Author Topic: Drilling concrete [solved]  (Read 7894 times)

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Offline ivan747

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Drilling concrete [solved]
« on: June 13, 2012, 07:28:19 pm »
This forum needs an offtopic section.

Hello, guys. It's been a while. I have been making my lab and I now need to drill some holes on my concrete wall. The problem is, once I pass a certain point (~1cm) it becomes incredibly hard to drill anything. I have tried putting pressure, I am using a big hammer drill and a ~5mm concrete bit.

I believe that at this point I am reaching a different layer of concrete, probably the bricks. In a different room with a different (bigger) bit we discovered that the bricks are hollow, except when they have with steel rods going trough the bricks.
So, what am I doing wrong?

Thanks,
Ivan
« Last Edit: June 13, 2012, 08:06:39 pm by ivan747 »
 

Offline DavidDLC

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Re: Drilling concrete
« Reply #1 on: June 13, 2012, 07:47:40 pm »
I can give you one recommendation that has worked for me.

Get a nail for concrete ( big enough ) and hammer the concrete with the nail several times in different points, and then try to drill. This method has worked for me when dealing with the same difficulty you are facing.

David.

 

Offline Kilroy

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Re: Drilling concrete
« Reply #2 on: June 13, 2012, 07:56:54 pm »
You should have zero probs, unless...


...you're not using a concrete bit

...your bit is wrecked

...you've hit the reinforcing bar

...you've hit a (really) badass hard stone



Usually, drilling concrete is easier than brushing your teeth.
The fool generalizes the particular; the nerd particularizes the general; some do both; and the wise does neither.
 

Offline ivan747

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Re: Drilling concrete
« Reply #3 on: June 13, 2012, 08:04:57 pm »
You nailed it! It works perfectly. Used a worn bit as a chisel and I was able to drill until I reached the hollow part of the bricks. Thank you very much.
 

Offline ivan747

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Re: Drilling concrete
« Reply #4 on: June 13, 2012, 08:06:22 pm »
...you've hit the reinforcing bar

...you've hit a (really) badass hard stone

Usually, drilling concrete is easier than brushing your teeth.

Yes, thats why I wondered why I was having so much trouble when I had (borrowed) pro tools.

How often does one hit a reinforcing bar?
 

Offline G7PSK

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Re: Drilling concrete [solved]
« Reply #5 on: June 13, 2012, 08:23:02 pm »
From many years experience in putting holes in concrete it is next best thin to useless using an impact drill what is required is an SDS type elctro-pneumatic drill. Something along the lines of this one, will go through concrete like a hot knife through butter.

  http://www.screwfix.com/p/dewalt-d25013n-lx-2kg-sds-plus-hammer-drill-110v/62531
 

Offline ivan747

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Re: Drilling concrete [solved]
« Reply #6 on: June 13, 2012, 08:52:47 pm »
From many years experience in putting holes in concrete it is next best thin to useless using an impact drill what is required is an SDS type elctro-pneumatic drill. Something along the lines of this one, will go through concrete like a hot knife through butter.

  http://www.screwfix.com/p/dewalt-d25013n-lx-2kg-sds-plus-hammer-drill-110v/62531

I borrowed this:
http://www.screwfix.com/p/bosch-gbh2-20d-2kg-sds-plus-hammer-drill-110v/89385
 

Offline Kilroy

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Re: Drilling concrete
« Reply #7 on: June 13, 2012, 08:54:00 pm »
Quote from: ivan747
How often does one hit a reinforcing bar?

Statistically remote...but it happens from time to time.
The fool generalizes the particular; the nerd particularizes the general; some do both; and the wise does neither.
 

Offline T4P

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Re: Drilling concrete [solved]
« Reply #8 on: June 13, 2012, 09:03:49 pm »
They are pretty cheap for a bosch! Sadly the same exact model here costs 2000$ so no, i'll try out the 68$ cheapie from E14
 

Offline Monkeh

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Re: Drilling concrete [solved]
« Reply #9 on: June 14, 2012, 12:13:28 am »
From many years experience in putting holes in concrete it is next best thin to useless using an impact drill what is required is an SDS type elctro-pneumatic drill. Something along the lines of this one, will go through concrete like a hot knife through butter.

  http://www.screwfix.com/p/dewalt-d25013n-lx-2kg-sds-plus-hammer-drill-110v/62531

I borrowed this:
http://www.screwfix.com/p/bosch-gbh2-20d-2kg-sds-plus-hammer-drill-110v/89385

Then you shouldn't have had any issues at all. For future reference, make sure the chuck is lubricated. Silicone grease on the end of the bit will do the job. They do not work properly dry, they overheat and expand and you end up bleeding most of the impact energy off in friction in the chuck.

And don't lean into them. SDS drills require a light touch.
 

Offline SeanB

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Re: Drilling concrete [solved]
« Reply #10 on: June 14, 2012, 05:00:07 am »
Correct, a SDS drill generally can drill down with only it's own mass providing force. I find the Bosch SDS bits are the best in the cheap range, provided that you replace them when worn, though I have drilled holes with a bit that broke the tip off after hitting a granite stone chip. Light pressure is all you need, if the drill slows down pull the bit out to remove dust and carry on.

The common sizes I use are 6mm, 10mm, 12mmx300, 20mmx250 and a 65mm core bit. Generally the bigger sizes take longer, I often drill a 6mm hole so fast I have to be careful not to drill too deep.
 

Offline T4P

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Re: Drilling concrete [solved]
« Reply #11 on: June 14, 2012, 05:04:15 am »
Correct, a SDS drill generally can drill down with only it's own mass providing force. I find the Bosch SDS bits are the best in the cheap range, provided that you replace them when worn, though I have drilled holes with a bit that broke the tip off after hitting a granite stone chip. Light pressure is all you need, if the drill slows down pull the bit out to remove dust and carry on.

