Drilling Cement

If the masonry drill bit is ok, the concrete normal (poured concrete foundation wall, 40 years old), and the drill spinning correctly---- could the presence of stones (aggregate) in the cement be a problem? Can a masonry drill deal with stones? Thanks for your help.

This TrueValue drill bit -- it is a masonry bit?

I have never had any success with masonry bits in a standard drill (and I have tried the expensive bits). As soon as the bit hits a piece of aggregate nothing happens except that the bit is destroyed. Rent, buy, or borrow a hammer drill instead.

You should be able to drill it faster than that by hand with a "star drill" and a small sledge hammer.

It sounds like you are using a metal-cutting bit instead of a masonary bit.

Bob

Don't worry too much about bit speed, Just brace yourself and put as much pressure as you can on the back of the drill motor. Try to keep the motor just above bogging down with forward pressure. You can also try drilling a pilot hole first maybe a 3/16 Dave

I use a regular variable speed drill on older concrete and standard masonry bits work - slow on the rpm's, not bad for 3/16 & 1/4. Too fast just heats/blues/polishes the edges of the cutters and if you don't keep it straight it rounds the tips all that much faster. Masonry `Carbide Tipped Bit` is designed to hammer & chip a hole, not really cut like a regular twist bit.

Diamond tipped bits drill quick & work easily,,, hammer drill will bust em quik too .

I appreciate all the input. Sounds like I need to fined a hammer drill with an appropriate masonry drill bit (yes I was using a masonry bit before). Typical "simple" project evolves into weekend project.

Thanks to all.

Buy a Tapcon Set , use Tapcon, Bit is included, 5-15$. Tapcon may or may not drill better , if it doesnt , rent a hammer drill.

Tapcon is best.

Why dont you get one of those tools that uses a 22cal shell to shoot a fastner. They shoot nails and (I believe) a nail sort of thing with a threaded end to put a nut on, like a stud (correct me if I am wrong, I have only shot nails in the past). These things do the job. I have fired them thru all sorts of stuff.

You could probably fasten tbe railing with JB Weld too, if you have a way to hold the rail in place till it dries. JB Weld holds on anything except those exposed to very hi temps like an enhaust manifold.

Of course a redneck would use duct tape :)

Mark

I should have said this too. I tend to drill a smaller hole first, then enlarge it. I'd use a 1/4" first, go to a 3/8" and finally the

Mark

Only a couple of things I can suggest:

Get a hammer drill, or rent one.

Make sure you don't keep spinning the drill when you feel it stop going in. This will "smoke" the bit, turning it blue. That is a sign of overheating. Keep the rpms up, but not high when you feel it stop penetrating. You can also spray some water into the hole.

Get a piece of cold rolled rod, or some steel that is very hard, but smaller diameter than the hole. Sharpen it to a chisel point. When you feel the bit hit something hard and stop penetrating, stop drilling. Put the smaller rod in the hole, and hit it lightly with a hammer. This will help fracture the piece of aggregate you have hit. If you don't have any cold rolled, stainless, or an old center punch, sacrifice an old screwdriver. Cut off the handle, as it will split. Just keep the point sharp.

A rotohammer will drill each hole in about ten seconds. A hammer drill will do it, but not as fast. A regular drill will do it, but you will probably burn up bits. A powder charge will also do it, but may fracture some concrete.

If you anticipate doing any more of this kind of project, go get a hammer drill. I have a Makita and a Metabo. They are okay, but I prefer a Milwaukee rotohammer for serious drilling of holes larger than 3/8". Any hammer drill will be better than a regular drill.

HTH - try the punch thing before buying a drill.

STeve

I agree with one other poster. Sometimes when you are drilling cement with small stones,a STAR drill works good when used in conjunction with a regular masonary drill. When your regular masonary drill hits a stone and stops making progress,then use your STAR drill with a hammer to break-up the stone before continueing with your electric drill.Renting a Hammer drill is to expensive and over-kill for doing a small job like yours! Good luck! been there done that!

I've used masonary bits, not all that epensive, for years for general drilling in concrete with no problem. I've gone as large as 3/4" for with my 19.2 volt cordless and get a good clean hole. It sounds like you are trying to use a regular bit that would be for wood or metal. Ask for a masonary bit at the hardware. They look a little different than a standard bit.

I often use a particular lead anchor that you 'set' into the hole with a special tool. It is theaded for a regular bolt. Since you setting the anchor first rather than asking the bolt to pull it tight, they seem to hold better.

Just think of years ago when most all holes in concrete were "drilled" with star point mason drills and a hammer.

Yes I tried all the modern technology, star drills, carbide drills, hardened drills pilot holes, and altogether $20+ worth of crap and no, you cannot drill treough concrete with aggregrate. think of it as a sunk cost. start fresh. the .22 gun works great.

Next time put some bolts in the concrete while it's still WET :)

I have never had a problem in any type of concrete with an ordinary masonry bit and a hammer drill.