Power HD TR-4 Axial SCX10 III shift and dig servo setup

thingiverse

I decided not to use the recommended Spektrum servos so I had to figure out the linkages for myself. I chose the Power HD TR-4 servos without servo savers and used the included long servo horns with the printed parts, adjusting the servo endpoints as needed. The Thing file is designed for one set of components, but you will need two sets to complete both servos. Keep in mind that the digital servo is mounted on the back side of the bosses to shorten the length of the standoff and firm up the action. To mount the servos, I used longer 2mm screws that were approximately 10mm long. The screws into the servo horns are the supplied 2mm servo mounting screws. The screws for the digital and shift actuators are 2.5mm in diameter, and I shortened both actuator standoffs to line up with the linkages. The screw for the shift is the supplied one, while the other is around 10mm long. Make sure not to overtighten the screws through the linkages so that they can move freely. It's also crucial to set the servo endpoints properly or you will risk burning out your servos. Josh at Harley Designs has a helpful video on YouTube explaining how to adjust them. Enjoy building! UPDATE: After finally getting some time, I measured the screws used in my installation and found that for mounting the servos using the tabs in the Thing file, M2x12mm screws were employed. The short servo arms that came with the servos were used, and the drag link was mounted in the outermost holes with M2x6 button-head screws. The control points on the digital and 2-speed actuators were trimmed down to match where the drag links would be, and M2.5x8 button-head screws were used for the digital actuator while M2.5x20 button-head screws were used for the 2-speed connections. Some of the included screws can be reused in these locations or are available from Dubro and Axial.