Product Description
CMT 378.052.12 Dowel Drill with Countersink for Through Holes is a left-hand rotation, carbide-tipped boring bit engineered for drilling, countersinking, and full through-penetration in a single pass. Designed for use on multi-spindle CNC boring machines, CNC boring centers, and panel processing equipment, this 5mm through-hole dowel drill delivers clean, accurate bores in chipboard, MDF, HDF, hardwood, softwood, plywood, laminates, and coated panels. The 2-flute geometry and precision-ground spurs make it a reliable choice for high-volume panel boring and cabinet production workflows.
Key Features
- Tungsten Carbide (HW) Cutting Material - hard-wearing carbide construction maintains a sharp cutting edge through repeated use in abrasive engineered wood panels, reducing downtime for bit changes in production environments.
- Left-Hand (LH) Rotation - designed specifically for left-hand spindle configurations on multi-spindle CNC boring machines and boring centers, ensuring proper chip evacuation and clean hole entry on the correct face of the panel.
- Through-Hole with Countersink Geometry (60 deg. tooth geometry) - combines drilling, countersinking, and through-penetration into one operation, eliminating secondary passes and improving cycle time on panel processing lines.
- 2 Flutes and 2 Precision-Ground Spurs - the dual-spur configuration scores the material ahead of the cutting edges, producing clean bore walls with minimal tearout on laminates, coated panels, and melamine surfaces.
- 10x20mm Shank with 25/64" Compatibility - the standardized shank dimensions allow direct insertion into boring machine adapters or chucks without modification, simplifying tool changes on compatible equipment.
- 35mm Cutting Height and 70mm Total Length - the extended cutting height accommodates through-drilling in standard panel thicknesses, while the compact overall length suits tight spindle spacing on multi-spindle heads.
Why This Product
- The integrated countersink profile performs drilling and countersinking simultaneously, making this bit a practical choice for cabinet manufacturers and panel processors who need clean through-holes without multiple tool setups.
- At 5mm diameter, this dowel drill matches standard dowel pin sizing used in cabinet assembly and furniture production, ensuring consistent fit and alignment for dowel joints in chipboard, MDF, and plywood panels.
- Left-hand rotation is a required specification on many multi-spindle boring heads - selecting the correct LH bit prevents tool damage, spindle stress, and poor hole quality that results from using mismatched rotation bits.
- Carbide-tipped (HW) construction holds up to the abrasive resins and adhesives found in MDF, HDF, laminates, and coated panels, making this bit a durable option for production shops processing large volumes of engineered sheet goods.
Specifications
- Manufacturer Part Number: 378.052.12
- Brand: CMT Orange Tools
- Diameter: 5mm
- Cutting Height: 35mm
- Cutting Height I1: 31mm
- Total Length: 70mm
- Shank: 10x20mm
- Shank Compatibility: 25/64" x 25
- Number of Flutes: 2
- Number of Spurs: 2
- Rotation: LH (Left-Hand)
- Tooth Geometry: Through holes 60
- Blade Material: HW (Tungsten Carbide)
- Product Series: With Countersink Through Hole
Approved Applications
- Chipboard and particleboard panel boring
- MDF and HDF panel drilling
- Hardwood and softwood through-hole drilling
- Plywood boring and countersinking
- Laminate and coated panel through-hole drilling
- Dowel joint preparation in cabinet and furniture production
- Multi-spindle CNC boring machine operations
- CNC boring center and panel processing center applications
- Boring machine with adapter or chuck setups
Frequently Asked Questions
What is the difference between the Cutting Height (I) of 35mm and the Cutting Height I1 of 31mm on this bit?
The Cutting Height (I) of 35mm represents the full usable cutting length of the flutes, while the Cutting Height I1 of 31mm refers to a secondary cutting height measurement - typically the distance from the tip to the base of the countersink geometry. Both dimensions are important when matching this bit to the panel thickness and spindle stroke of your boring machine.
Is this dowel drill compatible with boring machines that use a chuck or adapter?
Yes. The 10x20mm shank on this bit is designed for use in multi-spindle CNC boring machines, CNC boring centers, panel processing centers, and boring machines equipped with a compatible adapter or chuck. Always verify your machine's spindle accepts a 10x20mm or 25/64" shank before installing.
Why does rotation direction matter when selecting a dowel drill?
This bit is built for left-hand (LH) rotation exclusively. Using a left-hand bit in a right-hand spindle - or vice versa - can result in poor hole quality, rough bore walls, tearout on panel faces, and potential damage to the spindle or tool holder. Always match the bit rotation to your machine spindle's rotation direction before use.
What panel materials is this 5mm through-hole dowel drill suitable for?
This bit is suited for chipboard, MDF, HDF, hardwood, softwood, plywood, laminates, and coated panels. The tungsten carbide (HW) cutting material and precision-ground spurs handle the abrasive nature of engineered wood products and coated surfaces, producing clean hole walls and minimal tearout on both faces of the panel during through-drilling operations.
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