Finger bits are not interchangeable between machines — a CNC finger bit will not work on a radial arm machine, and a radial arm finger tip will not mount to a CNC spindle. Thread direction, shank size, segment design, and RPM range all vary by machine type and material. This guide breaks down every Weha finger bit and finger tip by machine type, material, and application so you order the right tool the first time.
The Two Categories: CNC vs Radial Arm
Before choosing a specific bit, identify which machine you’re running:
- CNC machines (Intermac, Park Industries, Breton, etc.) — use CNC finger bits with 1/2 Gas thread, high RPM capability, and segment designs optimized for automated feed rates
- Radial arm machines (Fab King, Thibault, Wizard, Scorpion, etc.) — use radial arm finger tips with M12 thread (or 1/2 Gas via adapter), designed for manual operator-controlled sink cutouts and edge profiling
CNC Finger Bits
CNC finger bits are engineered for automated feed rates, high spindle speeds, and consistent production volume. The key variables are segment count, RPM range, and feed rate capability.
Weha Top Racer High Speed CNC Finger Bit (40mm x 20mm – 8 Segment)
The Weha Top Racer is the high-production CNC finger bit in the lineup — built for aggressive material removal at feed rates up to 36 IPM. The 8-segment configuration produces fast, even cutting on granite, marble, quartz, and engineered stone. The faster you run it, the better it performs. At controlled speeds (5,800 RPM, 12–14 IPM), fabricators report approximately 700 linear feet of service life with consistent wear.
- Size: 20mm x 40mm
- Thread: 1/2 Gas
- Segments: 8
- RPM range: 5,500–8,500
- Feed rate: 24–36 IPM (high production capable)
- Best for: High-volume CNC shops running granite, marble, quartz, and engineered stone at production speeds
OMA HSA 8 Segment Finger Bit (20mm x 40mm)
The OMA HSA 8 Segment Finger Bit is an Italian-made CNC finger bit engineered for mixed stone production — particularly effective on quartzite, quartz, and granite in the same production run. The 8 double-segment design produces aggressive cutting with minimal apple coring and excellent consistency. Fabricators report 100–130 sink cutouts in mixed materials and 550–750 linear feet of service life, with some exceeding 1,000 linear feet depending on feed rate and material.
- Size: 20mm x 40mm
- Thread: 1/2 Gas
- Segments: 8 double segments
- Quartzite: 12–16 IPM | 7,000–8,500 RPM
- Quartz/Granite: 15–24 IPM | 7,000–8,500 RPM
- Best for: Mixed stone production shops, quartzite-heavy operations, shops prioritizing long service life over maximum feed rate
CNC Finger Bit Quick Comparison
| Bit | Segments | Max Feed Rate | RPM Range | Best For | Price |
|---|---|---|---|---|---|
| Top Racer | 8 | 36 IPM | 5,500–8,500 | High-speed production, granite/quartz/marble | $153 |
| OMA HSA 8 Segment | 8 double | 24 IPM | 7,000–8,500 | Mixed stone, quartzite, long service life | $169 |
Radial Arm Finger Tips
Radial arm finger tips are used on single-head radial arm machines for manual sink cutouts, vanity bowl profiling, and edge shaping. The critical variables are thread direction (standard vs. reverse) and material hardness (standard vs. quartzite incremental).
Thread Direction — Standard vs. Reverse: Why It Matters
On radial arm machines, the spindle rotation direction determines whether you need a standard (right-hand) or reverse (left-hand) thread finger tip. Using the wrong thread direction causes the finger tip to unscrew during operation — a safety hazard and source of tool damage. Always confirm your machine’s spindle direction before ordering. Weha color-codes reverse thread tips red for quick identification in a busy shop.
Standard vs. Incremental Design
Weha offers two segment designs for radial arm finger tips:
- Standard — general edge profiling on granite, marble, and quartz; single-pass material removal
- Incremental (Quartzite) — stepped diamond segments that progressively shape the edge in controlled passes; required for quartzite and hard engineered stone where single-pass profiling risks chipping or micro-fracturing
Weha Radial Arm Finger Tip — Standard Thread (20x23xM12)
The Weha Radial Arm Finger Tip (Standard Thread) is the go-to finger tip for sink cutouts and vanity bowl profiling on granite, marble, quartz, and quartzite using radial arm machines. Cuts up to 15 bowls with consistent performance and no glazing. Compatible with Thibault, Wizard, Fab King, Scorpion, and other major radial arm machines. Requires a 1/2 Gas adapter for machines with 1/2 Gas spindle thread.
