Center Foot Shell

The center foot shell was build pretty much the same way at the outside foot shell, although the middle foot doesn’t have any curved surfaces to I made it all from wood.

I started with the part where that foot attaches to the ankle which is made from plywood.

The front and back were made from luan plywood.  Here you can see how the edges were beveled so the edges matched up correctly.

To cut the slot I tapped the two pieces together so that they would match up when I cut them.

Here is the foot with the ends attached. I have also installed a t-nut where the angle will eventually bolt on.

I don’t have any pictures, but the sides were also made from luan playwood. I glued small strips of wood on the inside of the end panels to help attach the sides.

The bottom part of the foot shell was made just like I did for the outside feet, strips of pine cut with the appropriate angles and then attached to the bottom of the foot.

Foot Half Moon Details

On the side of the feet is the half moon foot detail. 

 I started by cutting paper templates from the styrene plans. The middle element has some smaller pieces that I didn't do templates for but just hand cut. I used these templates to cut the styrene parts.

To make the half moon I wrapped the outer part around the half circle element and glued it in place. You need to be sure you have it carefully aligned so that both ends end up in the correct location. Next I cut and glued in the triangular ribs to strengthen the part. 

The middle element is made of three parts. The front part with the two slots at the top, two thin triangles that form the sides and finally a small strip to close up the bottom. I glues up these parts and sanded them smooth and the glues the finish assembly to the half moon.

Since the side of the foot was skinned in styrene I could use styrene cement to glue on the detail. I used a couple clamps to hold it in place to dry. In this picture you can also see the three other details on the side of the foot. These were cut from styrene using templates made from the plans and glued in place with styrene cement. 

Outer Feet Part 4

The next step on the outer feet was to do that styrene pieces on the top of the foot. I cut the pieces larger then needed, glued them on with White Gorilla Glue and taped them in place.

Once this was dry I used a Dremel to sand the styrene flush.

Outer Feet Part 3

The next step in building the feet was to do the styrene skins. He is a picture of the initial state of the foot. The screw at the top are going to be used to hold the battery boxes, I removed them before starting to attach the skin.

For the curved side I place a piece of styrene tight to that side, traced the shape and then cut it larger then needed. To glue the piece on I used two-park epoxy. I generally use epoxy when the joint needs to be strong and there is a small surface to glue to, both of which are a concern for this part. Initially I just glued the styrene to the large flat area at the top since it was easy to clamp this firmly. Once that part dried I lifted the skin, and applied epoxy to the remaining surfaces. The trickiest part of this was hold the skin until it dried.

As you can see in the following pictures I used a combination of clamps, tape and even a spray paint can to hold the skin tight to the frame.

Once the glue was dry and I removed the clamps I applied some more epoxy along the seams on the inside of the foot to further strengthen in.

Here is what it looks like after unclamping. I next used a Dremel to sand the styrene flush with the frame.

The skin on the flat side of the foot was much easier. Here you can see the piece with the layout marks. The area between the lines needs to be cut out to form a groove. I first tried doing this cut after gluing the piece in place, but it turned out to be much easier to make the cuts ahead of time.

I started by gluing the inside piece first. Since this piece has a large surface area I used White Gorilla Glue for this. I used tape to prevent it from sliding until I could get some clamps on.

Once that was dry I attached the outside part using epoxy which I find holds better with the smaller surface area. I don’t have pictures of that.

Outer Feet Part 2

The next part of the feet is the trim piece along the bottom. I started this with a piece of pine cut on the table saw to the right thickness and angles.

I glued these pieces together and used some small nails in a nail gun to tack them together.

Once the glue was dry I glued them to the bottom of the foot shells I showed in my last post. I put two thin screws into the center plywood web to hold the trim on until the glue dried.

With the frame complete I started on the details along the bottom part. Below you can see the paper template I cut from the full sized plans.

I then used that template to markup the styrene for the part.

Finally I cut out the part. Two important notes about doing this. First I cut out the rectangular areas first before cutting it off the sheet because it makes it easier to hold the part as you cut. I also left the piece long on both ends and will cut it to size later so I am sure if fits the foot properly.

I could have attached this piece directly to the foot, but I found it was easier, and provided a cleaner result if I first glued this to a very thin piece of styrene and then glued the entire assembly to the foot. Here is the part being glued to the backing.

Here it is being glued to the foot shell.

Here is the foot shell with the trim pieces all attached. For the corners I used styrene glue to attach the pieces together and the sanded them smooth.

Foot Frame Part 1

I build the structure of the feet out of wood and eventually finished them with styrene details. In this post I will show the start of the process for building the outer feet. Here are the first three pieces cut out of plywood that form the channel where the foot connects to the leg.

Here you can see how the leg will connect to the foot.

I first drilled a hole in the smaller piece that will receive a bolt to hold the foot to the leg. Next I clamped the small piece to the larger one and drilled the whole through the larger piece. Doing it this way assures that the holes are perfectly lined up.

On the other side of the large piece I added a t-nut that the bolt will thread into.

With the holes drilled I glued up the three pieces and secured them with brad nails.

Next is another plywood piece that will be used to support the styrene on the curved side of the foot.

Here is that place glued in place. The two small holes at the bottom are to secure some old surplus drive units that just happened to have. More on that in another post.

I also created a long hole near the bolt hole that will allow the wires from the motors to be routed into the legs.

Next I cut the ends of the foot out of luan plywood. I didn’t get a good picture of them before I attached them. Before cutting the final shape of these parts I ran the raw piece on the table saw to cut the proper angle on the top and bottom of the part.

The next part is this block added to the back of the foot. The drive motor will go in the front section, and a caster wheel will go in the back. The block is set at just the right height for the wheel I plan to use.

The flat side of the foot is made with another piece of luan, so I first attached some small wood strips along the edge to better hold the side on. Here they are clamped on while the glue dries.

Here is the wood side glued and tacked on.