Initial Engagement
A standard 118-degree or split-point tip bites into the material to start the cut.
Drills / General-purpose drills
Jobber Length Drill Bits
What Are Jobber Length Drill Bits and How Do They Work?
Jobber length drill bits are widely used hole-making tools. Engineered with a flute length typically 9 to 14 times the tool diameter, a jobber length drill bit balances extended reach with structural rigidity.
Rotational Shearing
Two cutting lips slice through wood, metal, or plastic as the tool rotates.
Continuous Evacuation
Helical flutes carry chips and debris up and out of the cavity.
Hole Completion
The tool maintains a straight trajectory to produce a clean, uniform bore.
Key Features and Benefits of Jobber Length Drill Bits
Versatile Proportions
The length-to-diameter ratio balances reach and rigidity for general-purpose drilling.
Split Point Geometry (Optional)
A 135-degree split point helps prevent walking on slick metal surfaces.
Universal Shanks
Standard straight shanks fit handheld power drills and drill presses.
High Rigidity
Thicker webs than extra-long drills minimize the risk of snapping under lateral pressure.
Efficient Chip Clearing
Standard spiral flutes eject chips across varying material densities.
Cost-Effective
Broad material and machine compatibility supports economical general-purpose use.
Jobber Length Drill Bits Specifications
| Specification | Range / Details |
|---|---|
| Diameter Range | 1/64" to 1" (Standard, Metric, Wire, and Letter sizes) |
| Point Angle | 118° (Standard) or 135° (Split Point) |
| Flute Type | Standard Spiral (Right-Hand Cut) |
| Shank Type | Straight Cylindrical |
| Flute Length Ratio | Approximately 9x to 14x drill diameter |
| Operation Type | General-purpose hole boring |
Materials and Coatings Available for Jobber Length Drill Bits
| Material / Coating | Best For | Key Advantage |
|---|---|---|
| HSS (High-Speed Steel) | Wood, plastic, and mild steel. | A versatile and economical material for everyday jobber length drill bits. |
| Cobalt (HSS-Co) | Stainless steel and harder alloys. | Resists high heat during continuous drilling in tough metals. |
| TiN Coating (Titanium Nitride) | High-volume production and repetitive tasks. | Reduces friction, increases surface hardness, and extends tool life. |
HSS supports general work in wood, plastic, and mild steel; cobalt HSS adds heat resistance for tougher alloys; and TiN coating reduces friction in repetitive production.
Which Machines Use Jobber Length Drill Bits?
Handheld Power Drills
Support on-site drilling tasks for contractors and mechanics.
Drill Presses
Provide stable vertical control for accurate, repeatable hole creation in workshops.
CNC Machining Centers
Use jobber drills as general-purpose tools for automated, high-speed hole making.
Applications and Industries for Jobber Length Drill Bits
Metal Fabrication
Bores clearance holes for bolts and fasteners in mild-steel and aluminum framing.
Woodworking
Functions as a general-purpose drill for creating clean holes in cabinetry and construction timber.
Maintenance and Repair
Provides everyday hole creation for facility upkeep and automotive repairs.
Plastics and Composites
Drills through acrylics and PVC while controlling heat buildup.
Frequently Asked Questions About Jobber Length Drill Bits
What does "jobber length" actually mean?
"Jobber length" refers to the proportion of flute length to drill diameter. The flute is generally 9 to 14 times the diameter, balancing drilling depth and structural rigidity.
Should I choose a 118-degree or 135-degree point angle?
A 118-degree point suits softer materials such as wood, plastic, and aluminum. A flatter 135-degree point, often split, bites into harder materials such as stainless steel and helps prevent the bit from walking.
Can a general-purpose drill cut through hardened steel?
Standard HSS jobber drills can dull or overheat quickly in hardened steel. Cobalt HSS or solid carbide variants withstand more of the heat generated when drilling tough alloys.
How does modern general-purpose drilling technology improve these bits?
Modern improvements include metallurgical treatments, microscopic edge honing, and vacuum-applied coatings such as TiN or TiAlN that reduce friction and increase heat resistance.
Do I need a pilot hole when using jobber length drill bits?
Small diameters generally do not require a pilot hole, particularly with a 135-degree split point. For diameters above roughly 3/8 inch, a pilot hole reduces thrust force and helps center the final hole.
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