How do I drill a deep hole?
I need to drill a hole about 12" long to route a cord through a lamp base. Is there a way to drill a hole that deep and stay true?
—Michael Kelly, Summit, N.J.
The best way to drill a deep hole, Michael, is to forget about the drill. Turn instead to your tablesaw or router table.
If you’re cutting the lamp base from solid stock, cut your base blank to its final dimension, plus about 3⁄16 " extra width to account for your blade’s kerf. Joint or sand it to clean up the faces. Then rip the base in half at your tablesaw. (Be sure to use multiple passes with successively higher blade heights for stock thicker than 1" or so.) Otherwise, if you’re laminating a blank from multiple layers, build up two half-thicknesses, but don’t glue the two halves together, yet. Use a dado blade to cut a centered groove in the inside faces of the lamp base halves, as shown. Alternatively, if you absolutely need a round hole, you can use a core box bit at your router table. Then simply glue and clamp the two halves together.