- SKU: 30515
- Thread: Standard M12 (right-hand)
- Size: 20mm x 23mm
- Applications: Sink cutouts, vanity bowl profiling, edge shaping
- Price: $67.70
Weha Radial Arm Finger Tip — Reverse Thread (20x23xM12)
The Weha Radial Arm Finger Tip (Reverse Thread) is the same standard finger tip in left-hand thread — required for left-hand spindles on radial arm machines. Same applications as the standard thread version: granite, marble, quartz, quartzite, sink cutouts, and edge profiling.
- SKU: 30515RV
- Thread: Reverse M12 (left-hand, color-coded red)
- Size: 20mm x 23mm
- Price: $77.73
Weha Incremental Quartzite Radial Arm Finger Tip — Reverse Thread (20x23xM12)
The Weha Incremental Quartzite Finger Tip is the heavy-duty option for quartzite and hard engineered stone on left-hand spindle radial arm machines. The stepped incremental segment design removes material progressively rather than in a single aggressive pass — critical for preventing chipping and micro-fracturing on hard, brittle materials. Color-coded red for reverse thread identification.
- SKU: 30517RV
- Thread: Reverse M12 (left-hand, color-coded red)
- Size: 20mm x 23mm
- Best for: Quartzite, hard engineered stone, materials prone to chipping under single-pass profiling
- Price: $80.02
Weha Radial Arm Finger Tip Adapter — 1/2 Gas x 12mm Thread
The Weha Radial Arm Finger Tip Adapter connects M12 thread finger tips to radial arm machines with a 1/2 Gas spindle. If your machine has a 1/2 Gas spindle and you’re running M12 finger tips, this adapter is required. Total assembled length: 4". Compatible with Fab King and similar machines.
- SKU: 30520
- Thread: 1/2 Gas male x 12mm female
- Length: 4"
- Price: $56.61
Radial Arm Finger Tip Quick Comparison
| Finger Tip | Thread | Design | Best For | Price |
|---|---|---|---|---|
| Standard (30515) | M12 right-hand | Standard | Granite, marble, quartz — right-hand spindle | $67.70 |
| Reverse Thread (30515RV) | M12 left-hand | Standard | Granite, marble, quartz — left-hand spindle | $77.73 |
| Quartzite Incremental (30517RV) | M12 left-hand | Incremental | Quartzite, hard stone — left-hand spindle | $80.02 |
| 1/2 Gas Adapter (30520) | 1/2 Gas x M12 | Adapter | Connecting M12 tips to 1/2 Gas spindle machines | $56.61 |
OMA Antarex Finger Bit — For the OMA Antarex Bowl Router
The OMA Antarex Finger Bit is a machine-specific bit for the OMA Antarex bowl router — not compatible with standard CNC or radial arm machines. The Antarex cuts through 2cm and 3cm stone in 4–8 minutes, allowing up to 10 bowls per hour. Compatible with 2cm, 3cm, and 4cm stone. Made in Italy by OMA Systems of Rome.
- SKU: 8071
- Machine: OMA Antarex bowl router only
- Capacity: Up to 10 bowls/hour
- Compatible thickness: 2cm, 3cm, 4cm
- Price: $96.55
Profile Wheels for Radial Arm & Hand Grinder Use
For edge profiling and stock removal on radial arm machines and hand grinders, the Weha Vacuum Brazed Zero Tolerance Wheel is the companion tool to finger tips. Available in 1", 2", and 3" diameters with 5/8"-11 thread, these no-bearing wheels maintain their profile shape throughout their lifespan — vacuum brazed single-layer diamond technology bonds diamond directly to the steel body for consistent, repeatable edge profiles.
- 1" x 2" (SKU 30198) — tight-radius work, inside corners, small profile details — $82.26
- 2" x 2" (SKU 30205) — general edge shaping and stock removal, most common choice — $104.69
- 3" x 2" (SKU 30207) — wider contact for faster material removal on straight edges — $139.60
Quick Decision Guide
- CNC machine, high-speed production, granite/quartz/marble → Top Racer CNC Finger Bit
- CNC machine, mixed stone including quartzite, long service life → OMA HSA 8 Segment Finger Bit
- Radial arm machine, right-hand spindle, granite/marble/quartz → Radial Arm Finger Tip Standard Thread (30515)
- Radial arm machine, left-hand spindle, granite/marble/quartz → Radial Arm Finger Tip Reverse Thread (30515RV)
- Radial arm machine, left-hand spindle, quartzite or hard stone → Incremental Quartzite Finger Tip (30517RV)
- 1/2 Gas spindle machine, need M12 finger tip → 1/2 Gas x M12 Adapter (30520)
- OMA Antarex bowl router → OMA Antarex Finger Bit
- Edge profiling & stock removal on radial arm or hand grinder → Vacuum Brazed Zero Tolerance Wheel
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