The Family Handyman
The hole you drilled is too small for the pipe to slide through. Reader Henry Klatt sent us an elegant solution. You need two hole saws—a “pilot” saw the same diameter as the existing hole, and a larger one to create the desired size. Install them both on your pilot bit, then tighten the setscrews as shown.
Chuck the paired saws in the drill and run them in the hole, keeping the drill on slow speed so the pilot saw aligns the larger saw. Work gradually, with light pressure, pausing to check progress and minimize burning. When you’ve drilled through, loosen the setscrew on the larger hole saw, slide it off and knock out the waste.