Looking for 6 inch dia core drill plus ducting

[littlespark]

I've got a job to replace a recycling type cooker hood with a vented type.
The hood has been bought by the customer and has a 150mm duct hole on top

I cant find anywhere locally that will supply me with a 150mm dia elbow and straight duct. The store that she bought the hood from only had a round to rectangular duct kit.
Does anyone know a good online supplier?

I also need to buy a core drill kit, as I have nothing at the moment.
Screwfix has a 3 core size kit on offer, but only goes up to 117mm. I'd have to buy the 150mm one separate.
If I could get the ducting and the corer from the same place, could save on delivery.

I could hire the core drill locally if I need to.

 

[snowhead]

For ducting online;
Ventilation Grilles | Extract & Supply Air Grilles | Duct Supplies | Buy Online - http://www.ductstore.co.uk/acatalog/Grilles___Louvres_Standard_Range.html

These have local outlets, depends where you are;
Fans & Spares : Viewing 'Ducting & Fittings' - http://www.fansandspares.co.uk/shop/category/223-ducting--fittings

 

[Spoon]

You mean something like this and this for the ducting?

 

[Spoon]

Amazon do a 152mm core drill.
Something like this.

 

[mhar]

a 6" core is going to require a decent drill, a dedicated core drill definitely.

If it is only a short run could you use a reducer on the duct?

 

[Corbs]

Reduce it down to 4" straight off the hood

 

[littlespark]

Good point. The run is through a double brick cavity wall, so not a long run at all. If I get a 4" corer instead of 6 as i'll likely use the 4 again. more likely than the 6

I'm already looking on Amazon. might just change whats in the basket

 

[haptism]

Try these guys, they do allsorts

Ducting, ventilation, and damp control products in the UK - u-wants.it ... i-sells.it - http://www.i-sells.co.uk/

 

[Octopus]

You need to buy a "kit" of core drills .................. and a 6"

I just replace the 4" as and when it wears out

And of course a proper core drill.

 

[buzzlightyear]

save you self getting a 6in core cutter, drill centre hole and start working 3in ether side and start drilling both sides ,job done .

 

[telectrix]

use converter to rectangular. easy to stitch drill and chisel hole. saves the cost of a core drill.

 

[johnduffell]

1. don't use a 152mm drill as the rigid ducting has an *internal* diameter of 4 inches, the external will be bigger so around 160mm would be better.
2. don't reduce the diameter, as the air speed is a function of the area, so you get diminishing squares in terms of resistance, and depending on the fan the excessive back pressure will ruin the efficiency of the impeller and cause a lot of turbulence/noise, meaning even more losses. So a 4 inch duct has 7850mm2 and a 6 inch has 17660mm2 i.e. 2.25x as much area. Terminals are often the most resistive part of the system, so go up a size there and get one with a decent rated free area.
3. stitch drilling you can take out what you like, agreed with telectrix there.

 

[billyblade]

Some good advice here. Just want to chip in a little of my own. Most people are advising dry diamond core drills but in hard brick (engineering, 1930's houses, houses built with "Friday afternoon bricks") they just won't "cut" it
For those type of materials you either need wet diamond cores (expensive or hire) or tungsten carbide tipped core drills that you use on hammer action.
I am unaware of an SDS+ machine that is rated to core above 90mm so using this machine with those larger cores you are risking burning the power tool out. The clutches are also set up wrong for coring large diameters. As has been mentioned a dedicated coring machine would be an advantage. On these machines there is usually more choice of speeds to run at (as opposed to just the one on an SDS+ machine) so you can run the core drill closer to its recommended speed improving cutting efficiency and improving tool life.
What happens mostly is that people refuse to fork out for a coring machine and prefer to use a power tool they already own (SDS+) and cheaper dry diamond cores. There is also a misconception that dry diamond cores will cope with any masonry material "they're diamond, they'll cut anything". Unfortunately the matrix (the material that bonds the diamond crystals together in the segments is set up to core the softer end masonry (breeze blocks, ordinary red facing bricks etc). If used in harder, denser masonry progress is very slow to the point where it seems to stop. If this happens and there appears to be plenty of meat left on the segments it's usually because they have "glossed up". Many people discard core drills at this point because they think they have worn out. It is possible to rescue them again by sending the core through a breeze block a couple of times. This re-exposes the diamond crystals.

 

[1Justin]

It can get expensive.
If it helps any, my "ultra budget" (less than £100 for the drill and the bit!) experiment, gave me two clean 162mm holes in a cavity wall a few months ago. I can't claim it was fast. A surprisingly good quality diamond core from "UK Drills" (Ebay) and a cheap big Titan SDS from Screwfix. The clutch on the Titan is weak, but they went through fine. - I think only (an essential tip from this forum) because I put in a few stitching holes first to give the dust somewhere to go.