Concrete – Drilling holes in concrete

anchorconcretedrill

I'm not what you'd call a handy guy, and now wife wants me to put up curtains. This task is reduced primarily to getting a bit of metal stuck to the ceiling.

I bought screws and anchors. The anchors are a bit shorter than the screws. The clerk in the store told me that's normal. After some soul searching, I managed to drill the holes as deep as the screws. At first, I was worried that the holes were too big, since I can put the plastic anchors in with my finger.

When I try screwing in the screw, I'm physically unable to turn the screwdriver about halfway in (at this point I'm unable to yank it out of the hole either, so I'm assuming that the plastic bit expands on the inside). I don't have one of those screw-driving thingies, but I attached a screwdriver instead of the drillbit on the drill I used to make the hole, and it just "jumps out" every time I press the trigger.

I'm confused. The only possibilities that I can see are as follows:

  • I am not strong enough and the drill is in high gear so it can't be used this way.
  • Somehow I managed to mix up the anchors and the screws.

Well, here are the culprits:

The screw and the anchor
enter image description here

Oh, don't worry about the hole in the background. That one hit something shiny, so I abandoned it. Anyway, that's about as far as I can screw it the screw without losing my cool. Oh, it's my ceiling btw.

Best Answer

No, this isn't normal. Your anchors don't fit to your screws. What is happening is that the tip of the screw reached the concrete, and, of course, you can't force a screw into concrete - not even with a drill or a electric screwdriver, and certainly not by hand.

enter image description here

This picture shows how anchor and screw should fit into the hole. The hole definitely needs to be longer than the screw. The screw should be a bit longer than the anchor, but not as long. Maybe the clerk saw that you have picked an wood screw and gave you anchors suited for the second situation. It doesn't hurt to use wood screws with anchors in a concrete wall, you'll just have the cap jutting out a bit. But the length of the screw should be only a bit longer than that of the anchor (the surplus should equal the length of the tip + the length of the attached thing), and your cap will stick out a bit if the thing you are attaching isn't soft enough for the cap to sink in.

hole depths

The table shows how to determine the correct hole depth. It also tells you what diameter of anchor and drill to choose for a given screw. As for the length of the screw, it is determined by the weight it will have to carry. Vertical screws are more problematic than screws in walls, because gravity is pulling in the direction of the hole, not at 90° to it. Light curtains will be OK with your size screw, but don't put any molton on them.