Foot Channel

I'm going to back up a little bit here in my description of the building of the foot drive. As mentioned earlier the large aluminum tube would be used to house the wheels and the small aluminum tube would be the channel used to connect the wheel housing to the leg itself. Describing the how to cut the channel really depends on the foot shells being used. The channel is designed to fit inside the shell and be the pivot point for the leg/ankle and foot. Since the different foot shells have varying thicknesses the length of the channel would be affected by this. The channel is cut on both end of the tube at the same angle that the wheel housing would be cut and the top of the tube is cut off to make it a channel so the leg/ankle can slide in.

Foot Channel with ends cut to proper angles

I test fit the channel with the wheel housing in my styrene foot shell to make sure that everything lines up. This picture below should really show what is attempting to be done here.

Test Fit of Channel and Wheel housing

When the test fit is good and everything is where you want it to be, you need to drill the pivot holes where the leg/ankle will connect to the foot. Based on other builders plans I went with a 1/2" hole for the pivot hole and used a reducer bushing to take the size down to 3/8". Once the pivot holes were drilled, I centered the channel the best I could on the top of the wheel housing, drilled some holes, and fastened them together using some hex bolts.

Channel and wheel housing bolted together

That's about it for now. Still more to come on building the footdrive...

Foot Drives - Wheel Housing (Pt 2)

So at this point we have the basic frame for the wheel housing. The next logical part of the task is to determine the location for the wheels and drill some holes but before we can do that some work needs to be done on the wheels. I used Colson Performa 5" x 1 1/2" wheels that I found on ebay for a decent price. However instead of using the hubs which came with the wheels, I used some Derlin Keyed Reducer Hubs that I had purchased from NPC Robotics. These reducer hubs work best with the 1/2" keyed shafts which will be used as the axles.

Derlin Reducer Hubs

The hubs themselves were longer than needed so I cut them down to slightly less than 1 1/2". Also, the center area of the wheels were a little wider than the 1 1/2" of the outer part of the wheel and as a result prevented it from fitting in the housing. So I took the dremel with a sanding bit on it and sanded down the area around the hub until the thickness was reduced enough to fit in the housing. After doing that, I installed the reducer hubs.

Wheels sanded down with reducer hubs installed

Next step, determining the location of the wheels in the housing. Based on some advice from other builders, it is recommended that about 1 1/2" of the wheels stick out from the bottom (of the original tube, not the cut line) and that the wheels be far enough away from each other as possible in the housing. I played around with this and eventually found the optimal location and marked them off. I used a 3/4" bimetal hole saw bit and drilled through both sides of the housing to ensure that the holes lined up as close as possible for the axles.

Wheel Housing with axle holes cut

Having the hole saw bit go through and make pilot holes for the other side worked out great. and allowed me to drill the opposite side without much concern as to whether or not they would line up.

Wheel Housing with both sets of holes drilled

Next step was to prepare for the installation of the wheels in the housing. The axle size is 1/2" so I used some  bronze bearings for a 1/2" shaft. The bearings however were a little long so they needed to be cut down to fit with in the walls of the housing without protruding on the inside.  This meant taking the hack saw and cutting 8 of these little things down to size. Not a difficult task but very time consuming.

Full Size Bearing and one cut to size

Once the bearings were cut to size, I used some JB Weld and glued them into place using the axles to ensure that everything is aligned properly.

Fastening the bearings in place

Once that solidified, I did a test fit with the wheels and all looked good.

Test fit with wheels

Next up gears and motors!

Disney Buys Lucasfilm!!

Ok, as I'm sure everyone is aware by now, Disney has acquired Lucasfilm and in turn the Star Wars franchise for a mere $4 billion. As a result, a local website (www.rockincomics.com), asked me to participate in a Roundtable discussion about the sale. I felt honored to be asked and had a blast doing it. The podcast just made it online so here it is: http://www.rockincomics.com/podcast-rockin-comics-round-table-disneystar-wars/

Foot drives - wheels housing (pt 1)

Long time coming for this post...

Back in May, I went to work on building the foot drives for my R2. I decided to go with the Senna Drive model because it seemed to be the best drive out there I could find. Over a few months I slowly purchased all the parts needed for the drive and after watching the DVD tutorial I had several times, I finally got up the courage to get down to business.

The body of the foot drive is made out of 2 types of aluminum tube. The first tube is 4"x2" with a 3/16" wall and will house the wheels and the second tube is 2 1/2" x 1 1/4" with a 1/8" wall which will be used for the channel to connect to the legs.

I purchased some metal cutting blades for my chop saw and the first cuts I made were to get the tube ends at  the proper angle so the foot shells could fit on top of it with some clearance on each end. Now the tube was not cut so it would be flush with the inside of the foot shell but instead was cut to be slightly smaller than it so that the shell could fit over the top with plenty of room to spare.

wheel housing after ends cut to size

After cutting the sides the edges on each end were chopped off. This was to remove a sharp edge off the housing and allow for better clearance in the foot shell. That sharp pointed end would actually interfere with part of the shell so it best be removed.

