Quick Answer

Match the core bit to your hole diameter, depth, machine thread and material. For reinforced concrete use a wet bit with a hardened crown; for light concrete and masonry a dry bit works. Check the thread matches your drill or adapter.

Key Selection Factors

• Diameter: the hole size you need (25–200 mm+).
• Depth: bit length must cover the wall or slab thickness.
• Thread: 1-1/4" UNC or 1/2" BSP — must match the machine or adapter.
• Wet or dry: wet for concrete, dry for masonry and light work.

How to Choose the Right Bit

Job	Recommended Bit
Reinforced concrete slab	Wet bit, hardened crown
Light concrete, block	Dry bit with extraction
Tile and masonry	Diamond hole saw / dry bit
Deep holes (300 mm+)	Long tube wet bit

How to Use It Correctly

• Anchor the rig so the bit starts true and does not wander.
• Keep water flowing for wet drilling; pause for dry bits.
• Start slow, then increase feed once the crown is engaged.
• Withdraw the bit when the core is caught to clear it.

Frequently Asked Questions

Q: What thread do most core drills use?

A:Most use 1-1/4" UNC on the output; smaller machines use 1/2" BSP. Check your machine before buying bits.

Q>Can I drill concrete with a dry bit?

A:For light concrete yes; for hard or reinforced concrete use a wet bit — dry bits overheat and lose segments.

Q: How deep can a core bit drill?

A:As deep as the tube length, plus extension tubes if the machine supports them. Standard bits are 300–450 mm.

Conclusion

Diameter, thread, depth and wet/dry are the four decisions. The Diamond Core Drill Bit (Wet) — JOY-DCB-W covers concrete drilling, with the Diamond Segment Core Drill — JOY-CDS for segmented work and the Core Drill Accessories — JOY-ACC for adapters and accessories.