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I am curious as to other’s experience with drilling into concrete with an impact/drill drivers.
As I understand the current choices in “hammer” drills, there are the old time big fellows that used to run four hundred bucks and up that were a handful to operate and lord help you if a bit got stuck in the hole. Recently I rented a battery powered hammer drill punching 3/8” holes two inched deep for a wheel chair ramp. Worked well. Could I have used an increasingly popular impact/drill driver — frequently twined with a 3/8 drill — to do those same holes?
Geb
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The only real drill for drilling concrete is an sds if you drill enough holes to need it. Hammer drills don't really drill better than a regular drill. There just isn't enough impact to do anything with them.
An sds won't break your arm like a high torque drill will. IE 90* drill with an auger or hole saw can do some serious damage to you. BTDT when it decides to grab.
For drilling the holes you did a plain old cordless drill will do it just fine though slower than an sds and often it won't be as round of a hole. I find though that a regular drill does a better hole than it does if it's in hammer mode.
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I picked up a corded Hiatachi hammer drill awhile ago. I love it! For drilling for tapcons and 3/8 studs it wirks great. I am not a full time contractor, but it has been a great addition to my collection
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GEB said:
I am curious as to other’s experience with drilling into concrete with an impact/drill drivers.
As I understand the current choices in “hammer” drills, there are the old time big fellows that used to run four hundred bucks and up that were a handful to operate and lord help you if a bit got stuck in the hole. Recently I rented a battery powered hammer drill punching 3/8” holes two inched deep for a wheel chair ramp. Worked well. Could I have used an increasingly popular impact/drill driver — frequently twined with a 3/8 drill — to do those same holes?
Geb
I think that you're mixing up a couple of different term here: A "hammer drill" is a drill pretty much like a normal electric drill, except that it has serrated collar inside which can be engaged so that it imparts a "hammering" along the axis of the drill as it turns. A hammer drill usually has a Jacobs type chuck more or less like a normal drill and can holds any bit with a round or hex shank. A hammer drill, when it's not in hammer mode, is just an electric drill. Hammer Drill.  A "Rotary hammer" is a different sort machine that hammers along the axis of the drill, and also turns the drill. The hammering action dos not depend on the rotation of the drill, and in fact some rotary hammers can "hammer" without rotating. A rotary hammer usually has an SDS chuck which requires bits with grooved shanks. Rotary Hammer  SDS bits:  Hammer drills and rotary hammers are both used to drill holes in masonry, using masonry bits. An "Impact driver" is something completely different, with a different application. An impact driver imparts a *rotational* impact to it's bit. In general terms, it does the same thing as the air powered impact wrench the guy at the tire shop uses to strip the threads on your wheel lugs. Impact drivers are very good at driving large screws or lag bolts into wood, but they are the wrong tool for drilling holes in masonry. There is little or no impact lengthwise along the axis of the bit, and that is the key to how a masonry bit works, the lengthwise impact on the bit. An impact driver is a handy thing. I love mine, but it's not the tool for drilling masonry (or really any drilling) Impact Driver:  Now, as far as whether to use a hammer drill or a rotary hammer, it depends. The conventional wisdom is that a rotary hammer is much faster than a hammer drill. There's probably some truth to that, specially for larger diameter holes. However I have a Milwaukee hammer drill and a Hilti rotary hammer and out of curiosity, I timed them drilling 3/8" holes through 5" concrete blocks and I couldn't find any real difference in speed. It's worth noting that the blocks were made with nothing coarser than sand. It may very well be that if you had to drill thru concrete with lager (and harder) aggregate that the rotary drill would start to pull ahead. There's no question that a rotary hammer is more pleasant to use than a hammer drill. The hammer drill makes a nasty squeal/shriek when you're drilling. The advantages to a hammer drill is that they are usually a quite a bit less expensive than a rotary hammer, and when you switch it out of hammer mode, it's an electric drill, and everyone needs an electric drill.
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Robert Adams said:
Hammer drills don't really drill better than a regular drill. There just isn't enough impact to do anything with them.
I'm not sure what your experience is drilling holes in concrete, but it differs pretty drastically from mine. I've drilled a fair number of holes in concrete with my hammer drill, and it makes a *huge* difference in whether or not you have it in hammer mode. A masonry bit is intended to drill by the action of the axial impact. To a large degree a masonry bit is a chisel that you also turn. without the chiseling action, you're just wearing a hole by abrasion, which is not what the bit is designed to do. granted, you will eventually get a hole this way, especially in softer concrete, but I think that if you were drilling higher strength concrete, or drilling through a lot of rock, you'd find that you'd grind away a long time with no hammering.
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A Squared said:
[blockquote]Robert Adams said:
Hammer drills don't really drill better than a regular drill. There just isn't enough impact to do anything with them.
I'm not sure what your experience is drilling holes in concrete, but it differs pretty drastically from mine. I've drilled a fair number of holes in concrete with my hammer drill, and it makes a *huge* difference in whether or not you have it in hammer mode. A masonry bit is intended to drill by the action of the axial impact. To a large degree a masonry bit is a chisel that you also turn. without the chiseling action, you're just wearing a hole by abrasion, which is not what the bit is designed to do. granted, you will eventually get a hole this way, especially in softer concrete, but I think that if you were drilling higher strength concrete, or drilling through a lot of rock, you'd find that you'd grind away a long time with no hammering.
[/blockquote] I drill concrete most every day 1/4 to 2" holes usually I commercial construction. The hammer setting on the drill really doesn't help much and is just noisy. The biggest I will do with one hole is 4" but that's only through block or brick for conduit. If it's concrete and big I drill a chain of holes and break it out. For the average guy that doesn't drill much any drill will do. For lots of driving sds is the only way to go. Only the newbies on the site or guys with cheap tools will use a hammer drill and those guys are usually using ryobi or dw tools.
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I'm not sure what your battery tool brand of choice is, but if you have any ryobi batteries there is this web page . I bought one a while back for a job I didn't get around to it, but then I bought a safe and it made quick work out of drilling into the concrete floor to anchor it down. I was unsure how the thing would work, but it didn't let me down. Bob
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I drill concrete and bricks and so on all the time. I have set the hammer drill on just drill and notice a substantial difference. In fact, I have had to get the hammer drill when the regular drill just wouldn't do the job using the same bit. Perhaps there is a defect in your hammer drill? 
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A Squared gets two thumbs up, and a big thank-you for taking the time to fully explain how these tools work.
In the real world, I use a rotary hammer for up to about 1-1/2" dia., then it's definitely time for a core bit; a diamond tipped concrete hole saw that grinds (without hammering) and uses water to cool, lubricate, and flush away the "chips". They don't have a pilot bit so a guide is used to start smaller holes and for larger ones a drill stand is mounted to the concrete. I have (or have used) core bits from 3/8" up to 30" . The fractional ones can be used in a cordless drill for holes in ceramic and stone tiles or countertops, with a squirt bottle for water. Although a right angle drill has the power and slow speed required, it's a poor choice. A clutch is required to save the bit, the work piece, and/or yourself when it jambs.
Sign at N.E. Vocational School Cabinetmaking Shop 1976, "Free knowledge given daily... Bring your own container"
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For small diameter holes, like 1/2" and smaller an 18v hammer drill work great. I have a Milwaukee which works very well. My experience is like several others, you need a hammer drill. A regular drill will sorta work but takes infinitely longer, and forget it if you hit a rock. I recently drilled some Tapcon holes and was amazed at quickly the cordless drilled the holes. No need for my corded hammer drill.
John
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