Make sure you drill a Tap hole from the Top Face
Decide on the pre-punched tap holes you need.
Measure to locate the centre of the required pre-punched tap hole and cover the area with masking tape.
Crack the glaze from the centre of the required hole using a centre punch.
With the use of No.8 Masonry drill, carefully drill a small pilot hole from the top. Only one small hole is required.
Now enlarge the hole to the required size with your hammer and centre punch.