What a great idea this forum is..
You don't always find what you're looking for in advice on the DIY section of Bunnings website..
My question is...What's the best type of power tool to use for cutting a large diameter hole in fibre cement board?
That's some clever thinking Andy_Mann..I think that could work quite well..
I think that jigsaw blade should do the job very nicely ..
Thanks again for your help..
if the hole you have to cut is between 40mm and 300mm, then your best bet is an Xtorque XTO300 https://sydneytools.com.au/xtorque-xto300-40-300mm-adjustable-hole-cutter-kit
i just realised it would have been too big, as the smallest it can do is 40mm
That the look you are going for?
Upcut spiral router bit for 12.7mm and under will leave a clean bottom.
Forstner bit for larger holes, not the saw tooth ones as they are more like a holesaw, will leave a vee point in the bottom of the hole.
Problem will be dust, I would stick to minimum holes and cutting.
Welcome to Workshop and thanks for joining in the discussion. It's great to see you've already received a helpful reply from @Brad. I trust our knowledgeable and creative community members will be able to provide plenty of assistance and inspiration for all your projects. Feel free to post whenever you need a hand or have something new to share.