Thursday, December 24, 2015

Horseshoes Part 2

In my last post I showed how I created the the tempalte for the horeshoes, in this post I will show how I used the template and a pattern cutting bit to cut the actual parts. The first step was to cut a series of blanks out of 1/4” MDF and to trace the pattern on to them.


I then used the traced lines to rought cut the parts on the bandsaw.


Next I screwed the template to the first of the blanks. The template doesn’t need to line up perfectly with the traced lines as long as there is wood from the blank sticking out all the way around the template.


Cutting MDF puts out a lot of fine dust so I wanted to take some precautions before I made the cut. I used some cardboard to make a dust catcher that extended all the way over the cutter. I cut a hole in the back of the dust catcher to put the hose from the shop vac and tapped everything down to the router table. Even with this I still used a dust mask while making the cuts.


In my post on cutting the leg parts I talked about the importance of using a guide pin to start cuts on a router table. In this case I found the pin was really getting in way so I chose not to use it. If you don’t use the pin you just need to be very careful when you start the cut. With everything setup I cut all the pieces.


The final operation I did on the horeshoes for now was to form the ridges that are along the inside edge. To do this I used a pattern cutting bit in the router table just like I did to cut the shape. The difference for the ridges is that I replaced the bearing on the bit with one that was slightly smaller the the diameter of the bit.


I then set the depth of the router so the cut will be exactly half the thickness of the horeshoe pieces. Since the groove is only half the thickness of the part the template isn’t needed, you can just run the pieces without it and you will get perfect groove along the edge.


When stacked together you get the ridge effect.


On the horeshoe part nearest the leg I made this cut all the way around the piece. This provides the groove that is between the horesehoes and the leg frame.

Saturday, October 10, 2015



The next element I worked on for the legs was the shoulder horseshoes.The horseshoes attach to the outside of the leg frame that I have been building in my previous posts. The tricky part of making this component is the ridges that you can see along the inside edge of the horseshoe. There is also a groove between the horseshow and the main part of the leg.

R2_Shoulder .

Most people make these using eight thin layers stacked together. The even numbered layers are made a little smaller on the inside then the odd numbered layers so you get the groove effect. I took a slightly different approach. I made each horseshoe out of 4 layers of 1/4” MDF and then used a router to cut the groove on the bottom side of each piece.

To cut the shape of each layer I went back to the router table and a pattern cutting bit, so just like with the leg frames we need a template to start with. I started with a printout of a full size template from the plans which I glued to a piece of 1/4” MDF that was cut to the exact width of the part.


To make the outside cut I went back to my router table circle cutting jig that I used for the body frame components. The cross slide slot on the router table was to far from the bit for this cut so I attached a thin piece of plywood to it to get it close enough.


To make the inside circle I used a circle cutter mounted in a drill press. Cutting MDF generates a lot of dust so I clamped the hose of my shop vac as close to the cutter as possible and wore  dust mask. I also firmly clamped the piece I was cutting in place instead of trying to hold it.


For the straight cuts on the inside I used the table saw.


I made the angle cuts that lead into the center circle on the band saw. There was really no way to guide this cut so I carefully did it freehand. The final cuts were the angle cuts on the bottom, I made these on a miter saw. Here is the final template.


In my next post I will show how I used this template to make the actual parts.

Sunday, September 27, 2015

More Leg Work

The final operation I am going to do for now on the leg framework is to cut out the inside of the middle layer. There are two reasons to do this. First it reduces the weight of the let by a little bit. Second, if you plan to motorize the feet, it provides a place to run the wires. The cutout of the shoulder also provides some space for the leg mounting hardware.

On the 3/4” center layer I marked a line 1 1/4” in from the edge of the leg. It wasn’t necessary to follow all the contours of the edge, 1 1/4” provides enough clearance all the way around. The line goes right to the end of the foot leaving an open space to run wires if you want to.


Before making the cuts on the band saw I drilled some holes at key points to make if easier to turn the piece.


Here is the final piece temporarily pinned to the inside layer. This cutout will not be seen so the rough cut it not a problem.


Saturday, September 5, 2015

Leg Pockets


Where the legs meet the shoulder there is a detail feature that goes into a pocket on both sides of each leg.


This pocket is easier to cut out before the layers of the leg are assembled. To make these cuts I used a router with a guide collar and a template. I stared out by making a template out of a piece of scrap 1/4” MDF. The cut out on the right is the actual template.


The shape is pretty simple so I just laid it out based on the measurements in the plans being sure to add the distance between the edge of the guide collar and the edge of the bit to the measurements so that the template cutout is slightly larger then the final size of the pocket. Since the shape has some tight corners I used the smallest possible router bit, but it will still require some manual cleanup in the corners.

