Confession time. I actually filmed this a month ago! Holy crap I’m behind on posting this series!
Here it is, part 3 of my BD-1 build. Today we’re working on the body and getting the first major servo in place.
Below are my version of the instructions, simply based on how I put this together.
As always, a big shout out goes to Michael Baddeley for creating these amazing 3D files! Go support him on his Patreon (https://www.patreon.com/mrbaddeley/).
And now, the instructions! Oh, and the Amazon links are affiliate links so please help me out with a cup of coffee and buy from the links!
The Neck
Parts Needed
- Neck
- Head Frame B
- Lower Neck Hinge
Materials Needed
- Toothed belt (https://amzn.to/2YSITpV)
- Superglue or Epoxy
- 4mm brass tubing (https://amzn.to/2SSEGPf)
- M3x35 countersunk hex bolt (https://amzn.to/3duFkKx)
- M3x15 countersunk hex bolt (https://amzn.to/2Wjs1ak)
Step 1
Cut two pieces of toothed belt, exactly 42 teeth long.
Step 2
Insert one end of the belt into the pressure fit space on the Head Frame B, and insert the other end into the Lower Neck Hinge, and then repeat with the second piece of belt. Effectively making a loop.

Step 3
Cut two pieces of 4mm brass tubing about 8mm long and insert into the holes in both Head Frame B and the Lower Neck Hinge. These serve as a bearing for the bolts. I didn’t end up doing this.
Step 4
Insert the Head Frame B into the bottom of the neck and push through. You may have to use an Xacto knife to open up the hole a little bit.
Step 5
Insert a M3x15 countersunk bod into the lower hole of the neck so it holds the Lower Neck Hinge in place.
Step 6
Pull Head Frame B through the opposite end and apply tension to line up the holes. Use a M3x35 countersunk bolt to hold in place. This will be removed later.

Step 7
Play with it. You’ve earned this.
The Tilt Gear
Parts Needed
- Tilt Gear
- Main Body Bar
- Main Body
Materials Needed
- M4 square nut (https://amzn.to/2vunI15)
- M4x25 countersunk bolt (https://amzn.to/35J5Jlo)
- Hot glue (optional)
Step 1
Insert an M4 square nut into the nut slot on the Main Body Bar, you can use a bit of glue to hold it in place, mine was pretty tight so it’s just pressure fit in. There’s one for each end of the bar.
Step 2
Insert an M4 square nut into the nut slot on the Tiltgear.
Step 3
Hold the Tiltgear in the body and slide the Main Body Bar through the shoulder hole and into the Tiltgear.
Step 4
Line up the holes and screw in a M4x25 countersunk bolt.

Attach the Legs
Parts Needed
- Inner Cores
- Main Hubs
Materials Needed
- M4x25 countersunk bolt (https://amzn.to/35J5Jlo)
Step 1
Slide the inner cores over the Main Body Bar, and make sure that that the holes are all aligned.

Step 2
Place the Main Hubs on. These are a loose fit and not held on with any glue. Why? I couldn’t tell you.
Step 3
Run the servo cable from the legs through the holes and into the body, pull them through so they are facing the front of the body.
Step 4
Pull the cables through the top of the body.
Step 5
Make sure that there are no kinks in the cables, and carefully screw the legs to the Main Body Bar with M4x25 screws.
Step 6
You can now attach the Rockets and Booster covers onto the upper legs.
Finishing the Body
Parts Needed
- Body Rear Panel A
- Tilt Servo Gear
- Body Rear Panel B
Materials Needed
- MG996R Servo (https://amzn.to/2YPRHgc)
- Servo Tester (https://amzn.to/2WL8RsZ)
- M4x15 Countersunk Bolts
- M4x10 Countersunk Bolts (https://amzn.to/2SON4PI)
- M4 Square Nut (https://amzn.to/2vunI15)
Step 1
Attach the Tilt Servo Gear to the servo using the provided screws.
Step 2
Screw the servo into the Body Rear Panel A.
Step 3
Run the servo cable up through the top of the body with the other servo cables from the legs.

Step 4
Grab the neck, and feed the leg cables and the servo cable through the neck so they come out the other end.
Step 5
This part is tricky. Use two M4x15 bolts and M4 nuts to attach the neck to the body. You can try holding the nuts onto a stick with some tape, or hot glue.
Step 6
Slot Body Rear Panel B into place.
Step 7
Insert two M4 square nuts into the slots on the Body Rear Panel A.
Step 8
Level the body, then slide Body Rear Panel A into the back.
Step 9
Use two M4x10 bolts to hold this in place, screwed in from the top. The body should sit firmly on the legs now with very little movement.

Congrats! The body is now complete. And you’re about halfway through this entire build.
Check back soon for part 4, the head!
As always, thanks for watching and reading!

Credits
Intro Music; Straight Through by Groove Bakery | https://groovebakery.com
Music promoted by https://www.free-stock-music.com
Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0)