Drill bits are essential hardware tools that drill round holes in any type of material. They are useful on tiles, metal, wood, plastic, and so much more.
This article will guide you through the different types and sizes of drill bits and what you need to consider when choosing the appropriate drill bits for your toolbox.
What Are Drill Bits For?
Drill bits are very useful tools to create cylindrical holes on your walls at home or anywhere. There are different types of drill bits to match different materials.
You drill holes when you need to attach a shelf, build cabinets, or hang light bulbs on the ceiling.
The most common use of drill bits is drilling on wood. If you need to drill holes that are not round or cylindrical, you can still use drill bits since several drill bits have different shapes.
How Many Drill Bit Sizes Are There?
Knowing the right drill bit sizes is essential to drill accurate hole sizes. Generally speaking, there is an infinite number of hole sizes in the world.
However, different manufacturers have narrowed the sizes down to standard drill bit sizes made according to standard hole sizes.
The standard drill bit sizes are based on the most common drill bit applications. These applications include simple home constructions and repair, wood and metalworking, arts and crafts, commercial constructions and machinery, and other building hobbies and projects.
Many drill bits are bought in sets that typically consist of around 12 to 30 standard sizes. The number still differs depending on the number of drill bit kinds.
How Are Drill Bits Measured?
Measuring drill bits can be a challenge when you are just a beginner with these tools. However, as you become used to drilling bits, you will eye-ball and guess the accurate size over time.
You can start learning how to measure drill bits by having your hole card. A hole card is a small plastic drill size chart with round holes and markings. You can use the size card to measure your drill bits.
To use the drill hole size card, insert your screws into one of the holes and then read the corresponding marking on the card.
Aside from screws, you can also push the drill bits themselves through the holes, especially when you cannot read the small size markings on them.
Sometimes, you would also need a size conversion chart to cross-check metric measurements with the standard ones.
Does A 7/32 Drill Bit Size Exist?
A 7/32 drill bit size does exist. It is the fractional conversion of the metric size 0.1968 or 5mm. Various manufacturers are offering 7/32 drill bit sizes made with durable materials that you can use on metal and stainless steel.
Common Features of 7/32 Drill Bit
A 7/32 drill bit has the universal features of a standard drill bit. These features are important when deciding on a brand and drill bit size for a project you plan to work on. Generally, a 7/32 drill bit consists of:
- A cone-shaped point with a spur and a cutting lip that cuts
- A spur at the center of the point that secures the drill in place
- A specific cutting tip that scrapes off material
- A flute that starts from the cutting lip towards the shank of the drill bit. This feature helps the cutting lip to remove the scraped-off material.
- A shank that’s clamped into the spindle or the drill’s chuck
Things to Consider in Choosing the Drill Bit You Need
Getting the right drill bit is important for the success of what you are working on. There are things you need to consider to have the best drill bit for your next woodworking.
1. Know the materials you are working on.
Since drill bits are not one-size-fits-all tools, you have to know what materials you are working on. In this way, you will also know the corresponding drill bits for your job.
- Carbon steel – for soft materials like wood and plastic
- High-speed steel – for harder types of wood, metal, and steel
- Cobalt – for heavy-duty materials such as stainless steel
- Carbide – for industrial uses on heavy metal, irons, and other abrasive materials
- Diamond drill bits – for non-wood materials such as ceramics, porcelain, marble, and stone
2. Know the Flute design features.
The flute designs are important for material removal and passage of the cutting fluid on cutting surfaces. There are also several flute designs to choose from.
- Standard flute design – for a circular cross-section
- Straight flute – for short chipping materials when the drill’s rigidity is more important than the removal of the chips
- Parabolic flute – form a smooth evacuation of chipping materials with an open geometry
3. Choose the best coating type for drill bits.
The coating acts as a lubricant to prevent your drill bits from rusting when exposed to moisture over time. The coating also helps reduce the risk of drill bits from wearing and tearing.
