Product Description
CMT Dowel Drill for Through Holes - 5/16" x 35 x 70mm Left-Hand Rotation is a solid carbide boring bit engineered for clean, precise through-hole drilling in furniture manufacturing, panel processing, and dowel joinery applications. Built entirely from premium super micrograin carbide, this left-hand rotating drill delivers exceptional bore quality in hardwood, chipboard, MDF, HDF, particle board, and veneered panels. Its 35mm cutting height and 70mm total length make it well suited for through-hole work in panels, and its 10x26mm parallel shank with driving flat ensures secure, repeatable positioning on multi-spindle CNC boring machines and high-speed boring units alike.
Key Features
- Solid Carbide (HW) Construction - the entire bit is machined from premium super micrograin carbide sourced from Luxembourg, meaning no carbide-to-steel interface to fail under stress and an almost unlimited number of resharpenings over the tool's service life.
- Curved, Negatively Ground Spurs - produce exceptionally clean bore walls and flat-bottom entry/exit surfaces with no rough edges or tearout, reducing the need for secondary finishing on veneered or laminated panels.
- Centre-Point Balanced Tip - the precision balanced centre point keeps the drill on-axis from first contact, eliminating drift and delivering consistent, repeatable hole placement across high-volume production runs.
- Plunge Edge Running to Centre - reduces drilling resistance throughout the cut, allowing faster feed rates and higher production throughput without sacrificing bore quality.
- 2 Precision-Ground Cutting Edges (Z2) - the two spiral flutes with double-angle geometry clear chips efficiently and keep cutting forces balanced, extending time between sharpenings and maintaining consistent performance.
- Left-Hand (LH) Rotation - specifically designed for left-hand spindle positions on multi-spindle CNC boring centers, ensuring proper chip evacuation and clean entry on the correct face of the workpiece.
- Parallel Shank with Driving Flat - 10x26mm - the driving flat provides positive rotational engagement in the boring unit chuck, preventing slippage under load and simplifying tool changes.
- Extreme Sharpening Rating - the solid carbide body withstands repeated precision resharpening, making this bit a long-term investment compared to carbide-tipped alternatives that cannot be resharpened as aggressively.
- Ideal for Hardwood and Difficult Composites - the micro grain carbide cutting geometry handles the abrasive resins and grit present in particle board, MDF, and coated panels without premature edge breakdown.
Why This Product
- Through-hole geometry with a 35mm cutting height and 70mm overall length is designed specifically for panel-depth through-hole drilling, providing the reach needed for dowel connection applications without the tool length waste of longer general-purpose bits.
- Solid micrograin carbide construction - as opposed to carbide-tipped steel - means the bit can be resharpened an almost infinite number of times, lowering long-term cost per hole in high-volume furniture and panel processing environments.
- The negatively ground curved spurs and centre-balanced tip work together to eliminate exit tearout on veneered, laminated, and coated panel faces - directly protecting finished workpiece quality at the most critical moment of the cut.
- Left-hand rotation compatibility makes this bit a direct fit for LH spindle positions on multi-spindle CNC boring machines and panel processing centers, removing the need for adapters or workarounds that can introduce runout.
Specifications
- Manufacturer Part Number: 314.080.42
- Brand: CMT Orange Tools
- Diameter: 5/16"
- Cutting Height: 35mm
- Total Length: 70mm
- Shank: 10x26mm
- Number of Teeth: 2
- Rotation: Left-Hand (LH)
- Material: HW (Solid Carbide)
- Sharpening Rating: Extreme
Approved Applications
- Through-hole drilling for dowel connections
- Panel processing and furniture manufacturing
- Drilling in hardwood and softwood
- Boring in chipboard, particle board, and MDF
- Through-hole work in HDF, plywood, and laminates
- Coated and veneered panel boring
- High-speed multi-spindle boring unit operations
- CNC router and CNC boring 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 is designed to bore completely through the panel from one face to the other. This CMT bit has a 35mm cutting height and 70mm total length specifically sized for through-hole work. Blind-hole dowel drills are shorter and optimized to stop at a set depth without exiting the opposite face. The through-hole geometry on this bit - including the negatively ground curved spurs - is engineered to produce a clean exit bore with no tearout on the back face.
Why does this bit use left-hand (LH) rotation, and how do I know if my machine needs it?
Multi-spindle CNC boring machines and panel processing centers use both right-hand and left-hand spindle positions to drill multiple holes simultaneously. Left-hand spindles rotate counterclockwise and require LH-rotation bits to cut correctly and evacuate chips in the proper direction. Check your boring unit's spindle layout or machine documentation to confirm which spindle positions require LH tooling before ordering.
Can this solid carbide bit be resharpened, and how many times?
Yes. Because the bit is constructed entirely from solid micrograin carbide rather than a carbide tip brazed onto a steel body, it can be resharpened an almost infinite number of times according to CMT. The solid construction also means there is no brazed joint that could fail during resharpening. CMT rates this bit as "Extreme" for sharpening capability, making it a long-life investment in high-production environments.
What materials is this dowel drill compatible with?
This bit is ideal for hardwood and difficult composites including particle board, MDF, and veneered wood. It also performs well in chipboard, HDF, softwood, plywood, laminates, and coated panels. The super micrograin carbide cutting edges resist the abrasive fillers and resins found in engineered wood products, maintaining sharp cutting geometry longer than conventional tooling in these demanding materials.
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