ARRI Rosette & Locating Pin Standard (3/8"-16 & 31.8mm)
Direct Answer
The ARRI Rosette (31.8 mm diameter with 60 radial teeth and an M6 central thread) and ARRI 3/8"-16 Anti-Twist Locating Pins (dual 3.0 mm indexing holes flanking a 3/8"-16 screw) are the undisputed cinema standards developed by Arnold & Richter Cine Technik (ARRI) to prevent camera cage accessories from twisting under heavy rotational torque.
Source: ARRI (Arnold & Richter Cine Technik GmbH) Mechanical Engineering Standards
Specs
| ARRI Rosette Outer Diameter | 31.8 mm (1.25 in) |
| Tooth Configuration | 60 radial interlocking teeth (enables precise 6.0° rotational index adjustments) |
| Rosette Center Bolt | M6 × 1.0 mm internal metric thread (or 1/4"-20 on some consumer cages) |
| ARRI 3/8"-16 Anti-Twist Pattern | Central 3/8"-16 screw flanked by two 3.0 mm locating pin holes at 15.0 mm spacing |
| Primary Applications | Cinema handgrips (ARRI Alexa, RED, Sony Venice, FX9), extension arms, heavy top handles, monitor arms |
| Torque Resistance | 100% immune to rotational slippage (teeth physically mesh together) |
The 60-Tooth 6° Angle Locking
Because the ARRI rosette features 60 CNC-machined radial teeth, meshing the male and female rosettes locks them together with zero play. Loosening the center M6 knob allows the camera assistant to tilt the handgrip in discrete 6.0-degree increments (360° / 60 = 6°), locking it firmly against the heaviest handheld cinema camera packages.