How to drill a hole into a porcelain sink
I have recently been refitting my bathroom, and I wanted to move my sink for better use of the space to fit in with your new layout design.
The problem I had was that the mounting holes were not quite right to line up with the studs in the new position, and rather than have to rebuild the wall or buy a new sink, I looked at drilling new holes into the porcelain sink.
This would save me a whole bunch of time and money as I wouldn’t need to buy a new sink, here’s how I did it:
Drill a hole into a porcelain sink by covering the area with masking tape, mark the hole centre, attach a diamond drill bit to your drill, set the speed quite low and turn off the hammer action, apply light pressure to the sink, add water to the area using a sponge, use a jig or guide for accuracy.
Using these steps it is possible to modify and reuse most types of sink unit, either in the kitchen utility room or bathroom,
Following these steps helps to make this job easier and can be applied to any type of sink, but the last thing you want is to damage your sink, so to avoid any issues like cracks or chips on the surface, take a look at each step in more detail.
Covering the area with masking tape
Porcelain is a hard surface to drill into and also to mark, to make this easier, use masking tape to cover the area you want to drill into, use a single layer that is smoothed out to remove any air bubbles, apply the tape over the area you need to drill through.
Use the masking tape on both sides you are going to drill, the entry and exit, this will reduce any chip out when the drill breaks through the other side.
Masking tape will allow you to use a pencil or pen to mark the center of your hole, always remember to check the location with a good tape measure before drilling into the surface.
Remember to measure twice and cut once!
With the surface covered in masking tape, the tip of the drill bit will be less inclined to slip or move when you first start drilling a hole into porcelain.
Attach a diamond drill bit to your drill
To ensure that you can drill a good, clean hole with no damage to the surface, using a new or sharp drill will make a world of difference.
As porcelain is a very hard material a standard drill bit cannot be used to drill holes, there are a few options for drilling holes into porcelain they are:
- Arrow-head Drill bit
- Multipurpose Drill bit
- Diamond Drill bit
For drilling holes into a porcelain sink, which is quite thick, I would always use a diamond drill bit, Arrow-head and multipurpose drill bits are good for drilling small holes through the thinner bathroom or kitchen tiles and other thin materials, but for drilling holes into porcelain sinks, a diamond drill bit is much better.
Diamond drill bits are hollow and cut a core from the porcelain, drills of this type often have a drill bit acting as a center to keep the outer hole saw central to the hole and that it is cutting true.
It is often a good idea to pre-drill the guide hole for this before using the diamond drill
These types of drills come in various sizes usually ranging from 6mm dia up to 50mm and you get a good kit similar to the one that I used from Amazon for a good price.
Set the speed quite low and turn off the hammer action
Diamond drills need to be run quite slowly to get the best cutting action, typically between 300 Rpm & 600 Rpm should be plenty, keep the speed as constant as possible,
You may have to adjust the speed using your finger as you drill the hole, this will depend on your drill and the surface of the porcelain.
keep checking for discoloring which would indicate the drill is too fast and there is too much heat building up.
Ceramic surfaces including porcelain are quite brittle and need to be drilled carefully, the last thing you want is the hammer action on your drill bouncing up and down smashing the surface so make sure this is turned off.
I used my Hikoki 18v combi-drill set to slow speed and made sure the hammer function was off, with this setting the drill runs at the right speed and has the power to drill all sizes of holes, I use this drill for most jobs, check out our recommended tools page for a review of this drill and see why you should buy one
Remember to always wear appropriate PPE when using power tools, and goggles should always be worn whilst using a drill
Apply light pressure to the sink
Let the drill bit do the work and only apply light constant pressure to the drill allowing it to cut its own way through the material.
Build up the speed of your drill, starting slowly and hold the drill firmly using both hands to stop it from wandering away from your centre mark, the masking tape will help but you still need a firm grip.
Keep an eye on the surface and the drill bit, making sure to stop and clear any build-up of debris or dust.
Don’t drill too deep in one go, use a pecking technique to drill the hole, this reduces heat build-up and clears the drill of swarf and debris, typically you should drill no more than ¼ of the drill diameter in one go.
If the surface starts to discolor, the drill could be getting too hot either because there is too much pressure, or the drill is turning too fast. Try slowing the drill speed and using a lighter touch.
Add water to the area using a sponge
Keeping the heat down when drilling holes into a porcelain sink helps avoid the drill bit burning out and ensures a clean hole with no damage.
Using a sponge to drip water onto the surface of the porcelain and into the hole being drilled can really help reduce heat and clear debris away,
Try to keep the drilling face flat to allow water to stay on the surface, make sure that any slurry is cleared away regularly. You can use a wet sponge to wipe the area clear.
Remove the drill from the hole and wipe any debris or slurry away with an old rag, wet sponge, or paper towel. This will help to prevent the drill bit from being clogged.
Then add fresh clean water to the surface, you can also dip the drill bit into an open container of clean water to cool it down.
This also works when you are drilling horizontally or at an angle where water will run away from the surface.
Use a jig or guide for accuracy
It can be tricky to hold the sink and drill steady when drilling holes through porcelain, and using a guide or jig will help keep the hole on centre and square to the surface.
Depending on the space available Drilling a sink should be done outside or in a well prepared space, as the dust and slurry will make a mess whilst drilling.
Make sure the sink is well supported so that it will not move, working on a flat solid surface and use blocks to support where needed
Protect the surfaces by putting down an old cloth and wipe the sink clean before you clamp or hold it down, this will avoid any undue damage or scratches whilst you are drilling.
Following these tips will help drill a nice clean hole through the porcelain sink unit the only thing needed is to clean the sink down with a clean damp rag to remove any swarf, slurry or debris
The sink can now be refitted in its new home ready for plumbing in.
