Hammer drills

[Robinhood4x4]

Looks like my Ryobi 14V drill batteries are giving up the ghost so it's a perfect excuse to upgrade. I'm looking at the Ridgid 18V cordless hammer drill or a Milwaukee Hammer drill/impact combo kit.

Here's the Ridgid $250 http://www.ridgid.com/Tools/R8411503-18V-Hammer-Drill-Kit/EN/index.htm

And here's the Milwaukee $288
http://www.toolbarn.com/product/milwaukee/0824-24P/

So for $38 more I can get an impact wrench and Li-ion batteries. I think that's the way I'm going, but wanted to hear what you guys thought too.

Anybody tried using cordless for drilling into a concrete foundation? Is it an exercise in futility and I should rent a real hammer drill? Also, how do I find out if my foundation is pre-stressed concrete or not?

[Bob98SR5]

steve,

lance and i rented a dewalt rotohammer. i deleted the vid, but man, it cut through concrete like butter. imho, better to rent.

and my opinion of cordless tools: not worth it except for maybe a screwdriver where the power requirement is low and portability needs are high.

pre-stressed concrete: no clue. i was asking that myself in lance's garage, hoping not to hit a cable! :P

[Erich_870]

I've used an 18volt Bosch several times. Seams to work well. Just keep a back up battery or two.

About your foundation. Do you mean high strength concrete instead of prestressed? Prestressed concrete refers to placing the rebar under tension while the concrete is poured. It addresses concretes lack of handling tension. This requires jacks and such and is VERY unlikely for a normal home foundation. In regards to high strength concrete; it's all about the cost. You get what you pay for from the batch plant.

Are you concerned about drilling through harder than usual concrete? Remember that the older the concrete, the harder it is.

Erich

[MTL_4runner]

I gotta agree with Bob on renting unless you're just going to do a few holes. I have a large corded 1/2" milwaukee hammer drill and that thing goes through concrete like no one's business. I've also tried (ie rented) the corded Bosch hammer drill and that thing is even more impressive (as is the bosch electric jackhammer!).

Bosch Hammer Drill


Bosch Electric Jackhammer


If you go the cordless route, make sure to get li-ion, they last alot longer and usually have alot more power for the same battery weight. I even got the new B&D Li-ion VPX (I wouldn't suggest this for you) setup for X-mas and I was really impressed at how much torque it could produce from just a 7V battery. I also tried the Rigid Li-ion cordless drill and was similarly stunned. As far as I am concerned, Ni-cad is pretty much history. Only thing you need to watch with Li-ion batteries is to make sure the battery never totally runs out of charge.

[Robinhood4x4]

I meant pre-stressed because I've heard drilling into this kind of concrete will result in a cracked foundation later on.

This is going to be for bolting a couple safes down in my house so maybe 4-6 holes.

[reggie 00]

Steve

You are probably going to be using Red head anchor bolts if your going to do a safe install.

I have put in a lot of these anchors in using my Dewalt hammer drill. You definitely need the hammer drill option a regular drill just wont cut it.

We use them for Big satellite dish installs. These things are made to hold down a lot of weight, really over kill but we dont ever want them to come down by accident.

I can drill the 4 holes in about 5 min.
The only time we have had trouble was when the concrete had large rocks in it.

The Bosh drill from up above is the best option bring you down to 2-3 min, but a good hammer drill and a masonry bit will do fine.

[BruceTS]

If you have a few days, the cordless drill will work.........

With that said, rent one...... much quicker and less headache.

[4x4mike]

The foundation is most likely not pre stressed concrete. As already mentioned it requires a lot of work at the time of pouring and is really expensive, you also don't have problems with tension in house foundations. I believe most prestressed pieces are also pre cast pieces, like the new Bay Bridge. Most of that deck and bent caps are pre-cast and pre-stressed (not in that order) in Stockton. They're floated out there on a barge and installed. Now you could still run into rebar or welded wire mesh in your foundation. I don't think this will be a problem for the drill but you'll know when you hit it. I don't think it'll cause a problem with future cracking (although I am not an expert and it's been a while since I took my concrete design and pre-stressed classes).

Mike

[Bob98SR5]

steve,

did you buy the safe? let's see!

[slosurfer]

If you have a few days, the cordless drill will work.........

With that said, rent one...... much quicker and less headache.

rent one