Product Description
CMT 308.160.12 Dowel Drill - 5/8" x 1-3/16" x 2-17/64" Left-Hand Rotation is a precision-engineered left-hand (LH) rotating dowel drill built by CMT for high-volume blind hole drilling in wood panels, composite boards, and laminates. With a 16mm (5/8") cutting diameter, a 30mm cutting height, and a compact 57.5mm overall length, this short-series boring bit is purpose-built for use in multi-spindle CNC boring machines and panel processing centers where tight tooling clearances demand reliable, repeatable results. Its tungsten carbide (HW) construction and negatively ground spurs deliver clean, flat-bottom holes with smooth bore walls - making it a dependable choice for furniture manufacturing, cabinet production, and panel joinery applications where dowel alignment and hole quality directly affect final assembly fit.
Key Features
- Tungsten Carbide (HW) Blade Material - provides exceptional hardness and wear resistance, allowing the bit to maintain a sharp cutting edge through extended production runs on chipboard, MDF, hardwood, and coated panels without premature dulling.
- Negatively Ground Spurs - engineered to score the material cleanly before the main cutting faces engage, producing flat-bottom blind holes with crisp bore walls and virtually no tearout or fiber lifting on laminates and veneered surfaces.
- 2-Spur, 2-Tooth Geometry - the balanced cutting configuration reduces vibration during boring, contributing to consistent hole roundness and dimensional accuracy across repeated drilling cycles in automated equipment.
- Left-Hand (LH) Rotation - specifically designed for left-hand spindle positions on multi-spindle CNC boring machines and panel processing centers, ensuring correct chip evacuation direction and proper spur engagement for each bore.
- 10x20mm Parallel Shank - the rectangular driving flat on the shank provides positive torque transfer and prevents shank slippage in boring machine chucks or adapters, maintaining accurate hole positioning throughout the production cycle.
- Short Series 57.5mm Overall Length - the compact profile allows dense spindle packing on multi-row boring heads, maximizing the number of bits that can be positioned simultaneously for panel drilling operations.
Why This Product
- The left-hand rotation is a critical specification - using an RH bit in a LH spindle position causes improper spur contact and poor hole quality, so this bit is the correct tooling solution for LH spindle positions on multi-spindle boring machines and CNC boring centers.
- The negatively ground spur geometry means laminated panels, coated boards, and veneered surfaces are scored cleanly before material removal begins, reducing the risk of surface delamination or chipping around hole edges - a direct quality benefit in finished furniture and cabinet components.
- Tungsten carbide (HW) construction stands up to the abrasive nature of chipboard, MDF, and HDF far longer than high-speed steel alternatives, reducing downtime from bit changes and keeping production throughput consistent in high-cycle shop environments.
- The 30mm cutting height paired with the 57.5mm short-series body makes this bit well-suited for blind dowel holes where depth consistency matters - the geometry supports repeatable, accurately sized pockets that accept standard dowel pins without adjustment.
Specifications
- Manufacturer Part Number: 308.160.12
- Brand: CMT Orange Tools
- Diameter: 16mm (5/8")
- Cutting Height: 30mm (1-3/16")
- Total Length: 57.5mm (2-17/64")
- Shank: 10x20mm
- Rotation: Left-Hand (LH)
- Number of Spurs: 2
- Number of Teeth: 2
- Sharpening: Negatively ground spurs
- Blade Material: Tungsten Carbide (HW)
Approved Applications
- Chipboard and particle board panels
- MDF (medium-density fiberboard)
- HDF (high-density fiberboard)
- Solid hardwood and softwood
- Plywood
- Laminates and coated panels
- Blind dowel hole drilling in furniture and cabinet components
- Panel processing on multi-spindle CNC boring machines
- CNC boring centers and panel processing centers
- Boring machines equipped with an adapter or chuck
Frequently Asked Questions
What does left-hand (LH) rotation mean, and how do I know if this bit is correct for my machine?
Left-hand rotation means the spindle - and therefore the bit - turns counterclockwise when viewed from the cutting end. Multi-spindle CNC boring machines and panel boring centers use both right-hand and left-hand spindles arranged in specific positions across the boring head. This CMT 308.160.12 is designed exclusively for LH spindle positions. Installing an LH bit on an RH spindle - or vice versa - will cause incorrect spur engagement, poor hole quality, and potential damage to the tooling or workpiece. Always confirm the rotation direction of each spindle position on your machine before installing this bit.
What shank size and type does this dowel drill use, and is it compatible with standard boring machine chucks?
This bit uses a 10x20mm parallel shank with a driving flat. The driving flat is a machined flat surface on the round shank that mates with a corresponding flat inside the boring machine chuck or adapter, providing positive torque transfer and preventing the bit from spinning freely under load. This is the standard shank configuration used across a wide range of multi-spindle boring machines and CNC boring centers. Confirm your machine accepts a 10x20mm shank before installation.
What materials can this dowel drill cut, and are there any materials it is not suited for?
This bit is designed for drilling blind holes in chipboard, particle board, MDF, HDF, solid hardwood, softwood, plywood, laminates, and coated panels. The tungsten carbide (HW) cutting tips handle the abrasive silica and adhesive resins found in composite wood products without rapid edge degradation. The negatively ground spurs are particularly effective at producing clean entry holes in laminates and coated surfaces. This bit is not intended for metal, masonry, or non-wood substrates.
What is the significance of the negatively ground spurs on this bit compared to standard spur geometry?
Negatively ground spurs are angled so that the spur tip makes a scoring cut ahead of - and in a geometry that pulls slightly inward toward - the bore center as the bit rotates. This scoring action severs surface fibers cleanly before the main cutting faces remove material, which minimizes fiber lifting, splintering, and delamination around the hole opening. The result is a cleaner bore entry, particularly important on laminates, veneer surfaces, and coated panels where visible surface quality of the hole edge matters for the finished product.
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