CMT Dowel Drill with Countersink - 5/16" x 20 x 70mm, 10x33mm Shank, Left-Hand Rotation by CMT is a precision-engineered boring tool designed for drilling and countersinking in a single pass. Built around a tungsten carbide (HW) cutting head bonded to a super-strength steel body, this left-hand rotating drill delivers clean, accurate bores in panel materials such as chipboard, MDF, plywood, and coated panels. The integrated countersink geometry creates a flush recess for bolt heads and hardware connectors without requiring a secondary tool pass, making it a go-to choice for panel processing centers, multi-spindle CNC boring machines, and horizontal boring operations.

Key Features

• HW (Tungsten Carbide) Cutting Head - hard carbide material maintains sharp edges through high-volume boring cycles, reducing downtime for resharpening or tool changes.
• 2 Precision-Ground Cutting Edges (Z2) - dual cutting geometry produces consistent bore diameters and smooth hole walls across repeated passes in production environments.
• 2 Ground Spurs (V2) - precision-ground spurs score the material perimeter ahead of the cutting edges, preventing fiber tearout and delivering clean entry holes in laminates and coated panels.
• 2 Spiral Flutes with PTFE Coating - the orange or black P.T.F.E. non-stick coating on the spiral portion prevents pitch and adhesive buildup, extending tool life and keeping flutes clear for efficient chip evacuation.
• Integrated Countersink - combines drilling and countersinking in one operation, creating a clean recess for bolt heads and connectors in thicker panel stock without a secondary tool or setup change.
• Parallel Shank with Driving Flat and Length Adjusting Screw - the 10x33mm shank with driving flat ensures positive engagement in machine collets, while the length adjusting screw allows precise depth setting for repeatable results.
• Left-Hand (LH) Rotation - designed specifically for left-hand spindle positions on multi-spindle boring machines and CNC boring centers, enabling correct cutting action and clean hole geometry on LH stations.
• Super-Strength Steel Body - the steel shank and body resist deflection under load, supporting straight, true bores even at depth in dense panel materials.

Why This Product

• Combines drilling and countersinking into a single tool pass - eliminating the need for a separate countersink bit saves machine time and reduces setup complexity on panel processing lines.
• Purpose-built left-hand rotation makes it a direct fit for LH spindle stations on multi-spindle CNC boring machines and boring centers where a right-hand drill would cut incorrectly and damage the workpiece.
• The PTFE-coated spiral resists pitch and glue adhesion, which is especially valuable when boring through laminated, coated, or pre-glued panels where resin transfer can quickly degrade uncoated tooling.
• Ground spurs combined with a precision carbide head deliver tearout-free entry in delicate surfaces like laminates and coated chipboard, protecting finished panel faces that are visible in the final assembly.

Specifications

• Manufacturer Part Number: 377.082.12
• Brand: CMT Orange Tools
• Diameter: 5/16"
• Cutting Height: 20mm
• Total Length: 70mm
• Shank: 10x33mm
• Rotation: LH (Left-Hand)
• Number of Cutting Edges: 2
• Number of Spurs: 2
• Number of Flutes: 2
• Cutting Material: HW (Tungsten Carbide)
• Tool Type: Dowel Drill with Countersink

Approved Applications

• Drilling and countersinking in a single pass on panel stock
• Bolt head and connector recessing in thicker panels
• Dowel hole boring on multi-spindle CNC boring machines
• Panel processing on CNC boring centers and boring machines with adapter or chuck
• Left-hand spindle station boring operations