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Diamond Core Drill Bits & Accessories
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Diamond Core Drill Bits and Accessories for Trade and DIY
A standard drill bit will not cut through concrete, stone, or hard ceramic tile. You need a diamond core drill bit for clean, accurate holes every time. This range covers professional-grade diamond core drill bits and accessories. It includes dry diamond core bits, wet diamond core bits, pilot drill bits, and core drill arbors. All products are suited to concrete, brick, block, stone, porcelain, and reinforced materials. Whether you are on a building site or working at home, you will find the right bit here.
Why Diamond Core Drill Bits Cut Better
Diamond is the hardest natural material on earth. Diamond-tipped bits cut through hard surfaces that ordinary bits cannot handle.
The cutting segment on a diamond core bit is bonded with real industrial diamonds. These grind through the material cleanly. The result is a smooth, precise hole with no cracking.
This matters when you need holes for pipes, cables, fixings, or sockets. A ragged or cracked hole weakens the surrounding material. A diamond core bit avoids that problem entirely.
Quick tip: Always match your diamond core bit to the material you are cutting. Dry bits suit brick and softer masonry. Wet bits are better for hard concrete and stone. Using the wrong type will shorten the life of your bit quickly.
Types of Diamond Core Drill Bits and Accessories
There are several types of diamond core drill bits. Each one is built for a specific material or method. Here is what is available and when to use each.
Dry Diamond Core Drill Bits
Dry diamond core bits are used without water. They suit brick, block, aerated concrete, and soft stone. They are the most common type used on UK building sites. They fit most standard SDS core drill rigs and angle grinders with the right arbor.
Wet Diamond Core Drill Bits
Wet diamond core bits need a constant water feed during cutting. The water cools the segment and removes slurry from the hole. They last much longer than dry bits when used correctly. Best for hard concrete, reinforced concrete, granite, and natural stone.
Diamond Core Drill Bit Sets
A diamond core drill bit set gives you multiple sizes in one kit. This is the most cost-effective way to start. A good set typically includes sizes from 25mm up to 100mm or more. Sets are ideal for plumbers, electricians, and general builders who need various hole sizes.
Core Drill Arbors and Adaptors
An arbor connects your diamond core bit to your drill. Different drills use different fittings. Common types include SDS Plus, SDS Max, and straight shank. Always check the arbor thread matches your core bit before ordering.
Pilot Drill Bits
A pilot drill bit centres the core bit at the start of the cut. Without one, the core bit can wander and produce an off-centre hole. Most diamond core bit sets include a pilot bit. Replace it when it becomes blunt to keep your holes accurate.
Core Drill Accessories
Accessories include water swivels for wet cutting rigs, vacuum attachments for dust control, extension rods for deep holes, and guide plates for angled cuts. These make core drilling safer, cleaner, and more precise on site.
Which Diamond Core Bit Is Right for Your Material?
Not every diamond core bit suits every surface. Using the wrong bit wastes money and slows the job. Use this table to match your bit to your material.
| Material | Recommended Bit Type | Wet or Dry |
|---|---|---|
| Brick and Blockwork | Standard dry diamond core bit | Dry |
| Aerated Concrete (Aircrete) | Dry diamond core bit, soft bond | Dry |
| Dense Concrete | Hard bond wet diamond core bit | Wet |
| Reinforced Concrete | Reinforced concrete diamond core bit | Wet |
| Natural Stone and Granite | Wet diamond core bit, hard bond | Wet |
| Porcelain and Ceramic Tile | Thin-wall diamond core bit | Wet or dry with water |
| Sandstone and Soft Stone | Dry diamond core bit, medium bond | Dry |
If you are unsure about the material hardness, go for a medium-bond wet bit. It handles the widest range of surfaces safely.
Picking the Right Core Drill Bit Size for the Job
The hole size you need depends on what is going through it. Here is a quick guide to the most common sizes used in the UK.
25mm to 50mm Core Bits
These sizes suit electrical back boxes, small cable runs, and drainage pipe holes. They are the most commonly used sizes on domestic jobs. A standard SDS Plus drill handles these sizes with ease.
52mm to 80mm Core Bits
These suit soil pipes, conduit runs, and larger cable bundles. You will often need an SDS Max drill or a dedicated core drill rig at these sizes. The drill must have enough torque to drive the bit cleanly.
100mm to 150mm Core Bits
Larger sizes suit soil stacks, ventilation ducts, and structural openings. A dedicated core drill rig and water cooling are usually needed. Always support the drill properly at these sizes to avoid injury.
