What to Know About Left Hand Drill bits?

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The left-hand drill bit and reverse drill bit are the same in name and anticlockwise operated for the drilling tasks. These drill bits are used to remove the broken or tighten bolts in the material.

When you work with metal, you may know how difficult it is to remove a broken stud bolt or screw in the workpiece. Using a left-hand drill is easier than we think with the help of screw extractors. So left-hand drill bits are a really important tool in metalworking.

What is a Left Hand Drill Bit?

A left-hand drill bit is a metal drill bit. It has a left-side rotated flute and cutting edge. The left-hand drill bit is named as the reverse drill bit also. Due to the left side structure, this is widely used to remove broken bolts and screws.

Left-hand drill bits are operated anticlockwise. That is the opposite direction of the regular drill bit. We do not use left-hand drill bits regularly. It is used mostly in removing studs or broken bolts and screws.

Left-hand drill bits are made with stronger materials and coated with higher resistance materials in order to have more strength during their operation.

left right screw drill bits
Left-hand drill bit and screw extractors are used to remove broken or stud nuts. Those have anticlockwise spiral flute designs.

What is the Point Angle of the Left Hand Drill Bit?

The left-hand drill bit point angle is 135 -137 degrees. That really helps to drill into the metals.

What Are the Sizes of Left Hand Drill Bits?

Left-hand drill bit sizes are available in a range of sizes.

  • Left-hand drill bit shank size – 3/8” and 1/2”
  • Length of the left-hand drill bits – 3”-5”
  • Diameter Sizes – 1/4″, 5/16″, 3/8″, 7/16″, 1/2″, 9/16″, 5/8″, 11/16″, 3/4″, 13/16″, 7/8″, 1 5/16″, 1″, 1 1/16″, 1 1/8″, and 1 1/4″

What Materials Can Be Drilled Using Left-Hand Drill Bits?

Using a left-hand drill bit, you can drill,

  • Softwood,
  • Hardwood,
  • PVC,
  • Plaster board,
  • Sheet metal,
  • Aluminum,
  • Stainless Steel
  • Cast Iron (for cobalt drill bits)

Left-Hand Drill Bit Color and Material

Left-hand drill bits are manufactured with high-speed steel or cobalt that provides high surface hardness to help penetrate tough materials. More than that, these materials provide additional strength to the structure and rust-proofing surface.

As well as, left-hand drill bits are golden in color due to their coating. The coating consists of the titanium film. This thin titanium film can reduce the friction between the drilling material and increase the durability of the drill bit. Additionally, it can improve the strength of the drill bit.

Where to Use Left-Hand Drill Bits?

Left-hand drill bits are used to drill on broken fasteners, screws, bolts, and studs during home repairs, automotive garage projects, professional work, and more. The drill bit size should be less than the bolt size. Else it can damage the bolt thread while it is drilling.

When you use a lefthand drill bit on the broken bolt or screw, it will easily remove if that is not rusted or clogged inside the hole by changing the shape. For a better result, you can push and pull the rotating drill bit step by step. Probably, you can see the broken bolt or screw will loose easily.

Left-hand drill bit can be operated using an electric drill, lathe machine, press drill impact drivers, etc. When you use left-hand drill bit, you should follow the regular steps when drilling a hole.

You should use lubricants, use a center punch to mark the drilling point, and use the rotational side of the drill or driver.

Which Way Does a Left-Hand Drill Bit Rotate?

Generally, left-hand drill bits rotate anticlockwise. Because fasteners, screws, bolts, and studs are loosened to the left side.

You can use an electric drill, impact driver, or lathe for this. But fixed power tool is highly recommended for the task due to the higher torque generation.

left hand drill bit rotate anticlockwise
Left-hand drill bits rotate anticlockwise and drill inside the material. Due to the friction and torque, it can lose the broken or stud nut efficiently.

How to Remove Stud or Broken Nut Using a Left Hand Drill Bit?

When you remove the stud nut or screw, you can follow these quick steps every time.

Step 1: Wear the proper safety gear, such as safety glasses and gloves.

Step 2: Use a center punch to mark the drilling point of your broken fastener.

Step 3: Choose a left-handed drill bit that has a smaller diameter than your stuck fastener.

Step 4: Carefully drill down aligned straight with the screw about 1/8th to 1/4 inch.

Step 5: If the broken part is not loosened, you can Insert the tip of your screw extractor (spiral flute), turn the tool counterclockwise.

As you turn the extractor while forcing in, the threads will grip or bite into the hole; continue turning counterclockwise and pull to completely remove the stripped or broken screw.

What are the Pros and Cons of Left Hand Drill Bits?

These are the pros and cons of left hand drill bits.

Pros of left hand drill bits

  1. Left hand drill bit can remove broken screws or bolts with ease.
  2. Left hand drill bit can drill in reverse direction.
  3. Left-hand drill bit can provide more control and precision in certain applications.
  4. Left-hand drill bit can be used in conjunction with a right-hand drill bit to create a smoother finish.
  5. Left-hand drill bit can be used in tight spaces where a right-hand drill bit may not fit.

Cons of left hand drill bits

  1. Left-hand drill bit may not be as readily available in stores.
  2. Left-hand drill bit may not fit in all types of drills.
  3. Left-hand drill bit can be more expensive than right-hand drill bits.
  4. Left-hand drill bit may not be as durable as right-hand drill bits.
  5. Left-hand drill bit requires more skill and experience to use effectively.

Can Drill Chuck be Loosened When Using Left Hand Drill bit?

When you use the left-hand drill bit in the chuck, it will not loosen because the chuck is just used to tighten the jaws. Whether it is rotated left or right, it will not loosen at any time.

A drill chuck is always tight to the clockwise and loosened to the anticlockwise.


Tom Mackency

Tom Mackency

Hi, I am Tom Mackency. It has been 10 years that I have been working as a professional woodworker since 2013. I am really enjoying my carrier by creating many kinds of projects in my workshop. But mostly I like for home improvement projects. Home improvement and DIY projects are the most interesting things for me. More than that, the coolest things are power tools. Those are very precious and efficient than a decade ago. So I try to introduce so many things about power tools, woodworking, DIY projects, home improvement and many more interesting topics here.


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