Using Left Handed Drill Bits (Tips and Step Guide) DrillingAdvisor

Are you on the market for the best drill bits? Well, the market has plenty of them. Not to mention, they are available in different types to choose from.

As such, finding the right one for the task can be daunting. Generally, the most common drill bits are of the twist bit variety. These types are designed to twist to the right in a clockwise direction.

However, there are also drill bits that twist to the left or counter-clockwise direction. These are known as left-handed drill bits and are less common.

So, below, we’re going to discuss how to use left handed drill bits and everything you need to know about them. 

What are Left-Handed Drill Bits?

A left-handed drill bit is simply the reverse to a normal drill bit. They have flutes that are built to twist in a counter-clockwise direction. This means you can use it in reverse, unlike typical twist drill bits.

But you know what the best part is? Similar to other bits, left-handed bits come in many different sizes and lengths to choose from. On the flip side, though, their limited use can make them hard to find.

Additionally, left-hand drill bits are available in various types. However, the most common form of left-handed bit is the general-use twist bits. The good news is that some boast flatted shanks to minimize twisting in the drill chuck.

How to Use Left-Handed Drill Bits – Step-by-Step Guide

The most common use of left-handed bits is the removal of broken fasteners or bolts. You see, right-handed fasteners are usually loosened by turning to the left. Therefore, the torque applied by a left-handed drill bit helps loosen the broken screw.

Apparently, this method gives you a 50% chance of removing the stuck bolt without the use of other extractors. Of course, the drill must run in reverse when using a left-hand bit.

So, how do you use the lefthanded drill bit to extract the broken portion of the fastener? Here are the steps on how to use left hand drill bits. 

Step 1: Ensure the bolt is flat

To begin with, the bolt or fastener should be as flat as possible before using the left-hand drill. So, if it’s not already flat, we recommend you file or grind it until it is completely flat.

Step 2: Center punch the middle of the fastener

Next, place the center punch in the middle of the broken fastener and hit it with a hammer. This will ensure you have a starting point for drilling a pilot hole.

However, you should ensure the pilot hole is precise to avoid damaging the threads of the broken fastener during extraction. This is because if the threads are damaged, the removal of the bolt may be impossible.

Step 3: Slowly drill a pilot hole

Before creating a pilot hole, you should choose the proper-sized reverse drill bit. This is because these bits are available in various sizes. So, selecting the right size bit for the job is critical.

Next up, put the drill bit into the chuck and set it on reverse. And for the best results, make sure to use as slow a speed as possible, preferably 20 RPM. After that, hold the drill bit securely on the punch mark you made and slowly drill a hole in the fastener. The hole should be around 1/4-inch deep.

Step 4: Extract the bolt

Reverse-drilling a pilot hole is meant to loosen the bolt or faster enough to let you remove it. So, using vise grip pliers, try to extract the bolt. The pliers should bite the bolt to remove it from the hole.

However, in some cases, the left-handed drill bit may fail to loosen the bolt. When this happens, you might want to try out other extraction methods.

Step 5: Remove metal shavings

After successfully removing a broken bolt using your left-handed drill bit, the next step should be to remove any metal shavings.

If planning to insert a new bolt, you need to remove any metal filings or shavings left in the threaded hole. Simply use place a powerful magnet over the hole to attract the loose bits. You can also use compressed air to blast the hole clean.

Final Thoughts

Repairing broken fasteners or bolts can be time-consuming, especially if you don’t have the right tools. But with a left-hand drill bit, you can quickly and successfully extract the broken bolts in a record time. However, you must follow the proper procedure to ensure you do it correctly.

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