Printed by my Wanhao i3 using PLA. The nozzle is 0.4mm, but to get the needed spline teeth detail, I made it “pretend” to be 0.3mm by setting nozzle size to 0.3mm in Cura without actually changing the nozzle.
I printed these for my FTC robotics team because the metal horns from Tetrix could not fit onto the metal splines of the HSB-9360TH and REV Smart Servos.
November 15, 2017 Update
Upon subjecting the servo horn to the max torque of the REV Smart Servo (13.5kg·cm), the servo horn broke at its neck due to layer delamination. So, I made the neck fatter.