CMT 316.090.12 Countersink for 4 Flute Drills - 23/64 in. Diameter, Left-Hand Rotation by CMT is a precision-engineered left-hand countersink designed to pair with 4-flute dowel drills on multi-spindle CNC boring machines and CNC boring centers. With a 45 deg. cutting angle, 18mm cutting diameter, and a 9mm bore diameter, this carbide-tipped tool delivers clean, accurate countersinking in chipboard, MDF, HDF, plywood, hardwood, softwood, laminates, and coated panels. Its left-hand rotation makes it the correct choice for driven spindles that turn counter-clockwise, ensuring proper cutting geometry and chip ejection on every pass.

Key Features

• Hard Metal (HW) Carbide Construction - the tungsten carbide tool material maintains a sharp cutting edge through high-volume production runs, reducing downtime from tool changes and delivering consistent countersink quality across engineered wood panels and natural wood species.
• 45 deg. Cutting Angle - matches the geometry required for standard countersunk screw heads and dowel holes, producing a smooth, correctly angled seat in one pass without secondary operations.
• Left-Hand (LH) Rotation - engineered specifically for left-hand-driven spindles on multi-spindle CNC boring machines, ensuring the cutting edges engage the material correctly and do not rub or skip during operation.
• 2-Tooth Cutting Configuration - balanced twin cutting edges distribute cutting forces evenly, reducing vibration and surface tearout for cleaner hole edges on both face and edge applications.
• 18mm Diameter with 9mm Bore - the bore diameter seats precisely on compatible spindle shanks while the 18mm cutting diameter accommodates standard countersink requirements, minimizing adapter hardware and setup time.
• Compact 15mm Total Length - the short overall profile minimizes spindle overhang and deflection, improving concentricity and hole quality at higher feed rates.

Why This Product

• Purpose-built left-hand rotation geometry means this countersink works correctly on LH-driven spindles without improvised workarounds - the cutting edges are oriented to shear material cleanly rather than rub, which directly protects surface finish on laminated and coated panels.
• The HW carbide material and 2-tooth design support the elevated feed rates associated with 4-flute drill setups on CNC boring centers, keeping cycle times low without sacrificing hole quality.
• At 18mm cutting diameter with a 9mm bore, this tool fits standard multi-spindle tooling systems directly, reducing the need for adapters and keeping setup simple on panel processing centers and boring machines with adapter or chuck configurations.
• The 45 deg. angle is a production-standard geometry for furniture and cabinet hardware, making this countersink a direct drop-in solution for countersunk screw and fitting applications in chipboard, MDF, HDF, plywood, and solid wood components.

Specifications

• Manufacturer Part Number: 316.090.12
• Brand: CMT Orange Tools
• Diameter: 18mm
• Bore Diameter: 9mm
• Total Length: 15mm
• Cutting Angle: 45 deg.
• Number of Teeth: 2
• Rotation: Left-Hand (LH)
• Blade Material: HW (Hard Metal Carbide)

Approved Applications

• Chipboard
• MDF
• HDF
• Hardwood
• Softwood
• Plywood
• Laminates
• Coated Panels

Compatible Machines

• Multi-Spindle CNC Boring Machine
• CNC Boring Center
• Panel Processing Center
• Boring Machine with Adapter or Chuck