Leg Template

 

In my last post I talked about using a router to do pattern cutting, so the next step is to make the template of the leg. I started with this drawing which includes both the leg and the ankle:

CS-L Leg and Ankle drawing

There are a couple things to note about this drawing. Above the ankle is a feature called the ankle bracelet. This is a separate piece which is added later so you need to make the pattern so the side of the leg goes all the way down to the ankle. I have circled this in blue below. The red circle shows a notch in the leg which is also something that will be added later.

I printed out the template full size and used it to trace the pattern onto a piece of lauan plywood, but you could also glue the template down like I did for the frame components. With the pattern transferred to the plywood I need to find accurate ways of cutting it out. For the long cuts I used a circular saw and a guide fence. I have a small, battery powered circular saw which is perfect for making these sorts of cuts.

For the curve of the shoulder I did a rough cut on the band saw and then finished it using the router table jig that I have used for the frame cuts.

The angle on the ankle were just on a miter saw, and the rest of the cuts were finished on a band saw. Finally I cleaned up the rounded end of the angle on a drum sander.

Web Resources

I don't think I would have tackled this project if it wasn't for the wealth of information available on the web. Here are some good source of information on droid building.

Astromech.net - The official web site of the R2 Builder's Club. If you are going to do a build this is the first site you should sign up for. The message board has a wealth of great information and a lot of active member that can answer any questions you might have. There is a community of people who make droid parts so there are a couple forums on this site that announce when people are going to do runs of the parts. Also be sure to check out the Builders Logs forum which has build logs like this one.

Astromech.net now also hosts all the official blueprints that were alson on the Yahoo Group. You can find these files here.

R2-D2 Builders Club Yahoo Group - You will want to sign up for this group if for no other reason then to access the files area. Here you will find an archive of "official" blueprints as well as tons of other files to help with your build.

Droid Wiki - Part of the Astromech.net site, this has some nicely organized information on droid building. If you are starting out I highly recommend reading the Introduction, Beginners Guide, and the CSR Overview.
Besides the builders logs on the Astromech.net forum, you will find a lot of blogs that show people’s builds. I find my self referring to James Feurtado’s blog a lot because he built an R5 and he did a lot of it from scratch using wood so it’s a close match to how I plan to build. I also like a lot of the techniques found in this blog.
These are just a few of the resources I have been using so far. I will post more as I go along.

Leg Structure Part 1

 

Once I finished the basics of the frame I turned my attention to the side legs. The basic structure of the legs has five layers made out of various thicknesses of plywood. The shape of each layer is the same, the only difference being the length of the part. Here you can see the five parts for one leg and there corresponding thicknesses.

A good way to make multiple parts of the same shape is you a router with a pattern cutting bit. A pattern cutting bit is a straight cutting bit with bearing on the end. To use it you attach a wood template to the piece you want to cut so that the bearing runs along the template and the bit cuts the piece to the exact same shape as the template.

It’s easiest to do pattern cuts on a router table, but what if you don’t have one? First option is to build a simple one. For the purpose of pattern cutting you will really only need a smooth piece of plywood or MDF that you can mount the router to. You can then set that up on a couple saw horses. For pattern  cutting you will not need  fence, but you will need some sort of starting pin which I will talk about later. Here is an article that explains how to build a simple table, and I am sure there are others.

Another option is to use a handheld router. In this case you will want a pattern cutting bit that has the bearing on the bottom, not the top., You will need to clamp the piece to the edge of a workbench so you will need to unclamp and move it a couple times to complete the cut.

Frame Complete

 

With all the frame parts complete I did a dry assembly of the frame. It can be a little tricky to assemble; there is a good video here that can help if you are having trouble:

https://www.youtube.com/watch?v=LcgW66o0N9s 

Once assembled there were a few checks I did to make sure everything was cut right. First I checked that the full length uprights didn’t have gaps at the top or bottom which would indicate that one or more of them was to long or to short. That looked ok so I then took some measurements of the overall height at a few spots around the body.

I also checked that the uprights did not stick out beyond the edge of the top and bottom plates, or any of the rings. I had to do a little sanding and filing to get them to fit perfectly. The one area where I did have some problems was with the back left upright which was hitting the side plate. I had to file down the edge of the upright a bit to get it to fit. I am not really sure why this upright goes the full height of the frame, but the corresponding one on the other side doesn’t.

 

I don’t have any plans to glue up the frame until much later in the build process.

Frame Uprights

 

The final set of parts I needed to make for the frame were the frame uprights. Here is the drawing of these parts for reference.

The first step was to rip some 1/2” plywood down into 1 1/4” strips. Once this was done I cut the pieces to length. You will notice that there are only three sizes of upright, so I setup a stop block for each size on my miter saw bench to assure that each set of pieces was exactly the same length even if the exact length measurement was a little off.

 

Instead of using a printed template for these I decided to just measure the locations of the slots since the measurements are pretty simple. You will notice in the plans that a lot of the slots line up across pieces, so I started by marking the slots on the piece with the most slots. I then transferred those marks to the other pieces only measuring when a slot was in a position that wasn’t on the original piece. Again, just like the length, this assures that the slots line up even if your original measurement is a little off.

Since the slots in the rings were squared off I made the slots in the uprights square also by cutting them on a table saw with a dado blade. Just remember there is a slot on two pieces that is smaller then the others so it can hold the 1/4” piece that goes under the large data port.

Frame Side Plates

 

With all the curved pieces done this left just the side plates and uprights which can be made with more traditional woodworking techniques. The side plates are made from 3/4” plywood and become the mounting point for the side legs.

I started by cutting the pieces to size on a table saw. I also cut most of the long side of the notch on the table saw to get a straight cut and finished the cut on the band saw.

The only other cut that needs to be made on these parts is a slot to hold the shoulder wings. This slot was far enough from the end of the board to allow me to simply clamp on a piece of wood as a guide fence that the edge of the router plate could run along. This is simpler then trying to setup for a guide collar.

The plans show notches cut at the top and bottom of these parts that are used to help align the parts during assembly. For now I decided not to cut these.

Frame Misc Pieces

There are a couple miscellaneous curved pieces of the frame left to make. The first one I mentioned in my last post, the ring segment that goes under the large dataport. Unlike the other ring segments this one is only 1/4” thick. The best material for this was 1/4” MDF. I made this piece the same way as the other ring segments.

The final two curved pieces are he shoulder wings. I cut the outside edge on the router table using the same jig from the ring segments, and I did the notches on the table saw jig. The straight edge on the back was rough cut on a band saw and then I sanded it down to the line on a belt sander. The notches were carefully cut on the band saw.