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Snaketails
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What's This and Where Would You Use It?

02/01/2010 8:14 AM

Working in a mates workshop, I came across this "bit" and asked the friend what it was, he said "I don't know, I didn't know I had one of those"

So, I'm here to find out what this is, and what you'd use it for?

The images are directly off my mobile phone...

I'm sorry, I cannot give you the answer of what it actually is, that's why I'm here ;o)

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user-deleted-1105
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#1

Re: Whats this and where would you use it?

02/01/2010 8:22 AM

It's a left handed bit for undrilling holes.
Del

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Snaketails
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#2
In reply to #1

Re: Whats this and where would you use it?

02/01/2010 8:31 AM

I just said "Its like any left hander, totally useless"

Both my brother who were standing there at the time are Lefty's

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lyn
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#5
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Re: Whats this and where would you use it?

02/01/2010 9:42 AM

I need a set of those!
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bhankiii
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#6
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Re: Whats this and where would you use it?

02/01/2010 10:18 AM

Well that's just about useless. What I need is a left handed sander for unsanding wood.
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gsuhas
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#8
In reply to #1

Re: Whats this and where would you use it?

02/01/2010 10:55 PM

It may be undrill.... to undrill the already drilled hole!
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JohnDG
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#3

Re: Whats this and where would you use it?

02/01/2010 8:34 AM

http://en.wikipedia.org/wiki/Drill_bit#Left-hand_bit

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lyn
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#4

Re: What's This and Where Would You Use It?

02/01/2010 9:31 AM

It is a Coriolis drill bit, for use in the southern hemisphere.
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chrisg288
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#16
In reply to #4

Re: What's This and Where Would You Use It?

02/02/2010 1:21 AM

definitely an Ozzie drill bit!
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#7

Re: What's This and Where Would You Use It?

02/01/2010 10:54 PM

Hi

If it is a left hand spiral drill bit it was probably used in a multiple drill head. I have seen these used on old Herbert production drills where the set up to drill multiple holes would not allow a RH drill bit in that location due to the arrangement of gears in the head.

I would have supplied such drills from the tool store when I worked for Kelvinator in Keswick South Aust

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#9

Re: What's This and Where Would You Use It?

02/01/2010 11:31 PM

An undrill for unbolting broken holes...

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#10

Re: What's This and Where Would You Use It?

02/01/2010 11:46 PM

The left-handed bit is used to make bolts with broken off heads come out of a hole. They work great!

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#13
In reply to #10

Re: What's This and Where Would You Use It?

02/01/2010 11:55 PM

That's what I wrote...

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Smeaton
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#20
In reply to #10

Re: What's This and Where Would You Use It?

02/02/2010 2:08 PM

The bit used to take broken bolts out is a left-handed tapered tap not a drill.
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Kiwi_Bloke
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#22
In reply to #10

Re: What's This and Where Would You Use It?

02/02/2010 4:33 PM

What you're thinking of is called an Ezyout...completely different in that they are tapered and the flutes are shaped for grabbing the broken bolt etc.

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#24
In reply to #22

Re: What's This and Where Would You Use It?

02/02/2010 6:28 PM

Yup. Though I could see it working for larger bolts as a pilot for the EZout.

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NobMan
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#11

Re: What's This and Where Would You Use It?

02/01/2010 11:50 PM

That looks like a masonary drill bit, and the two 'protuding' objects at the end of the bit are normally tungsten pieces, to help cut through the masonary (concrete, plaster, brick,, etc) hence the odd looking shape.
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#12

Re: What's This and Where Would You Use It?

02/01/2010 11:54 PM

Too many people say it's useless! They are wrong--I wish I had a couple in the smaller sizes to use on broken-off bolts. There are probably other uses, but for this use the stuck/broken bolt (or stud) is drilled down the center. You hope the bolt you are drilling loses its "stuckness" and backs out before you get thru it. If not then you use some sort of remover to get the piece out. If that doesn't work, drill successively larger holes until the bolt is just a thin shell--why you need the initial hole to be in the center.

This may work for a couple of reasons. The heat and vibration of the drilling may loosen the bolt and the left-handed torque will then unscrew the bolt (assuming it is right-handed as most are.) If you get to the thin shell condition, a pointy tool can be used to pick the shell out of the hole.

For those who work on old junque, stuck fasteners are all to common. 50 or more years rusting together can make them difficult. As a matter of information, if a fastener breaks off due to the torque of trying to remove it, the usual "easy out" won't work either, nor will most other techniques

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#14
In reply to #12

Re: What's This and Where Would You Use It?

02/01/2010 11:58 PM

If the undrill for unbolting broken holes...doesn't work it maybe the hole is lefthanded.

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#15

Re: What's This and Where Would You Use It?

02/02/2010 12:42 AM

a couple got it right. click link below.

Use right hand drill bits to make a hole in the broken screw before the extractor is inserted. Left-hand drill bits tend to loosen screws for easier removal.
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#19
In reply to #15

Re: What's This and Where Would You Use It?

02/02/2010 11:47 AM

I'm surprise you did receive more GA's

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#17

Re: What's This and Where Would You Use It?

02/02/2010 5:47 AM

On a recent Home Improvement show I saw them using a special drill press gadget for drilling adjustable shelf mounting holes. It had about a half dozen bits all evenly spaced to drill at the same time. They had every other drill bit with a reverse cut so that the bits wouldn't torque the piece of wood. They were even painted in 2 colors, red and blue so you knew which cutting direction they were without looking too close.

It sure beat drilling a couple of dozen holes for each self pin one at a time and made then much more accurately spaced than even if you used a template of some sort.

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#18

Re: What's This and Where Would You Use It?

02/02/2010 6:03 AM

It's like all those nails and screws I have been saving for the times I have to work on the other side of my projects.

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#21

Re: What's This and Where Would You Use It?

02/02/2010 4:12 PM

You can also use them if you have to drill from the other side of your workpiece.

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#23
In reply to #21

Re: What's This and Where Would You Use It?

02/02/2010 5:57 PM

Good one!

Welcome back. Haven't seen much of you lately.
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#25

Re: What's This and Where Would You Use It?

02/02/2010 9:06 PM

You mean they make drills spin the other way in the Northern Hemisphere!!

I was wondering why he put those "normal" drills in the frame.

Where can I get some of the good ones?

All jokes aside, I made a drill like that a few years back. "Bargain" shop drill being used to put holes into hardwood. The drill was so soft that it "unwound" itself and ended up looking a little like the one in the picture.

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wlewis6100
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#26

Re: What's This and Where Would You Use It?

02/02/2010 10:15 PM

Left handed drill bits are traditionally used to remove broken bolts/screws, heavy pressure is applied and more often than not the broken bolt or screw can be "unscrewed" out of the thread set, which saves a lot of wear and tear on extractors (and the removal of broken ones)!
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#27

Re: What's This and Where Would You Use It?

02/02/2010 10:19 PM

I just noticed that the thread title prior to this is "Buffer Tank".

How the heck did we miss that one?

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Anonymous Poster (1); bhankiii (1); bwire (3); chrisg288 (1); Geode Hunter (1); gsuhas (1); JohnDG (1); Just an Engineer (1); Kiwi_Bloke (1); Lehman57 (1); lyn (3); NobMan (1); phoenix911 (1); scotchdrnkr (1); Smeaton (1); Snaketails (1); StandardsGuy (1); TexasCharley (3); user-deleted-1105 (1); wlewis6100 (1); Yosemit3 (1)

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