Shape acute setting corners, level tight bearing floors, and mill refractory alloys without tool deflection, rapid dulling, or flute chatter. The Busch® 38AU Series Carbide Cone Bur (Konischer Fräser) is an industrial-grade rotary milling instrument engineered specifically for master goldsmiths, diamond setters, horologists, and precision metal fabricators.
Belonging to the specialized HighTech-TOOL series, Figure 38AU is manufactured from hot isostatically compressed (HIP) finest-grain tungsten carbide, providing maximum density and uniform structural integrity. Featuring a tapered conical head with a precision end-cutting flat face, this geometry combines lateral side clearance with controlled bottom-leveling capability. While conventional tool steel burs dull quickly in abrasive or work-hardened metals, the 38AU cuts aggressively through jewelry steel, platinum, titanium, white gold, and hard non-ferrous alloys without loss of dimensional accuracy. Its cross-cut helical fluting breaks metal shavings into fine particles, preventing tooth clogging and surface galling. Finished with a signature gold identification ring and an industry-standard 2.35 mm (3/32") shank, the series mounts directly into jeweler flex shaft handpieces, precision micromotors, and quick-change bench systems. Available in 6 micro diameters from 0.50 mm to 1.00 mm (38AU-005 to 38AU-010), supplied as a single-piece package (1 pc/pack).
Why Choose Busch® Carbide Cone Burs 38AU
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Hot Isostatically Compressed Carbide: HIP treatment eliminates microscopic voids in the material matrix, providing high edge strength and thermal shock resistance under heavy bench loads.
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Tapered Body with Flat End-Cutting Face: Slender conical taper (taper angles from 3.80° to 4.90°) provides line-of-sight in restricted setting zones while the flat end face levels bearing seats.
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Cross-Cut Helical Fluting: Engineered multi-flute architecture breaks continuous chips into small fragments, preventing metal smear and tool loading in gummy white gold and platinum.
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Engineered for Difficult Alloys: Cuts cleanly through jewelry steel, platinum, titanium, 18K/14K white gold, yellow gold, and silver.
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HighTech-TOOL Gold Ring ID: Features the signature gold ring band on the neck for rapid bench identification.
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Low-Vibration Concentric Operation: Precision-ground German construction minimizes radial runout, eliminating tool bounce and chatter marks under high microscope magnification.
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Universal 2.35 mm (3/32") Shank: Provides seamless compatibility across standard flexible shafts, bench micromotors, and quick-change handpieces.
Technical Specifications
| Parameter Metric | Certified Factory Specification |
| Brand | Busch® |
| Product Model Number | Series 38AU Cone Bur (Konischer Fräser) |
| Head Material | Hot Isostatically Compressed Finest-Grain Carbide |
| Shank Diameter | Standard 2.35 mm (3/32 in) Reinforced Shank |
| Bur Head Profile | Tapered Cone with Flat End Face (Cone Squared) |
| Flute Architecture | Cross-Cut Helical Flutes with End-Cutting Face Teeth |
| Available Diameters (D1 / D) | 0.50 mm to 1.00 mm (6 Calibrated Micro Sizes) |
| Working Length (L1 / L) | 3.00 mm to 4.00 mm |
| Taper Angle (a) | 3.80° to 4.90° |
| Recommended Speed Range | 5,000 – 10,000 RPM |
Free Global Shipping
We process orders within 1-3 business days. Estimated standard international delivery is 6-12 business days.
14-Day Returns
We have a 14-day return policy. Items must be unused, with all original accessories, and in original packaging.
For full details, please refer to our Shipping and Refund policies at the bottom of the page.
