3D Printed RC Servo Case (Hitec HS-645MG)

A project I'm working on required that I reduce the overall size of a sub-assembly. I've contemplated modeling and printing RC servo cases in the past, access to an Object printer presented an opportunity to experiment.

I'm using Hitec's HS-645MG servo. I've included my file set at the end of the instructable.

Step 1: Servo Case Modifications

3D Printed RC Servo Case (Hitec HS-645MG)
3D Printed RC Servo Case (Hitec HS-645MG)
3D Printed RC Servo Case (Hitec HS-645MG)
Here's a few images of the original servo case next to the modified servo case. I've noted in the images the changes I've made.

Step 2: Removing the Servo Horn and Servo Case Back

3D Printed RC Servo Case (Hitec HS-645MG)
3D Printed RC Servo Case (Hitec HS-645MG)
Start by removing the servo horn, then remove the four fasteners that hold the servo together.

Step 3: Removing the Top Cap, Gear Train, and Bearings

3D Printed RC Servo Case (Hitec HS-645MG)
3D Printed RC Servo Case (Hitec HS-645MG)
3D Printed RC Servo Case (Hitec HS-645MG)
3D Printed RC Servo Case (Hitec HS-645MG)
Gently pull the top cap away from the body. The gear train may fall out as you do this. I took a picture of it still attached to the servo body for reference.

I've also included a shot of all the parts on a post it, make sure not to lose any of them.

Next, pull the bearing off the servo body and push the bearing out of the servo top cap.

Step 4: Removing the Potentiometer and Motor

3D Printed RC Servo Case (Hitec HS-645MG)
3D Printed RC Servo Case (Hitec HS-645MG)
The potentiometer is held in place with a small screw. Remove the screw and gently push the potentiometer out of the servo body.

The motor is a tight fit into the servo body, there may also be a dab of adhesive that you'll need to scrape off with the tip of a screw driver. Don't pull on the motor wires unless you want to solder them back on later.

Step 5: Inserting the Motor and the Potentiometer

3D Printed RC Servo Case (Hitec HS-645MG)
3D Printed RC Servo Case (Hitec HS-645MG)
Reverse the process, start by inserting the motor. It should be a press fit, and a dab of glue.

Step 6: Attaching Servo Back Cap and Bearing

3D Printed RC Servo Case (Hitec HS-645MG)
3D Printed RC Servo Case (Hitec HS-645MG)
You'll notice that I also changed the orientation of the servo cable, instead of exiting on to the side it exits to the bottom.

Press the bearing on the servo body and into the servo cap.

Step 7: Reassemble Gear Train and Attach Top Cap

3D Printed RC Servo Case (Hitec HS-645MG)
3D Printed RC Servo Case (Hitec HS-645MG)
Reassemble gear train. Note the orientation of the servo limit post it should look like the picture.

Wiggle the servo top cap onto the servo, you shouldn't have to force it. If the gear train isn't reassembled correctly the top cap will not fit.

Step 8: Insert and Tighten the Servo Case Screws

3D Printed RC Servo Case (Hitec HS-645MG)
Slide the case screws into their holes and tighten them up.

I like to test the servo at this point if it doesn't move smoothly I double check the gear train assembly.

Step 9: Attach New Servo Horn

3D Printed RC Servo Case (Hitec HS-645MG)
I 3D printed a servo horn that would allow me to mount something at 90 degrees to the splined shaft.

Step 10: Removing the Servo Horn (HS-65MG)

3D Printed RC Servo Case (Hitec HS-645MG)
In my design I've attached a smaller servo to the back of the larger servo. Here we remove the stock servo horn from the HS65MG.

Step 11: Mounting the New Servo Horn and Attaching the Smaller Servo.

3D Printed RC Servo Case (Hitec HS-645MG)
3D Printed RC Servo Case (Hitec HS-645MG)
Push the new servo horn on the smaller servo and then attach the smaller servo to the larger servo.

Step 12: The Complete Assembly

3D Printed RC Servo Case (Hitec HS-645MG)
3D Printed RC Servo Case (Hitec HS-645MG)
3D Printed RC Servo Case (Hitec HS-645MG)
Here are a few picture of the assembly.

Step 13: The Files

I've attached the file I printed on an Objet 500. Even if you don't plan on using the HS-645MG they are useful in understanding servos. sf-1511-r3.stl
3D Printed RC Servo Case (Hitec HS-645MG)
sf-1511-r3.stl92 KB sf-4513-r1.stl
3D Printed RC Servo Case (Hitec HS-645MG)
sf-4513-r1.stl391 KB sf-4651-r8.stl
3D Printed RC Servo Case (Hitec HS-645MG)
sf-4651-r8.stl279 KB sf-4652-r9.stl
3D Printed RC Servo Case (Hitec HS-645MG)
sf-4652-r9.stl957 KB sf-4653-r5.stl
3D Printed RC Servo Case (Hitec HS-645MG)
sf-4653-r5.stl454 KB
 
 

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