There are several coating types, and the most common forms are
- Cobalt – for materials needing high levels of heat
- Titanium – helps in maintaining the drill bit’s resistance to corrosion and heat
- Titanium Carbonitride – a wear-resistant coating for cast iron, stainless steel, and aluminum
- Zirconium – for drill bits working with brittle materials such as cobalt and stainless steel
- Black Oxide – helps reduce tarnish and friction on nonferrous materials
4. Choose the right drill bit point angles.
Drill point angles are important for more efficient drilling of drill bits. Different materials will require different drill bit point angles.
Efficient drilling will minimize friction and overheating of your equipment. It will also save you time and effort because you will be drilling for a shorter amount of time.
The most common point angles are 118 degrees and 135 degrees.
For soft materials such as aluminum, plastic, and wood, your drill bit point angle should at least be 118 degrees. This angle will allow efficient cutting from a sharper tip with a much smaller chisel.
For harder materials such as metal and other stainless steel, the recommended point angle is 135 degrees. Drill bits with 135 degrees point angle are flatter and have a longer chisel.
5. Choose between a Ready-Made or go for customized drill bits.
Customized drill bits will be more effective in the long run since they are designed according to your preferred style and size.
If you go for ready-made ones, you may have to purchase another set if they do not go well with other materials you will be working on.
The bottom line is, that you have to know what you’re working on and how to choose the perfect drill bits for you. If you know how to properly use drill bits, choosing the right one will not be that difficult anymore.
Is 7/32 drill bit same as 1/4?
No, They aren’t the same size!
How to use a small drill bit size?
It may be hard to manipulate small drill bits because some may be too small for your hands. They can also be difficult to insert in most drill chucks.
If they are not securely inserted, they may slip off during use and cause hand injuries. Remember to read the manufacturer’s manual, especially when the drill bit is too small to hold and insert.
There are instances when hand insertion of the drill bit is easier and more appropriate than machine insertion. When in use, remember not to put too much force or pressure on the drill.
What are the numbered drill bits for?
Drill bits with letters and numbers are designed to fill in the gaps between fractional and metric sizes. The most common use of these numbered drill bits is for using taps.
There are no exact conversions for fractional sizes, so you have to refer to the closest fractional drill bit size larger than the numbered drill bit.
How to read a drill bit size?
To size and read drill bit sizes, you will need the drill bits, screws or bolts, a handheld drill, a caliper, and a flat metal piece if you have one.
Normally, the shanks of drill bit sizes have size markings above the threads. They’re small markings, so you cannot see them immediately. These markings are usually the drill-bit diameter in its fractional conversion.
If the measurements on the drill bit shanks are unclear or blurry, you can always use the handheld tools you have at home or in your toolbox. A caliper can help you read a drill bit size measurement.
You can also test your drill bits by drilling them through a flat metal piece. After drilling them, mark the holes depending on the drill bit size you used.
How to find the drill size for the screw?
The drill bit size should be the size of the screw shaft without the threads. To measure and cross-check the screw with the drill bit, you just have to align the screw with the drill bit.
If both the drill bit and the screw are of the same size when you align them, then it’s good. Most drill bits and screws also have written size markings on them to check these as well.
An important point that you must remember is that when you line the screw up together with the drill bit, and they’re the same size with the screw threads included, the hole you will make might be too big.
How do I choose the right size drill bit for a wall plug?
A drill bit has to be of the right size to accommodate the right side of the wall plug. Before choosing the right drill bit size, you have to choose the right wall plug first.
- Choose the correct plug by counting in the weight of the object. The object’s weight will determine what screw gauge you need, determining the wall plug size you need.
- Match the chosen wall plug to the screw type to be used and ensure that the wall is durable and strong enough to hold the wall plug with the screw in place.
- To install the plug, ensure that the right drill bit size is inserted into the drill chuck. The drill bit size should correspond to the pilot hole.
- Start drilling the pilot hole through the wall.
- Remove a plug and insert it into the pilot hole.
- Twist the screw using the drill. Once it starts to tighten, switch to a more appropriate tool like a screwdriver.
- Tighten the screw to hold and secure the wall plug in place.
Drill bits are tiny essential tools that you use with any construction. No matter how small they are, they also have to be in the right kind and size to perform their drilling job efficiently.