Jobber length drill bits are the most commonly used type of drill bit because they are relatively inexpensive and are suitable for drilling most materials. Jobber length drill bits typically measure 6 to 8 inches long and feature a 118-degree point angle.
They are designed to drill through a variety of materials, from wood to metal, in everyday drilling applications.
Mechanics drill bits, on the other hand, are specifically designed for drilling through harder materials like metal, stone, and masonry. They measure between about 10 and 14 inches long and feature a 135- to 140-degree point angle.
The longer length of the mechanics drill bit is beneficial when deeper holes are required, as multiple revolutions are possible before the drill bit needs to be pulled out and reinserted. The increased hardness of the materials being drilled also requires a more aggressive cutting action than is necessary when using jobber length drill bits.
Mechanics drill bits work best when paired with higher torque drills, as the additional power allows the cutting edges to cut more efficiently.
Why is it called a jobber drill?
Jobber drills—also known as twist drills—get their name from a trade that was once practiced in late 19th and early 20th century Europe called “jobbing”. Jobbing was a type of contract labor, where independent artisans or small businesses were hired to complete certain pieces of work.
This type of work often included intricate finishing or detailing to a masterpiece created by the bigger manufactures of the day. The jobbers would utilize twist or jobber drills to perform this type of detailed jobbing.
The twist drill is short and slender, designed to reach into tight spaces and to be able to maneuver into machined slots or tight radius corners. The drill consists of a tapered steel shaft with flutes that extend along the shaft to the point.
The point itself has two cutting edges with a center spur which helps to keep the drill pointed in the right direction. The straight fluted shaft is designed to pull out chips during drilling and the flutes usually have a spiral grind to the front.
Twist drills are the classic jobber drill and due to their design, the term “jobber” has become synonymous with drill bits of this type.
What are the types of drill sizes?
There are a variety of drill sizes and types available, depending on the application. The most common types of drill sizes are letter, metric, and fractional.
Letter drills, also known as “wire gauge” or “letter gauge” are defined by a single letter and designated in letters from A (smallest) to Z (largest). Letter drill sizes are primarily used for tapping holes in thin materials like sheet metal, but can be used for other applications as well.
Metric drill sizes are defined using the metric system in millimeters (mm) and are the most commonly used drill sizes around the world. They are measured in diameter, and are usually only used in increments of 0.5mm.
Fractional drill sizes are defined in inches and consist of two parts, the numerator and denominator. The numerator is the diameter of the drill and the denominator is a number which is used to identify the type of drill with different numbered drills that have different spiral structures.
In addition, there are rotary files, masonry bits, jobber length drill bits, stub length drill bits, taper length drill bits, screw machine length drill bits, and aircraft extensions drill bits. Each type of drill bit range in sizes and are used for specific applications.
How do I choose the right drill?
Choosing the right drill for the job can seem daunting, but it doesn’t have to be. First, consider the type of work you plan to do and the materials you’ll need to drill into. Different materials require different types of drill bits, so you’ll want to make sure the drill you select can accommodate the types of bits you need.
For instance, wood typically requires brad-point bits, and steel and aluminum work best with twist or high-speed steel bits. If you’ll be drilling into concrete or masonry, you’ll need a special bit designed for that purpose as well as a drill with sufficient power to handle heavier-duty jobs.
Cordless drills generally have enough power to handle lighter-duty tasks like drilling into wood, but you’ll want to make sure it can handle the types of bits you need.
Once you’ve determined the type and power of drill you need, you can start to compare features. Consider the chuck size and adjustability, clutch settings, torque, ergonomics and battery life when making your selection.
Also bear in mind the weight and size of the drill – you don’t want a large, heavy unit if you’ll only be doing lightweight tasks occasionally.
Finally, source the drill from a reliable and trusted supplier. If possible, read reviews from other users, get recommendations from professionals, and make sure the drill is covered for warranty and return policies.
With these tips, you should be able to find the right drill for the job.
Are corded drills more powerful than cordless?
Corded drills are generally more powerful than cordless drills. Corded drills have access to a steady supply of power that’s connected to a wall outlet as opposed to cordless drills which rely on a battery.
Therefore, a corded drill has a much longer run time and can operate with higher torque, making it more powerful than a cordless drill. Additionally, corded drills can handle heavy-duty jobs because they don’t heat up as quickly, allowing them to work for extended periods of time without sacrificing the power of the drill.
However, cordless drills are much more convenient than corded ones, as they do not require an outlet or a cord to be dragged around, giving the user much more maneuverability. Both corded and cordless drills have advantages, however overall corded drills are more powerful than cordless drills.
How powerful should my drill be?
When choosing a drill it’s important to consider the power of the drill. The power of a drill is measured in amps. A more powerful drill will provide more torque and be able to drill into harder materials.
A lower powered drill may struggle with certain materials and not be able to go as deep. For most general DIY usage, a corded 3/8 – 1/2 inch drill of around 7-8 amps should provide plenty of power. For heavy-duty drilling, such as drilling into masonry, you may need a more powerful drill such as one with amps ranging from 10 to 13 amps.
Similarly, for a cordless drill, a voltage of around 18 to 24 volts should be enough to handle most DIY needs.
When selecting a powerful drill, it’s also important to consider what materials you’ll be drilling into. If you’ll be drilling into concrete or brick, then you’ll need a hammer drill or rotary hammer with additional power.
Additionally, if you’re using a cordless drill you may need to look for a drill with brushless motor technology as this will improve energy efficiency and length of battery life.
How can you tell if a drill bit is for concrete?
Generally, it is easy to determine if a drill bit is designed for concrete drilling. Look for several characteristics such as a tungsten carbide tip, thick walls, and tapered flutes. The tungsten carbide tip will be thicker and sturdier than most other types of drill bits, and it will often have a pointed tip that is designed to penetrate concrete easily.
