Sometimes when drilling a hole you find it is too tight for a fitting to pass through.
This could be a disaster if the tile has already been fitted on the wall. This rescue is not pretty but it will get you out of trouble in certain situations.
Conventional drilling with a pilot drill would definately be a disaster because the centre has been removed. But with a diamond drill kit it is possible to rescue the tile and ease the edges out.Start by placing the drill guide slightly over the edge of the tile to form a moon crescent. 
Press the drill plate and start to drill a crescent. Here you can see we are drilling a series of them. If you want an even wider hole then just make more moon shapes like this 
Eventyally you can cut the slices out. 
Test your fitting to see if it passes in. 
This is not a pretty sight. But its done the job 
A final wash with the sponge is good enough to clean up the hole. 
Obviously this is an ugly looking hole and only for items which will be capped off with a shroud or in places where the fitting is hidden.
If you want a better looking hole then you are better off buying a bigger size core drill. For example this is a 30mm core and you would be better off using a 35mm core. Only do this sort of work if you are in a hurry, emergency or the fitting in not ever going to be seen.
Richard
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