A studio photograph of the 21-piece Bosch black oxide drill bit set housed in its durable, clear-faced plastic storage case with retail labeling.
A studio photograph displaying the full 21-piece assortment of black oxide jobber length twist drill bits arranged by size from largest to smallest.
An instructional graphic showing various metal stocks, including stainless steel tubing and diamond plate, with text stating the bits are best for cutting metals like stainless steel.
A close-up studio photograph of the spiral flutes on a black oxide drill bit, featuring text that identifies the design as a Long Flute for effective material removal and universal drilling.
A close-up studio photograph highlighting the 135-degree split-point tip of a black oxide drill bit, with text overlaying the image stating No Skate Tip for clean accurate starts.
A studio photograph of the 21-piece Bosch black oxide drill bit set housed in its durable, clear-faced plastic storage case with retail labeling.
A studio photograph displaying the full 21-piece assortment of black oxide jobber length twist drill bits arranged by size from largest to smallest.
An instructional graphic showing various metal stocks, including stainless steel tubing and diamond plate, with text stating the bits are best for cutting metals like stainless steel.
A close-up studio photograph of the spiral flutes on a black oxide drill bit, featuring text that identifies the design as a Long Flute for effective material removal and universal drilling.
A close-up studio photograph highlighting the 135-degree split-point tip of a black oxide drill bit, with text overlaying the image stating No Skate Tip for clean accurate starts.
BOSCH

Bosch Drill Bit Set BL2133 21 Piece 1/16 In to 1/2 In (135 Deg Split Point Black Oxide HSS Three Flat Shank Wood Plastic Metal Jobber Case)

In stock
SKU: BL21A
$23.79 USD

Description

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Industrial Bosch 21 Piece Black Oxide HSS Jobber Length Twist Drill Bit Set BL2133

The Bosch 21-Piece Black Oxide HSS Jobber Length Twist Drill Bit Set (BL2133) functions as a commercial-grade rotary cutting tool kit engineered to execute precise, burr-free hole generation in light-gauge sheet metal, structural plastics, fiberglass, and dense hardwoods. Manufactured from high-speed steel treated with a heat-reducing black oxide protective finish, these jobber length bits incorporate 135-degree split-point tips that initiate immediate surface penetration to eliminate bit skating without requiring a center punch. Featuring three-flat shanks on all bit sizes 3/16-inch and larger to prevent chuck slipping under high torque, this 21-piece contractor set provides a complete range of fractionally sized bits from 1/16 inch up to 1/2 inch inside a durable storage case for general construction and maintenance tasks.

Best Used For:

  • Light-Gauge Sheet Metal Fabrication: Penetrating steel studs, aluminum ductwork, and thin sheet metal without bit walk or edge tearing.
  • Electrical & HVAC Enclosure Drilling: Creating clean pilot holes and pass-through openings in PVC junction boxes, fiberglass panels, and metal control cabinets.
  • Hardwood & Composite Construction: Drilling clean pilot and clearance holes in hardwoods, composite lumber, and structural plastics using standard drill drivers.

Key Performance & Safety Features

  • 135-Degree Split-Point Tip Geometry: Self-centering tip design eliminates bit skating on smooth metallic surfaces and reduces thrust force during hole entry.
  • Friction-Reducing Black Oxide Coating: Thermal barrier coating lowers operating temperature and extends high-speed steel cutting edge life.
  • Anti-Slip Three-Flat Shank Design: Machined flats on sizes 3/16-inch and larger lock securely into 3-jaw drill chucks to prevent spin-out under heavy torque load.
  • High-Visibility Laser Etched Diameter Markings: Permanent shank markings allow fast size identification inside the jobsite storage case.
  • Standard Jobber Length Flute Profile: Parabolic flute geometry evacuates wood chips and metal swarf efficiently up to 3.0 inches of drilling depth.
  • 21-Piece Fractional Contractor Assortment: Comprehensive range includes double duplicates of high-use sizes (1/16, 5/64, 1/8, 3/16, 1/4 in.) for uninterrupted workflow.

What's Included

  • (2) 1/16 In., (2) 5/64 In., (1) 3/32 In., (1) 7/64 In. Black Oxide HSS Twist Drill Bits
  • (2) 1/8 In., (1) 9/64 In., (1) 5/32 In., (1) 11/64 In. Black Oxide HSS Twist Drill Bits
  • (2) 3/16 In., (1) 13/64 In., (1) 7/32 In., (1) 15/64 In. Three-Flat Shank Twist Drill Bits
  • (2) 1/4 In., (1) 5/16 In., (1) 3/8 In., (1) 1/2 In. Three-Flat Shank Twist Drill Bits
  • (1) Heavy-Duty Tough Storage Case with Size Indexing

Technical Specifications

Brand Name Bosch
Model Number SKU BL2133
Product Tool Classification Jobber Length Twist Drill Bit Set
Set Piece Count 21 Pieces
Size Range Spectrum 1/16 in. to 1/2 in. (Fractional Increments)
Bit Material Substrate High-Speed Steel (HSS)
Surface Protection Coating Black Oxide Finish
Cutting Tip Angle 135-Degree Split-Point Self-Centering
Shank Interface Geometry Three-Flat Shank (3/16 in. and larger) / Straight Round Shank (under 3/16 in.)
Maximum Drilling Depth 3.00 in. (76.2 mm)
Spiral Helix Direction Right-Handed Standard Twist
Primary Machine Compatibility 3/8 in. and 1/2 in. Corded and Cordless Drill Drivers, Drill Presses
Target Materials Light-Gauge Sheet Metal, PVC, Fiberglass, Hardwoods, Softwoods

Pro-Tip: When drilling holes in light-gauge steel or thick PVC using the larger bits in this set (3/8" or 1/2"), apply a few drops of cutting fluid to the bit tip and operate your drill driver at a moderate RPM setting. Lowering rotation speed prevents frictional heat build-up, preserving the black oxide coating and keeping the 135-degree split-point cutting edges sharp for hundreds of additional cycles.