Drilling in concrete for post anchors


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Old 07-09-09, 12:36 PM
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Drilling in concrete for post anchors

We were going to redo our deck, but when we tore it out we found a perfect slab under it. So we decided to keep the cement. Not many years ago we built a fairly large arbor over the deck(about 14x20)and it was anchored to the deck framing.
Now I'm in the process of replacing the support posts(4x4's) and intend to use post anchors. For the anchors it requires a 3/4" hole for the lead anchors. I tried drilling the first hole with a good 3/4" bit, but only got down less than an inch, need to go 2" deep.The cement is pretty old and was a 5 bag mix so it's really hard. I was using the drills I have,first a variable 3/8" and then I tried my old 1/2" drill, but no luck.
Would a hammer drill hopefully work?
Do I need a special bit(bought a professional 3/4" bit from our local ACE Hardware)?
Would drilling smaller sizes at first help?
Any advice sure would be appreciated.
Rich
 
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Old 07-09-09, 07:02 PM
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It's probably not the bit, but the drill. For a few bucks you can rent an SDS+ hammer drill (that's a type of drill, not a brand name) and 3/4 inch bit from a rental yard and have all the holes drilled in about 5 minutes. Normal drills with masonry bits, and typical hammer drills are worthless toys compared with this type of drill. You can buy a Bosch Bulldog at Lowe's for around $140, but I'm sure you can rent one much cheaper.

good luck.

Pecos
 
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Old 07-10-09, 07:46 PM
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you can get a masonry drill at harbor freight with the right bits for around $50-60. Its not top quality but it works fine, been using mine for 3yrs almost every day and its still plugging away with ease. Just an option and you must use masonry bits.
 
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Old 07-11-09, 07:07 AM
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Well that's exactly what I did. Went to Harbor Freight and bought a cheap hammer drill. It's a 1/2" drill and works great.
I started with a small bit, then a medium bit, and then went to the 3/4" bit. I drilled the holes just over 2" deep which took about 2 minutes a hole.
And the drill was on sale for $29.99!
Ordinarily I would go with better tools but I don't make a living with them. So if this drill will get me the six holes I need then it was a bargain to say the least.
Thanks for the replys.
Rich
 
 

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