Sunday, January 22, 2012
Books
On Sat I received two books from Amazon which hopefully will fill in some of the knowledge gaps I'm missing in this project. They are "Robot Builder's Bonanza" 4th Edition by Gordon McComb and "Robot Building for Beginners" 2nd Edition by David Cook. Lots of bedtime reading there.
Center Ankle/Foot
Not a lot of posts this week but I have been busy working on the center leg/ankle and the center foot for my R2. First the center foot. I decided that the center foot would be made out of styrene so following a design of a fellow builder I printed out the plans and went to work. After 3 or 4 nights of cutting I have a blisters on my hands and all but 1 or 2 small parts for the center foot done.
I started gluing some parts together and that proved to be a little troublesome finding a glue that would work. Using some scrap pieces of styrene, I tried several different glues to see which would hold the best. I started with Loctite Superglue and Testors model glue and neither would hold at all. After that I moved to a hot glue gun and that held but the glue was too thick and even after clamping it seemed to show a gap in the pieces. Next, I tried plumbers PVC cement and that seemed to work but was a little messy to work with. Finally, I found some JB Weld epoxy and that seemed to do the job well.
I started gluing some parts together and was able to build the channel which will eventually connect the foot to the ankle. The pencil in the picture was to ensure that the holes lined up while gluing. And this is where the foot work ended this week.
I also started work on the main part of center leg and ankle. The leg itself will consist of 2 pieces of .5" plywood sandwiched between 2 pieces of .75" plywood. There isn't really much to show you for that particular piece because all I did was cut the wood to length and make some measurements. However I do have pictures of the work I've done for the ankle. I read some blogs and posts at the astromech.net forum and found that one member used a PVC pipe to make his own ankles and decided that I could do the same. After all, you get much more satisfaction out of a part you've built yourself rather than one you've bought (although the parts you can buy do look great). Anyway, after much searching and a very helpful Lowes employee I was able to find the PVC pipe that he had used. It was a 2 ft long drainage pipe that had a diameter slightly larger than what the prints called for (6.2" d vs 6" d) but decided it was close enough for what I was doing. Once I got it home, I needed to figure out how to cut it. The part itself only calls for a small arc from the pipe so I would need to make 2 cuts the length of the pipe to get the arc that I needed. In order to make the cuts as straight as possible I screwed a piece of wood to the side of the pipe to run along the fence of my table saw.
I measured, cut and after much trial and error, I was finally able to get the arc piece to the correct size.
Once I was satisfied it was correct, I cut the arc to the 4" length.
Only 2 are needed for a single center ankle on a droid so I have 2 more for the next droid :-)
The next step will be interesting in that I need to cut an angle into the arcs but that is a task for another day. Hopefully, I can find some time to work on both the foot and ankle this week. It would be nice to be able to scratch another part off the list.
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| Center Foot Styrene Parts |
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| Center Foot Channel |
I also started work on the main part of center leg and ankle. The leg itself will consist of 2 pieces of .5" plywood sandwiched between 2 pieces of .75" plywood. There isn't really much to show you for that particular piece because all I did was cut the wood to length and make some measurements. However I do have pictures of the work I've done for the ankle. I read some blogs and posts at the astromech.net forum and found that one member used a PVC pipe to make his own ankles and decided that I could do the same. After all, you get much more satisfaction out of a part you've built yourself rather than one you've bought (although the parts you can buy do look great). Anyway, after much searching and a very helpful Lowes employee I was able to find the PVC pipe that he had used. It was a 2 ft long drainage pipe that had a diameter slightly larger than what the prints called for (6.2" d vs 6" d) but decided it was close enough for what I was doing. Once I got it home, I needed to figure out how to cut it. The part itself only calls for a small arc from the pipe so I would need to make 2 cuts the length of the pipe to get the arc that I needed. In order to make the cuts as straight as possible I screwed a piece of wood to the side of the pipe to run along the fence of my table saw.
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| PVC Arc Jig |
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| Ankle Arc |
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| Ankle Arcs cut to 4" lengths |
The next step will be interesting in that I need to cut an angle into the arcs but that is a task for another day. Hopefully, I can find some time to work on both the foot and ankle this week. It would be nice to be able to scratch another part off the list.
