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Contractor
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Discussion Starter · #1 ·
I've been picking up what bits I can for drilling some anchor holes in well cured concrete but keep burning them up (hitting aggragate). What bits have you used which have provided longer life? I'm using a cordless dewalt hammer drill...not cream of the crop but it's convenient and gets the job done (it's rare for me to have to drill in concrete)
 

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Project Manager
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I've had good luck with Hilti bits, but then again, I only use Hilti for concrete drilling.

I'm not a Hilti expert, but depending on the chuck type of your DeWalt, you may be able to get some Hilti bits.
 

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KemoSabe
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I like the Bosch bits as well as their rotary hammer. I always start with about a 3/16 hole. If there is aggregate in the path, the smaller bit will do a good job of breaking it up. Then I step up to the appropriate size bit.:thumbsup:

I have a set of bosch bits that I use in my DeWalt hammer drill and I am yet to destroy one of them after nearly 7 years of light use.
 

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I got all hilti.

What size and depth holes?

Is your drill an sds sds plus sdsmax or spline?

Or is it a half inch?

If you said half inch, go get an sdsplus.
 

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Discussion Starter · #6 · (Edited)
that's the drill-it's convenient and works great for the lighter masonary stuff. does the little dewalt not have enough hammer action to effectively get the job done? I've been using the bosch bits at the box stores and they are not holding up long. I may be to blame as the speed is a little to high and is likekly heating up the tip.

1/2" holes 3" deep.

I tried a smaller diameter hole then moving up to a 1/2" but the larger bit wandered and then the hole was off center-not cool when working from the top to the bottom trying to keep posts straight.
 

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I originally had a 1/2" corded dewalt hammer drill, it burnt up bits like a mofo no matter what brand of bit i used, even in low speed it was just too fast...which is the same thing i bet your experiencing with your cordless since my cordless hammer drill is too fast and just does'nt have the hammer action the bigger drills have.

I had 80 red heads i had to sink into sonotubes to hold up a boat load of steel posts supporting a large deck we were building so i bought a Bosche SDS demo hammer/drill and the past 5 yrs have bought nothing but the Bosche masonry bits for it and like the Hilti guys will attest to, there is simply nothing that compares to these drills for boring into anything cementious, everytime we use it i'm still blown away at how quickly it sinks the bits into even the oldest hardest concrete. I know that's not the answer your looking for, but the real answer is simple, your drill is just spinning way to fast, creating way to much heat and literally burning itself out and then eventually burning a flat tip on it LOL!! These Bosche SDS drills are very affordable, and are like any other "right tool for the job", even if it's only called upon a few times a year, those few times make it WELL worth the investment. PLUS as an added bonus there's a LARGE array or chipping/chiseling bits that you can call into action for a number of tasks...they make removing tile a breeze:clap:
 

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Make sure your using the correct drill to start with. A proper sds hammer drill will drill holes through concrete 10x faster than a cordless style hammer drill with a lot less heat. Use the smallest bit you have and work your way up. If it's a core drill bit then chose the correct size and drill away. But remember dont use core bits on hammer. You can also use water to keep the bits cool if you like.
 

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Fentoozler
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that's the drill-it's convenient and works great for the lighter masonary stuff. does the little dewalt not have enough hammer action to effectively get the job done? I've been using the bosch bits at the box stores and they are not holding up long. I may be to blame as the speed is a little to high and is likekly heating up the tip.
It's a case of "no balls" ~ it's great on cinder/cement blocks ...but once you get into a pour...NFG.

Time to get a "real" hammer drill....rent one...try it out....try another drill [Hilti....Bosch..]...the cordless will be the choice for block and that's about it.
 

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You will continue to burn up drill bits with that drill motor until you get a roto-hammer. A hammer drill spins very fast, and uses a lot of light hitting to accompliush it's task. Because of this, the tip of the drill is in contact with the concrete all the time. A roto hammer drills its hole entirely by chisel action, the rotation is only to ensure that the hole is round.

Look at your drills, are they chisel point, or inclined like a HSS drill?

1/2" by 3" is a huge hole to drill by anything other than a roto-hammer, no matter who makes your drill bits
 

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that's the drill-it's convenient and works great for the lighter masonary stuff. does the little dewalt not have enough hammer action to effectively get the job done? I've been using the bosch bits at the box stores and they are not holding up long. I may be to blame as the speed is a little to high and is likekly heating up the tip.

1/2" holes 3" deep.
Holy Crap!

Are you nuts? :laughing: I could piss a hole in concrete faster then that drill could drill it, and I had (one was stolen) 2 of thoes XRP hammer drills. Great cordless drill, sh!tty hammer drill!

They are only good for 3/16 by 2" tapcons and your too lazy to go to the truck for the hammer drill.

Seriously get an SDS it will pay for itself after the first hole, and I do mean first hole!
 

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I have used Bosch SDS bits in a hammer drill before, they hold up way better then a regular masonary bit. You have to really tighten up the chuck. For most my holes in concrete I use my Dewalt roto-hammer. It will knock out a 5/8" x 6" hole in 20 seconds. A roto-hammer is worth its weight in gold. You would never use a hammer drill for conrete again. I have drilled hundreds of 5/8s holes with only using a couple of bits. trying to use lesser bits isnt cost effective.
 

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Anchors with small diameter I use Millwaukee 1/2 hammerdrill.
I've had to do 1 1/2" diameter x 15" deep a few times in WELL cured foundations. Hilti did the trick. They only have 12" long bits, though. I put an extender on the Milli to breat through and then finished from the other side. It was a biatch because of the agregate. The carbide bits were key. Not sure of the make on the bit, sorry.
 

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They only have 12" long bits, though.
What style? I've got hiltis from 6 inches to 24 inches, and half inch percussions that are about 4 feet.
 

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Did you buy a "hammer drill" or a "rotary hammer"? There is a big difference.

I have owned a Milwaukee and a AEG 1/2" hammer drill for quite a few years, both exactly the same just different colors since they are both part of the same company. When I got my Bosch SDS-plus rotary hammer, what a difference. And like every says it is at least 10 times faster, and you find quite a few more uses for one. Like getting the spade bit to chip out tile, etc. I even have some small bits for tapcons, and it is a lot faster than the hammer drills. By the time the trigger is fully seated, the hole is done. Also the bits seem to last almost forever.
 

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I don't know much about those Bosch 7/8" SDS rotary hammers. Also have wondered how they are since they are SDS and called rotary hammers instead of hammer drills.


Here is a pic of mine. The old AEG is the designated mixer drill now, to mix jet set mortar in buckets.

 
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