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?
Would this do the job @Prof?
@Prof, if you're to be cutting circular holes, then a carbide/diamond tipped jigsaw or reciprocating saw would seem ideal, but there's a problem. The dust is nasty stuff, check out post #8 by Peter Kelly:
You could try to vacuum the dust while cutting, but you'd need a vacuum with a HEPA filter (expensive), & that's able to contain the dust completely for disposal, or you're back to square one. Even then, you'd still have to remove the contamination from the nozzle, hose, & filter compartment.
Wet cutting would be ideal to contain the dust, but instead of using a Wet/Dry Vac (more problems than it's worth), let the residue run into a disposable bag/container that can be sealed & disposed of safely.
Sorry if I sound like a drama queen, but it's you, & your family's health that could be at risk.
My suggestion would be to wet, then scribe & snap your eave panels to length, leaving a gap between them, that you can fit with a panel that's safer, & easily cut to install your fittings.
Tile holesaw would have a diamond edge.
57mm is the largest size in that kit. You can get larger sizes in tungston teeth at bunnies.
I might end up in the naughty corner but you can look here too.
@Prof for drilling the 30mm hole on an installed vertical panel, either a carbide tipped, or diamond coated hole saw would be fine, but I wouldn't recommend doing it dry.
For a cheap hack, set up your hole saw as normal, but before you fit it to your drill, scrounge a cheap stubby holder, make a small cross cut in the centre of its base & slide it onto hole saw shaft. Grab a spray bottle of water & dampen the inside of the stubby holder, & also where you're about to drill (it doesn't have to be saturated, just moist).
Partially drill, & hold a damp cloth under the stubby holder to collect any dribbles, as you'll need to repeatedly remove the hole saw to remoisten the hole site.
Repeat the process until you're done.
Then rinse the hole saw thoroughly under a tap, & thoroughly rinse the basin/trough. The hole saw's safely ready for another day.
Rather than rinse the rag, put it in a pastic bag, tie the bag securely, & drop it into your rubbish bin.
I'll get back to you on the cut out for your air-con later.