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Whenever I try to make a hole slightly larger with my cordless drill, the drill bit catches and wanders, and doesn't stay centered. Normally I use twist bits, but I'm pretty sure I would have the same problem with most (or all?) other types of bits (e.g., brad point, spade, hole saw, Forstner). I know I could fill and redrill the hole, but that would be a pain, I'd have to wait for the filler to dry or cure, and I'd have to re-mark the center.

How can I quickly and easily enlarge a drilled hole without moving the hole or having to resort to some other tool like a drill press (which often wouldn't be practical) or a router jig (as mentioned in Enlarging a stepped through hole -- which would not work for small holes)?

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If you use some sort of bushing to guide the drill and keep it on course.

I use these from Big Gator Tools at Woodcraft.

Big Gator Tools

10

The short answer is to use a guide.

You can take a larger piece of hardwood and drill a hole of the larger size through it, then clamp it over the hole you wish to enlarge.

If you're lucky and the hole you wish to embiggen is the 'next' size up, a step drill bit may work, too.

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    +1 for not requiring any other tools. I've succeeded in doing this with a softwood guide, too, for one or two holes. – lars Apr 4 '15 at 7:35
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There are times when Bondo can save the day. Fill the hole then 10 minutes later re-drill. Yeah I know, Bondo is crass, but it works.

  • I could see this being an answer for how to make a hole smaller but how does this address making a hole larger.? I might just be missing something here. – Matt Apr 27 '15 at 11:33
  • Re-drill with a larger bit or hole-cutting saw and the hole will now be larger than the Bondo and completely in the wood. The Bondo is only temporary. Its job is to hold the bit in place when beginning then disappear with the waste. – Carl Carlson Apr 27 '15 at 15:54
  • Thanks for the clarification. Might be worth putting that in your answer since I missed it. – Matt Apr 27 '15 at 18:07
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Personally if the bits are small enough that they are 'solid' not spades or forsner etc, I generally have no issue running a larger bit through, sometimes I even use small bits to make a pilot hole to follow.

However, as the holes get bigger it becomes difficult to impossible, without a guide or a drill press. But there are stepped drill bits and these can help enlarge a hole, they are basically 'self-guided' bits.

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    I don't know if this is in the spirit of ww.se, but the cheap stepped bits that Harbor Freight sells have lasted me for quite a long time and still cut well. I think it was $10 or $11 USD for a set of three different stepped bits. Compare to $30-50 each for name-brand equivalents at another store. I've mostly used them for drilling mild steel and I think I've drilled over 75 holes in 1/4" thick steel with one of the bits. – cathode Apr 2 '15 at 20:01
  • I agree with bowlturner. I don't see why, even if we're going a couple sizes up, a step bit wouldn't be a good, fast, cheap way to increase the size of the hole at the surface, then use your twist bit to fit that hole, using that new edge to keep your twist bit centered, completing the hole I've done this many times. It requires a steady hand but just being a bit meticulous gets the job done faster and without error. – GoldPaintedLemons Apr 3 '15 at 15:32

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