One brand new piece of 5*8mm flexible shaft coupling for DIY CNC machine and other projects. 5mm to 8mm shaft coupler can connect your driving shaft with the driven shaft. 5x8mm Flexible Coupling Shaft, it is very efficient in eliminating any misalignment to the possible extent. Minimum backlash is another great advantage of this 8mm shaft coupler. Shaft coupler with the outer diameter of 19mm and the length of 25mm is machined aluminium coupling. First bore diameter is 5mm and the second bore diameter is of 8mm also. Coupler shaft comes with the spiral cut in the middle along its length which makes it exible so they can be shafts even if they are not perfectly co-linear and will help reduce binding effects. 8mm shaft couplings are also known as Beam coupling, helical coupling, Flexible coupling. Flexible shaft coupling for marine application.