Core drilling in concrete

[47chevycoupe]

I need to drill 18, 3" holes in my 6" thick concrete floor. This is to install anchor pots. I was told the holes need to go all the way through the floor. How is the best way to do it? How do I go through 6" of concrete with a bit that's only about 2" deep?

Have asked locally and to hire someone to do it will be about $50 a hole plus travel time. Went to my local tool rental store and they do not have a bit that size. He recommended me to buy a Harbor Freight drill and buy the bit online.

 

[Kaizen]

depends how nice the holes need to be. you can use a basic hammer drill with a good masonary bit and drill holes at north south east west points of the circle then continue until you mostly connect. give it a wack with a sledge and see if that pops it free. i'd probably go bigger then 3 inches a little if you need to get something 3 inches in the hole

 

[sabercatt]

you need an 8" long bit. i put 9 pots in my floor for my dyno. borrowed large drill w/water attachment that bolted to the floor (or pushed against the ceiling), but i just stood on it and took my time. 9 holes, with one guy drilling and one guy with a mop took 4 hours or so. i used these post: http://www.autobodytoolmart.com/champ-floor-anchor-pot-1600-p-11538.aspx .They work great. I used them to straighten bumpers, frames, etc as well. They fit my holes perfectly and look great. I tensioned some of them with a forklift pulling up and a couple with a floor jack.

 

[gearhead1]

Also interested to see the replies. My pots didn't arrive in time for the pour and I will be doing the same thing, unfortunately.

 

[JCQuick]

I have installed hundreds of anchors pots #1 are you sure about the 3" all the ones I installed were 4"
The drill rig we had used a 4" diamond bit that was about 18" long and the reason for drilling thru the concrete is so that dirt and water will fall thru and not rust the chain out

 

[rburke65]

Ya might want to try a larger rental company. There has to be someone renting a hammer drill and a core bit!.

 

[sabercatt]

the ones i listed are 3.5". also, i would rather drill them in then pour around them.

 

[gregtwojeeps]

Rent it !!!!!!!!


.https://www.sunbeltrentals.com/equipment/detail/930/0320730/core-drill-rig-20-amp-2-speed/

 

[Jackfre]

You do this with a hammer drill and walk around a circle with a small bit and you will not believe how cheap $50/hole is. This is a job for a base mounted core drill. Far safer and faster.

 

[Radix2]

I just made 7 - 3in core drilled holes through 7 to 12 inch thick 60 year old reinforced concrete. It was much easier than I thought it might be. Bought the core drill from Amazon for about $60 and the drill adapter for another $15. Used a standard heavy duty 1/2 drill and simply stood on a board with a 3in hole in it as a starting guide. Wife sprayed water with a pump sprayer. Easy peasy.

The 12 in deep hole was through a side wall, and I did it laying down under a overhang. Made a 1/4 hole first, screwed the guide on the wall, wife sprayed water in the hole from the inside, drilled though in about 15min.

I thought a rig, ect was needed - nope

And the core drill still looks like new, even after cutting rebar in a few of the holes.

Here is the drill I used -http://www.amazon.com/gp/product/B00LQKTX74?psc=1&redirect=true&ref_=oh_aui_detailpage_o05_s00

 

[Jon_E]

I cored a 5" hole through my basement wall with a Bosch SDS-Max hammer drill and a 5" bit I bought on eBay. Trick is to drill in to the maximum depth of the coring bit, and then switch to a chisel and break the concrete core out of the hole. Then switch back and drill again. It took me less than half an hour to drill one hole completely through an 8" reinforced wall, and I was able to sell the bit again on eBay as a used bit. 3" holes are easier because the core is smaller diameter and thus will break off easier. Also drilled the hole dry, but a water spray would aid in dust control.

 

[strutaeng]

I was at jobsite a few months ago where they were going to take about 8-10 cores 4" in diameter. The coring guy did not specialize doing this and did not think bolting his rig to the slab was necessary...after spending a few hours he had only cored 2 holes. The next day they had a real coring guy and finished the job in about 4 hours.

Long story short: hire the pro!

 

[Radix2]

I was at jobsite a few months ago where they were going to take about 8-10 cores 4" in diameter. The coring guy did not specialize doing this and did not think bolting his rig to the slab was necessary...after spending a few hours he had only cored 2 holes. The next day they had a real coring guy and finished the job in about 4 hours.

Long story short: hire the pro!

At some diameter and if using a powerful drill it certainly becomes an issue - for a 3 in ? After doing it, I can't see it.

Don't be a fool and use a great big hole hawg that is going to break your arm if it jams though...

And make sure it is a bit for concrete and hard stones not one of those bits for soft blocks and brick.

 

[Rookie2]

You may be able to work out a deal with a plumber, larger companies have them.
Milwaukee makes one with a vacuum base attachment that reduces the operators work to a fraction.
https://www.milwaukeetool.com/power-tools/corded/4115-22
This company at one time would rent or repair the core bits. pittindustrialdiamond.com

 

[Vt_k9]

I used the pots from www.autobodytoolmart.com and placed them during the pour. I only put in 6 as I am not planning on frame machine, but wanted to be able to pull or secure an item to the floor. If I were doing it to a specific pattern I would drill and install after the concrete us cured.

