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This maybe a dumb question but I simply want to make sure I got it right because the manual seems to be defective. I already got one of my drill bits ruined.

So, could anyone show me both pictures of a left-handed drill bit and a right-handed drill bit (because I'm not sure which I'm using) and what direction should they rotate for each to drill forward assuming that the user is facing the tip of the drill bit? (e.g. clockwise or counterclockwise when facing the tip of the drill bit).

When I say tip of the drill bit, I mean the end of the drill bit that makes contact to the surface to make holes.

Please forgive my English.

UPDATE:

Here's the picture of my power drill and the manual.

enter image description here enter image description here enter image description here enter image description here enter image description here

As you can see in the picture it is currently set to "R" which turns, as the manual says, the drill bit to the right or clockwise. I'm assuming the manual meant that from the perspective when the drill bit is facing you as shown in the image from the manual. It actually does that. So from my perspective behind the drill it's rotating counterclockwise. As written in the manual, you have to set it to "R" if you want to drill forward and "L" if you want to reverse drill.

Update:

And the video http://vimeo.com/m/64855403

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    The manual is correct, you're thinking backwards. Clockwise and counterclockwise is from the perspective of you behind the drill -- That is, how you would normally hold it, looking down on the work. That being said, most drills use F and R, for forward and reverse, or have little arrows on the switch. Bad User Interface design in my opinion. – Chris Cudmore Apr 23 '13 at 16:59
  • R is the same as right, forward or clockwise. I have never seen a reverse drill or left handed drill bit. – Roscoe Apr 23 '13 at 19:07
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    "Righty, tighty. Lefty, loosy" – DA01 Apr 23 '13 at 19:40
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    See the edit to my answer. I've added an image of the drill in action with clearly indicated clockwise/forward. – Chris Cudmore Apr 24 '13 at 13:22
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    @supertonsky: Yeap, the manual is right (and the drawings in it are correct), but the drill case has letters R and L swapped. Excellent video btw. – sharptooth Apr 26 '13 at 6:36
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Think back to your high school physics class and use the Right Hand Rule.

Lay the drill bit across your palm, with the point towards your thumb. If the fingers curl around the bit (or screw) in the direction of the threads, then it's a right handed bit. That means you turn clockwise to drill (from the perspective of looking down on the work).

enter image description here

This rule is also extremely helpful when you are working upside down and backwards trying to tighten something. Point your right thumb in the direction you want the screw or nut to travel, and turn the object in the direction your fingers curl to tighten.

When in action, Clockwise/Forward looks like this.

enter image description here

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    I don't understand your use of the "right hand rule". How are your fingers "in the direction of the threads"? Couldn't you put that same bit in your left hand and say the same thing? Your second statement, about pointing your thumb in the direction of travel, makes more sense. – Hank Apr 26 '13 at 4:48
  • @HenryJackson he means this en.wikipedia.org/wiki/Right-hand_rule. There's no left-hand-rule :) – Steve Zhan Nov 11 '16 at 20:44
  • @SteveZhan: I'm aware of the right-hand rule, I just though the description in this answer about the "direction of the threads" was unhelpful and ambiguous. And FYI there IS a "left-hand rule" for left-hand threads (and various physical phenomena). – Hank Nov 14 '16 at 2:40
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TL;DR; almost all drilling bits have to be rotated clockwise to achieve drilling and sometimes you will need to rotate them counter-clockwise when they stuck in the material and you want to extract them easier. I've never seen a drill bit that has to be rotated counter-clockwise for drilling.

When you look at a drilling bit you'll see it has grooves which more or less resemble grooves on a threaded part like a screw or a bolt. The same way you identify an X-threaded (usually right-threaded) screw you can identify an "X-threaded" (usually "right-threaded") drilling bit - the grooves will be oriented the same way. If you have a "right-threaded" (actually "right-grooved") drilling bit it has to be rotated clockwise to achieve drilling.

Here's an example (original from Wikipedia, I rotated it and added an arrow showing how to rotate the bit to achieve drilling). This is a "right-grooved" (most typical) bit, it has to be rotated clockwise.

enter image description here

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Here is your asked for "end on view" of a drill bit with the cutting edges and direction of rotation indicated. This shows the "normal type" of drill bit that you would find for most applications.

enter image description here

You also asked for an "end on" picture of the non-standard type of drill bit that operates in the opposite direction. Those likely do exist out in the wild world of the machine shop but I have provided that through the magic of a flipped video image. So the following would be the picture for a "left handed" drill bit.

enter image description here

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Don't worry about clockwise or counter-clockwise - instead, just examine the drill bit turning at a slow rotation. A bit is designed to remove the drilled material as it turns. When drilling a hole, make sure that the grooves are turning so that material will be ejected from the hole. This will also tend to pull the bit into the material. You can also visualize the bit as a screw to know what direction to turn.

Along the same lines, the chuck will turn in a direction that tightens when drilling into a material.

  • AKA use your common sense. I got that but got confused when I saw the manual that says otherwise. – supertonsky Apr 24 '13 at 4:00
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Just Rotate the drill bit slowly in one direction and observe it carefully. The correct direction will be that in which the groove in the drill bit will appear to be going upward towards the drilling machine rather than inwards towards the hole. This is due to the fact that after drilling the material also needs to removed out of the hole via the grooves made in the drill bit.

2

I have bought a set drill and received an additional small set of "Reverse Drills" supposedly free, so yes they do exist but I have no idea when I would need to use them and have been in engineering for over fifty years but thinking about it I suppose if you had to drill out a broken bolt or screw it might tend to bite and drive the broken piece out rather than driving it harder in.

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Using the drill with a screw driver bit

There are some specialty screws for special situations, like securing something to a rotating shaft in certain situations, that have reverse threads. However, virtually all screws you will normally encounter screw into the material when turned clockwise and out of the material when turned counter-clockwise.

In terms of drill rotation, think in terms of what the screw does. That's the direction the bit turns from the perspective of the drill pointed away from you. If you turn the drill around and look at the tip of the bit, it will be reversed.

Using the drill with a drill bit

There are some specialty bits that are reversed, but these are only of the type you think of as a "regular" style drill bit, the fluted type). I can't think of any other style bit (e.g., spade, Forstner, etc.), that has a reversed version.

To recognize a reverse fluted bit from a normal fluted bit, lay the bit on something with the point facing right and look at the flutes (the grooves running around the stem to remove material). From this perspective, the flutes will run diagonally across the stem of the bit. On a normal bit, the top of the flute will be to the left of the bottom. On a reverse bit, the bottom of the flute will be to the left of the top. A reverse bit will work in the opposite direction of a normal bit.

Any normal bit will work the same as a screw. Clockwise will drill into the material. Counter-clockwise will extract the bit.

Using the drill with grinding bits and sanding/polishing heads

There are a few specialty sanding heads, like flap disks, that are designed to work in a specific direction. This will almost always be clockwise, but it will usually be apparent from looking at it. The intended direction will allow the flaps to flex, either by bending a little more in the direction they are already curved or by moving in relation to an adjacent flap. The opposite direction will work against the design. Think of a string mop. If you pull it in one direction, the strings line up behind the head. If you then try to reverse direction, you're working against the orientation of the strings, and the strings will crumple in random directions.

Grinding bits and sanding/polishing heads that are a continuous surface can be used in either direction. The best direction is typically to take advantage of where dust or debris will be thrown. All other things being equal, use the direction that sprays the least toward you.

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