Edges chopped off 

The previous 2 cuts were done fairly easily using the chop saw. The next cuts were much more difficult because I would be using a jigsaw. At this point we just have a tube still and there was no opening for the wheels. So I basically had to remove the bottom section of the tube. To do this I put the metal cutting blades on the table saw and cut a couple of starter cuts large enough to fit the jigsaw blade in.

Starter cuts to remove the bottom section

Using the jigsaw I cut the bottom section out. Due to the width of the tube, I had to make the cuts on each side of the tube individually. I couldn't just make one cut and have it go through both ends. Note that to ensure that the housing remains sturdy and keeps it's shape, a section of the bottom of the tube was left intact on each side of the tube.

Bottom section removed (Sorry the pic is blurry but you should get the point

Cutting this with the jigsaw was not easy. I ended up using 10-12 metal cutting blades for the two housings. I held the jigsaw steady but it still jumped and bucked the entire time. Besides having them go dull, several blades broke as well so this was done as carefully as possible. Safety glasses, long sleeves, and other protective gear were worn at all times.

Sorry...

Sorry about the lack of updates over the past 5 months. So much has been going on in my life that R2 had been put on the backshelf for a little bit. However, I have been getting back to him so I hope to have some updates of what I have done recently up soon.

Frame Work and Painting

I finally got back to adjusting my frame. In an earlier post I mentioned that the quarter rings in the front of the frame were causing tension in the frame and wouldn't line up correctly. I took the frame apart and compared the positions of the cuts on the quarter ring to that of the middle ring and saw what needed to be done to correct the problem. So I pulled out the band saw and made a few cuts and voila! things looked good.

Frame with corrected quarter rings

Along with fixing the frame I also primed the bottom of the bottom ring since it will be visible to the outside world.

Bottom Ring Primed

I was also able to get the ankle wedges and cylinder holders primed and painted

Ankle Wedges Painted

Cylinder Holders Painted

I can't wait to be able to start putting a lot of this stuff together. It gets to be a little frustrating to do all this work and still not be able to see anything substantial yet. Need to keep going and keep my eye on the prize.

Ankle Cylinders

Wow, it feels like forever since I updated this. Things slowed down a little bit the last few weeks but over the last few days I've been able to get a little bit done. So I got a chance to continue working on my ankle cylinders. When last I left, I had notched out the inner section of the cylinder which sits on the leg. With that completed, the next step is to use the dado blade on the table saw to notch out part of the outer sections of the cylinder to get the trapezoidal shape on the end.

Ankle Cylinder showing the dado cut on the end

I made several runs on the table saw with dado blade and tried to get as close to the PVC as possible then repeated the cuts on the other side. Using the current configuration, you can only get the cuts made on the inner half of the cylinder so a new jig had to be made to make the cuts on the outer half.

Ankle Cylinder jig

I broke the wood guides off the end of the cylinders and slid the cylinder into the jig I made.

Ankle Cylinder inside of Jig

The jig is required to keep the cylinder from rocking when attempting to make the dado cuts. So after making a few passes to get the height of the dado correct, I went to work on the cylinder. Again, I made several passes and got as close as possible to the PVC. Once that was done, I used the band saw and cut the ends to the correct height and then made the angle cuts to get the trapezoidal look. I repeated this process with all 4 cylinders.

Once they were done, I primed them and did a test fit on the center leg with a few other details.

Center leg test fit

Then I painted them metallic aluminum

Ankle Cylinders being painted

The next step was determining how to attach the cylinders to the leg. I decided to use the same method I had used in attaching the shoulder horseshoes and outer ankle cylinders in that I will use the grille guides.

Center Leg showing grill guides

Using some of the blueprints from the club I was able to determine the location of the ankle cylinders. I then made a template from some polystyrene I had so that I could make sure the holes on the leg lined up with the ones on the cylinder.

Female Grill Guide Holes Countersunk

Grill Guides installed

Ankle Cylinder

I repeated the process on the other side and both lined up pretty nicely. So, at this point the ankle cylinders are just about done. I need to do a little bit more painting on them but otherwise they are done and I am happy with them.

Working on the Skirt

Wow, it seems like forever since I've posted anything. The last month or so has been a little busy with other things. I have been working on my R2, but not as much as I had hoped. Most of the time I only get to work on it after my kids go to bed so it limits what I can do. Anyway, enough about that. One of the things I have been able to work over the last month in the evening hours has been the skirt.

