Dome Top Section

To make the stop section of the dome I first needed to create two more discs. Since the top of the head slopes in I needed to cut the discs with edges beveled to that angle. To do this I used the same fixture I used in my last post to create the two next discs.

I cut these discs out of 1/2 plywood. I added a stop block to the fixture to set the finished diameter of the disc. The angle of the fixture will control the angle of the bevel on the edge of the disc. I used this technique to cut both the bottom and top discs.
Next I drew the layout lines on the disc. I first divided the disk into 10 equal segments. The sides and back of of R5’s head have pockets in them so you can see the wider layout lines in those positions. The remaining segments have layout lines for plywood pieces that will form the frame of the head.

With the layout complete I could cut out the inside of the disc to form a ring. Since this edge will not be seen it could be cut free hand or on the router table.

The support ribs are cut out of 3/4” plywood with the ends cut at the same angle as the angle cut on the edge of the disc. I rounded the outside edge of the ribs slightly so that the styrene skin will go on smoothly. To do this I just put the edge on a belt sander and gently rocked it back and forth to knock the edges off.
Here is the top ring that was made the same way as the bottom ring.

Head pockets

 

On either side and back of the head are these pockets.

These are the pieces for each pocket. The sides go the full height of the head and the small blocks are used to form the top and bottom edge of the pocket. These pieces are rounded slightly on one side to match the curve of the head. I also slightly rounded the edge of the side pieces, again to match the head curve. Finally there is a piece of 1/4” luan that forms the back.

Here are the assembled sides and back. Ignore the yellow, it was just a piece of wood I had laying around that was already painted.

Before installing the finished pockets in the head I painted them with some white spray primer.

Dome Rings

I chose to build an R5-D4 because I wanted a dome that I felt I could build from scratch, but this doesn’t mean that R5’s wasn’t without challenges. The first part of the dome I worked on was the two angled rings that form the neck. I did see a build log for an R5 where the builder created wooden ribs the shape of the head and then used curved strips of styrene for the surface of the angled piece.
I decided to take a different approach, I made the slopped pieces as rings of MDF with the slopes cut into them on a router table. To do this I created another jig, here is what the finished product looks like:

I started with a sloped table with a nail that the part will rotate on. I screwed on the angle pieces so that I could change because the top and bottom rings have a different angle. At the bottom middle of the table is a small slot to provide clearance for the router bit. Next I clamped two strips of wood to the router table to allow the sloped table to slide straight in and out of the bit. Finally I added a stop block so I knew when I was at the finished depth. This technically wasn’t needed since the design of the jig would allow the bit to pass under the part at the end of the bevel.
To use the jig I first cut a disc of MDF using the router table circle jig I have used for other parts. Here you can see the disc mounted to the jig.

Here you can see a close up of how the bit makes the cut.

To make the cut I started with the bit lower then the final depth since a lot of material needs to be removed along the outside edge. Since I was cutting MDF I also took some time to setup some good dust collection. I slowly slid the piece into the bit, rotated the disc all he way around, moved it in a little further and repeated the process. Next I raised the bit to it’s final height and repeated the process to get the finished angle. Here is one of the finished rings. To complete it I hand sanded the angle to get it smooth and then  I cut the center out using a jig saw since it doesn’t need to be precise.