The common sizes I use are 6mm, 10mm, 12mmx300, 20mmx250 and a 65mm core bit. Generally the bigger sizes take longer, I often drill a 6mm hole so fast I have to be careful not to drill too deep.

Thanks for the info!  :D
 

Online senso

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Re: Drilling concrete [solved]
« Reply #12 on: June 14, 2012, 06:25:04 am »
All the said above and, use branded drills and no cheapish ones..
I have a DeWallt drill, a 1000 and something watts version that costed about 250€ 6 or 7 years ago, and the DeWalt concrete drill bits (SDS system) will drill anything, even the typical rebars used at houses will be obliterated by their awesome drill bits.
 

Offline T4P

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Re: Drilling concrete [solved]
« Reply #13 on: June 14, 2012, 08:44:26 am »
But you know man, DeWalt is no better then a cheapie nowadays, especially when DeWalt is now under B&D
 

Offline G7PSK

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Re: Drilling concrete [solved]
« Reply #14 on: June 14, 2012, 08:49:34 am »
I have found that the cheap SDS kits sold by Screwfix work well for most things.

http://www.screwfix.com/p/erbauer-sds-chisel-bits-set-12pcs/81229
 

Offline G7PSK

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Re: Drilling concrete [solved]
« Reply #15 on: June 14, 2012, 08:58:35 am »
But you know man, DeWalt is no better then a cheapie nowadays, especially when DeWalt is now under B&D

Bosh have gone downhill in recent years as well and dont last like they used to ten years ago, the power tools on the market at present are Metabo and Milwaukee.
 

Offline T4P

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Re: Drilling concrete [solved]
« Reply #16 on: June 14, 2012, 09:45:04 am »
But you know man, DeWalt is no better then a cheapie nowadays, especially when DeWalt is now under B&D

Bosh have gone downhill in recent years as well and dont last like they used to ten years ago, the power tools on the market at present are Metabo and Milwaukee.

And Hilti
 

Offline G7PSK

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Re: Drilling concrete [solved]
« Reply #17 on: June 14, 2012, 10:29:29 am »
But you know man, DeWalt is no better then a cheapie nowadays, especially when DeWalt is now under B&D

Bosh have gone downhill in recent years as well and dont last like they used to ten years ago, the power tools on the market at present are Metabo and Milwaukee.

And Hilti
Yes Hilti are most likely the best available but unless you have an industrial quantity of holes to drill You cant warrant the cost of them.
 

Offline Monkeh

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Re: Drilling concrete [solved]
« Reply #18 on: June 14, 2012, 02:06:59 pm »
But you know man, DeWalt is no better then a cheapie nowadays, especially when DeWalt is now under B&D

Where do people get this crap from..

B&D have owned Dewalt since 1960. Dewalt didn't even produce hand held tools until the early 90s, they were a stationary woodworking company.
 

Offline SeanB

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Re: Drilling concrete [solved]
« Reply #19 on: June 14, 2012, 03:35:41 pm »
The Bosch at least have a stepped carbide tip, which reduces the chances of the bit skipping when starting a hole, as well as the flute really removes dust fast. I have tried some cheap bits, but they are only good for when I need an odd size ( 25mm every so often so the Bosch was not a good buy on a price per hole basis) or where I know I will hit rebar and have a good chance of breaking a bit.

I rented a Hitachi SDS Plus once to core a floor, with a true diamond coring bit. Nicked a 12mm rebar near the bottom, but it cut through half of it with no problem. Did take 4 hours to drill 2 holes though, 400mm well cured high strength properly mixed concrete that had had 40 years to cure up in strength.
 

Offline G7PSK

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Re: Drilling concrete [solved]
« Reply #20 on: June 14, 2012, 03:35:57 pm »
DeWalt became B&D's route to escape from the crap quality badge and at first they were better than the B&D branded products but over the years the quality of DeWalt has dropped along with others in the same market like Bosch. For a short time in the early 1970's i worked for a company that had a retail tool side to it, The B&D rep told me that they sold multiple quality levels of their power drills and the run time of the motors was rated in minuets not hours different outlets would be supplied with different  run time units Woolworths had the lowest rated ones as they sold the cheapest drills at that time (the orange triangular cardboard boxed ones) the life of the motors in those was 15 minuets or less the ones that the company that I was working for and sold to a slightly higher grade of DIY'ers had a motor life of about 90 minuets but they were retailing for about £15-00 to £20-00 instead of the £5-00 t0 £7-50 range that Woolworths had. We often got people coming into the shop to look at power tools (which at that time meant drills and attachments)  to have their use and features explained they would then trot of to Woolworths and buy the cheap unit and when it burn out would come to us and try to claim that they had purchased it from us, however hard they tried they could not get away with it as the serial and type numbers were always wrong.In the mid 80's to late 90's B&D had an industrial tool division which did make some good products in Italy I had a 9 inch grinder that fell over 30 feet onto hard ground it cracked the gearbox but was still usable it was not binned until about 2 years ago I also still have a B&D electric shear for 2.5mm steel that dates from 97 Bosch ones I have bought since then have long passed away. But now in general I would say that not many in the trades would rate DeWalt the best they get used a lot as they are cheap and very often the DIY tools are getting used by tradesmen But in true industrial situations they are rarely seen.
 

Offline T4P

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Re: Drilling concrete [solved]
« Reply #21 on: June 14, 2012, 04:01:11 pm »
DeWalt's and B&D quality is so slipshod, the OEM cheapies work better ...

I saw the 9.6V B&D drill the other day at a hypermarket i instantly recognized the motor, it was a bog standard 12V motor you find in car air pumps  :o
 


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