Primed Skirt

The last work I had done on the skirt was to get a few coats of primer on it and see how it looked. I did some sanding and a few more coats. At this point now, I needed to make the curved pieces that end up being the front and back of the skirt. Using Mike Senna's tutorial from "R2LA IV", I was able to cut out 6 of the curved sections from styrene.

Skirt and 6 cut sections of styrene

Using masking tape to hold the styrene in place, I attached 1 piece of styrene to the end of the skirt. I adjusted and readjusted it until I determined that it was a good fit. Then used some Loctite Super Glue Gel to hold it into place. I started at one end of the curve and on the inside of the skirt glued little sections at a time making sure the glue was nice and dry before moving to the next part.

Styrene held on by tape

Curve being glued on

Once I was done gluing the first piece of styrene to the skirt, I added 2 more layers of styrene to the inside to make it a little more sturdy. I then used Plastruct Weldene on the top of the top edges of the styrene layers because it basically melts the plastic together making a stronger bond and giving them the appearance of a single piece of styrene.

Once I was finished with both sides of the skirt, I needed to make the ribs which will attach to the outside of the styrene. This took some trial and error to get the correct size for the ribs. They need to run from the bottom of the skirt to the top at the angle of the curved section. I used MDF and started with a piece that was .5" x .5" and put a 30 degree angle on it. Then I increased the angle a little at a time until I got the one that fit the best. It ended up being 37 degrees for me. Once I got the angle correct, I sanded down the rib until I found the correct size for a flush smooth fit. Once done with that I cut all 12 ribs at once to the same size. As a note, I made sure to cut the ribs a little longer than I might need with the idea that I would trim them down later.

Cutting all the ribs

Once done with the cutting, I needed to determine placement of the ribs. This took some time but using the plans I was eventually able to determine the approx  location of the each of the ribs. Once the location was determined, I choose a rib and because of the curved section of the skirt, needed to do a little sanding to ensure a good flush fit. Each rib was unique in this respect so once I got a nice fit with one I glued it to that spot.

Ribs glued into place. Notice the height.

Ribs glued into place

Once all the ribs were glued into place, I used my router to trim off the excess. Again, there were instructions on how to do this in the "R2LA IV" video. The end result was a fairly straight smooth looking skirt that lies fairly flush against the bottom of my R2 frame.

Skirt with ribs attached and trimmed.

There are a few areas that need to be sanded, trimmed, and filled before it will be considered complete but that it to be expected. Overall I'm very happy with how it turned out.

Cylinders, Skirts, Legs and more

Today I got a few hours to work on my droid so I did as much as I could.

First thing I started to work on were some ankle cylinders for the center leg. I started with a 1.375" OD PVC tubing and cut it to the proper length. I had enough PVC to get 4 pieces out of it.

PVC Pipe Cut to Size

Next, I needed to cut the grooves into the pipe. Using some scrap PVC I did some trial and error to get the correct depth for the groove cut on my table saw. I then measured for the first cut and slowly pushed the pipe over the blade and while keeping it there turned the pipe until I had a groove completely around the pipe.

Cutting the First Groove

Since the grooves are equidistance from each end, once I completed the groove on one side I flipped it over and made another groove on the opposite end. Once done with the outer most grooves, I measured for the next set, and after that the last set.

Cutting the Last Groove

All in all, there are 6 total grooves in the cylinder. I only need 2 cylinders for the center ankle, but since I have 4 pieces cut, makes sense to just do all 4 and save the other 2 for another droid :-)

PVC with Dowels Inserted

Once the last groove was cut on the last cylinder, I found a 1" dowel and cut it into approx 8-9" pieces and inserted them into the PVC. The dowel does 2 things for the cylinder: 1) It will give you more of a surface area to use when attaching it to the ankle and 2) Gives you material to fashion the trapezoidal end of the cylinder. These 2 points will make more sense as I get further along in it. Unfortunately, I only had enough 1" dowel for 3 of the cylinders so I will need to get more of it before I can continue. I would like to do all 4 at once and not leave one hanging.

After the cylinders I moved on to the cylinder holder. In an earlier post I showed the cylinder holders that I had cut from .75" plywood. Now, I needed to fashion an arc in the bottom of the cylinder so that it will sit flush against the ankle cylinders on the outside legs. I had been attempting to get the arc by holding some course sandpaper around some PVC and sanding the flat cut edge of the holder. I did this for a little bit every night this week but it was extremely slow going and I made very little progress. After much thinking and discussing it with a co-worker I decided to try and cut away a little of the wood with the table saw. I raised the blade a little bit and cut a small groove lengthwise down the middle of the holder. Then I lowered the blade a little bit and cut 2 smaller grooves on each side of the first groove. The end result gave me a step look on the inside of the holder and removed much of the wood for me. Then I resorted to the sandpaper on the PVC and sanded away. It took some time but I'm starting to see the results I wanted.

