M100RAK Robotic Arm Kit User Guide

RobotShop Inc. www.RobotShop.com
SPG785A-BM Power Gearbox
The SPG785A-BM (Bottom Mount) Servo Power Gearbox is intended to
be used with a stock HS-785HB servo which can rotate 1260 degrees total
(version shown includes optional metal/metal gears). When the HS-785HB
servo is installed into the 5:1 power gearbox, the rotation is decreased by a
factor of 5, providing 252 degrees at the final output shaft. Similarly, the
power and accuracy is increased by a factor of 5. Position feedback
remains since the internal potentiometer is not removed. The SPG785A-
5.0 can handle tremendous side loads with the dual ABEC-5 precision ball bearing supported
hardened 3/8” stainless steel hollow shaft. The shaft is hollow to allow wires from cameras,
sensors or other devices to not tangle during multi-turn rotations. The frame of the SPG785A-
4.5 is machined from 6061-T6 aluminum (anodized) and offers a standard hub pattern.
 Weight with servo: 7.1oz
 Rotation: 252 degrees
 4.8V power: 765 oz-in
 6.0V power: 915 oz-in
 4.8V speed: 1.40 sec/60 degrees
 6.0V speed: 1.15 sec/60 degrees