What size is a #7 drill bit? This is a question that is commonly asked by both professionals and amateurs when it comes to drilling. The answer can be confusing, as there are different types of drill bits with varying sizes. In this article, we will provide a complete guide to drill bit sizes, including what the number 7 means in terms of drill bits. We will also provide tips on how to choose the right size drill bit for your needs and answer some common questions about drill bits.
What Do the Numbers Represent on a Drill Bit?
The numbers on a drill bit represent the diameter of the bit in inches. The larger the number, the larger the diameter of the bit. For example, a #12 drill bit has a diameter of 12/64 inches, or 0.1875 inches. A #14 drill bit has a diameter of 14/64 inches, or 0.21875 inches.
When it comes to choosing a drill bit size, there are several factors that you need to consider. The first is the material that you will be drilling into. Different materials require different sized bits. For example, softwoods such as pine or cedar will require smaller bits than hardwoods like oak or maple. Second, you need to consider the type of hole that you want to drill.
A deeper hole will require a longer drill bit, while a shallower hole can be drilled with a shorter bit. [1]
Drill Bit Sizes
The size of a drill bit is determined by the diameter of its shaft, and this measurement is given in inches or millimeters. The larger the number, the larger the diameter – so a #12 drill bit would be larger than a #16.
Most drill bits will have their size stamped somewhere on the shaft, so it should be easy to tell what size you need. If there’s no stamp, then you can use a ruler or tape measure to get an accurate measurement. [1]
What Size Is a #7 Drill Bit?
When it comes to drill bits, there are two main types: standard and metric.
Metric drill bits are available in sizes ranging from 0.35mm all the way up to 60mm. So, a drill bit could be anything from slightly larger than a human hair up to almost two and a half inches in diameter! [1]
How to Choose the Correct Drill Bit Size for a Screw
Option 1
Use a Drill Bit Size Chart
If you have a variety of drill bits and are unsure of which one to use, consult a drill bit size chart. A chart will list the recommended bit size for various screw sizes. [1]
Option 2
Option two is to use an online calculator. Simply enter the type and size of screw you plan to use, and it will recommend the appropriate drill bit size. [1]
Option 3
Option three is to bring the screws you intend to use with you to the store when purchasing your drill bit. This way, you can ensure that you get the perfect fit. [1]
How to Choose a Drill Bit By Type?
Flat Wood Bits
Flat wood bits, or spade bits, have a chisel-like tip that’s ideal for quick drilling in soft woods. The size of the bit is determined by the width of its cutting edge. A larger bit will bore a wider hole, but it will also require more power to do so.
These bits are typically used for making holes for screws and other fasteners, as well as for drilling pilot holes for dowels and other joinery.
Spade bits come in sizes from #0 (smallest) to #16 (largest). The most common sizes are #0-#12. [1]
Hole Saw Bits
Hole saw bits come in a variety of sizes, and the size you need will depend on the job you’re doing. A hole saw bit is a good all-purpose size that can be used for a variety of tasks. If you’re not sure what size to get, err on the side of getting a larger bit; you can always use a smaller one if you need to, but you can’t use a larger one if your project calls for a smaller hole.
Keep in mind that hole saw bits are not meant to be used with impact drivers; they should only be used with drill presses or hand drills. Using an impact driver could cause the bit to break or damage your tool. [1]
Forstner Bits
Forstner bits are another type of drill bit that is commonly used for drilling large, clean holes. These bits have a tendency to wander off course if not held perfectly straight, so they are not recommended for beginners. Forstner bits come in a variety of sizes, but the most common size is #15. [1]
Wood Auger
If you need a longer bit, you can get up to 36″ bits, but they are less common. [1]
Tile Bits
Tile bits are designed to make clean, precise holes in ceramic tile, porcelain, marble, and glass. They have a tungsten carbide tip that stays sharp longer than other types of drill bits and they can be used with a hammer drill.
To use a tile bit, first mark the center of where you want to drill your hole with a pencil. Then, put the tip of the bit into the center of the mark and apply pressure as you start to drill. Be sure to keep the bit level so that it doesn’t wander off course and crack the tile. [1]
Countersink
Countersink drill bits are used to create a conical shape on the top of a workpiece. This is often done in order to allow for the head of a screw or bolt to be flush with, or below, the surface of the workpiece. Countersink drill bits are available in several different angles, the most common being 82° and 90°.