Over 150mm Core Bits
Very large diameter bits are used by specialist contractors. They cut through thick walls and floors for major pipe runs or structural alterations. These always need a wet-cut rig with full water supply.
Important: Always add 5mm to 10mm to the pipe or cable diameter when picking a core bit size. This gives enough clearance to pass the pipe or cable through cleanly. A tight fit makes installation harder and can damage the pipe surface.
Dry Core Drilling vs Wet Core Drilling
Both methods use diamond core bits. The key difference is whether water is used during cutting. Each method has its own strengths.
Dry core drilling is quicker to set up. You do not need a water supply or a wet-cut rig. It is ideal for brick, block, and aerated concrete. The dust produced must be controlled. Use a vacuum shroud or dust extraction attachment to keep the work area safe.
Wet core drilling keeps the bit cool during cutting. This extends the life of the diamond segments significantly. It produces slurry instead of dust. Wet drilling is essential for hard concrete, stone, and reinforced concrete. It is cleaner in terms of airborne particles but messier on the floor.
For most trade work in the UK, dry core drilling covers the majority of everyday tasks. Wet core drilling is needed for harder materials and larger diameter holes in dense concrete.
How to Make Your Diamond Core Bits Last Longer
Diamond core bits are a worthwhile investment. With the right technique, they last much longer between replacements.
Use the Correct Speed
Larger bits need lower RPM. Running a large core bit too fast causes the diamond segments to overheat. This glazes the segment and stops it from cutting. Check the manufacturer's speed guide for each size.
Keep the Bit Cool
For dry cutting, take short breaks between cuts. Let the bit cool down naturally. For wet cutting, maintain a steady water flow at all times. Never run a wet core bit without water present.
Use Steady Pressure
Let the bit do the work. Apply firm, even pressure without forcing it. Excessive force causes segment damage and can crack the surrounding material. Steady progress gives a cleaner result.
Re-dress a Glazed Bit
If the bit stops cutting efficiently, it may be glazed. Run it briefly through a soft abrasive block or sandstone to re-expose the diamond segments. This restores cutting performance quickly.
Store Bits Correctly
Store diamond core bits in a dry place. Protect the cutting segments from knocks and drops. Even minor damage to a segment reduces cutting performance and creates uneven holes.
Use the Right Arbor
Always fit the correct arbor for your drill and core bit thread. A loose or mismatched arbor causes wobble during cutting. This damages both the bit and the drill, and reduces hole accuracy.
Find the Right Diamond Core Drill Bit for Your Job
Use the filters above to search by diameter, material type, and cutting method. Check individual product pages for segment depth, segment height, and compatible drill fittings before ordering.
Whether you need a single dry diamond core bit for a quick domestic job, a full diamond core drill bit set for trade use, or wet-cutting accessories for reinforced concrete work, this range has what UK tradespeople and builders need to get the job done cleanly and efficiently.
For drill bits used alongside core drilling work, see our drill bits range. For fixings used after the hole is made, see our masonry and concrete fixings.
Frequently Asked Questions
What are diamond core drill bits used for?
Diamond core drill bits cut large, clean holes through hard materials. Common uses include holes for soil pipes, electrical back boxes, cable runs, and ventilation ducts in concrete, brick, and stone.
What is the best diamond core drill bit for concrete?
For dense or reinforced concrete, a wet diamond core bit with a hard bond segment is best. It stays cool during cutting and lasts far longer than a dry bit used on hard concrete.
Can I use a diamond core bit with a standard drill?
Small diameter dry diamond core bits can be used with a standard rotary drill. For larger bits or hard materials, you need an SDS Plus or SDS Max drill, or a dedicated core drill rig.
Do I need water when using a diamond core drill bit?
Dry diamond core bits do not need water. Wet diamond core bits must always have a constant water supply during cutting. Running a wet bit without water will ruin the segment very quickly.
What size diamond core bit do I need for a soil pipe?
A 110mm soil pipe typically needs a 125mm core bit to allow clearance for fitting. Always add 5mm to 10mm above the pipe diameter when picking the core bit size.
Why has my diamond core bit stopped cutting?
The segment may be glazed. This happens when the diamonds become capped with material residue. Run the bit briefly through a soft abrasive block or sandstone to re-expose the cutting surface.
Is a diamond core drill bit set worth buying?
Yes. A diamond core drill bit set gives you multiple sizes at a better price per bit than buying individually. It is a practical investment for tradespeople who regularly core-drill on site.