With the legs temporarily assembled I marked the location of the pockets. These lines will be used to align the template.


Next I screwed the template to the inside surface of one of the leg side pieces. The cut does not go all the way through this piece so I adjusted the router for the correct depth and then made the cut.


The center layer is cut the same way, but I put a scrap piece of wood under the leg piece because this cut needs to be all the way through.


With the legs again temporarily re-assembled you can see the finished pocket.


Saturday, August 29, 2015

Leg Guide Pegs

The next thing I did on the legs was to drill holes for guide pins. This isn’t strictly necessary, but it will help temporarily hold the legs together while I do other work on them and will also help align them when I go to do the final assembly. I started by drilling the hold in my template, one at the top and two at the bottom. I have seen people do more pegs but I thought this would be enough.


Before drilling the holes I made sure that I marked all the leg pieces with which leg they go to, left or right, and which layer they are, inside or outside. In theory if you are very accurate in drilling the holes the pieces should be interchangeable, but I am not going to take that chance. I used this template to mark the holes on the 3/4” center layer of the legs and drilled these holes all the way through. I used a Forstner bit for this which gives a nice clean hole with a flat bottom which will help for they areas where I don’t want to drill all the way through.


Next, I put the middle layer I just drilled on top of the outside layer and used the drill bit to mark the location of the holes.


I drilled the bottom two holes all the way through since there is that small outside ankle layer that will cover them. The top hole I only drilled part of the way through since the hole would be see if I went all he way through. Next I used the middle layer to mark the inside layer. When you do this, remember to flip the middle layer over so the surfaces are together the same way they will be when it’s assembled. As I said earlier, if everything was measured perfectly this wouldn’t make a difference, but I prefer no to take that chance. Just like the outside layer the top hole on the inside layer should not go all the way through, but the bottom two can since they will be covered by another small ankle piece.

I drilled the bottom holes into the outside ankle piece so it could be pinned in place, but the inside ankle layer is so thin, I chose not to drill the holes in it.

Once all the holes were drilled I measured the depth of  the holes and cut dowel pins for each hole.

Saturday, August 8, 2015

Leg Structure Part 3


In my last post I showed how I cut out the three main pieces of each leg. In this post I will cover a few more of the details of the leg body.DSC00954

The first thing thing that needs to be done is to cut the point off the middle and inside layers of the leg, leaving only the outside full length. I did this by simply measuring the length and then cutting it off on a miter saw.


Next, two small layers of the ankle need to be made. The outside layer, on the left, is made out of 1/2” plywood. The inside layer, on the right, is only 1/4” thick so I made it from a piece of MDF. I could have cut these on the router table like the other layers, but they are pretty simple shapes so I just traced them from the template, and cut them on the table saw and miter saw. For the rounded end I made a rough cut on a band saw and then finished it on the drum sander.


Sunday, July 5, 2015

Leg Structure Part 2


In my last post I showed how I created the template to cut the layers of the leg frame, in this post I will show how the cuts were made. The first step was to layout how the pieces will be cut from the plywood and trace around each piece. Since the legs are wider at the top then at the bottom you can get them a little closer together by alternating directions.

DSC00949 - Copy

The next step was to rough cut them on the band saw to make the pattern cutting a little easier. I started by just cutting between them to separate each piece. I then drilled some holes at the bottom of the shoulder on each side to make it easier to make the rough cut and then cut close to the line on a band saw.


Once the pieces were rough cut I screwed the template to one of the pieces. The template doesn’t need to line back up perfectly with the trace line as long as there is wood sticking out all the way around. I attached the template with two screws. Since only one side of the outside pieces will be seen I won’t even need to patch these holes.


I made the pattern cut in a router table with a small pattern cutting bit. Before making the cut the height of the bit needs to be set carefully so that the bearing runs along the edge of the template and the cutter goes the full height of the plywood. When you are switching between cutting he 1/2” and 3/4” pieces, don’t forget to reset the height! I forgot to do this when switching from a 3/4” cut to a 1/2” and took a chunk out of both my template and the leg piece.


When making a pattern cut it is a good idea to use a starting pin. This gives you something to hold the piece firmly against as you bring it into the cutter. Without it the piece will tend to kick out when you first touch the cutter.

With everything setup the cuts go pretty quickly.


Sunday, June 28, 2015

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.


Sunday, June 21, 2015

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. - 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. 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 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 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.

Saturday, June 20, 2015

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.

Saturday, June 13, 2015

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: 


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.

Sunday, June 7, 2015

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.


Friday, June 5, 2015

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.

Tuesday, June 2, 2015

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.