How to Use a Flexible Drill Bit for Electrical Work (By an Electrician)
Some specialty tools are pivotal throughout the lifecycle of a construction project. The Flexible Drill Bit or “Bell Hanger Bit” has gotten me out of a pinch more often than naught while conducting service work and during punch list tasks at the end of a job. The ability to drill holes behind walls and pass wires without ripping out finished and painted sheetrock is a blessing. It saves time and money and is a way to garner gratitude from your fellow drywallers and carpenters. When used properly, this handy long drill bit can give you an advantage. Perfect when a more surgical approach is needed for hard-to-reach areas.
What are Flexible Drill Bits?
In case you’re new to the wonderful world of flexible drill bits, their defining traits are that they’re long and have spring-like flexibility. They can help with accessing unreachable studs and avoiding obstacles while doing so. It’s like having a normal drill bit attached to a fish stick that won’t snap on you under too much pressure. Though they may bend permanently if pushed too hard.
With that said, they’re also great wire fishing tools and even come with a small hole in the flute and shank for attaching wires or jet line after you’ve drilled your holes. 
They can range in length but can be as long as, if not longer than 54”. There are also different fixed tip styles as well as switchable or modular tips that can vary from auger-style bits for cutting wood, high-speed bits for metal, and even carbide bits for masonry. A good rule of thumb to follow when choosing the right length and diameter of your flex bit is to remember that the longer and thinner the shank, the more flexible it will be.
Check out the Switchbit Interchangeable Head Flex Bit
What’s the advantage?
Having a flexible drill bit conveniently stashed in my gang box or truck has made me feel more confident in situations where a client has unexpectedly asked me to move or install a switch or receptacle, or to add recessed lighting to a finished ceiling. Instead of cutting openings to reach and navigate around any studs in my way, I’ve been able to use the holes already made for my receptacle boxes or lights. Simply feel around for the studs as you drill through them. The screw point feature at the end of the auger shank pulls the bit through as you drill. You may think this would be a cause for concern as the shank could accidentally pass through drywall instead of a stud, but there are ways to prevent these hazards, which I’ll discuss later.
There have been some instances when a 54-inch bit just wasn’t long enough to get across and through the studs or fire stops in a ceiling, so I’ve had to use an extension to keep my path straight for my wire pull. Alarm and security system installations at doors and entryways have also become a lot easier to complete. Blindly fishing for wires to pass through door frames without a clear path is an extremely frustrating task.
Proper Uses for Flexible Drill Bits
As I mentioned before, there is sometimes a risk of driving your flex bit through a wall instead of the intended stud or floorboard if used improperly. Though an easy touch-up in the wall outweighs having to remove any drywall, it can still make quite a mess and can be avoided with the help of some useful accessories for the flex bit. One way to help better direct your flex bit as you’re drilling is to use a Rack-A-Tiers Piranhabit. This is much more effective and safer than using a rod, screwdriver, or even your hand to stabilize the bit. Especially on a high torque setting on your electric drill.
Another impressive product that I love is the Rack-A-Tiers Bumper Balls Kit. These are so simple and an absolute no-brainer if one wants to work anxiety free with a flex bit. Before Bumper Ball, I would drill in short bursts to walk the bit onto a suitable surface. I couldn’t be sure if my shank was meeting a nail, or the corner of a wall and stud. With the Bumper Balls, I don’t have to think twice. I just slip the ball onto the shaft of the bit, and it keeps the shank on a safe track. This way I know I won’t drill through the wall at an awkward corner. They are lightweight and won’t weigh down the bit as they’re made of plastic.
The kit comes in 1 ½” and 2” diameters depending on your needs. To see a great video demonstration of how they work, check out this YouTube video.
Check out the Rack-A-Tiers Bumper Balls
Conclusion
Here are some final words of advice to help you get started with your flex bit. Make sure you always drill at a proper angle and avoid bending the bit too much while drilling. This could cause the bit to go off course and create issues. Light pressure and a high torque setting will get the job done a lot easier and won’t dull the bit. With safety in mind, always make sure you’re wearing the proper PPE. These bits can get hot while drilling and contact with your skin will cause a burn. Lastly, keeping your bits sharpened with the Rack-A-Tiers Auger File will extend the life of your auger bits.