Cylinder Holders (Left sanded, Right Not Sanded)

The above picture should make some sense out of what I've been talking about. The one on the right shows that cuts that were made. 1 tall one in the middle and shorter cut on each side. The one on the left, shows what the end result will look like after sanding. It took a long time to sand down the one on the left and it still needs some work but I had to take a break from it so I stopped there.

At this point I decided to try and get the other leg to the point where I can consider priming it. The sides of the leg had been skinned with styrene but I need to put some wood filler on the edges to make the styrene and wood blend together so I spent some time doing that.

Filling the Outer Edges of the Leg

Once the wood filler is dry I'll use a sanding block to smooth it down. I'll repeat this process 2-3 more times before I will consider priming it.

Moving on...
This past week, the weather had turned unseasonably warm so I decided to see if I could get the skirt sanded and primed.

Bare Skirt

I used the wood filler to fill in the edges and level off some pits and sanded it down nicely with a palm sander. It really did a nice job with smoothing out the wood. I got lucky and the following day the temp was suitable for priming. Not great, but suitable. So I gave it a whirl. I put 3 coats on during the week. Then today I noticed a few rough spots so I used the palm sander again and went over everything. After that I gave it another coat of primer.

Primed Skirt

I'm very happy with the look of it right now. I will give it a few more coats of primer and then sand it again with a fine grit sandpaper. After all the priming and sanding I will need to attach the ends (which I cut out earlier this week), a few ribs, and then prime it some more. I hope to be able to complete it in about 2 weeks.

So anyway, that was my hodge-podge day/week of not concentrating on any one thing but trying to do as much as I can. I feel like it may be this way for the next few weeks as I try to get a lot of this done before I move to the big stuff.

Cylinder Holders

Well, I said I made good progress today and I didn't lie. I was also able to cut out the 2 cylinder holders for the outer legs. I had plenty of scraps lying around so I chose a .75" piece of plywood that I would be able to get both pieces out of. I used my router table to cut the small arcs and then my table saw to cut the length of the piece.

The uncut Cylinder Holders (upper top left) after Routing the arcs

Since the scrap piece of wood I was using was round I needed to create a flat edge to run along the table saw fence to ensure a good straight cut.

Cylinder Holder Straight Cut

And here is the end result after the cut was made

Ankle Cylinder Holder

Now, this piece sits flush up against the ankle cylinders so I still need to sand the bottom of the cylinder holder so that I can get a good clean fit. I originally hoped I could find a core box router bit large enough to achieve the clean fit but I could not find one that has a radius cut of .6875". I figured it was a long shot but had to try anyway. So as I mentioned earlier I will just need to sand it by hand. But that is a job for another day.

Center Leg Ankle

I made some good progress today in my build. I was able to get the center leg ankles pretty much done. As mentioned in a previous post, I had taken a 6.25" diameter drainage pipe and cut a strip out of it to represent the arc of the ankles and then cut that strip into 4" pieces. Now I needed to cut an angle into the edge of the piece. Using some suggestions from other blogs that I've read, I set up the 4" piece as in the following photo.

Cutting the Angle in the PVC Arc for the Ankle

Setting the table saw blade at 35 degrees, I decided to practice on a scrap piece of the PVC before working on the good ones. Once I saw how the saw and PVC reacted to the cut I moved forward with the good pieces and ended up with a clean cut on the PVC.

Finished Ankle Cut

Once I finished the cut on the other piece I cut a piece of styrene to fit on the ends. In order to get a nice fit on the styrene, I cut the piece a little too big (not much) and decided I would sand it down. The end result turned out pretty nice. I repeated with the second ankle.

Completed Center Ankle

I still need to prime and paint but it's a little cold where I live so I decided that instead of painting the pieces in the garage and moving them to the basement to dry, I will just wait until spring and paint as many things as I can then and let them dry outside.

Center Leg

Today I was able to get the center leg for my R2 cut out. It consists of 2  .75" and 2   .5" pieces of plywood. The .75" pieces will be on the exterior of the leg and the .5" will make up the interior.

4 Pieces of the center leg (2 on left are interior, 2 on right are exterior)

I set up my router table so that I could get the nice arc on one of the .75" pieces of plywood. Once I was satisfied with the arc I had, I placed that piece on top of the uncut .75" piece and using the trim router bit was able to make and exact duplicate. For the interior .5" pieces, I found a straight piece of wood and used that as a guide for the trim router bit to get the nice angular cuts on one of the pieces. Again, once I was satisfied with what I had, I used the finished piece as a guide for the other .5" piece.

Center Leg Unglued

The above picture is a good idea of what the pieces of the leg will look like once they are glued together. As of now, the leg is more that likely longer than what I need, but until I see how it fits into R2 and how I will secure it, I don't want to cut it. You can always makes things shorter, a little more difficult making it longer though.