Ruland Manufacturing FSMR19-8-8-A Flexible Coupling

FSMR19-8-8-A is a compact, zero-backlash six-beam flexible coupling designed for 8 mm shaft bores on both sides. Machined from a single piece of 7075 aluminum, it offers lightweight, low-inertia torque transfer with a balanced, precision profile. The two sets of three spiral cuts provide higher torque capacity and reduced windup compared with single- or four-beam designs, making it suitable for light-duty power transmission tasks such as coupling a servo motor to a lead screw. Key dimensions are 19.1 mm (0.750 in) outer diameter, 31.8 mm (1.25 in) overall length, and 8 mm bores with a bore tolerance of +0.025 mm / -0.000 mm; shaft penetration is limited to 15.4 mm. Hardware is metric, with seating torque specified at 1.76 Nm for the M4 screws to ensure proper alignment and clamping force. FSMR19-8-8-A is RoHS3 and REACH compliant and manufactured in Marlborough, MA under ISO 9001:2015 quality controls; it is designed for high-speed operation up to 6,000 RPM and is engineered to minimize vibration during fast rotation. This model is commonly used in servo-driven and automation applications where precise, backlash-free coupling is essential for reliable, repeatable motion.