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Discussion Starter #1 (Edited)
I have a 7.5 amp motor hammer drill. It takes me approximately 45 minutes to drill a 3/8" hole 2.5" deep into some beach stones.
My question is . . .
How much less time would it take me to drill the same hole using a 5.2 Amp SDS Plus Rotary Hammer, 2920 blows per minute?

TIA,
Kurango

P.S. It only takes a few seconds to drill same hole in concrete, using my hammer drill.
 

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Discussion Starter #4
I have the stop watch, that's how I figured the time it took for the hammer drill.

I am trying to figure out if it is worth my wild to buy the rotary hammer.

I have been using a Bosch blue granite hammer drill bit, drilling slow, in water, so I won't wear out the bit.

Come on guys, you can give me some better educated guess answers!
Just tell me . . . for example

It will cut your time by approximately 10 minutes? or It will take you approximately 75% less time with a rotary hammer?
 

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I really don't know the answer but maybe rent the rotary for 1/2 day to see. Let us know what you find out.
 

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Never took the time to time it but I know for a fast a My Bosch Bull Dog will out drill a hammer drill everytime.
CPO Tools has them on sale.
Plus The bull dog can be use as a chisle for things like busting out tile.
 
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joes right.. i dont mess around with hammer drills unless i have to drill one hole thats 1/4 diameter. anything bigger i use our hitachi sds hammer.. it drills 1" holes into 90 yr old rock hard concrete like its butter
 

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woodworkbykirk said:
joes right.. i dont mess around with hammer drills unless i have to drill one hole thats 1/4 diameter. anything bigger i use our hitachi sds hammer.. it drills 1" holes into 90 yr old rock hard concrete like its butter
I use a older German made bosch 1224 bulldog. I got my friend, the mechanic( who now works for the local water/sewer company, a hitachi d handle rotary. The bosch is a little more refined BUT I can't believe how hard those Hitachis hit! Blows the bosch away. Very fast drilling and/ or chiseling.
 

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I have to go to the way-back machine for this one since I don't use hammer drills that often anymore. But back in the early 80s when I was working as a CATV installer and using a normal Milwaukee hammer drill on a daily basis, I would occasionally rent a rotary hammer drill if I knew I was going to be drilling numerous larger holes (5/8 to 1") through concrete or hard brick. It was a night-and-day difference. The rotary hammer would just eat through stuff. I would have bought one but they were crazy expensive back then.
 

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Discussion Starter #11
What I am hearing is . . .

hammer drills are antiquated so no one here ever uses one, so no one can tell me if it would make much of a difference.

No one ever has a reason to drill a 3/8" (larger or smaller) hole 2 1/2" deep in solid rock, so no one knows?

I do appreciate the better answers.

Thanks, Kathi
 

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I'd go to Home Depot, purchase the Bosch Bull Dog, appropriate bit, and try it yourself. If it works then keep the rotary hammer and if it's not to your liking then return it.
 

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What I am hearing is . . .

hammer drills are antiquated so no one here ever uses one, so no one can tell me if it would make much of a difference.

No one ever has a reason to drill a 3/8" (larger or smaller) hole 2 1/2" deep in solid rock, so no one knows?

I do appreciate the better answers.

Thanks, Kathi
That's not what I hear at all. What I hear is the rotary hammer is a lot better.
 

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I've got limited experience with both types of drills but my neighbor has an arsenal of tools which he is always willing to lend out to me. I borrowed the Bosch Bulldog to drill a dozen holes in concrete and blew thru the holes absolutely quicker than the corded hammer drill.
 

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We call drills with hammering action a hammer drill. A chipping machine with the option to bore holes is called a rotary hammer. It all comes down to BPM, tool weight, and quality of the machine itself. The answer your looking for can only be had in a head to head comparison. My suggestion would be to go to YouTube and check out some videos on the machine you're interested in.

Good luck.
 

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I just spent a frustrating couple days trying to drill several 1/4 inch holes in 50 year old concrete with a makita hammer drill. Then yesterday I was in a Harbor Freight store ( I know, I know...) and I saw a SDS rotary hammer for 70 bucks. I had a 20 off coupon burning a hole in my pocket so I bought it.
Long story short, I drilled way more holes in the next hour than I had the previous two days.

The rotary hammer is definitely the way to go. I can't think of any good reasons to use my hammer drill ever again.
 

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dftc said:
I just spent a frustrating couple days trying to drill several 1/4 inch holes in 50 year old concrete with a makita hammer drill. Then yesterday I was in a Harbor Freight store ( I know, I know...) and I saw a SDS rotary hammer for 70 bucks. I had a 20 off coupon burning a hole in my pocket so I bought it.
Long story short, I drilled way more holes in the next hour than I had the previous two days.

The rotary hammer is definitely the way to go. I can't think of any good reasons to use my hammer drill ever again.
Use your hammer drill on things like ceramic tile. A rotary hits too hard and would crack it. Plus hammer drills make great regular drills. Rotary hammers w/ SDS 1/2 inch conversion chuck do not make for great drills cause chuck wobbles in SDS bit holder.
 

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Watch Hammer drill vs. rotary hammer. The guy is drilling through concrete pretty easily with what he says is a 1/2" bit. I'm not sure he's right about the size though.

I was told that I could drill 1" holes in concrete with a hammer drill occasionally if I give the drill a rest and don't do it straight. Maybe you're using the wrong or a worn out bit or maybe you're not in hammer mode. Make sure it's a bit made for hammer drills. You could also drill a pilot hole. "45 minutes to drill a 3/8" hole 2.5" deep" just can't be right. I never used a hammer drill though.

Oh...beach stones...I know nothing about the hardness of beach stones
 

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if your drilling holes smaller than 3/8 youll want a hammer drill.. rotary's generate too much impact and torque for smaller bits and will snap them like a twig
 

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if your drilling holes smaller than 3/8 youll want a hammer drill.. rotary's generate too much impact and torque for smaller bits and will snap them like a twig
Nonsense, or buy better bits. We probably drill a few thousand holes for Tapcons a year, with a 3/16" bit. As long as the employees (or myself) don't push the bit harder than they should, or bend the bit while drilling, we can easily get several hundred holes out of the 3/16" bit. If longevity is an issue, you need to buy the shortest bits that you typically need, and reserve the long ones for the few times you need them................
 
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