DIY Network

How to Enlarge a Hole

Have you ever had to throw out expensive stock because the holes that were cut in it turned out to be too small? Host David Thiel demonstrates how to enlarge an existing hole using a router.

More in Home Improvement

enlarge an existing hole using router
  • Time

    30 Minutes

  • Price Range

    $1 - $50

  • Difficulty

    Easy to Moderate


Step 1: Plunge the Bit into the Hole

Use a rabbeting bit and a plunge router. (A Forstner bit can't be used to enlarge a hole -- there’s no center to orient the bit properly so that the hole ends up the right size and in the right place.) A rabbeting bit has a bearing in the center that rides along the edges of the inside of the hole to help guide the bit (Image 1).

Plunge into the hole as far as the bit will go. The bit may not be long enough to cut all the way through, but it is a relatively large bit, so run the router at a slower speed while cutting into the wood (Image 2).

Step 2: Plunge the Opposite Side

Turn the board over and plunge into the other side of the same hole.

Use a flush-cutting bit to finish the hole.

plunge opposite side of board