Tips or tools for drilling up at a weird / inaccessible angles

Question

Disclaimer: I realize this may not have a good answer other than "yeah it's hard", but I thought to ask just in case.

I'm contemplating running a dedicated electric circuit for my fridge. Last night I went into the crawlspace and found the wood board I'd need to drill up into to run the 12/2 romex, but I couldn't find a good way to drill straight up from where I was.

Here is the area I want to drill through (between the black plumbing pipe and the red one), and here is the accessible area around it (I can't get too close due to some horizontal pipes in the way). Even if I were able to get close and over the horizontal pipes, I can't fit the drill + augur bit directly under the wood board at a 90° angle because of the concrete, so I can't go straight up (and would prefer not to go in at 45°).

Here are the ideas I've thought of:

1. Drill from above. Would be ideal, but I'd prefer to avoid taking off more drywall to avoid drywall repair in more visible areas, and would prefer to keep the new hole the exact size of the 1-gang box. The new hole I made is exactly the size of the electric box I'd need.
2. Use a right-angle drill bit adapter. I have one of these, but they require getting pretty close up and supporting it / pushing up with my hand from under it, which would be very difficult to do given the limited access.

Am I missing anything else obvious? Any tips or tools that can make this job easier?

Answer 1

I've done this job many times in many tight places without anything more than a spade bit extension. It's usually just a matter of lining up the hole properly. Some tips:

• You usually want to come out in the center of a wall plate, so plan for that. A typical North American wall is 4½" thick, so from face of drywall you want 2¼".

• Take accurate position measurements from some reference point. It's often a duct opening, continuous wall, or plumbing penetration.

• You can also drill from above outside the wall for a positioning reference. The gap under base trim over carpet is a good place for this. And you can run long screws down from above for positioning. Just be sure you don't snag carpet and wrap it up, sending a stripe down the hall.

• Determine the drill angle. Position your drill and bit how it fits in the area, then use an adjustable square or angle gauge to parallel the bit. Or just go by eye if you're confident.

• Draw a line on something at the same angle, then measure square up from the bottom the same distance as your hole depth. This is often 3/4" to 1½" of subfloor plus the 1½" wall plate.

• Now measure the horizontal offset along the bottom. This gives you your actual offset. As long as you stick to roughly the same angle you should have no trouble hitting the mark.

• If your angle is severe, err to the near side of the wall plate to avoid punching out the far drywall.

• Start with a thin bit in case you miss. Go slowly and have someone above observe.

• Put a depth mark on your bit with a marker or tape. If you go significantly past that depth you may have hit a stud or other framing. You may need to shift to one side and try again.