Busch® Carbide Inverted Cone, Front Not Serrated Bur

Mill precise undercuts in square bezel corners, separate setting grains, and remove metal bars between gemstones without accidental floor milling or edge damage. The Busch® 2K-AU Series Carbide Inverted Cone Bur is an industrial-grade rotary instrument engineered for diamond setters, goldsmiths, and high-precision jewelry fabricators. 

Setting angular stones such as princess cuts and baguettes presents a major risk of chipping delicate gemstone corners against metal setting walls. The 2K-AU solves this problem with its smooth, non-serrated front face paired with peripheral cutting flutes. This architecture prevents axial cutting action, ensuring that existing polished seat floors and delicate stone bearing planes remain completely untouched while the lateral edges undercut sidewalls and true square corners. It serves as an alternative to hand gravers in tight corners where mechanical tool access is restricted. The 2K-AU also excels at separating individual beads during grain setting and clearing metal bridges between closely grouped stones. Machined from finest-grain solid tungsten carbide (Feinstkornhartmetall), Figure 2K-AU belongs to the HighTech-TOOL family and maintains sharp cutting edges across platinum, titanium, 18K/14K white gold, and jewelry steel. Fitted with a gold identification ring and an industry-standard 2.35 mm (3/32") shank, it drops directly into jeweler flexible shaft handpieces and precision bench micromotors. Available in 10 calibrated diameters from 0.60 mm to 2.30 mm (2K-AU-006 to 2K-AU-023), supplied as a single-piece package (1 pc/pack).

Why Choose Busch® Carbide Inverted Cone Burs 2K-AU

• Smooth Non-Serrated Front Face: Eliminates axial cutting, preventing unintentional gouging of polished seat bottoms and protecting delicate gemstone corners.

• Square & Princess Cut Optimization: Reaches deep into square bezel corners to mill clean corner relief notches where traditional gravers cannot maneuver.

• Grain Setting Bead Separation: Accurately separates and shapes individual holding grains and clears metal bars between neighboring pavé stones.

• Finest-Grain Solid Carbide Core: Provides high edge retention and thermal resistance, outlasting standard steel inverted cone burs in abrasive and work-hardened metals.

• Broad Hard-Metal Capability: Cuts cleanly through platinum, titanium, white gold, jewelry steel, yellow gold, and silver.

• HighTech-TOOL Gold Ring ID: Features the signature gold ring band on the neck for rapid bench identification.

• Low-Vibration Concentric Operation: Precision-ground German shank minimizes radial runout, eliminating tool bounce and chatter under microscope magnification.

• Universal 2.35 mm (3/32") Shank: Provides seamless compatibility across standard flexible shafts, bench micromotors, and quick-change handpieces.

Technical Specifications