Product Description
CMT Two Flute Dowel Drill for Through Holes - 5/16" x 44 x 77mm Left-Hand Rotation is a professional-grade boring tool engineered for clean, accurate through-hole drilling in panel processing and furniture manufacturing. Built on a super-strength steel body with a tungsten carbide (HW) cutting head, this left-hand rotation drill delivers precision-balanced performance in multi-spindle CNC boring machines, panel processing centers, and compatible boring equipment. The 77mm overall length and 44mm cutting height make it well-suited for through-hole applications in thick panels, while the PTFE-coated spiral flutes resist pitch and glue buildup - keeping the tool cutting cleanly across extended production runs in solid wood, chipboard, MDF, laminates, and coated panels.
Key Features
- Tungsten carbide (HW) cutting head - delivers long-lasting sharpness and wear resistance in abrasive engineered wood materials like MDF, chipboard, and laminates, reducing tool change frequency in high-volume operations.
- Super-strength steel body - provides the structural rigidity needed to maintain consistent bore geometry and dimensional accuracy under the demands of repetitive CNC and multi-spindle boring cycles.
- Spiral portion coated with PTFE (orange or black) - resists pitch and glue adhesion so chips evacuate freely and the tool stays cleaner between sharpenings, extending usable tool life.
- Precision-balanced centre point - ensures accurate hole entry and centering on every plunge, reducing misalignment and scrap in dowel joint and panel assembly work.
- 2 precision-ground cutting edges (Z2) - produce clean bore walls and smooth hole exits for consistent dowel fit and clean-faced through-holes without secondary finishing.
- 2 spiral flutes - promote efficient chip evacuation during deep through-hole drilling, preventing clogging and heat buildup in thick panel stock.
- Parallel shank (10 x 26mm) with driving flat and length-adjusting screw - provides secure, repeatable tool registration in boring machine chucks and adapters, allowing quick depth setting without losing positional accuracy.
- Left-hand (LH) rotation - designed specifically for left-hand spindle positions on multi-spindle boring machines, ensuring proper cutting geometry and surface quality on the correct side of the work.
- Through-hole geometry optimized for 60 deg. sharpening - allows the tool to be resharpened and returned to service, supporting a lower cost-per-hole over the working life of the drill.
Why This Product
- Purpose-built for through-hole boring at 77mm total length - the extended 77mm length and 44mm cutting height reach through thick panels in a single pass, eliminating the need for step drilling or secondary operations on full-thickness workpieces.
- Carbide head paired with a PTFE-coated spiral - combines two independent durability features in one tool: hard-wearing cutting edges for abrasive materials and a non-stick coating that keeps the flutes clear, making this drill suitable for high-cycle production environments.
- Left-hand rotation fills a specific spindle position requirement - multi-spindle boring machines require matched LH and RH drills for each side. This LH drill ensures correct cutting direction, clean entry, and proper chip evacuation on left-hand spindle stations.
- Resharpenable design reduces long-term tooling cost - with a 60 deg. through-hole sharpening specification, worn cutting edges can be reground rather than replaced, making this drill a practical choice for shops managing tooling budgets in continuous panel production.
Specifications
- Manufacturer Part Number: 366.080.12
- Brand: CMT Orange Tools
- Diameter: 5/16"
- Cutting Height: 44mm
- Total Length: 77mm
- Shank: 10 x 26mm
- Number of Flutes: 2
- Blade Material: HW (Tungsten Carbide)
- Rotation: LH (Left-Hand)
- Sharpening: Through holes 60
Approved Applications
- Through-hole drilling for dowel connections
- Panel processing in furniture manufacturing
- Boring through chipboard, MDF, HDF, and coated panels
- Through-hole drilling in solid hardwood and softwood
- Drilling through plywood and laminate panel stock
- Multi-spindle CNC boring machine operations (left-hand spindle positions)
- CNC boring center and panel processing center applications
Frequently Asked Questions
What is the difference between a through-hole dowel drill and a blind-hole dowel drill?
A through-hole dowel drill like this CMT 366.080.12 is designed to bore completely through the workpiece from one face to the other. The geometry of the cutting head and flutes is optimized to exit the panel cleanly without blowout. A blind-hole drill, by contrast, stops at a set depth and leaves a closed bottom. For dowel connections in thick panels where full panel penetration is needed, a through-hole drill is the correct tool choice.
Why does this drill use left-hand (LH) rotation?
Multi-spindle boring machines and CNC boring centers are configured with both left-hand and right-hand spindles arranged symmetrically across the boring head. The LH rotation on this drill is required for correct cutting action on left-hand spindle positions. Using a right-hand drill on a left-hand spindle would cause the cutting edges to rub rather than cut, producing poor hole quality and rapid tool wear. Always match the drill rotation to the spindle direction of the machine position being used.
Can this drill be resharpened, and how?
Yes. This drill is designed to be resharpened to the through-hole 60 deg. specification listed in the product data. The 2 precision-ground cutting edges (Z2) can be reground to restore cutting performance, allowing the tool to be returned to service rather than discarded when edges become dull. Resharpening should be performed by a qualified tool grinding service familiar with tungsten carbide boring drills.
What shank size and configuration does this drill use?
This drill uses a 10 x 26mm parallel shank with a driving flat and a length-adjusting screw. The driving flat provides a positive rotational lock in the boring machine chuck or adapter, preventing the tool from spinning under load. The length-adjusting screw allows precise depth setting for repeatable, consistent hole depths across a production run without re-measuring after each tool change.
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