The F-series flexible beam couplings with high torsional rigidity are introduced by Ruland Manufacturing Co., Inc. Couplings feature six beams as configured by two sets of three spiral cuts. Compared to typical beam couplings that have fewer spiral cuts, the beams are shorter and have a steeper helix angle to make the F-series coupling more resistant to wind-up and have a higher torque capacity. According to the company’s press release, this makes the couplings suitable for light-duty power transmission applications such as coupling a servo motor to a lead screw in a motion control system. Ruland manufactures the torsionally rigid F-series couplings in five different body sizes with outside diameters ranging from 5/8" (15.9 mm) to 1 1/2" (38.1 mm). Available bores range from 3/16" (5 mm)to 3/4" (19 mm). Both set screw style and clamp-style hubs are offered. The F-series range is manufactured in both aluminum and stainless steel. In addition to added corrosion resistance, the stainless steel couplings have even higher torsional rigidity than aluminum versions.