and aerated concrete. Wet diamond cores require a continuous water supply and are used on reinforced or dense concrete. Using a wet-rated core bit dry will overheat and destroy the segments.
What drill do I need to use diamond core bits?
Diamond core bits need a dedicated core drill machine with a ½" BSP threaded chuck. For holes up to 52mm, SDS Plus or SDS Max adaptors allow use with a rotary hammer on rotation-only mode. Anything above 65mm needs a 1000W+ core drill motor for safe torque handling.
Is it better to hire or buy a diamond core drill?
For one or two holes a year, hire at £20–£40 per day is cost-effective. If you drill more than 10–15 holes annually as a trade professional, buying a core drill from £150–£600 pays back quickly in time saved and consistent bit compatibility.
What size core drill bit do I need for a waste pipe?
A 110mm soil and waste pipe requires a 117mm core bit. A 40mm basin or shower waste needs 52mm or 65mm. For a 4-inch toilet soil stack, use a 127mm bit. Always drill 5–10mm larger than the pipe outer diameter to allow for alignment.