Widening Core Opening

[alanthomaswatson]

Hello

What is the best way to make a core opening wider in circumference?
Just discoverered that the person who fitted my cooker hood chose to use a 100mm bathroom kit to vent it rather than the required 125mm, which means it doesn't fit the cooker hood adaptor (lots of duct tape!).

I need to fit a 125mm duct kit which is easy in itself but the core is too narrow. What is the best way to make it the right circumference? Drill out? Re-core?

Wall is brick and block, with 100mm part filled cavity.

Many thanks

Alan

 

[Johnmelad]

https://www.youtube.com/watch?v=jurSZR1Se6A

 

[mfarrow]

You need a guide for the bigger core bit:

- Core through a piece of ply/old melamine door front etc with your 125 bit
- Drill the wall in 4 places and screw the holed piece of board concentrically over your old hole
- Drill through with your 125 bit. The piece of board will hold it steady as you core through.

You probably want a bit slightly bigger than 125 if that's your duct size.