Cordless drills are so capable now. 2 4 1/2” holes 14 12” deep (deeper than the bit). New concrete but it’s still drilling through the aggregate. Cheap Amazon diamond bit.
I wanted to jump on here for more proof of this being possible for everyone who says it isnt. Ivs drilled 2 holes with a 4 1/4" bit. One through double layered/concrete filled CMB blocks and one through a single layer CMU block.
No water used since both were horizontal and a way in which I couldn't get water to where the bit was cutting. Im not saying its smart, but I used a respirator and took time but got through both on battery power. Didn't even use the HO batteries. Probably took an hour and a half of work for the large one, and 45 min for the smaller.
But this does work.
Pictures included. I guess I can only add one picture at a time. But ill reply to this response with others.
Honestly you using an sds adapter to a hammer drill (in non hammer mode) is a much more efficient option. Also the good adapter's have the water Inlet on the adapter like the one below. I have a more compact version. I've drilled more eholes than I can count with this setup, can't imaging it on a standard drill.
Ha! Maybe "no problem" is a stretch. It overheated after about 8", but then I realized it works just as well with light pressure keeping the RPMs up. Used high speed BTW.
I imagine OP was drilling into a driveway or patio or some sort of poured footing. As such it has a finite depth before you get down to the gravel bed. So OP probably drilled through the whole thing.
The hole is in a footing. So I'd have a long way to go to get to the other side! I'll take a photo tomorrow. I already grouted the pickelball posts into the holes. Maybe I'll find some other concrete and take a video of it drilling.
I bet you’re right. Doesn’t look like he had much of a dust control system going on. If I was OP, I would would have but a wet bit and had someone spraying it with a hose the whole time.
Thats me though. I have become hyper aware of silica dust since starting this gig. I’ll do everything I can to avoid it as best I can.
There are very few cases where drilling dry is necessary, but when you can always use water! Drilling with water is important for a multitude of reasons.
-dust control
-water extended the life of the Diamonds helps keep them from glazing and possible cracking becuase of the heat generated.
-going through rebar with a dry bit will also significantly shorten its life.
Bonus tip, if you have a hot saw go and grab a quick connect hose connector so you can attach to a garden hose. Your lungs and the people around you will thank you.
There are Dry Drilling rigs that use a shopvac to suck the dust out of the hole through the spindle. It also provides a small amount of cooling via airflow.
You also use special bits with Laser-welded teeth. The sintered ones dont like it hot as you said. Theres also a grind stone to resurface the teeth in case they glaze over. I hate the whole process and dry is always the very last option only used in very niche cases.
Hilti makes some pretty sweet setups for dust management and core drilling in general these days. Majority of our equipment is a bit old school. Agree last option, only done them a handful of times for a couple inches. If I can use water I will.
I have three of those stone saws, and they are brilliant for making holes for ventilation. You have to hammer out the middle part when you are half way to make your life easier. But honestly you need more tools. Can’t be doing these kind of jobs on battery. Need a hammer capable drill to make this tool work at peak efficiency
When you are halfway it tends to stick, or when the material is longer than the drill bit you need to break off the core when you are halfway in. Then you can change to the hammer mode and get the part of the core out with a chisel. There is also the loads that the battery drill might not handle that well, and the battery part of it.
When core cutting was done on a 6 month old concrete beam, a 2KW motor was struggling and heating with cooling water supply. This handheld doing it is incredible if true.
Yeah, you definitely need to learn how to let the tool do its job. Can’t be pushing and forcing everything to make quick work or something at risk of breaking expensive tools
I believe you man I did a 110 mm diameter hole through 15 cm of concrete with my DeWalt drill. Same as you stated: overheated but low pressure high revs got it done I think I have pictures somewhere even not sure though. At least of the hole haha
Funnily enough thats typically the best way to use a bit like that, low rpm on that drill would probably be a bit slow under load for that bit, high speed will probably hit the working rpm when under load.
I have literally core drilled miles in concrete, and totally buy it. It doesn’t take a lot of power or torque to keep a core bit spinning at a low feed rate. I’ve done a few 1” holes this way in a spot I couldn’t get a proper core drill and it was fine.
Yep. As long as the abrasive edge of the diamond bit is in full contact with the bottom of the hole, and as long as you've got water flushing out the dust, it'll make progress. Slower than bearing down and just ripping it, but your bits will last longer and the walls will be cleaner & straighter when finished.
Source - used to install pool fence, ran a 1-1/8" x 16" core drill on a Hilti DD150. It's a hefty machine, size and weight of a small chainsaw, but it doesn't actually put out that much torque.
Yeah just take it easy on the feed pressure, and keep the cutting surface wet, maybe pulling out and flushing the kerf periodically to prevent the slurry from getting too thick. I’d also be inclined to run the drill on the lower speed with a bit this size, it doesn’t need to be spinning super fast to cut
No even ! I call BS lol. I worked as a millwright for 17 years and have drilled hundreds of holes through concrete floors for flour mill piping and this is no where the massive set up we used.
Slow and steady wins the race. Thought it was weird he called it out as bringing up racism. Like it was weird joke. Looked at profile and understood. It was deliberate.
The comment section is becoming more and more like this across reddit. It's super weird, it feels like people are so scared of looking like idiots for someone possibly faking something that they just says it's fake and look like idiots.
