Advice coring a 4" hole

[Richard]

Morning all,

I need a bit of advice. I need to core a 4" hole for a friend. I'v got the machine and the core bits, but (embbaressingly) i'v honestly never been shown how to core a hole. The firm i'm with always leaves it to the builders to sort.

Do i need to pre-drill the pilot hole first with the sds? or just use the pilot bit supplied (i think its a 10mm ish sized bit) and go straight through just using that? Thanks in advance.

Rich

 

[nickblake]

Well to honest this is how i do it get a drill bit the same size as the pilot bit in the core, long enough to drill right through the wall to the out side drill the hole through then drill from the inside to the cavity then go out side and find the pilot hole and drill from the out side in this way you'll get a nice clean cut on the out side no blown off render or brick and makes it easier to fit the cowl / vent , put in the duct fan and cowel and bobs your uncle ,HSE bit: safety googles , ear protection ,gloves and a mask is a must for this noise dust and flying brick and make sure the drill is a proper core drill not just a drill other wise you could end up with a broken wrist if the core binds and take your time dont rush or force the core it takes time especially if the brick or block is hard

 

[malcolmsanford]

Morning all,

I need a bit of advice. I need to core a 4" hole for a friend. I'v got the machine and the core bits, but (embbaressingly) i'v honestly never been shown how to core a hole. The firm i'm with always leaves it to the builders to sort.

Do i need to pre-drill the pilot hole first with the sds? or just use the pilot bit supplied (i think its a 10mm ish sized bit) and go straight through just using that? Thanks in advance.

Rich

Richard it is without doubt the worse jobs I know, I lost count of the times I've had a drill wrenched out of my hads doing this.

Nick is spot on and great if your not up 2 floors lol. All I would say is keep cleaning out the hole, to avoid the bit bitting, do it slowly and don't put trigger lock on the drill ..................

 

[nickblake]

Richard it is without doubt the worse jobs I know, I lost count of the times I've had a drill wrenched out of my hads doing this.

Nick is spot on and great if your not up 2 floors lol. All I would say is keep cleaning out the hole, to avoid the bit bitting, do it slowly and don't put trigger lock on the drill ..................

opps never thought of that lol , if thats the case then you'll need a scaffold or cherry picker wouldnt recommend you do this sort of work off a ladder !!! if you use a core drill it has a slipping clutch so if it does bind in doesnt break or wrench you wrist can be a pain but as malcom has said clean out the hole and you should be ok

 

[Richard]

Nice one cheers boys.

Luckily i'v got access to a proper core drill, but unfortuantly it is on the 1st floor.

Thanks again

Rich

 

[Short Circuit]

Nick, just another pointer mate, not sure what core drill you have, but once you get the hole started (the 4 inch one), take out the pilot from inside the core bit!

Also the advice about the drill type is good - i still have problems with my hand after breaking it about 6 yrs ago drilling a 4" hole with a drill that did didnt have a clutch on!

 

[nickblake]

Gad Damit you guys are just to good lol , the core drill i have is the cheapest mother you can get lol 4 " from screw fix eurbour i think set of 4 for £75.00 been dam good cant get the bit out of that one also got a set from JCB drill bit keeps falling out of that one lol , ill keep the removing drill bit in mind thanks short circuit the drill i have is a blue one havent a clue what make it is it just blue and cost a fortune lol

 

[robsparky1975]

its a dusty horrible job,but we dont have to do it very often thankfully,just let the core bit cut steadily,dont force pressure on it,if i didnt have scaffold up,i would drill from the inside out as would not be happy holding a big heavy core drill off a ladder,a lot of dust i know but safer.

 

[markharris]

If your using an SDS drill with it, have it on normal drill setting and not hammer drill, and every time you stop, when starting again have the drill rotating before you push it onto the surface being drilled or you'll get thrown like a rag doll!!!

 

[sjm]

Just a quick mention about High Rise Ducting Kits. These are designed to be fitted from inside without the need for a ladder/scaffold to fit the vent.
Core drilling can be a horrible job, recently spent the best part of 4 hrs drilling through 20 inches of granite wall, so good luck.

 

[nickblake]

Just a quick mention about High Rise Ducting Kits. These are designed to be fitted from inside without the need for a ladder/scaffold to fit the vent.
Core drilling can be a horrible job, recently spent the best part of 4 hrs drilling through 20 inches of granite wall, so good luck.

lol welcome to my world living in wales there are lots of stone walls to drill through , like the idea of high rise ducting kits sounds good sjm ,zatisgoodya if your using a standard SDS drill you must be mad , its so easy to break a bone ie wrist for the cost of a core drill or hiring one will be a hell of alot less than what it will cost you for loss of earnings due to a broken arm or wrist

 

[mayfair]

Agree with all the above best advice is be careful still nursing 2 very sore fingers from sds .........I did it last July! still sore everytime i do crimping .Not got an apprentice to do it, LOL

 

[sythai]

but once you get the hole started (the 4 inch one), take out the pilot from inside the core bit!

Good tip..... lost a couple of bits down the cavity this way