So the cooker hood that I have has a 147mm hole where the extraction part is
The reducer that came with the cooker hood reduces it to pretty much exactly 120mm
My friend who has lent me their Erbauer core drill kit which has a 117mm at the largest size - https://www.screwfix.com/p/erbauer-diamond-core-drill-bit-117mm/5827v
I offered them both upto each other and its pretty much an exact match sizewise :
So the hole itself will probably exactly match the 120mm but obviously i'm thinking that surely the hole needs to be bigger? because once the pipe/duct is slotted onto the reducer that would make it slightly wider than the 120mm and hence not fit into the 120mm hole created by the core drill? either that or it will be a very very tight squeeze?
I'm assuming that maybe I either need a bigger core drill bit? 127mm? or a different reducer 150mm to 100mm (6 inch to 4 inch)?
another 2 problems arise :
if I went for an even smaller reducer there would be a sizable 20mm gap which Im guessing I would need to fill in with some type of foam or insulation as to stop any backdraft. and i'm assuming it may affect the extraction rate since i've read that it can reduce it by upto 30-50% and possibly make the unit noisier. Apparently 120mm (5 inch) is still suitable for the extraction rate of my hood which is 558m/h because 150mm ducting is best for 750m/h
if I went for the bigger core drill bit obviously that would require me purchasing a new core drill bit (£40-50) and i'm not sure what exact size I would need? Also some 120mm kits seem to say in the reviews that the actual pipe/ducting that comes with it is actually 100mm, which would then not fit my actual unit. Slightly confused on this one but dont know if its just retailer specific or if the 120mm applies to the vent and not the ducting itself.
The ducting itself will be a pretty short run (less than 1m) as it is essentially going straight to the outside wall directly from the back of the hood).
Any advice would be much appreciated as I thought this would be pretty straight forward with standard sizing but doesn't seem so lol
The reducer that came with the cooker hood reduces it to pretty much exactly 120mm
My friend who has lent me their Erbauer core drill kit which has a 117mm at the largest size - https://www.screwfix.com/p/erbauer-diamond-core-drill-bit-117mm/5827v
I offered them both upto each other and its pretty much an exact match sizewise :
So the hole itself will probably exactly match the 120mm but obviously i'm thinking that surely the hole needs to be bigger? because once the pipe/duct is slotted onto the reducer that would make it slightly wider than the 120mm and hence not fit into the 120mm hole created by the core drill? either that or it will be a very very tight squeeze?
I'm assuming that maybe I either need a bigger core drill bit? 127mm? or a different reducer 150mm to 100mm (6 inch to 4 inch)?
another 2 problems arise :
if I went for an even smaller reducer there would be a sizable 20mm gap which Im guessing I would need to fill in with some type of foam or insulation as to stop any backdraft. and i'm assuming it may affect the extraction rate since i've read that it can reduce it by upto 30-50% and possibly make the unit noisier. Apparently 120mm (5 inch) is still suitable for the extraction rate of my hood which is 558m/h because 150mm ducting is best for 750m/h
if I went for the bigger core drill bit obviously that would require me purchasing a new core drill bit (£40-50) and i'm not sure what exact size I would need? Also some 120mm kits seem to say in the reviews that the actual pipe/ducting that comes with it is actually 100mm, which would then not fit my actual unit. Slightly confused on this one but dont know if its just retailer specific or if the 120mm applies to the vent and not the ducting itself.
The ducting itself will be a pretty short run (less than 1m) as it is essentially going straight to the outside wall directly from the back of the hood).
Any advice would be much appreciated as I thought this would be pretty straight forward with standard sizing but doesn't seem so lol
