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We’ve all been there. You have everything ready to drill – and suddenly, you realize you have the wrong drill bit. It’s infuriating!
One of the most critical distinctions in drill bits is the size. Some drill bits are long and thin, and some are shorter and stouter. Differently-sized drill bits are designed for drilling into different types of material.
The most common length is a jobber drill bit. But a lot of people don’t know what that means.
We’re here to help you understand what we mean by a jobber drill bit and know which type you should use for various projects.
- What Is a Jobber Drill Bit?
- Parts of a Drill Bit
- Jobber Drill Bit Measurements
- Jobber vs. Mechanics Drill Bits
- When to Use a Jobber vs. Mechanics Drill Bit
- What Are the Other Types of Drill Bit Lengths?
- What Other Factors Should I Consider When Choosing a Drill Bit?
What Is a Jobber Drill Bit?
A jobber drill bit is the most commonly used and is longer compared to its diameter than other drill bits. If you see a long, slender drill bit, you can bet it’s a jobber. Jobber drill bits are ideal for softer materials like wood, soft metals, or composite.
Parts of a Drill Bit
Believe it or not, drill bits as a tool go back to 1861. They are one of the most basic and standard tools in construction and home improvement. Drill bits are used to drill holes in many different kinds of materials. They work by cutting and removing material along the spiraled channels down their sides.
Drill bits come in fairly standard sizes and can be divided into three main parts:
- Shank: The shank is the cylindrical part at the base that you secure into your drill.
- Body and Flutes: The body is the part that looks like a corkscrew. The deep slots that make the corkscrew and spiral towards the point are flutes.
- Point: The sharp drill bit tip.
There are many other names for many other parts of a drill bit, but these are the most important for understanding the difference between a jobber and a mechanics drill bit.
When we talk about diameter, we’re discussing the diameter of the shank. When we talk about length, we’re talking about the body or flute length. The diameter of a drill bit determines what the length will be, depending on what type.
Jobber Drill Bit Measurements
Jobber length is measured in comparison to the diameter of the shank. Jobber drill bits tend to be between 9-14 times the shank’s diameter. While bits can vary in this measurement, we do have a general rule of thumb: a jobber-length bit should be about ten times longer than its diameter.
So if you have a reasonably standard 0.25-inch drill bit, the flute length would be around 2.5 inches.
In addition to the flutes’ added length, the body of a jobber drill bit is usually smaller in diameter than a mechanics drill bit. They’re made for softer materials and don’t need to be extremely sturdy. The smaller the diameter, the less to patch up if you ever need to undo your work.
Jobber vs. Mechanics Drill Bits
So if a jobber-length drill bit is long, thin, and made for drilling into a softer material, what other types of drill bits are out there?
While there are many types of drill bits, the other length option is a mechanics-length drill bit.
Mechanics-length drill bits are shorter and stouter than a jobber length. They are designed to drill into tighter spaces or harder surfaces. The shorter length helps them fit into a small space — for example, a thin piece of furniture or shelving.
Because they’re thicker and shorter, they’re also more resistant to breaking. So the mechanics-length drill bits are perfect for hard materials like hard metal.
When to Use a Jobber vs. Mechanics Drill Bit
With everything you know now, deciding which drill bit length to use is pretty easy! The key is to evaluate the amount of space you have to drill through, whether your surface might not require or allow drilling, and the type of material you’re drilling.
If you only have an inch or so to drill into, you need a shorter bit, a mechanics-length.
The most important distinction, though, is the type of material. If you have a hard material like granite or metal, you need to change your drill bit into a mechanics drill bit. If you’re drilling into something softer like wood or composite, use a jobber drill bit.
What Are the Other Types of Drill Bit Lengths?
While jobber and mechanics-length drill bits are the most common, drill bits come in five standard length categories:
- Jobber Length Drill Bits
- Mechanics Length Drill Bits
- Taper Length Drill Bits: These drill bits are specifically designed to prep for wood screws.
- Extra Length or Aircraft-Length Drill Bits: These are made specifically for airplanes.
- Screw Machine Length Drill Bits: These drill bits are the shortest and have the lowest length-to-diameter ratio.
Each of these lengths is designed for various specific materials and projects.
What Other Factors Should I Consider When Choosing a Drill Bit?
Once you know what surface material you’re drilling into and the length of drill you need, you will need to consider the following factors as well.
What Material Is the Bit?
All drill bits are metal. However, the different types of metal will decide whether you’re successful in drilling into your surface or not. The key is to choose a material that’s harder than the surface you’re drilling. Generally, follow these rules:
- High-Speed Steel (HSS): use this for general purposes like drywall, wood, etc.
- Cobalt: use this for stainless steel and other hard metals
- Carbide: use this for complex or abrasive materials like brick, cast iron, fiberglass, etc.
What Is the Drill Bit Point Type?
Explore what type of drill bit point you need for different materials. Conventional point drill bits are sufficient for general-purpose applications like drywall, wood, and other softer materials.
If you need a more heavy-duty drill bit, you’ll want to look into the 135° split point.
Is the Bit Coated?
Drill bit manufacturers often provide a coating and sharpening tools for the drill bits. This can help extend their life or improve performance with certain types of projects.
While we could go on and on about varieties of drill bits, you now know the basics of a jobber drill bit. Knowing the difference between drill bits is key to using them successfully – and takes a lot of the stress out of home improvement!