The size of a #82° countersink drill bit is determined by its cutting diameter, which should be just slightly larger than the major diameter of the screws that will be used with it. For example, if you will be using #12 screws, you will need to use a #12 countersink bit. The depth-of-cut (how far the bit extends below the screw head) is also important, and is determined by the length of the screws being used.
When choosing a 90° countersink drill bit, you again need to consider both the cutting diameter and depth-of-cut. The cutting diameter should be slightly larger than the major diameter of the screws being used, and the depth-of-cut should be equal to or slightly less than half the length of those screws. [1]
Pilot Bullet Point
There are three main types of drill bits that you can choose from: spade, auger, and hole saw. You’ll want to select the type of bit based on the material you’re drilling into and the size of the hole you need.
Spade bits are great for drilling large holes in softer materials like wood. Auger bits are designed for drilling through tougher materials like metal or concrete. Hole saws are ideal for making very large holes in a variety of materials. [1]
Twist Drill Bits
The first type of drill bit is the twist drill bit. It is the most common type of drill bit and can be used for a variety of materials, including wood, metal, and plastic. Twist drill bits come in a variety of sizes and can be either straight or tapered. [1]
Screwdriver Drill Bits
There are two types of drill bits that can be used with a screwdriver: standard and impact. Standard bits are the most common type and are made of high-carbon steel. They’re ideal for drilling holes in wood, plastic, and light metals. Impact bits are made of tempered steel and have a tungsten carbide tip. They’re designed for use with an impact driver and are ideal for drilling into tougher materials like metal or concrete. [1]
Masonry Bits
Masonry bits are used to drill into concrete, brick, or stone. They have a tungsten carbide tip that is very hard and can withstand the high speeds needed to drill through masonry materials. The shank of the drill bit is usually made from carbon steel for strength.
The most common sizes of masonry bits are:
- 16mm
- 20mm
- 22mm
- 25mm
You will need a hammer drill to use masonry bits. Hammer drills have a setting that allows them to hammer as they rotate, which is necessary to drill through tough materials like concrete. Be sure to use the correct size and type of bit for the material you’re drilling into. [1]
Spur Point Bits
Spur point bits have a sharp, conical point that is used to drill accurate pilot holes. These bits are ideal for use in softwoods and hardwoods. The spur point helps to keep the bit from walking across the surface of the wood as it starts the hole. [1]
What Are Numbered Drill Bits Used For?
Numbered drill bits are most commonly used in construction and metalworking. They are also used in a variety of other applications, such as woodworking, plastics, and composite materials. Drill bits are designed to create holes of a specific diameter and depth in a material. The size of the drill bit is determined by the diameter of the hole it will create.
The number assigned to a drill bit corresponds to the width of the tip of the drill bit, measured in 64ths of an inch. So, for example, a #64 drill bit has a tip that is one 64th of an inch wide. A #32 drill bit has a tip that is two times as wide as a #64 bit – one 32nd of an inch. The larger the number, the wider the tip of the drill bit.
Most drill bits used in construction and metalworking are between #40 and #60. This range includes the most common sizes of screws and nails used in these applications.
The most popular size of drill bit for home use is probably the #29 or #30. These bits are small enough to create pilot holes for screws, but large enough to be used for a variety of tasks around the house. [1]
Number and letter gauge drill bit sizes
The size of a drill bit is determined by two different measurements; the number gauge and letter gauge systems. The number gauge system is used in the United States, while the letter gauge system is more common in Europe and other parts of the world.
The number gauges range from 0 to 60, with larger numbers indicating smaller diameters. The most common sizes are #0-14, with #0 being the smallest and #14 being the largest.
The letter gauges range from A to Z, with A being the smallest and Z being the largest. The most common sizes are F-H, with F being the smallest and H being the largest. [2]
Drill bit conversion table
Number letter metric(mm)
0 A/B 0.7969
0.2560
00 C/D 0.9921
0.2362
Screw-machine-length drill
Screw-machine-length drill bits are the shortest, measuring about two inches in total length. These are ideal for portable drilling applications and light-duty use in a drill press.
