...on drilling concrete. Got any? I just need a few inch and a half deep holes to put in some posts for steps on my front porch. I've got a regular drill - nothing fancy there - and masonry bits. It seems to be chewing through the bits because I would make fair progress but then go nowhere. I got a special bit that looks like the tip is made out of a different type of metal, but that stopped working after a while too.
Is there any trick to this? Is it just a matter of getting a drill with a hammering function? (mine doesn't have that).
Are masonry nails useful? I don't have one but I could get one of those. When I started I was worried I might crack the concrete, but after a while at this I'm not worried about that anymore!
Saturday, July 7, 2012
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Water.
ReplyDeleteYeah, you need a hammer drill. I have never successfully worked with concrete without one. They are like $25 or so for 4 hours from Home Depot. And, yeah, you need to make sure you get the special masonry bits which is seems like you have but you'll probably have to buy a fresh one.
ReplyDeleteHammer drill. There's no pretty way to do it, in my experience. Alternately, a hammer and a chisel, but that might take a while.
ReplyDeleteWeird, I recently put steps on my front porch, though we didn't have to drill any concrete.
Also, don't put too much pressure on the bit, because you'll heat it up and when it gets really hot, the metal will soften (wearing the bit out faster). Also, make sure to pull out a few times to ensure you're getting all of the waste out, otherwise the aggregate powder can act as a dry lubricant. I prefer to use a decent amount of water because it helps to create a slurry (which allows the bit to push the waste material out easier), and it also cools the bit. The company I work for also has a concrete cutting/drilling division, so I know what I speak of.
ReplyDeleteJust take your time, it isn't a fast process. Also, let the tool do most of the work. You should apply some pressure, but you certainly shouldn't be putting a ton of force into it.
It's true, you probably won't get a conventional drill to work. Rent a hammer drill and you will be surprised how quick and easy it is.
ReplyDeleteDude, they're 1.5 x .25-.375 inch holes, you don't need a freaking hammer drill for that. He's just wrecking his bits. He already said that he makes progress and then the bit stops working. I could cut holes big enough for your entire arm to fit through without using a hammer drill, you just have to know how to do it correctly. Use plenty of water, keep enough pressure on the drill that you can feel blades digging in but not so much that you overheat the bit's tip, and back out often. Also, be sure that if you're using a rotary drill, that you're also using rotary bits (rather than hammer bits).
DeleteHere's an example of a rotary masonry bit: http://www.dewalt.com/tool-parts/drilling-accessories-concrete--masonry-drilling-multi-material-drill-bits-dwa56205.aspx
Here's an example of a hammer masonry bit: http://www.dewalt.com/tool-parts/drilling-accessories-concrete--masonry-drilling-rock-carbide-drill-bits-sds-plus-drill-bits-sds-plus-bits-dw5400.aspx
The easiest way to tell the difference is that the rotary bit will have a spade tip, whereas the hammer bit will have a star tip (or similar shape). I imagine that Daniel is using the wrong combination of bit to drill, as well as using the wrong technique.
I don't know if I needed a hammer drill or not, but I was definitely using a hammer masonry bit with a regular drill yesterday. The hammer drill cut through it like butter today. Perhaps unnecessary, but it certainly worked well.
DeleteI needed a new drill anyway - I think I got the one I have at a yard sale way back when and we've been living in apartments so I haven't really needed one. I got one with a hammer function and a drill function, and I'm glad to have a new one. I'm certainly not concerned if I need to go into concrete again.
I think the water was important too - I made sure it didn't get dry.
Yeah, a little late on that. I figured that you probably already got one. I was looking at it from the perspective of you could buy a $10 bit, or you can throw down anywhere from $200 to $1000 on a good hammer drill (there are cheaper ones, but they aren't as well-built). Yes, it is always best to get dual functionality, at the very least. I've got one that has 3 functions: rotary, hammer drill and chipping hammer. It is freaking awesome! I am a big fan of DeWalt for any sort of drill or hammer tools. What did you end up getting?
DeleteSince I'm just going to be using it for the odd job I didn't go with anything like a DeWalt, although I was looking at those. I got a dual functional Makita for $80, just because it was pretty tempting when I was considering paying to rent a hammer drill. It's not a Bosch or DeWalt, but it got decent reviews and the guy said he's never heard complaints about the brand.
DeleteBTW, Daniel. Make sure that you check with your local building codes to ensure that your hole depth and diameter are correct. DC may not even have a code for this application, but it would be wise to look into it. Almost all codes have height and spacing requirements for the railing and posts (most store-bought stuff will be in spec), but some localities also have lateral pressure standards (usually around 200-250 pounds), which would mean that the railing anchorage would be part of that regulation. Personally, I work in demolition, so I am more familiar with blowing shit up, cutting it, drilling it, burning it, abating it, and wrecking it than actually building anything. So, for me all I really need to know is keep the dust to a minimum and don't drop shit on my head or anybody else's (though, it happens on occasion), and try not to allow hazardous/toxic substance come into contact with me or the general public. Fun stuff.
ReplyDeleteChecked the building codes on the spacing and that's fine (actually I accidentally put it a little bit higher so the gap is a little big on the bottom, but I'm hoping no one will care... I can always put in a spacer if necessary to bring it back to code). I did not think to check the codes for the hole diameter but that's kind of pre-determined by the holes in the post I got (my wife wanted vinyl so I had to get some a kit).
DeleteHopefully that's all fine. This is actually for the home insurance company, and I think they just wanted one there. I'm not sure how close they're going to be paying attention to code.
btw - I'm not a complete novice (yes, I feel the need to mention this in light of your own experience... if I were a better many I probably wouldn't feel the need). I worked for a contractor during college, which was nice because I got to do a variety of stuff. I know just enough to be dangerous, I think. Although I did some rewiring when we moved in and didn't kill myself or burn the house down, so perhaps not as dangerous as I thought.
DeleteThanks everyone! This has been helpful.
ReplyDelete