Thick walls help to provide additional strength and stability, while the tapered flutes create the swirling action necessary to move away debris from the hole. If the drill bit has any of these characteristics, it should provide good performance when drilling into concrete.
What do drill size numbers mean?
Drill size numbers refer to the diameter of a drill bit, both in metric and imperial measurements. Drill size numbers usually range from 0.0039 inches to 3.875 inches for imperial drill bits, and from 0.
090 to 98mm for metric drill bits. The larger the number, the larger the drill bit’s diameter. Depending on the size of the drill bit, it can create both large and small holes. For instance, a 53 drill-bit size number (which is around 0.
069 inches in diameter) would create small holes in thin materials like sheet metal or thin plastic, while an 8 drill-size number (which is around 0.2160 inches in diameter) would create large holes in thicker materials like stone or concrete.
Also, drill numbers can also help signify the type of surface it is suitable for drilling into. For instance, a drill bit designated with an “M” after its size number means that it is suitable for drilling into machinable metals.
What size is a 38 drill?
A 38 drill has a size of 0.1880 inches. This is equivalent to 4.7624 millimeters. This size is slightly larger than the SAE 3/32 size, which is 0.0938 inches, or 2.381 millimeters. It is a bit smaller than the SAE 7/64 size, which is 0.
1094 inches, or 2.7864 millimeters.
How are drill sizes measured?
Drill sizes are typically measured in two different ways – either by the diameter of the drill bit itself, or by a numerical sizing system such as the US Drill Size System, also known as the American Wire Gauge (AWG) system.
In terms of the diameter of the drill bit, sizes are typically marked in either inches or millimeters on the bit itself, so you can measure the exact diameter of your bit by simply taking a ruler or measuring tape to it.
This is especially useful when looking for drill bits that are broken or worn down, as you won’t have to rely on estimations or guesswork.
In terms of the US Drill Size System, drill bit sizes range from 80 (the smallest) to 1 (the largest) with each size increasing or decreasing by a power of 2. Drill bits of the same size but different degrees of angle are also marked – for example, a bit might be marked as a #80-deg, indicating that it has a #80 degree angle.
All drill bits in this system must adhere to a specific set of diameter measurements.
In any case, it’s important to ensure that your drill bit is the correct size for the intended purpose to ensure a safer, more effective result. It can be helpful to have a chart or guide available to check the size of your drill bit.
How long are jobber length drills?
Jobber length drills are typically 6-7 inches long. They are made from HSS (High Speed Steel) and are used for a variety of drilling applications. They have a standard 118-degree point angle, allowing them to work well on both softer and harder materials.
The length of the jobber drill is ideal for reaching into deep holes, and the greater cutting surface area can result in improved cutting performance. The high speed steel construction ensures that jobber length drills are capable of producing high-quality results under tough drilling conditions.
These drills offer a great balance between cost, performance, and reliability.
What kind of drill bits go through metal?
When drilling through metal, it is important to use specialized metal drill bits designed to cut through tough materials. These drill bits typically have sharper, thicker and more durable cutting edges, meaning they can hold up for longer and drill deeper before becoming dull or wearing out.
Some common types of metal drill bits include: Cobalt drill bits, Carbide-tipped drill bits, High-Speed Steel (HSS) drill bits, and Black Oxide drill bits. Cobalt drill bits are predominantly used for drilling through harder steel and cast iron.
Carbide-tipped drill bits are designed for drilling into larger metallic components and metals of any hardness while HSS drill bits are great for softer metals. Lastly, Black Oxide drill bits are a general-purpose drill bit and good for drilling through aluminum, brass and some grades of steel.
Overall, the type of drill bit you choose will depend on the type and hardness of the metal that needs to be drilled into.
What drill bits are for stainless steel?
The type of drill bit used to work with stainless steel depends on the size, hardness, and thickness of the steel being drilled. Generally, a 135-degree split-point bit or a 29-degree parabolic bit are the best choices for stainless steel, as they have better tip strength and can withstand higher temperatures than standard twist drill bits.
When drilling into thick stainless steel, abrasion-resistant high cobalt drill bits are recommended. They are usually coated with titanium or black oxide and have a sharper cutting edge which works well with tough metals like stainless steel.
When drilling small, thin pieces of stainless steel, carbide drill bits are the ideal choice. They generate less heat than cobalt bits and provide longer life, as well as better performance.
Finally, cobalt drill bits are for larger, harder pieces of stainless steel. They feature more cobalt in the steel matrix and are generally about 40 percent harder than standard high-speed steel (HSS) drill bits.
Why are they called aircraft drill bits?
Aircraft drill bits are so named because they are designed to drill material that is often used in the aircraft industry. These bits are designed to cut through metals like aluminum and stainless steel, which are used in the manufacture of aircraft components.
They are made from specific, high-strength steel alloys that can handle the force and integrity needed to cut through these materials. The coating of aircraft drill bits feature a special titanium nitride coating that helps dissipate heat and prevent chipping and wear as you work.
This provides stability and accuracy with each drilling job.
What are parabolic drill bits used for?
Parabolic drill bits are a type of drill bit that features a curved parabolic shaped flute. The parabolic shape enables this type of bit to cut faster under the same amount of pressure, resulting in a much smoother cutting action.
Parabolic drill bits are most commonly used on materials like wood, plastic, or mild steel, where faster speed and a smoother cut are desired. They are especially useful when cutting long curvatures or tightly curved edges because they create quick, clean results.
They also reduce the risk of pull-out or splitting common when cutting softer materials by creating a deeper, broader chip. Parabolic drill bits are also available in a variety of sizes and configurations, and they come with a variety of point styles depending on the application.
