Dual-Point Stylus Azimuth Calibration Ruler

Specialised dual-reference azimuth calibration tool fabricated from optically pure, transparent acrylic. Exact dimensions engineered for compatibility with IEC-standard turntable geometry. Thickness: 3mm — sufficient rigidity to prevent flex during stylus contact, yet thin enough to avoid tonearm clearance issues. Surface: matte-finished underside reduces slippage on glossy platters; polished top face maximises light transmission for mirror-assisted reading. Two-phase alignment process: First, stylus is lowered onto Point A to align its leading edge with the reflected horizontal datum — establishing rotational zero. Second, stylus is moved to Point B to verify square intersection with vertical grid lines — confirming rotational symmetry across the groove plane. Both steps must converge before final tightening — enforcing discipline often missing in informal setup routines. Real-world utility: Widely adopted by UK-based vinyl repair technicians, community hi-fi forums (e.g., Vinyl Engine, Hi-Fi Wigwam), and independent record shops offering cartridge installation services. Also used by educators teaching analogue audio fundamentals at UK colleges and music technology courses.