The B-20 Half Bullnose Diamond Router Bit – Position 1 is a sintered metal-bond, continuous rim diamond router bit engineered to shape a half bullnose (B-Shape) profile on quartz, granite, and quartzite.
What “B-20” Means
• B = Half bullnose profile
• 20 = 20 mm profile height
• 20 mm equals approximately 3/4 inches
This produces a clean, smooth radius on the top edge while keeping the bottom edge straight — the classic half bullnose look popular in both residential and commercial stonework.
What “Position 1” Means
Position 1 is the coarse shaping stage, using approximately 30/40 grit diamonds.
This step:
• Removes material quickly
• Establishes the half bullnose radius
• Prepares the edge for Position 2 and polishing steps
The sintered metal bond uses high diamond concentration, ensuring long life and consistent shaping performance, especially on hard quartzite.
The continuous rim design provides smoother contact and reduces chipping.
BOLT / THREAD SYSTEM (IMPORTANT)
Stone router bits do not use a half-inch arbor.
✔ True arbor shaft: 10 mm
Each bit includes two bolts, both with 10 mm shafts, but different thread sizes:
• 10 mm shaft with 10 mm thread
• 10 mm shaft with 8 mm thread
This allows compatibility with nearly all portable stone routers.
Both bolts are included with every router bit.
OTHER PROFILES AVAILABLE
Matching router bit shapes we also offer:
• V-Shape (Full Bullnose)
• F-Shape (Ogee) – 20, 25, 30 mm
• E-Shape (Bevel)
• L-Shape (Cove)
• H-Shape (Dupont)
• PE Shape (Crescent / Bookend)
Each listing contains its exact mm-to-inches conversion.
FEATURES
• True B-20 half bullnose — 20 mm (3/4 inches)
• Position 1 coarse profiling (approx. 30/40 grit)
• Sintered metal bond construction
• Continuous rim for smooth shaping
• High diamond concentration for long life
• Great for quartzite, granite, quartz, and engineered stone
• Includes two 10 mm shaft bolts (10 mm thread + 8 mm thread)
• Precision-balanced for low vibration
• Designed for wet routing
TECHNICAL DATA
• Position: 1 (coarse shaping)
• Profile: B-20 Half Bullnose
• Profile Height: 20 mm ≈ 3/4 inches
• Bond Type: Sintered metal bond
• Rim Type: Continuous rim
• Diamond Bond: High concentration
• Arbor Shaft: 10 mm
• Included Bolts:
– 10 mm shaft / 10 mm thread
– 10 mm shaft / 8 mm thread
• Stone Types: Quartz, Granite, Quartzite, Engineered Stone
• Use: Wet routing
USAGE NOTES
• Always use continuous water
• Avoid dry routing, especially on quartzite
• Clean slurry from rim after use
• Store completely dry
• Recommended RPM: 4,000 to 6,000
