CMT Hinge Boring Bit 38 x 57.5mm Left-Hand Rotation by CMT is a precision-engineered left-hand rotation boring bit designed for drilling flat-bottom hinge cup holes in cabinet doors, face frames, and panel components. Built for use on boring machines equipped with adaptors or chucks, this bit delivers the clean, consistent bore geometry required for European-style concealed hinge installation. With a tungsten carbide (HW) cutting head, negatively ground spurs, and a PTFE-coated cutter portion, it combines long tool life with chip-free performance in solid wood, composite panels, and engineered sheet goods.

Key Features

• HW (Tungsten Carbide) Cutting Head - hard-wearing carbide construction maintains a sharp cutting edge through high-volume production runs, reducing downtime from frequent sharpening or replacement.
• 2 Precision Ground Cutting Edges (Z2) - dual balanced cutting edges distribute cutting forces evenly, producing a flat-bottom bore with minimal tear-out and consistent hole quality across workpieces.
• 2 Negatively Ground Spurs (V2) - negatively ground spurs score the material perimeter ahead of the cutters, delivering clean bore walls that require little or no sanding before hinge cup installation.
• PTFE Coating on Cutter Portion - orange or black PTFE coating prevents pitch and glue buildup on the bit body, so the tool stays cleaner longer and maintains consistent feed performance in resinous or adhesive-saturated materials.
• Precision Balanced Centre Point - the HW centre point self-locates accurately at the marked bore position, reducing layout error and keeping the hole centered without pre-drilling a pilot hole.
• Super-Strength Steel Body - the steel body withstands the torsional stress of machine boring operations, providing a rigid, vibration-resistant platform that protects the carbide head.
• Parallel Shank with Driving Flat and Length Adjusting Screw - the 10 x 26mm parallel shank with driving flat locks securely in machine adaptors or chucks, while the length adjusting screw allows precise boring depth setting without additional spacers.
• Left-Hand Rotation (LH) - designed specifically for left-hand spindle positions on multi-spindle boring machines, ensuring correct cutting geometry and chip evacuation when paired with the appropriate machine station.

Why This Product

• The flat-bottom bore geometry and negatively ground spur design produce the exact hole profile needed for European concealed hinges - eliminating fit issues and reducing rework during cabinet door hanging.
• The HW carbide head with PTFE-coated cutter portion is built for machine boring environments where bits cycle continuously through chipboard, MDF, plywood, and hardwood - materials that quickly dull uncoated or lesser-grade tooling.
• The parallel shank with driving flat and length adjusting screw integrates directly with boring machine adaptors and chucks, making depth setup straightforward and repeatable from the first hole to the last.
• Left-hand rotation matches the spindle direction of LH-designated stations on multi-spindle CNC boring machines and boring centers, so this bit slots into an existing tooling layout without requiring machine reconfiguration.

Specifications

• Manufacturer Part Number: 317.380.12
• Brand: CMT Orange Tools
• Product Type: Hinge Boring Bit
• Diameter: 38mm
• Total Length: 57.5mm
• Shank: 10 x 26mm
• Rotation: Left-Hand (LH)
• Number of Cutting Edges: 2 (Z2)
• Number of Spurs: 2 (V2)
• Spur Geometry: Negatively ground spurs
• Material: HW (Tungsten Carbide)

Approved Applications

• Drilling flat-bottom hinge cup holes for European concealed hinge installation
• Cabinet door hinge cup boring
• Face frame hinge pocket drilling
• Panel component boring on multi-spindle CNC boring machines
• Boring centers and panel processing centers equipped with adaptors or chucks
• Boring machines equipped with parallel shank chucks or adaptors