Generally, twist drill bits are the most common type of drill bits. However, there is another type of bit called the left-handed drill bit. This type may seem less common, but it’s available in many different sizes and lengths.
Now you may ask what is a left-handed drill bit.
A left-handed drill bit is ideally used to remove broken bolts, screws, and studs. Before it was used to change the rotation of the drill. These days, left-handed drill bits are used to extract broken fasteners.
The left-handed drill bit is either used to help in extractor work or works as an extractor itself.
What Is the Purpose of a Left-Hand Drill Bit?
If you have a left-handed drill bit, you won’t need a screw extractor. While drilling a hole, a left-handed drill bit loosens the broken stud and prevents additional tightening of the broken piece. Thus, no need to use a screw extractor.
Moreover, you’ll get a more accurate, rounder hole with left-handed drill bits. No need for any center punch or pilot hole either.
What Does a Left-Handed Drill Bit Look Like
Usually, drill bits have narrow grooves or slots curved into their surface. These slots wind around the surface similar to a corkscrew.
For a right-handed drill bit, these slots wind upward and twist to the right in a clockwise direction. While the left-handed bit has flutes that twist to the left side when viewed from the bottom to the top.
The counter-clockwise arrangement gives the left-handed drill bits a different appearance compared to the right-handed ones.
What Are the Differences Between Left-Hand Drill Bits and Right-Hand Drill Bits
Some people think right-hand drill bits are for right-handed people and the left-hand drill bits are for left-handed ones. But that’s not actually how it works.
Left-hand bits are mostly used to drill out broken-off bolts or screws. A right-hand drill bit will screw it in further, while a left-hand bit will unscrew it.
But the biggest difference is in the direction of rotation of the bits. A right-handed drill bit rotates on the right in a clockwise direction. Whereas a left-handed bit rotates in the counter-clockwise direction.
Left-Handed Drill Bit Uses
As mentioned earlier, removing broken fasteners is the most common use for left-handed drill bits. Left-handed drill bits can loosen the bolts or screws by turning them counter-clockwise.
If you have broken off fasteners in a threaded hole, it’ll definitely be a time-consuming project when repairing. Left-handed drill bits can save your time and money with easy removal of the broken fastener.
You can also try removing screws or bolts using a punch or a mole wrench. However, using left-handed bits will be much easier and faster to ger results in this case.
How To Use Left-Handed Drill Bit to Remove Bolt
Removing a broken bolt or a stuck stud can be really difficult to extract. But it can be made easier by using a left-handed drill bit.
Using a left-handed drill bit to remove the bolt is a straightforward process that takes only a little bit of time. Here is a step-by-step guide to help you accomplish this task.
Step 1: Get the Right Tools
To get the job done you’re going to need the following tools:
- A left-handed drill bit
- A drill with a reverse gear
- A center punch
- A hammer
- Thread cutting or penetrating oil
- Safety goggles
- Safety gloves
Step 2: Take Safety Precaution
After gathering the tools above, get your goggles and gloves and put them on. The safety gear will protect you from any injury resulting from flying debris.
Step 3: Mark the Center
Before marking, make sure the bolt is as flat as possible. If it’s not yet flat, file or grind the bolt. Now use a center punch and a hammer to mark the center of the bolt. This indentation will help guide the drill bit.
Step 4: Start Drilling
Coat the left-hand drill bit in a small amount of thread cutting oil. Next set the drill to the reverse setting and position it against the bolt’s center mark.
Start drilling at a slow speed and make a hole roughly 2/3 the diameter of the bolt you want to remove. When the bit penetrates the bolt, it’ll start to unfasten it.
There are lots of high-quality left-handed drill bit sets you can use. Here are the 2 best left-hand drill bit sets.
Irwin 30520 Left Hand Cobalt Drill Bit Set
Irwin’s 30520 Cobalt Drill Bit Set is the perfect choice for drilling in tough metals like steel and aluminum. These Cobalt drill bits are made with M-42 8% cobalt alloy steel and feature a 135° split point, which helps you to penetrate tough materials without work hardening.
They also have a spiral flute design that produces fast chip ejection for easy drilling. In addition to all this, they have shorter cutting lips that reduce torque for drilling in high-tensile strength materials.
This drill bit set comes with five pieces and the sizes range from 5/64 to 19/64 inches.
Neiko 10037A Left Hand Drill Bit Set
The Neiko 10037A Left Hand Drill Bit Set is designed with a 135-degree angled tip for precise self-centering and faster-cutting speed. The high-speed steel provides the required durability and strength for drilling through tough materials, while the titanium nitride coating ensures a sharp point that will penetrate fast and easily.
Each piece has an assigned hole in a drill bit holder with size index markings for quick organization. And all the 15 bits come in an easy-to-organize holder so that you can easily store them when not in use.
How To Sharpen Left Hand Drill Bits
You can sharpen left-hand drill bits with a normal drill sharpener. You just need to use left-hand chuck adapters along with sharpeners. Many manufacturers provide left-hand chucks to sharpen left-hand drill bits for you to use without any worry.
Will Drill Doctor Sharpen Left Hand Drill Bits?
Yes, the Drill Doctor will be able to sharpen left-hand drill bits. Especially the Drill Doctor DDXP series, DD500X, and the DD750X can sharpen the left-hand drill bit effectively. However, you need to use a left-hand chuck adapter with that.