Assembling A Robot

This will be a short post, but it will also be a VERY sweet one!

I’ve done a post on assembling the legs, the feet, the hubs and the body, which means now we get to stick them all together!

The first step to attaching the legs to the body is taking the hubs and marking out where the slots need to be cut into the skeleton. Now, this was marked on the original plans but over time I fear that the paper has drifted around and let’s face it – the bolt holes I drilled into the hubs are not perfectly lined up. So in order to determine the right locations I borrowed some nail polish and put it on the ends of the bots. I then held the leg up to the body and pressed it together, painting streaks where the slots should approximately be.

Hub and body with nail polish on them

As you can see, the holes are mostly the correct distance from the center, but are not even close to correctly positioned to ensure the leg sits at the correct angle. I think this is a result of the way I drilled the holes from the template – something may have gotten mirrored. Regardless of why, once I knew where to make the holes I was able to drill and dremel them out to ensure the legs would fit.

Here you can see the body of R2 with the legs attached, but not the feet. At this point the feet hadn’t been permanently attached to the legs, and I wanted to test that I could get the legs to approximately the same angle on each side before I added the additional weight of the feet. Because of the weight of the motor and wheels the legs become very awkward to work with once you attach the feet to them. And I still get nervous holding the legs without supporting the feet even though they seem to be fairly robust.

Body with legs attached to test alignment

In the above photo you can see how the hub is almost entirely concealed from view by the leg and the body. You can also see on the far side of R2 that the bolts extend into the body a fair amount, allowing you to put washers and bolts onto them. These bolts will always be accessible so that the legs can be detached in the future for easier transport. He’s definitely not small, so this modularity is extremely welcome – otherwise getting him anywhere would be a major pain.

Once I knew for certain that the legs could be attached successfully, it was time to try and get the feet on. As discussed in the foot building post, a .5″ diameter dowel was used to attach the feet to the ankles on the leg. The solution for the center foot was a little more simple, if not just as much of a hassle. For the center foot, two holes are drilled into the bottom of R2, and through them two wood screws are drilled into the center ankle. The center ankle itself is basically a little nub that sticks out just to get the center foot into the right angle. The below picture is from when the center ankle was permanently attached later in the process and I had begun painting.

Center ankle attached to R2, without center foot

Once this was successfully attached (which wasn’t easy, because the layers of plastic kept splitting while drilling), I was ready to attach the center foot and the legs as previously described culminating in the following picture.

All parts attached, but none permanently

As you can clearly see in this photo the legs are far out of alignment and the dome is simply placed on top of the body – but for the first time it’s actually recognizable as an R2-D2! This was a huge milestone, literally years in the making. With everything put together like this, it’s starting to feel like the home stretch!

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