If your shop is considering a specific drilling operation, it has a choice of one of several different models and styles of drill bits. Popular ones include stab drills, twist drills, and taper length drills. However, if the decision is to choose the most commonly available drill bit, it will more likely not be either of these types. Instead, it will probably be the jobber length drill bit.
What Is a Jobber Length Drill Bit?
Browsing through any machine too magazine will reveal the vast availability of jobber length drill bits. An exact definition of this type of bill for any drilling operation is elusive, however, according to the professionals, it indicates the length of the flute to be “8-12 times the diameter of the drill bit.”Accessible in different materials, brands and sizes, further confusion arises from the different measurement systems in use to describe them. Among them are:
- Fractional
- Letter
- Metric
- Wire
All describe the width of the drill bit. For the length of the jobber, machinists must consider other terms. These are:
- Mechanics length: a sturdy drill bit due to the flute being shorter than that of the average jobber
- Reduced shank: Jobber bits with a short shank to fit specific machines
- Screw machine length: this has a shorter flute than the norm allowing for sturdiness while drilling shallow holes
The size, type, and model an operator will select for a job differ according to the project or application at hand and individual preference. This is common to most drilling operations.
Jobber Drill Bit and The Drilling Operation
A drilling operation is an extractive process. It involves the removal of material through drilling a hole. Diverse projects and equipment will require a different type of drill bit. Among the most common types available for use in a machine shop is the jobber length drill bit.
