As I am drilling in wood my drill bit tends to grab the wood and launch forward. Never had this happen before. I go in a back and forth motion and am not forcing or nothing. Why is it doing this and how can I prevent it? It creates many chips in the wood.

  • 3
    What type of bit and what type of drill are you using? Chips in the wood - are you perhaps referring to tear-out? – Ast Pace May 18 '16 at 2:30
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    I'm reading forward as into the wood (down the hole), is that what you mean? – Graphus May 18 '16 at 8:15
  • Unless someone with experience answers properly I would try higher rotational speed. Softness/type of wood and angle of attack might have something to do with it. Raise the angle to make it more scraping and less cutting. – LosManos May 18 '16 at 10:16
  • This is interesting. I recently sharpened the tip of a dull bit and found it grabbing and pulling the bit into the wood. I have been wondering what exactly is causing it. – Ashlar May 18 '16 at 14:11
  • Some pictures of the bit(s), the wood (highlighting the issue), and possibly some details on the drill setup would be most useful. That said, it's possible you're hitting a knot and that's forcing the bit off course. – FreeMan May 18 '16 at 14:40
up vote 2 down vote accepted

Because you're working with a softwood like pine there's one very simple explanation here.

The majority of hardwoods are quite uniform in density and drill fairly predictably as a result, but almost all softwoods have soft earlywood (the pale part of the grain) and much harder latewood (the darker stripes).

This means the material is alternately hard, soft, hard, soft so it's not hard to visualise how, depending on the grain orientation, a drill bit can be working more slowly and then suddenly jump forward when it reaches a softer patch of earlywood. This can be very disconcerting and the loss of control in the drill will often lead to rougher holes than you'd like. This is one reason of many I generally drill all holes in softwood by hand, using twist bits or brad-and-spur bits in a hand drill (eggbeater type) and for larger holes a swing brace. I enjoy using vintage hand tools anyway, but the greater control offered by drilling at speeds makes it much easier to deal with this sort of thing.

  • That answers my question very well! thank you. I never truly came to thinking about those lines in the wood. I never thought it made a difference. – Ljk2000 Jun 27 '16 at 3:10

Brand new, 3/4" diameter, titanium coated bit in a hand held electric drill used to make a hole in clear pine.

I think the problem is most likely speed, combined with power. With a large diameter bit, you should use a slower speed, assuming a multi-speed drill.

If you are drilling at a high speed and if for some reason the bit loses its bite (say when you pull back on the drill) there is a tendency for the bit to burnish the end of the hole, making it a bit harder, then suddenly get a bite again the pull the drill along.

After pulling the drill outward to clear shavings, push it back in with some force to make certain the tip gains a bite. It's okay to use a little muscle from time to time even though all conventional wisdom says "let the tool do the work".

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