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.