CMT 310.040.21 Dowel Drill 4 x 20 x 57.5mm RH is a solid carbide boring bit engineered for high-precision dowel hole drilling in demanding woodworking and panel processing applications. Built entirely from premium super-micrograin carbide sourced from Ceratizit, this 4mm diameter drill delivers exceptionally clean, flat-bottom blind holes in hardwood, MDF, particle board, veneered panels, and difficult composite materials. With a right-hand rotation, 2 cutting edges, and a 10 x 25mm parallel shank with driving flat, it is purpose-built for high-speed boring units and CNC routers where accuracy and productivity are non-negotiable.

Key Features

• Solid super-micrograin carbide construction (HWM) - the entire bit is made from a single unit of premium Ceratizit carbide, providing exceptional wear resistance and supporting an almost infinite number of resharpenings, reducing long-term tooling costs significantly.
• Curved, negatively ground spurs (V2) - the 2 precision-ground spurs produce exceptionally clear bore walls and flat-bottom holes with no rough edges or tearout, even in veneered and coated panels where surface quality is critical.
• Centre-point balanced tip design - the balanced centre point ensures accurate hole placement and consistent entry every time, minimising drift and improving positional accuracy on multi-spindle and CNC boring operations.
• Plunge edge runs to the centre of the bit - this design reduces drilling resistance during plunge entry, allowing faster production speeds and less load on the machine spindle during high-volume runs.
• Oversized cylindrical head - larger than traditional boring bit tips, the cylindrical head is extremely resistant to prolonged use, maintaining dimensional accuracy over extended production cycles.
• 20mm cutting height (I) with 57.5mm total length - the short-series form factor is optimised for multi-spindle boring machines and CNC boring centres where compact tool projection and tight gang-drilling layouts are required.
• 10 x 25mm parallel shank with driving flat - ensures secure, non-slip seating in standard boring machine chucks and adjustable-screw holders, preventing tool rotation under load.
• Rated for extreme sharpening - the solid carbide body can be resharpened to the highest degree, maintaining performance geometry and extending the usable life of the tool well beyond conventional HSS alternatives.
• 2 spiral flutes (Z2) - dual-flute geometry provides efficient chip evacuation from blind holes, reducing heat buildup and maintaining clean bore quality during continuous operation.

Why This Product

• For furniture manufacturers and cabinet shops running CNC boring centres or multi-spindle machines, the solid carbide body and negatively ground spurs deliver consistently clean, splinter-free holes in veneered panels and MDF - materials where tearout around the bore entry is a common production problem with lower-grade bits.
• The almost infinite resharpening capability of the solid carbide construction means this bit remains a cost-effective long-term tooling investment, particularly for high-volume production environments where conventional bits wear out quickly and require frequent replacement.
• The reduced drilling resistance from the centre-reaching plunge edge directly translates to faster cycle times on CNC and multi-spindle boring equipment - a measurable productivity advantage in panel processing and flat-pack furniture production.
• With a 4mm diameter and right-hand rotation at 57.5mm overall length, this bit is a direct-fit solution for standard dowel connection drilling in particle board and hardwood components, covering the most common joinery boring diameter used in furniture and cabinet assembly.

Specifications

• Manufacturer Part Number: 310.040.21
• Brand: CMT Orange Tools
• Diameter: 4mm
• Cutting Height: 20mm
• Total Length: 57.5mm
• Shank: 10 x 25mm (parallel shank with driving flat)
• Rotation: Right-hand (RH)
• Number of Cutting Edges: 2
• Number of Spiral Flutes: 2
• Number of Spurs: 2
• Blade Material: HWM solid super-micrograin carbide
• Sharpening Rating: Extreme

Approved Applications

• Blind hole drilling for dowel connections and panel joinery
• Furniture manufacturing and flat-pack component drilling
• Cabinet making and case construction
• Panel processing on multi-spindle CNC boring machines
• High-speed boring in hardwood and softwood
• Drilling in particle board, MDF, HDF, and veneered panels
• Difficult composite materials including coated and laminated panels