If you’re installing a new faucet and find that the faucet hole in your porcelain sink is too small, you’ll need to carefully enlarge it. Porcelain sinks are strong but brittle, meaning the wrong technique can cause chips or cracks. Enlarging a faucet hole isn’t difficult, but it requires the right tools, patience, and safety precautions. This guide will show you step by step how to safely enlarge a faucet hole in a porcelain sink.
Before You Begin: Things to Know
Porcelain is usually a ceramic base coated with a tough glaze. This makes it resistant to scratches but prone to cracking if drilled incorrectly. Keep these points in mind:
- Porcelain must be cut slowly to avoid cracking.
- Water cooling is essential to reduce heat and friction.
- Specialized drill bits are required for cutting hard, glazed surfaces.
- Measure carefully—once enlarged, the hole cannot be made smaller.
Tools and Materials You’ll Need
- Variable-speed power drill
- Diamond-coated hole saw (the same size as your desired hole)
- Diamond grinding bit or rotary tool (for fine adjustments)
- Masking tape
- Permanent marker or pencil
- Spray bottle or sponge with water (for cooling)
- Safety glasses and gloves
Step-by-Step: Enlarging a Faucet Hole in Porcelain
Step 1: Measure the New Hole Size
Check the faucet’s installation manual for the exact hole size required (usually 1 ⅜” or 35mm for most faucets). Mark the correct size around the existing hole with a marker.
Step 2: Apply Masking Tape
Cover the hole area with masking tape to prevent the drill from slipping and to protect the glaze from chipping.
Step 3: Use a Diamond Hole Saw
Attach a diamond-coated hole saw to your drill. Align it with the existing hole and begin cutting at a slight angle to create a groove, then straighten to a 90° angle once the bit bites into the surface.
Step 4: Keep the Area Wet
Spray water constantly on the drill bit and porcelain surface to cool the cutting area and reduce cracking risk.
Step 5: Drill Slowly
Use low speed and light pressure. Let the diamond bit grind through the porcelain instead of forcing it.
Step 6: Smooth and Fine-Tune
If the hole is close to size but needs slight enlarging, use a diamond grinding bit or rotary tool to carefully widen the edges.
Step 7: Clean the Area
Rinse the sink to remove porcelain dust and test-fit the faucet. If needed, grind a little more until the faucet fits snugly.
Tips for Success
- Always wear safety glasses and gloves to protect from sharp porcelain chips.
- Work slowly and patiently—forcing the drill increases the chance of cracks.
- Clamp the sink securely if it’s not installed yet.
- If enlarging more than a few millimeters, consider starting with a hole saw slightly larger than the existing hole.
- For precise adjustments, use a rotary tool with a diamond burr instead of drilling again.
Common Mistakes to Avoid
- Using the wrong drill bit: Standard metal or wood bits will not work on porcelain and may crack the sink.
- Drilling too fast: High speed creates heat and cracks porcelain.
- Skipping water cooling: Overheating weakens the porcelain glaze.
- Forcing the bit: Let the bit grind naturally—extra force causes chips.
Cost of Tools and Materials
- Diamond hole saw bit: ₦8,000–₦20,000 ($20–$40 internationally).
- Rotary tool with diamond grinding bit: ₦15,000–₦35,000 ($40–$70 internationally).
- Variable speed drill: ₦25,000–₦70,000 ($80–$200 internationally).
- Professional service: ₦20,000–₦50,000 ($50–$100 internationally) per hole enlargement.
FAQs
1. Can I use a regular drill bit on porcelain?
No. You must use diamond-tipped bits. Regular bits will slip, overheat, or crack the sink.
2. How big are faucet holes usually?
Most faucets require a 1 ⅜” (35mm) hole, but some need larger holes for handles or sprayers. Always check the faucet manual.
3. Can I enlarge the hole after the sink is installed?
Yes, but it’s trickier. Protect your countertop and work carefully with water cooling to avoid cracks.
4. Will enlarging the hole damage the sink?
Not if done correctly with diamond tools and plenty of water. Rushing or forcing the drill is what causes cracks.
5. Should I hire a professional instead of DIY?
If you don’t have the right tools or experience, hiring a pro is safer and can save the cost of replacing a cracked sink.
Conclusion
Enlarging a faucet hole in a porcelain sink requires the right tools and careful technique. By using a diamond-coated hole saw, drilling slowly, and keeping the surface cool with water, you can safely expand the hole without cracking the sink. For minor adjustments, a rotary tool with a diamond grinding bit works perfectly. If you’re unsure, hiring a professional fabricator is a smart option. With the right approach, your new faucet will fit securely and your porcelain sink will remain beautiful and functional.