I am trying to drill holes upward through a wooden stop of a window. But the drill goes on and then it stops, can't go any further. I wondering what is above the wood stop. Here is a picture. This is a 1930 house. Could it be metal? I don't know. I remember when we did a remodel we took all the window mouldings off and all that was left was the window frame. The head, Jamba. It was dark brown. I thought is was wood. But if that is the case, then how come a drill can't get through it.