Core drill purchase

[rattlehead85]

Would appreciate some advice on this please.
Got a contract starting next month rewiring 200 kitchens within a chalet complex. They require 6" extractor fans to be core cut through the concrete structure roughly 350mm in depth. I am looking at buying a dedicated core drill to do this. What recommendations do you have for a decent core drill to do this and what size core bit size will i need to complete the job. I have a 7kg DeWalt sds max drill but not sure this is any use as it doesn't appear to have the clutch device which i think is an important safety issue when coring holes this thick.
Thanks[emoji106][emoji106]

 

[sammyshooter]

Must have a clutch, when they snatch up especially on the larger cores it whips around with a vengeance. We have a makita one, 3 years old? Still going strong.

 

[Geordie Spark]

Must have a clutch, when they snatch up especially on the larger cores it whips around with a vengeance. We have a makita one, 3 years old? Still going strong.

Agreed!!

Don't even THINK about using the SDS for this!

1. It doesn't run fast enough.

2. It will try it's damnedest to break your wrist if it jams.

I have a Makita and it's fine, but I think if I were to buy again I may like to try Milwaukee.

 

[rattlehead85]

Must have a clutch, when they snatch up especially on the larger cores it whips around with a vengeance. We have a makita one, 3 years old? Still going strong.

May i ask what the model of your makita is and also what size core bit do i need for the 6" fan hole. I think its a 150mm bit but im a bit confused as i know to fit a window fan 6" you need to cut a 71/4" hole in the glass.

 

[Geordie Spark]

Makita UK

 

[shanky887614]

May i ask what the model of your makita is and also what size core bit do i need for the 6" fan hole. I think its a 150mm bit but im a bit confused as i know to fit a window fan 6" you need to cut a 71/4" hole in the glass.

25.1mm is one inch. so 6" is just over 150mm

 

[LankyWill]

I use one of the Milwaukee dedicated core drills and it's a tank. I've probably done 300+ with it. 4,5,6" is what's it's ideal for. It's very power and reliable. Watch your wrists though because when it catches it's like wrestling a stuck pig. I would personally buy an engineering core drill as it's quicker and less prone to jamming. The ones with the dust extraction vent on the side bite constantly. Wear ear defs and gloves because you need them

 

[Geordie Spark]

I use one of the Milwaukee dedicated core drills and it's a tank. I've probably done 300+ with it. 4,5,6" is what's it's ideal for. It's very power and reliable. Watch your wrists though because when it catches it's like wrestling a stuck pig. I would personally buy an engineering core drill as it's quicker and less prone to jamming. The ones with the dust extraction vent on the side bite constantly. Wear ear defs and gloves because you need them

I agree - and if the OP is drilling a lot of 6" holes then the Makita could be struggling a bit.

 

[sammyshooter]

Makita UK

That's the cookie.

Think it's a 152mm core you need, but seeing as your doing so many fans it wouldn't hurt to take it along with you and offer it up.

Again, looking at the amount of holes you'll be doing maybe get one with thermal overload and stuff.

 

[LankyWill]

It will happily do them. Just takes a bit longer 10minutes or so

 

[Andy78]

6" is 150mm, but you will want a bigger size core hole to fit your ducting through.

for eg, to fit a 100mm/4" fan duct I have to use a 107mm core for poly and steel flexi duct, and a 112mm at least for solid pipe ducting.

 

[shanky887614]

6" is 150mm, but you will want a bigger size core hole to fit your ducting through.

for eg, to fit a 100mm/4" fan duct I have to use a 107mm core for poly and steel flexi duct, and a 112mm at least for solid pipe ducting.

6" is 152 though (ive got a set of digital calipers to hand)

2" holesaw is 51mm so 6" is 153ish as a rough measure

 

[rattlehead85]

I use one of the Milwaukee dedicated core drills and it's a tank. I've probably done 300+ with it. 4,5,6" is what's it's ideal for. It's very power and reliable. Watch your wrists though because when it catches it's like wrestling a stuck pig. I would personally buy an engineering core drill as it's quicker and less prone to jamming. The ones with the dust extraction vent on the side bite constantly. Wear ear defs and gloves because you need them

Milwaukee model you use?

 

[LankyWill]

DD2-160xe2 it designed for dry diamond cores

 

[LankyWill]

I've used the makita one also and it just hasn't got the guts for it. It's too weak and spins at too low an rpm. The design is also weak