Need to largen standard overflow hole in a Carronite bath

[adambc]

I am fitting a new Carronite Swallow 1800 bath ...

(http://www.carronbathrooms.com/Carron%20Bathrooms%20-%201800x700.html)

...with a Hansgrohe Exafill S filler/overflow ...

(http://www.hansgrohe.co.uk/uk_en/110381_32313533305F32355F3632313539.htm) ...

so have a overflow and waste holes ONLY

The problem is that the overflow hole is too small for the Exafill filler/overflow component and I need to drill it out - but I am concerned for two reasons ...

1. if I cut the Carronite with a regular hole saw, do I risk splitting the bath?

2. given there is a hole there already, how can I stop myslef slipping?

HELP PLEASE!!!!!!

 

[roguetrader]

get a pice of ply 6 or 7 inches wide. cut a hole in the same size that you need so forming a template. clamp it in place with a couple of squeezy clamps and use this to run your holesaw through.

 

[adambc]

Just come inside and seen your response - many thanks ...

I did it the other way ...

Clamped a piece of ply to the outside - with the centre of the old hole marked/lined up - masked the whole area - used the mark for the holesaw arbor - job done ...

And Exafill S fitted ...