Linear Servo HiTEC HS-645MG

thingiverse

A linear servo designed for use with the ultra-torque metal gear HiTEC HS-645MG, capable of lifting ten pounds and reaching 50mm. After researching 3D printable linear servos on Thingiverse, I found several models with fine teeth that would not provide sufficient holding force and required tight tolerances. Furthermore, the gears lacked any mechanism to prevent slipping on the servo axle. Therefore, I designed my own last night using a HiTEC MG servo and created a gear with holes aligned to the HiTEC servo horns. This linear servo can work with any HiTEC servo of this size. The metal gears make it stronger for robotics and less prone to wear out. 5-16-2017: I made adjustments to the three hole positions in the servo horn gear. The HiTEC Servo Horn Wheel features three rings of holes arranged in groups of three, ten degrees apart from nearest neighbors, at radial distances of 7mm, 8.5mm, and 10mm. My previous gear had only three holes in the 8.5mm radius ring and nine holes in the 10mm radius ring. I also added a bevel to the screw holes on the gear and widened the clearance for the gear in the fixture. Additionally, I added 1/8-in screw holes to the ends of the LINEAR ARM for more attachment options. If needed, servo position may be adjusted by adding washers to servo mount screws. I also created a square servo horn mounted gear. Most HiTEC servos come equipped with a square horn, simplifying the gear attachment to one screw.