Drilling big holes

[TimO]

I'm going to need to drill a hole, around 100mm in diameter, for a tumble dryer vent.  Can I do this by fitting one of these to a bog standard drill:

Turbolite Dry Diamond Core Drill

or

Performance Power Holesaw

...or should I hire a set of Diamond Drill kit from HSS for a day?

Clearly the HSS drill is a chunkier beast, but the Core Drills/Holesaws are cheaper, and I could use them again if necessary, plus I don't have to rely on HSS, and returning the kit on time etc.

Both of the bits above imply in their descriptions that they can go through brickwork, but clearly the teeth are quite different.  Is a holesaw going to work, or am I better off with the Diamond Core Drill?  I suspect the latter, simply because it can cut a hole to a deeper depth.

Obviously I'll also need to buy a suitable Mandrel etc.

[tiermat]

How thick is the wall you need to drill through?

What is it made of?

Can you get a handyman to do it??? (It would only take someone with the right kit about 10-15 to do the job on a double skinned wall, so the charge would only be about a tenner, much cheaper than buying the kit, unless of course you plan on making a buisness out of drilling big holes in walls!!)

[TimO]

I haven't actually measured the wall thickness yet (it'll take a bit of effort, given where it is), but I think it's just a single layer brick wall (sort of a lean too utility room on the back of the kitchen).

A handyman sounds like a plausible idea, except in and around London, finding a reliable bod to do such things can be interesting!

[Chris S]

When I did this, I hired a drill and core drill set.

A 100mm core drill requires something with a bit of wellie behind it; my own Bosch power drill was a bit weedy - hence I hired one.

Hard work too - and even harder to get the very slightly downward slope toward the outside to ensure condensate runs out of the house, not into.

Great fun for a Saturday afternoon though  .

Edit: BTW - they are f*cking loud 

[rogerzilla]

When I did it I drilled a ring of holes with an 8mm masonry bit and then attacked it with a 4lb club hammer and a cold chisel.  I needed a BIG hole though.

[rae]

A High Speed Steel (HSS) hole saw will blunt in seconds when used on brick.  Try running an HSS (metal) drill on a piece of brick and see how far it gets.  

You need a proper core drill, mandrel and something with the chuff to turn it.  Any drill over about 700W will turn one of these as long as you are careful.   One thing to think about - you want a drill with a clutch that disengages if the core gets stuck.  If you don't have a clutch, then the drill will come straight out of your hands if the core binds, which will probably hurt rather a lot.   Of course, you can be careful and not let the core bind - your call.  

The local hire shop should be able to help out.  

Edit: BTW - they are f*cking loud   

And make a lot of mess.

[urban_biker]

Ok - this is how you do it.

Buy a good quality masonary drill long enough to pass through the inner and outer wall. You will also need a fairly tough hammer drill.

Draw a 100mm circle on the inside wall where you want the hole. At every 10 mm around that circle drill a hole out through both walls.

Drill multiple further holes within the circle so that there is very little brick left. Now hammer out the remaining  interior of the circle with a masonary chisel and bolster hammer.

You may have to tidy up the edges of your hole with the hammer and chisel to get the pipe through.

When you put the tumble dryer tube through the hole, seal any gaps around the edges using mortar or you could use expanding foam.

Job Done.

[rogerzilla]

It took me 2 hours from start to finish and ruined the first masonry bit I used, but it was a bigger hole (for a meaty cooker hood vent) and I had to work up a ladder.

Worth it though - our kitchen never, ever steams up when cooking, nor does it fill with a nasty blue haze when doing a stir-fry.

[Chris S]

Blimey u_b - that's a lot of holes. I'd imagine one big 'ole is easier than many smaller ones.

Of course all this went to hell when I came to drill the next one in the kitchen - only to find the wall was flint  .

[urban_biker]

It took me 2 hours from start to finish and ruined the first masonry bit I used, but it was a bigger hole (for a meaty cooker hood vent) and I had to work up a ladder.

Worth it though - our kitchen never, ever steams up when cooking, nor does it fill with a nasty blue haze when doing a stir-fry.

I have one to do this summer. Recently bought a new house (1990's) with original extractor/filter hood fan mounted on an outside wall. Guess what - they even hadn't bothered to drill through the wall! Crazy in a house with concrete floors and modern insulation. Winter cooking means that way too much moisture is let loose in the house. It will be fixed using the above method  - another item on my DIY list

[urban_biker]

Blimey u_b - that's a lot of holes. I'd imagine one big 'ole is easier than many smaller ones.

Of course all this went to hell when I came to drill the next one in the kitchen - only to find the wall was flint  .

Surprisingly enough drilling one small hole through a double skinned wall with a good masonary bit and a hammer drill takes seconds.

Unless you have flint walls of course!   

[mrcharly-YHT]

I'm with RZ and U_B on this one.

I've seen the big core drills shatter bricks - so there ended up being an untidy mess anyway. Lots of small holes is easier.

One caveat; you need to draw the circle on both sides of the wall, and keep checking your angle. Otherwise you could end up with a large-enough hole on one side, and too small at the other . . . .

The other way to do this is to just take a brick out. Chisel out all the mortar, and smash out the brick. Put the flue pipe in (at suitable angle), with 1/4 bricks either side, then point with mortar. 

[nuttycyclist]

When the guy put our extractor fan in in the kitchen it took him about a minute to drill a large bore hole through both skins of the kitchen.

I then had a large circular block, with central hole, to try to work out whether to turn into a garden feature of some sort.



A diamond hole cutter seems a hell of a lot easier than any of the above methods.   He just put it in the end of his cordless electric drill.  And there was no mess either.

[FatBloke]

Obviously I'll also need to buy a suitable Mandrel etc.

 

[urban_biker]

Yep - its easier and its quicker. But you have to be doing it every day for that kind of equipment to be worth owning and hiring also costs you. You probably need to hire an SDS drill as well as a diamond cutter.

I have a standard electric hammer drill hanging around my house, and a hammer and chisel too. I could probably pay £50 or more to hire something but why bother?

I also kind of like fettling things myself   

[TimO]

rae comments about a clutch was relevant, since I'm pretty sure that my drill doesn't have any sort of clutch like that.  With those cutters, it's pretty much a given that they are going to stick along the way, if only a bit, and it's going to damn well hurt!

I suspect I'll do the lots of little holes approach, since I've got all that I need already.  I may need to do this again, since I've got a cunning plan to run a vent in for the cooker hood, but I still think it's not worth buying more expensive kit, since this would probably have to include a new drill!

[Tim Hall]

Go for the HSS Diamond Drill.  It's not that noisy (it's not a hammer drill, like a Kango) and it won't bust bricks.   And the kit comes complete with a powerful enough drill.

44 quid a day plus VAT. YKIMS.

[David Martin]

I have done this kind of job.

I have an SDS+ drill. I have biggish masonry bits with which I could have bodged the hole.

I hired the right kit. Cost not very much and took very little time. It will be quicker to go down the hire shop, pick up the kit, drill the two holes (pilot and large) and return it than it will be to faff around with drilling lots of holes and trying to make the job neat afterwards.

Unless you really like to be drilling holes in the wall.

Personally I'd rather spend the extra time riding the bike.

..d