Core Drill Bit Size Chart | Concrete & Asphalt Contractor Guide
Core Drill Bit Size Chart for Concrete & Asphalt
Selecting the correct core drill bit size is important for clean, accurate holes in concrete and asphalt. Contractors typically drill holes slightly larger than the pipe, conduit, or anchor being installed to allow for proper clearance, alignment, and sealing materials such as grout or epoxy.
This guide provides a quick reference chart for common hole sizes used in utility work, construction, and infrastructure drilling, along with tips for choosing the correct diamond core bit for the job.
Why Core Drill Holes Are Larger Than the Pipe
When installing utilities through concrete or asphalt, the hole must usually be larger than the pipe or conduit itself. This extra clearance allows room for positioning, insulation, and sealing materials used to secure the installation.
For example, a 2 inch water line may require a 3 inch core bit to provide enough space for installation and grout sealing. This is why contractors often reference a core drill size chart when planning drilling work.
Core Drill Bit Size Chart
| Pipe / Conduit Size | Recommended Core Bit Size |
|---|---|
| 1/2 inch | 1-1/4 inch bit |
| 3/4 inch | 1-1/2 inch bit |
| 1 inch | 1-3/4 inch bit |
| 1-1/4 inch | 2 inch bit |
| 1-1/2 inch | 2-1/2 inch bit |
| 2 inch | 3 inch bit |
| 3 inch | 4 inch bit |
| 4 inch | 5 inch bit |
Browse professional diamond core drill bits designed for concrete and asphalt drilling applications.
Core Drilling in Concrete vs Asphalt
Core drilling through concrete typically requires slower drilling speeds and water cooling to protect the diamond segments. Reinforced concrete can also contain rebar, which requires high quality diamond bits designed for heavy duty cutting.
Asphalt drilling is generally faster and produces less resistance, but still requires durable core bits that can withstand heat and abrasive materials found in road surfaces.
Selecting the correct bit type and machine ensures efficient drilling and longer bit life in both materials.
Recommended Core Drill Equipment
Choosing the correct core drill depends on the jobsite conditions, hole diameter, and available power source. KOR-IT manufactures a wide range of professional drilling equipment used by contractors across construction, utility, and infrastructure industries.
New to core drilling? Learn the full process in our How to Core Drill Concrete guide , which explains drilling setup, equipment options, and safety tips used by professional contractors.
Frequently Asked Questions
What size core drill bit should I use?
The core bit should typically be larger than the pipe or conduit being installed to allow clearance for alignment and sealing materials.
Can the same core bit be used for concrete and asphalt?
Some diamond core bits are designed to work in both materials, but specialized bits may provide better performance depending on the job conditions.
Do you need water when core drilling?
Water is often used when drilling concrete to cool the bit and remove debris. Asphalt drilling may sometimes be performed dry depending on the equipment and bit type.
