The sides of the ankles both on the outside and center legs have a rounded over section. I found this part to be a little challenging to create. I look at various methods others had used to build it and eventually settled on a method using a plywood frame and styrene covering. I Initially tried to build this directly on to the leg, but found it to difficult to clamp the styrene sufficiently while the glued dried. In the end I decide to build them as sperate components and then attach it afterwards.
Here is a look a the basic structure of the part. The frame is made from three pieces 1/2” plywood, two curved pieces and a rib that holds the two pieces together. I cut the styrene using the template from the styrene R2 plans and glues it to the frame using clear Gorilla Glue.
For the end cap I again used the styrene template to cut the part. I left the curved part larger then necessary and sanded it down after gluing it up. Before gluing I sanded the part of the left gently on the belt sander to get a proper angle on the edge of the styrene so there would be sufficient gluing surface. For this type of sanding I generally just move it across the belt sander belt without the sander turned on. The running belt is just to aggressive to safely use on styrene.
To add a little more strength to the joint I applied some hobby putty to the back at the joint between the two pieces. I also put some strips of styrene around the slot to build up it’s depth.
Here is the part after the front piece has been sanded smooth.
To mount the part to the leg I used dowels to attach the wood part, you can see the holes drilled in the leg and the corresponding hold on the part in the previous photo. I also added some strips of styrene to the leg to give the styrene something to attach to.
To attach the part to the leg I used wood glue on the wood frame, and styrene cement on the styrene surfaces. Once the glue dried I used hobby putty to fill in the seams.