Core drills

[David Hearn]

I want to put a clean hole through a cavity wall which has render on the outside (and tiles on the inside!) for a tumble drier outlet as having the window open whilst drying is making the kitchen very cold at this time of year.

I guess a core drill would be the way to go (as opposed to drilling, chipping out bits of brick manually). I've a basic 500w mains drill which I think may not be enough for this sort of thing (or am I wrong). Also, the cost of the core drills are quite expensive. So - I thought about hiring one. Quick look on HSS's website says £38 + VAT for a day's hire (or £47.50

• VAT for a weekend). This seems quite expensive for what should (hopefully) be less than 30 minutes use.

So - any other suggestions/ideas? Anywhere I may hire this cheaper from? Are there cheap core drills out there which I may be able to use my 500w drill to do just one single job and then throw (the core drill) away?

Is it possible to make a neat hole through render for this purpose without using a core drill? I'm happy to do it manually just drilling and chipping away at bricks - but I don't want to damage the render by doing this.

Thanks

D

[David Hearn]

BTW - the £38 + VAT is for a core drill and the drill itself - not just the core drill bit. Erm... maybe I've got my terms muddled. Drills are what you put bits into - so I guess I mean drill and core bit is £38 + VAT.

D

[Christian McArdle]

I wouldn't try it with a standard drill. You need an SDS at a minimum, preferably a powerful one. Screwfix do a "light duty" range of core drills suitable for entry level SDS drills.

My solution to this problem is to only buy condensing dryers. Then they can be moved into whatever position you like, and you don't have to drill unsightly holes in the wall.

Christian.

[RichardS]

If you have any local independent hire shops then give them a call.

My local pretty much always beats HSS prices (they were set up by disgruntled ex-HSS'ers, as I suspect a few of these outlets are).

When I drilled a couple of 6" holes through the wall I used a TCT core bit and their Hilti TE24 drill - cost was something like £10 for the drill, £3 for the transformer and £4 for the core bit for the day (plus VAT).

Compared to your average percussion or SDS drill this thing is a bit of a beast. If you hire one check before leaving the shop that the front handle grips the collar securely - I had one that didn't and it almost threw me off the work surface when the bit jammed and the collar slipped.

cheers Richard

-- Richard Sampson

email me at richard at olifant d-ot co do-t uk

[Lee Blaver]

Yes, try an independent, the local one quoted me £21 inc vat for a Diamond core bit, drill, chuck extensions and pilot drill bit. There was also an addition cost per mm of wear on the diamond bit, be wary of this because most make a similar charge.

If they offer TCT core bits, they don't usually charge for wear, although they will probably still make a charge for "abuse" if you blunt it ;)

Lee

[David]

In article , David Hearn writes

Check that you need to do this, I borrowed a core drill opened the outlet kit and found...... a rectangular shaped piece that was about the size of a std house brick.

[Rick Dipper]

What I did was hire one for half a day, cuts the cost down a bit. The drill they give you weighs a fair bit, so take care choosing where to drill.

Don't forget, that once the "middle" is through, you have to go round the ther side and drill back.

Rick

[PoP]

I must be pricing myself wrong somewhere. I charge less than that to come out, supply drill and core drill, and drill the hole for customers. And I feel I make a decent profit out of doing the job to make it worthwhile.

For not a lot more I will finish the job properly with the extractor accessories (materials costs added on top).

And before someone leaps up and down shouting "oi! no advertising on this newsgroup!", I'm not advertising. I'm just putting this into context that sometimes hiring tools can be more expensive than shopping around to get someone who has the tools to come and do the job.

PoP

[Mike Harrison]

Might also be worth a word in the ear of your local friendly plumber/heating engineer. 20 quid cash for a few mins work might be appealing....

[Gnube]

engineer. 20 quid cash

!? I would imagine the OP wanted to use it THIS winter! :O)

Take Care, Gnube {too thick for linux}

[BillR]

If you want a clean breakout use a diamond corer. You could try a SDS drill with TCT bit but an SDS drill will make helluva mess of your render unless you carefully drill from each size. I can't see this being any cheaper than hiring...

I doubt a 500w normal drill is anywhere powerful enough to drill this large hole. I hired 117mm diamond corer inc dedicated Makita drill machine for £36 inc vat from a small independant hire place in SW London. I find the render I've come accross one of the hardest things to drill . A normal hammer drill was pretty hopeless even on small holes whereas SDS makes dust out of it.

[ARWadsworth]

You are not joking. I have drilled render with a 5.5mm drill on a SDS machine and had to insert a brown plasplug to make the screw fit tightly. From now on it is 4mm drill on render and I will work up to a 5.5 mm hole.

-- Adam

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[DKSanders]

£38 is nothing against the potential for an accident! I had to cut two 110mm holes through a new extension the other day. I already owned a suitable, new, diamond core drill bit but my SDS was probably going to be underpowered so I went to a local tool hire and hired a core drill for £10.

All was going well, both sides of the first hole drilled, inside of the second hole drilled, then up the ladder outside to drill the last for the second hole.

Just as it got to the point where the bricks were going to come away (when the bit will bind if it's going to), I braced myself ready, when the trigger stuck on. Pressing the release button or the trigger did nothing, it stayed on. Then the bit cut through and the bricks came away, and the bit stuck.

I was now up a ladder, it had started to rain, and I was fighting the immense torque of the core drill trying to keep it still. A losing battle which resulted in the drill twisting out of my hands, a loop of the mains cable corkscrewing around the base of my left thumb, and the side handle of the drill smashing into my right forearm.

As these things do, it flashed through my mind that I was going to lose the thumb, and that the only way out was to try and kick the lead out of the extension reel. Luckily at that point, the 1/2" dia. guide rod for the bit, sheared off (before the side handle broke my forearm) and me, drill, brick core, and ladder, fell in a heap at the bottom of the wall.

On later examination, the hired drill had not been maintained properly (ever?) and the trigger had a groove worn in it from the casing on which it had stuck.

That £10 may have been cheap but it cost me a couple of days when I couldn't work, and nearly cost me a broken arm and a lost thumb or even worse. It's £38 from HSS for me > > I want to put a clean hole through a cavity wall which has render on

[Martin Angove]

I'm new to this lark of making big holes (apart from a bit of chiselling a while back). I recently made a 50mm hole in whatever passes for breeze block in a 1930s ex-council house using a TCT core drill and a 760W drill. It happened to be an SDS machine, but I had the hammer turned off. It went through like the proverbial hot knife through butter. From reading the above, it seems as if others would do this job with the hammer turned on...

Next job will probably involve hard brick. To Hammer or Not To Hammer?

Hwyl!

M.

[ARWadsworth]

I never use the hammer action when using a core drill. Good luck with the hard brick.

-- Adam

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