As far as running a drill...its pretty simple. I have done it on 2 occassions. The first on I bolted the rail system to the wall and it was slick. A couple months back I drilled 2 holes in 8 inch concrete wall. I drilled from the outside to cut down on water on the inside of the basement and used the 2" insulation to help keep the bit on track while it started into the concrete. It went pretty smooth. I would use the mount secured to the floor for the most accurate results.

Good luck,

Mike

 

[BFBOB]

ROTARY HAMMER. It is NOT a hammer drill. I drill 2" holes with some regularity with my 1" rated Milwaukee SDS Plus rotary hammer. The Milwaukee core drill I use goes about 2" deep. Then, break out the core with a chisel, wedge, small prybar, whatever - and keep drilling. No great pressure is needed, not much more than the weight of the tool; the hammering action does all the work. No water needed.
No problem with jamming the bit. Torque is very low compared to a HD drill (think Hole Hawg), because it just isn't needed. The hammering action does all the work. There's a clutch that limits the torque very much like a screw gun. You'd have to be really working at it to get hurt by a grabby bit. The hammering does the work.

 

[willymakeit]

Rent one with a vacuum base. You wont have bolt it to floor. Needs a smooth surface and plenty of water.

 

[crf731]

Rent one of these or something similar

 

[wssix99]

All the Home Depots in my area rent these rotary hammers. I just rented one and recall the tool and bit was around $100 for 4 hours.

It's a PITA. Given the cost of the rental, $50 a hole is a great deal.

 

[wnstwolf]

I have contractors boring holes all the time doing work at the various hospitals I have been at. The tool has always been more like a portable drill press with water set up not a hammer drill for the larger diameter holes. Not sure if you can rent them but if you can it looks like a big hole saw bit with long share to get you through thick slab. I have seen 6" hole in 8" slab cut in about 5 mins.

 

[matt_i]

In my opinion, you have to get the core drill rig if you are putting in frame pulling pots. The pots need a smooth hole the diamond tips will make, not a jagged mess from chain drilling and chipping.

 

[JCQuick]

the ones i listed are 3.5". also, i would rather drill them in then pour around them.

That's it I knew it was bigger than 3" dam old brain of mine.
Like others have said rent a rig or pay some one to do it. It ain't easy work

 

[mygarageone]

We have drilled hundreds of holes for plumbing systems , all threw pre stressed concrete.
A core drill is the only way to do this , with out wearing you out in the process.
A hammer drill with a drill bit will do nothing but wear you out period.
And core drill bits are plenty long enough to drill your concrete all the way threw.

 

[DonPowers]

Rent a Hilti Core Drill. Have used them to cut countless holes in concrete.

https://www.us.hilti.com/diamond-coring-&-sawing/diamond-drilling-tools/r3081

 

[JCQuick]

Rent a Hilti Core Drill. Have used them to cut countless holes in concrete.

https://www.us.hilti.com/diamond-coring-&-sawing/diamond-drilling-tools/r3081

yep that's like what I use to use. and then I used a tool like this to set them

http://protools.ws/Frame Equipment/Floor Pots/pict0010.jpg

 

[ShakinLM7]

I've drilled many a hole through concrete and all the advice I could think to offer has already been mentioned.
The base on the large core drills does not need to be fastened when drilling vertical holes (unless your working several stories up and you're close to an edge with nothing between you and the ground but air) The mounting system is mainly used for horizontal holes (drilling through walls / etc) Most drills will tilt forward but thats not a problem once you get it where you want it, let that weight a little pressure on the depth adjustment lever do the work for you.

Its not a fun job but anyone with half a brain in "OK" physical shape can do it. Hardest part is dragging the heavy drill between holes.

BTW if you ever find an excuse to use a concrete chainsaw DO IT! Definitely one of the cooler (manliest) tools I've used. Cut through 12 inch cinder block filled with concrete and 3/4 rebar like butter! Makes a demo saw look like a Joke!

 

[tcianci]

Ya might want to try a larger rental company. There has to be someone renting a hammer drill and a core bit!.

You don't use a hammer drill with a core bit

 

[tab2]

Rent a core rig wth a vacuum base and get the right bit. You don't need the vacuum base but it goes a lot faster. At 18 of them, it will add up.

My old job had 2 Hilti rigs with bits of all sizes, 2" up to 12". We could do 20-30 holes a day easy in fresh concrete no matter the size of the hole.

Pay the pro or pay the rental company, just use the right tool for clean efficient results.

 

[47chevycoupe]

Thanks for all the advice. The closest home depot is about 75 miles. I had a brain fart also, the pots are 3 1/2". All the local plumbers I contacted use a hammer drill with a small bit and drill several holes then chip out to make a larger hole. I work with a guy that his cousin works for a company that bores holes and he can use their equipment to drill the holes I need. Now I have to supply the liquid refreshments.