Sunday, May 04, 2014

Finished Drilling New Shoulder Discs to Fix Lean Problem for Droid #2

Today I celebrated a good portion of Star Wars Day working to get droid #2 to lean at the proper 36 degree angle. (I also fixed a motor keystock problem I mentioned a few days ago.) May the Fourth be with me.

One thing I realized is that the holes in the vertical bar through which the U-bolt passes were not well-aligned with the gas pipe that the U-bolt circumscribes. This caused the U-bolt to not be perpendicular with the vertical rail and gas pipe. I used the Dremel with a grinding bit to widen these holes.

Now the U-bolt fits properly around the gas pipe, and also passes through the holes in the vertical rail in a perpendicular fashion. Note that the vertical rail is flush against the flat spot I filed on the gas pipe.

This doesn't fix the problem with R2 leaning too far back, though. Just how far is he leaning, anyway?

Looks like about 44-45 degrees. He should be leaning 36 degrees, so he's leaning a good 8-9 degrees too far back. This is because I didn't file the flat spot on the gas pipe in the proper location.

The last few days I thought about how to fix this, and decided to cut new shoulder discs, where the flange that secures the gas pipe would be rotated from it's current position. I bolted together the outer holes of original shoulder disc and the new one, and made an alignment mark.

I then measured 9 degrees from this mark. I checked my measurements with four different protractors, as it was important to get this right.

I made a second alignment mark, to know where to rotate the original disc with respect to the new disc.

I made a third alignment mark for the other shoulder disc. The left shoulder disc was to rotate clockwise, the right disc counter-clockwise. I then stacked the first disc to be redrilled onto the original, and rotated it to the new alignment mark.

Before drilling, I quadruple-checked my logic on the actual gas pipe, to make sure everything was right, and as far as I could tell, it was.

Time to drill the offset holes for the gas pipe flange. The disc is rotated nine degrees from the original.

The newly drilled disc on the left, and the retired disc on the right.

Before drilling the left shoulder disc, I wanted to sanity-check that this work had the intended effect. When the gas pipes are bolted together, the right leg should be less rotated that the left, and indeed it was. Phew!

And time to drill the left shoulder disc, nine degrees offset in the opposite direction.

Everything should line up when the gas pipes are bolted together. Happily, they do. So far, so good.

And now, the moment of truth. Time to try all this out on the actual droid.

Success! Or at least, I think it is.

The flat spot on the gas pipe is aligned such that R2 is leaning properly now. I did some very minimal driving, and again, so far, so good. Hopefully this fixes the issue once and for all, but I need some more drive time with droid #2 before I declare complete victory.


perello23 said...

That's good to here & see.

kresty said...

Wow, all that makes my droid look easy!

Victor Franco said...

If I hadn't goofed it up, it would have looked a lot easier for me too.