Taper-shank drill bits have the longest flutes and overall length of any type of drill bit. They’re designed for heavy duty use on large machines such as floor-mounted horizontal boring mills. [2]
Jobber-length drill
Jobber-length drill bits are the most common type of drill bit and can be used for a wide range of applications. The length of the jobber-length drill bit is about 12 inches.
The size of a #12 drill bit is about 0.2280 inches. This is just a slightly larger than a #11 drill bit. A #12 drill bit can be used to create pilot holes for screws or to enlarge existing holes.
A number 21 drill bit has a diameter of 0.0960 inches, making it one of the smallest sizes available. These bits are typically used for very small pilot holes or for drilling in tight spaces where a larger bit would not be able to fit. [2]
Aircraft-length drill
Aircraft-length drill bits are the longest and most common type of drill bit. They range in size from about four inches to more than twelve inches long. The most common sizes are between six and ten inches long.
The vast majority of aircraft-length drill bits have a diameter of one-quarter inch, although some bits may be as small as one-eighth inch or as large as three-eighths inch. The smaller bits are used for drilling pilot holes, while the larger ones are used for drilling through metal or thick wood.
Straight bits have a uniform diameter along their entire length, while tapered bits get progressively narrower towards the tip. Most aircraft-length drill bits are straight, but tapered bits are sometimes used for drilling through metal or thick wood. [2]
Center drill bit sizes
The two most common center drill bit sizes are #40 and #41. These will usually produce a pilot hole that’s between 0.0860″ and 0.0935″ in diameter, which is just slightly larger than the screw’s major diameter (0.0850″). This is plenty of space for the screw to start threads without stripping them, but not so much space that the threads will be loose.
For hardwoods and metals, you can also use a brad-point bit or a Forstner bit to make precisely-sized holes for your screws. Just be sure to select a bit with a cutting diameter that’s slightly smaller than the screw’s major diameter. [2]
Spotting drill bit sizes
There are a few ways you can tell the size of your drill bit. The first is by looking at the markings on the drill bit itself. These will be either numeric or lettered (or both).
The second way to tell is by measuring the diameter of the cutting edge with a ruler or caliper. If you don’t have either of those tools handy, you can also use a piece of string or strip of paper. Just wrap it around the cutting edge and then measure the length with a ruler. [2]
FAQ
How Big Is A Number 7 Drill Bit?
The diameter of a #07 drill bit is 0.201 inches (a little over five-sixteenths of an inch). This is slightly larger than a quarter inch. This is the most common size used for general-purpose drilling in wood, metal, and plastic.
How Do I Know What Size Drill Bit To Use?
There are a few ways to determine what size drill bit you need. The first is by using a sizing chart, which lists the various diameters of drill bits and their corresponding fractional inch or metric sizes. You can also use a tape measure or ruler to measure the diameter of the hole you need to drill, then convert that measurement to the appropriate drill bit size.
Another way to figure out what size drill bit you need is by using a drill bit guide. This tool attaches to your power drill and has markings that correspond to different drill bit sizes. To use it, simply insert the desired drill bit into the guide and line up the marking with the edge of the hole you need to drill; then, select the appropriate setting on your drill and start drilling.
Finally, if you’re still not sure what size drill bit to use, ask a salesperson or another expert at your local home improvement or hardware store for help. With a little guidance, you’ll be able to find the perfect drill bit for your next project in no time!
What Is A Number 7 Drill Bit?
The most common type of drill bit is the twist drill bit, which is used to create cylindrical holes. The size of a twist drill bit is determined by its diameter, and the larger the diameter, the larger the hole that can be created.
What Is A Tap Drill Size?
This hole is usually slightly smaller than the outside diameter of the tap. The difference between these two diameters allows for a tight fit between the threads of the tap and those being cut into the workpiece.
Useful Video: Overview on the Types of Drill Bits
Conclusion
We hope this article has helped answer the question “What size is a #? Drill bit?” and given some helpful tips on choosing the right type of drill bit for your project. If you have any further questions, feel free to reach out to us in the comments below or visit our website for more information. Thanks for reading!
References
- https://www.drillanddriver.com/number-7-drill-bit/
- https://en.wikipedia.org/wiki/Drill_bit_sizes#Screw-machine-length_drill