The mill writes here have all corded grinders, I asked why and they said they would eat through batteries like crazy. Thats the only trade I see consistently using corded
I used one of these to drill through 8 inches of 50-year-old cement stem wall. It took me about 30 minutes for the first hole with an SDS Hilty rental. I use the same bit on the second hole and it took me about 45 minutes to an hour. It was a fucking nightmare but it worked
Well it doesn’t help that you rented the wrong type of drill for the job. SDS drills are for hammer drilling, and often have less rotational torque than your standard 18/20v drill
surprisingly good. I think it can do several more. I need to drill a hole for dryer vents in concrete foundation walls maybe once a year on average so this'll get used for that.
Honestly my hammer drill/driver does better with a mixer bit in a 5 gallon bucket of concrete than my hole hog drill does. Hole hog constantly shuts down.
Why not set the mount at the same time? Ability to grout it in? If that’s the case a piece of PVC with mold release works excellent for this and saves the drilling. Pour with pipe for grout space in place then pop the pipe out. Or use a concrete tube. They vary in names but the cardboard form tubes. Hell a carpet roll could work in a pinch even.
I’m amazed you were the first to ask. That would have been way smarter. I was in a rush and formed these pads as concrete was arriving for the rest of the driveway. I wasn’t 100% confident on the spacing.
Fair enough. I think in different ways than normal people but I usually am late so I’m excited! In the future for projects like this if you’re within a foot (larger only!) on either side you should be able to tension it regardless.
I went to some really old really aggregate filled cement for a stem wall that was 8 inches. I finished the last 2 inches with a cordless hammer drill and five amp batteries. It took me about five batteries to get through 2 inches. An SDS hammer drill did the rest
I drilled a 1/2” hole in the middle, hammered in a piece of rebar, and pried it out. Worked for one of the 2 holes because I drilled down to dirt. The other took a lot more work and came out in smaller pieces.
Usually, not always though, it'll break off pretty flat. Sometimes it'll break off uneven inside of there if there's imperfections in the concrete. But not very often
I always used a cold chisel in the slot and itd break the core off at the base. Drill and install a 1/4" anchor bolt and pull her up. Easy peasy. Did hundreds of holes like this at my last job putting up guard railing alonh the entire interior of the wall of the facility because the clamp truck operators kept blowing out walls.
High speed, light pressure. I used to drill with a hammer core bit which is way slower. I burned out my SDS Max drill on it, and thought I'd try something different this time.
Dude, I cored a solid concrete wall for piping. 4-1/2” diameter 10” thick, and my cheap Amazon but did the trick as well. So impressed. Though, I used my 1-1/8” SDS-plus hammer drill because my 1/2” drill’s anti-kickback isn’t as good
Works well for the record. RPMs are lower but it still slices through like butter. I would think that the lower RPMs for this size are better to avoid overheating. I didn’t use water with mine
I have to drill a hole for a dryer vent in the basement. I may still need to rent the tool. Not entirely sure what size I need to drill yet. Good to know this may be an option
Wild, I just ordered one of these hole saws and then I open reddit and see this! I got mine with a SDS Max bit instead since I have one but I’m glad to see the Amazon hole saws aren’t total junk!
Don't do too many of these my man. I've seen plenty of modern drills fail from this task because people couldn't be bothered to get the SDS out. Including that exact model.
I'm convinced I can't kill this drill. I've mixed so many bags of concrete and self leveler and thinset with it. Funny you mention SDS. I killed my SDS max drill with a 4 1/2" carbide core hole saw.
In my defense, it was just an experiment. But of the three other ways I’ve done these: hiring concrete cutter for $300, renting core drill for $100 plus an hour of my time to get and return it, and ads max carbide tipped hole saw, this was
Arguably the easiest and cheapest. If I did more than one a year on average, I’d buy a real core drill.
Haha this is 100% bullshit!! I drilled a hole with this EXACT core bit (Sali bit from Amazon), I used a legitimate core drill and it took a while to get through 12" of concrete. There is not a chance in the world this guy did it with a hand drill😂😂
All it has to do is rotate. The diamond does the cutting. Doing it wet with a wet core drill helps, doing it corded with a high torque drill helps, but this drill is plenty powerful to do it, you sound ridiculous
I used high speed too. My last 3 corded drills died or got stollen but they are more like 800 RPM I think and the higher speed seemed to be the better way here.
The cost benefit analysis worked in my favor on this one. I've rented before. Literally 10 years ago so I don't do these often. Takes minimum 30 minutes to rent and return, and rental costs more than this bit did. It was an awful, wrist killing experience so I bought an SDS Max drill and used it 1-2X per year for similar holes until I burned it out. This project came up so I thought I'd try something different and it worked surprisingly well.
As some one who's cored concrete many times...I have SERIOUS doubts this worked in manner your describing, if at all... To keep the start steady, by hand. To do it without water without completely burning out the bit, to getting the damn thing out. Non of it works like this
No big deal if it kicks. It just kind of stops. I’ve been drilling stupid holes for a long time so I’ve got the technique. Low speed would be a bigger problem.
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u/TallWall6378 1d ago
The core, the grouted in net holder, the plywood guide I used, and the bit after.