The image shows a drill bit with a countersink attachment, designed to drill a hole and a beveled recess for a screw head in one step. The top portion is a standard spiral-fluted drill bit, while the bottom is a wider, black countersink sleeve with a hexagonal shank for a quick-change chuck.
The image shows a drill bit with a countersink attachment, designed to drill a hole and a beveled recess for a screw head in one step. The top portion is a standard spiral-fluted drill bit, while the bottom is a wider, black countersink sleeve with a hexagonal shank for a quick-change chuck.
Retail hang-card packaging for the Bosch SP508 #8 hex shank screw pilot bit, showing its ability to drill a pilot hole and countersink in one easy step for wood and PVC.
The image shows a drill bit with a countersink attachment, designed to drill a hole and a beveled recess for a screw head in one step. The top portion is a standard spiral-fluted drill bit, while the bottom is a wider, black countersink sleeve with a hexagonal shank for a quick-change chuck.
The image shows a drill bit with a countersink attachment, designed to drill a hole and a beveled recess for a screw head in one step. The top portion is a standard spiral-fluted drill bit, while the bottom is a wider, black countersink sleeve with a hexagonal shank for a quick-change chuck.
The image shows a drill bit with a countersink attachment, designed to drill a hole and a beveled recess for a screw head in one step. The top portion is a standard spiral-fluted drill bit, while the bottom is a wider, black countersink sleeve with a hexagonal shank for a quick-change chuck.
Retail hang-card packaging for the Bosch SP508 #8 hex shank screw pilot bit, showing its ability to drill a pilot hole and countersink in one easy step for wood and PVC.
The image shows a drill bit with a countersink attachment, designed to drill a hole and a beveled recess for a screw head in one step. The top portion is a standard spiral-fluted drill bit, while the bottom is a wider, black countersink sleeve with a hexagonal shank for a quick-change chuck.
BOSCH

Bosch Countersink Bit SP508 Number 8 Screw Pilot (1/4 Hex Shank Adjustable Depth Counterbore Wood Plastic Composite Cabinetry Drilling Tool)

In stock
SKU: SP508
$5.99 USD

Description

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Bosch SP508 #8 Hex Shank Screw Pilot Countersink Bit

The Bosch SP508 #8 hex shank countersink drill bit bores pilot holes and bevels flush countersinks or deep counterbores in a single pass across wood, plastic, and composite decking. Engineered with an adjustable set-screw depth collar and a replaceable high-speed steel center pilot bit, this 0.038-pound accessory eliminates material splitting around #8 flat-head fasteners. Outfitted with a non-slip 1/4-inch quick-change hex shank for instant chuck seating in impact drivers, drills, and stationary drill presses, it equips cabinetmakers, deck builders, and finish carpenters with precise, repeatable screw seating performance.

Best Used For:

  • Cabinetry and Furniture Face Frame Fastening: Boring flush pilot recesses for #8 wood screws in fine hardwoods to prevent surface splitting.
  • Composite Decking and Subfloor Installation: Counterboring deep seating holes for structural screws and hidden wood plug installations.
  • Repetitive Production Drill Press Operations: Setting standardized screw depths across plastics, softwoods, and composite panels on assembly lines.

Key Performance & Safety Features

  • One-Step Drilling and Countersinking: Bores the center pilot hole and cuts the chamfered screw head recess simultaneously to save time.
  • Adjustable Depth Counterbore: Precision set-screw collar adjusts easily with a standard hex key to customize screw head depth.
  • Universal 1/4-Inch Hex Shank: Power-grooved hex shank prevents slippage inside standard three-jaw drill chucks and quick-change adapters.
  • Field-Replaceable Center Pilot Bit: Allows worn or broken center twist bits to be swapped out rapidly without replacing the countersink body.
  • Multi-Substrate Flute Geometry: Engineered cutting flutes clear chips rapidly in dense hardwoods, softwoods, plastics, and composite boards.

What's Included

  • (1) Bosch SP508 #8 Hex Shank Screw Pilot Countersink Bit

Technical Specifications

Manufacturer Robert Bosch Tool Corporation
Model Number SP508
Product Classification Screw Pilot Countersink & Counterbore Bit
Screw Size Compatibility #8 Wood & Deck Fasteners (0.164" Screw Size)
Shank Interface Style 0.250 inches (1/4 in Quick-Change Hex Shank)
Overall Assembled Length 3.25 inches (82.55 mm)
Depth Adjustment Mechanism Adjustable Set Screw (Standard Allen Hex Key)
Center Bit Replaceability Fully Replaceable Twist Pilot Drill Bit
Total Assembled Weight 0.038 lbs (0.017 kg)
Target Substrates Hardwood, Softwood, Plastic, & Composite Decking
Product Condition Brand New OEM Power Tool Accessory
Compatible Tool Platforms Impact Drivers, Cordless Drills, & Drill Presses

Pro-Tip: When countersinking brittle hardwoods like oak or maple, adjust the pilot bit so it extends roughly 1/8-inch past the overall length of your #8 screw; this fully clears core wood fibers and prevents the screw shank from binding or snapping under final driving torque.