Core Bit

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ElectricianJeff

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Southern Illinois
I moved a 200 amp. service entrance yesterday. I needed to drill a 2.75" hole through a brick wall into a basement for this service. My set up was my standard hammer drill and a core bit I bought new on ebay from a guy that makes them in various sizes and had lots of good feedback. I figured the hole would take about 30 mins. to complete but I ended working on it for well over an hour and began to wonder if I would ever make it. Took everything I had to get it through.

I will be doing more of these and was wondering what others used for this task and if there were any tips and tricks to doing this. I used a combination of drilling and hammer and chiseling to get it through. I don't want to spend big bucks on something I might use 3-4 times a year but theres got to be a better way. Or did I just luck out and find the hardest brick known to mankind on my first attempt at this?

Any suggestions short of dynamite would be greatly appreciated.

Jeff
 
I hope you weren't using a wood bit. :grin:

Seriously-- I hope you weren't using a wood bit.:grin:

Okay enough-- I use a bosch hammer drill with a core bit and can drill solid concrete 12 inches thick in less than 15 minutes-- unless I hit rebar. Sounds like a weak drill-- what do you mean by a standard hammer drill.

This is what I use with a 2 9/16" core bit
BOS_11248EVS.jpg
 
"I don't want to spend big bucks on something I might use 3-4 times a year"

Time is money, your not spending, when your in business, your investing.
 
Need a strong drill, water to cool the bit!!!and a good core bit. I have tryed all the aftermarket (no name brand bits) and they are just not good, they dull fast and dont seem to cut very well. spend the extra $ on a good bit, it will do a better job, faster, and last longer.

Make sure you cool it while drilling!!

Joe
 
Rent the drill and bit. Or you could buy one and rent it out to your buddies when they ask to use it
 
Dennis Alwon said:
I use a bosch hammer drill . . .
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No, you use a Bosch rotary hammer. A large hammer drill is fairly useless for much over 1/2" carbide bits; a smaller one tops out at 1/4".
 
LarryFine said:
No, you use a Bosch rotary hammer. A large hammer drill is fairly useless for much over 1/2" carbide bits; a smaller one tops out at 1/4".
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I am glad you know what I use, cause I sure as heck didn't. My bad
 
wet core

wet core

Buy a wet core setup on ebay Hilti makes a good wet core drill I have seen them go thru for under 500 bucks if you are patient. Bits go fo about a hundred bucks per inch.
 
Those eBay core bits from "Hamilton Core Bits" are the biggest pieces of crap I've ever used. I bought a 4-3/8" and a 2", and ruined the big one on the first use, and all but two teeth fell out of the 2" after maybe a half-dozen uses. I've resolved to continue to just buy the regular Milwaukee and Hilti core bits.
 
The original poster did mention brick, and though I do not get to succumb to the madness of drilling bricks often, I do notice that some of the red bricks are pretty easy, while some are extremely tough on drill bits. I once burned up 4 tapcon bits for about a dozen two hole pvc staps on red bricks. Is there different grades of red clay bricks or is it a hit and miss thing?
 
Some of the old soft red brick you could thread a drywall screw into. Some of the more modern stuff is hard as ceramic, and you will burn up bits. Depends on how long and how hot it was fired at, I suppose. I wonder if the OP got into some of this super hard more modern brick? Possibly.
 
quogueelectric said:
Bits go fo about a hundred bucks per inch.
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I sure hope that's diameter and not depth of hole! :grin:


One piece of advice: I've never seen a sharp masonry bit that cuts any faster with excess pressure. Be patient and let the hammering do the work.

Sometimes I see my guys bearing down or even pushing and letting up repeatedly. I ask them, "What's the hurry; you have somewhere else to go?"
 
LarryFine said:
I sure hope that's diameter and not depth of hole! :grin:


One piece of advice: I've never seen a sharp masonry bit that cuts any faster with excess pressure. Be patient and let the hammering do the work.

Sometimes I see my guys bearing down or even pushing and letting up repeatedly. I ask them, "What's the hurry; you have somewhere else to go?"
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Ummm, I've never seen a wet core drill that hammers. Is there such a puppy?
 
Smart $ said:
Ummm, I've never seen a wet core drill that hammers. Is there such a puppy?
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Okay, no. That's not what I meant. You got me. Fine. You happy now?

Just kidding.

I was referring to percussion core drilling, as I thought everyone was.
 
Embarrassing story about holes.

Embarrassing story about holes.

While back, I needed to drill a bunch of 1 1/2" holes on solid concrete block... And it was suggested to me by a guy I see around alot that there is a dry diamond grinder attachment that you can get, and he told me where to get it. (A tool store not far from the supply house that I frequent) And that you hook this up to the grinder, and guide it to the hole with a GLOVED HAND..... "Been doing it for a few years now" he says. I said - "No way!" But curious, and the tool shop is only two doors down I went to check it out and asked the salesman about it. (Normally a very helpfull tool guy.) He says, "Oh I sell lots of those..." and decribes a 5/8" grinder and this "Gloved hand" thing again. 1800+ RPM and you hold this in your hand I ask, "Yep, well not tightly..."

Well, I either didn't have my full dose of coffee, or cigs or was low on blood suger... I bought one, went to the job pulled out a leather glove, put this thing on my grinder, started it up and laid my hand against the side of the core saw, started the initial kerf, and went about making 10 holes. It worked great - fast - clean....

Sometime after lunch, I kept say to myself that just can not be right - so I called the company that makes it, and asked about this "Gloved hand" thing. Turns out - "Hand held drill" - And "Wear gloves when handling the bit, as it will get rather hot". Can you use it with a grinder - "Oh no, thats probhably a bad idea" not variable speed, or has a clutch. I have since corrected my buddy, and the tool guy about this!!!! Both were very embarrassed about it, and so was I for doing it too... But have since found a better tool for it - much safer and works like a dream. A dry diamond core, variable speed SDS hammer drill on the no hammer setting, with a clutch, and one of these, and yes a gloved hand.
 
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My daughters 21st B'day was yesterday and I spent yesterday afternoon and evening teaching her how to drink :rolleyes: so I got away from this thread for awhile. Wow, 17 responses you guys are awesome.

To answer a few of the questions:

Yes, it was brick....this house was about 30 years old....it wasn't the soft brick but the real hard stuff. Just a band board behind the brick which I drilled from the inside.

I used my Black & Decker hammer drill and the "Hamilton Core Bit" that I bought for this job. Guess thats part of where I went wrong.

I guess the bottom line is I need to invest in a rotary hammer drill and better bit set. It appears the wet type bit is the way to go. I will rent when needed until the right deal comes along.

Thanks again to everyone that responded.

Jeff
 
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