Product Description
CMT Hinge Boring Bit 20 x 57.5mm Left-Hand Rotation by CMT is a precision-engineered boring bit designed for drilling flat-bottom hinge cup holes in cabinet doors, face frames, and panel components. Built specifically for European-style concealed hinge installation, this 20mm diameter bit delivers clean, accurate bores in solid hardwood, softwood, chipboard, MDF, and plywood. The left-hand (LH) rotation makes it the correct choice for multi-spindle boring machines and CNC boring centers equipped with adaptors or chucks that require counter-clockwise tooling. Whether you are outfitting a cabinet shop or a panel processing line, this bit provides the geometry and material quality needed for repeatable, professional results.
Key Features
- Tungsten Carbide (HW) Cutting Head - the carbide head holds a sharper edge longer than standard steel, reducing replacement frequency and maintaining consistent bore quality across high-volume production runs.
- 2 Precision-Ground Cutting Edges (Z2) - dual cutting edges balanced across the head deliver smooth, even material removal, producing flat-bottom holes that seat European concealed hinges accurately and securely.
- 2 Negatively Ground Spurs (V2) - the negatively ground spur geometry scores the material perimeter before the cutters clear the waste, producing clean bore walls and a crisp entry circle with minimal tearout on finished panel surfaces.
- Precision-Balanced Centre Point - the HW centre point locates the bit precisely on the marked position and keeps the bore on-centre throughout the cut, critical for hinge cup holes that must align with face frame or door edge geometry.
- PTFE-Coated Cutter Portion - the orange or black P.T.F.E. coating on the cutter portion reduces pitch and resin buildup from chipboard and MDF, keeping the bit running freely and extending tool life in continuous production use.
- Super-Strength Steel Body - the steel body resists flex and vibration during boring, contributing to bore accuracy and reducing the risk of chatter marks inside the hinge cup cavity.
- 10 x 26mm Parallel Shank with Driving Flat and Length Adjusting Screw - the parallel shank format with a driving flat and length adjusting screw allows precise depth setting and secure chuck or adaptor engagement on boring machines, CNC boring centers, and panel processing centers.
- Left-Hand (LH) Rotation - correctly matches counter-clockwise spindle configurations on multi-spindle boring machines equipped with LH positions, ensuring the bit cuts rather than backs out during operation.
Why This Product
- The 20mm diameter and flat-bottom boring geometry are the exact requirements for standard European concealed hinge cups - using the correct bit eliminates the fitting problems caused by incorrect bore depth or profile.
- The carbide (HW) head combined with the P.T.F.E.-coated cutter portion makes this bit well-suited for production work in composite panels such as chipboard and MDF, where resin buildup quickly degrades standard steel tooling.
- The negatively ground spurs and precision-balanced centre point work together to produce clean, consistent holes in a single pass, reducing the need for secondary cleanup work on hinge cup bores in finished or pre-finished components.
- The parallel shank with driving flat and length adjusting screw gives operators repeatable depth control across every spindle position, which is essential when boring multiple hinge locations on a cabinet door in a single machine cycle.
Specifications
- Manufacturer Part Number: 317.200.12
- Brand: CMT Orange Tools
- Product Type: Hinge Boring Bit
- Diameter: 20mm
- 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
- Head Material: HW (Tungsten Carbide)
- Body Material: Super-strength steel
- Coating: P.T.F.E. (orange or black) on cutter portion
- Shank Style: Parallel shank with driving flat and length adjusting screw
Approved Applications
- Drilling flat-bottom hinge cup holes for European concealed hinge installation
- Cabinet door hinge cup boring
- Face frame hinge mounting preparation
- Use on boring machines equipped with adaptors or chucks
- Use on multi-spindle CNC boring machines and panel processing centers at LH spindle positions
- Compatible materials: solid hardwood, softwood, chipboard, MDF, and plywood
Frequently Asked Questions
Why does this bit rotate left-hand (LH) instead of right-hand?
Multi-spindle boring machines use both right-hand and left-hand spindle positions to allow close spacing of drill heads. The LH rotation on this bit matches the counter-clockwise spindle positions on those machines. Installing a right-hand bit in a left-hand spindle position would cause the bit to back out rather than cut into the material.
What is the purpose of the negatively ground spurs on a hinge boring bit?
The negatively ground spurs (V2) score and sever the wood fibers at the outer perimeter of the bore before the main cutting edges remove the material. This sequence produces a clean, crisp entry circle and flat-bottom cavity with minimal tearout - an important result when boring hinge cups in pre-finished or veneered panel surfaces.
What does the P.T.F.E. coating on the cutter portion do?
The P.T.F.E. coating reduces the adhesion of pitch, resin, and glue to the cutter portion of the bit. This is particularly useful when boring chipboard and MDF, which contain adhesive resins that can accumulate on uncoated tooling and increase friction, heat, and cutting resistance over time.
What machines can use this bit?
This bit is designed for boring machines equipped with adaptors or chucks. Compatible machine types include multi-spindle CNC boring machines, CNC boring centers, and panel processing centers that accept the 10 x 26mm parallel shank with driving flat and length adjusting screw.
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