Product Description
CMT 309.120.12 Dowel Drill 12 x 43 x 70mm LH is a left-hand rotation, four-flute boring tool engineered by CMT for precision blind-hole drilling in furniture panels, cabinet components, and flat-pack assemblies. Built around a tungsten carbide (HW) cutting head mounted on a super-strength steel body, this 12mm dowel drill delivers the clean, flat-bottomed holes required for reliable dowel joinery in solid wood, chipboard, MDF, laminates, and coated panel materials. The long-series 70mm overall length accommodates thicker panel stock where standard-length drills fall short, and the PTFE-coated cutter portion actively resists pitch and adhesive buildup during production runs.
Key Features
- Tungsten Carbide (HW) Cutting Head - hard-wearing carbide material stays sharp through extended runs in abrasive materials like chipboard, MDF, and laminates, reducing regrind frequency and downtime.
- PTFE Coating on the Cutter Portion - black or orange PTFE surface prevents pitch and glue from adhering to the flutes, keeping the drill running freely and extending tool life between cleanings.
- 2 Precision-Ground Cutting Edges (Z2) - balanced dual cutting edges produce consistently flat hole bottoms essential for flush-seating dowels and confirmat-style joints.
- 2 Negatively Ground Spurs (V2) - negatively set spurs score the panel surface cleanly before the cutting edges engage, eliminating tearout on veneered, laminated, and coated boards.
- 4 Spiral Flutes - four-flute geometry provides efficient chip evacuation from the bore, preventing chip packing that can cause overheating or surface damage in blind-hole drilling.
- Precision Balanced Centre Point - the HW centre point self-locates accurately at the bore position, keeping the drill on target and producing holes that align reliably across multi-row drilling patterns.
- 10 x 20mm Parallel Shank with Driving Flat and Length-Adjusting Screw - the standardised shank fits multi-spindle CNC boring heads and single-spindle chucks, while the adjusting screw lets operators fine-tune drilling depth without changing tooling.
- Left-Hand (LH) Rotation - designed specifically for left-hand spindle positions on multi-spindle boring machines, ensuring correct cutting geometry and spur orientation on that side of the head.
- Long-Series 70mm Overall Length - the extended body reaches deeper into thick panel stock compared to short-series equivalents, making this drill suitable for panels that require deeper blind holes.
Why This Product
- The negatively ground spurs combined with the carbide cutting edges make this drill a precise choice for coated, veneered, and laminated panels where surface tearout around the bore entry would be visible in the finished piece.
- The 70mm long-series length addresses a specific production need - panels thick enough to require deeper blind holes that a standard short-series dowel drill cannot reach, without requiring a longer shank adapter.
- The PTFE-coated flutes reduce adhesive and resin buildup during glue-dowel assembly operations, meaning the drill maintains cutting performance longer between stoppages for cleaning.
- The left-hand rotation designation makes this drill a direct, correctly-oriented replacement for LH spindle positions on twin-row and multi-row boring machines used in cabinet and furniture panel processing, where using a right-hand drill in an LH spindle would produce incorrect cutting geometry.
Specifications
- Manufacturer Part Number: 309.120.12
- Brand: CMT Orange Tools
- Diameter: 12mm
- Cutting Height: 43mm
- Total Length: 70mm
- Shank: 10 x 20mm (parallel shank with driving flat and length-adjusting screw)
- Rotation: Left-Hand (LH)
- Number of Flutes: 4
- Number of Cutting Edges: 2 (Z2)
- Number of Spurs: 2 (V2)
- Spur Sharpening: Negatively ground spurs
- Blade Material: HW (Tungsten Carbide)
- Cutter Coating: Black or orange PTFE
- Body Material: Super-strength steel
- Product Type: Dowel Drill - Long Series
Approved Applications
- Blind-hole drilling for dowel connections in furniture and cabinet panels
- Dowel joinery in solid hardwood and softwood
- Panel drilling in chipboard and particleboard
- Boring in MDF and HDF sheet materials
- Drilling in laminated and coated panels
- Multi-spindle CNC boring machine operations (LH spindle positions)
- Flat-pack furniture component manufacturing
- Cabinet making and case construction
Frequently Asked Questions
Why does this dowel drill have left-hand (LH) rotation, and how do I know if I need it?
Multi-spindle horizontal boring machines used in panel processing have both right-hand and left-hand spindles arranged in opposing rows. The LH designation on this drill means it is ground to cut correctly when spinning counter-clockwise, which is the direction of left-hand spindle positions. Installing a right-hand drill in a left-hand spindle reverses the cutting geometry and the spur orientation, producing poor hole quality and accelerated wear. Check your machine's spindle layout and match the rotation direction to the specific spindle position you are filling.
What is the purpose of the negatively ground spurs on this drill?
The two negatively ground spurs score the panel surface cleanly at the outer perimeter of the bore before the main cutting edges remove material. This pre-scoring action severs surface fibres, veneer layers, laminate films, or coatings cleanly rather than lifting or tearing them. The result is a clean bore entry with no chipping or delamination around the hole edge - a critical quality requirement for dowel holes that will be visible or that seat decorative hardware.
What does the PTFE coating on the cutter portion do in practice?
PTFE (polytetrafluoroethylene) is a low-friction, non-stick surface coating applied to the spiral flutes and cutter area. In production environments where dowel drilling is followed by glue application, resin from MDF binders, wood pitch from solid timber, and adhesive residue can accumulate on drill flutes and slow chip evacuation. The PTFE coating reduces adhesion of these materials to the drill surface, keeping the flutes cleaner during extended runs and helping maintain consistent bore quality and cutting speed between tool changes.
How does the length-adjusting screw on the shank work, and why is it useful?
The parallel shank on this drill includes a driving flat and a length-adjusting screw. When the drill is mounted in a boring head or chuck, the adjusting screw allows the operator to set the drill's protrusion depth precisely without removing or swapping the tool. This is particularly useful when setting up multi-spindle boring heads where each drill must reach exactly the same depth to produce uniform blind holes across a row - small depth inconsistencies cause dowels to seat unevenly, affecting joint strength and panel alignment.
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