Monday, January 16, 2012
Wooden Frame (2)
This past weekend I was able to get in the garage and make the necessary cuts for the top ring of my Senna Frame. With everything to be cut away already laid out it was just a matter of setting the router to the correct depth and taking my time.
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| Top Ring after routing |
I was satisfied with the end results. Here is a pic of the top ring with the rest of the frame.
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| Senna Frame with top ring |
It looked pretty good but I am having problems with the two upper quarter ring pieces on the front of the frame. They are causing some serious stress and buckling and and won't allow the frame to come together nicely. I'm not too worried about that though. I can do one of two things to correct that: 1) adjust the notches so the stress is reduced or 2) remeasure and cut out two new quarter rings. I will try #1 first and if that doesn't go too well then I will find some scraps that I kept and recut the pieces. Tasks for another day.
Friday, January 13, 2012
Wooden Frame
A couple of weeks ago I started to make the 2nd frame for my R2. The first frame I made was based on some JAG blueprints that I had found.
It turned out nice for a first attempt but it had some deficiencies and I was ok with that. Then when one of my cats peed on the skirt and the rest of the frame had an untimely accident, I decided I would try my hand at the Senna Frame. I followed the prints to the best of my ability and ended up with some nice results.
I ended up having enough wood left over when planning the frame that I went right ahead and decided to see if I could get a second set out of the wood. I didn't have enough to make a complete second frame but I was able to get an extra .75" ring, .5" ring, and a complete set of uprights with 2 left over. I cut all the uprights at the same time to ensure that I had uniform cuts but left the rings alone. I figured I would wait and see how I did with the first set and if I needed to replace one I had the extra to cut as needed. Always nice to have extras. Anyway this leads us to where I stand today, The bottom ring had a rough cut center hole and I needed to clean it up. I decided to use my router with a trim bit and follow a guide to make a nice clean cut.
In retrospect it would have been better if I had just used a jigsaw because the guide I was using for the trim bit moved when I was trimming the left side. I noticed it a bit too late. The cut looks bad but it isn't a big deal because it's hidden inside the R2. Lesson learned on this one.
After finishing the trimming I moved on to the top ring. This piece I had done no work on so I spent most of my time determining where I need to cut. I used the dimensions on the plans and then checked them against the bottom ring and everything lined up pretty close.
Next step is to use the router and do some cutting. That however will be for another day.
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| My First Frame |
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| Senna Frame (Unfinished) |
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| Bottom Ring with rough cut center |
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| Bottom Ring after cut |
After finishing the trimming I moved on to the top ring. This piece I had done no work on so I spent most of my time determining where I need to cut. I used the dimensions on the plans and then checked them against the bottom ring and everything lined up pretty close.
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| Upper Ring cut lines drawn out |
Upper Center Vent
Today I was able to get the rest of the Upper Center Vent completed.
It turned out pretty nice
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| Upper Center Vent |
Thursday, January 12, 2012
Center Vents
On the front of R2 there are 2 vent like areas which have been aptly named, the Upper and Lower Center Vents. Tonight, I finished putting the lower center vent together.
I purchased the pieces for the vent from a fellow builder a few years ago but for some reason just had not gotten around to putting them together. Although the pieces for the vent are meant to fit together it does take some work to get them to fit properly. Over the last few days, I've had to sand down the edges of the of the internal pieces until they fit just right. Once I got the proper fit, I polished the aluminum sides to a nice shine and secured them together using a Loctite epoxy for metals.
I also started to work on the Upper Center Vent. This one appears to fit quite nicely without any sanding so I polished up the parts and started to glue them together.
I hope to finish the Upper Vent tomorrow.
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| Assembled Lower Center Vent |
I also started to work on the Upper Center Vent. This one appears to fit quite nicely without any sanding so I polished up the parts and started to glue them together.
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| Unassembled Upper Center Vent |
Ankle Cylinders
I considered purchasing resin cylinders for my droid until I got a good look at the specs for it. The cylinders are 1.375" rods with a trapezoidal outcropping on each side. I decided I would give a go with this and see if I could make them myself. I started with a 1.375" PVC tube and I inserted a 1" wooden dowel into it. The dowel was cut to be about 2 inches longer than the PVC tube. It was a nice fit but the combination of the 2 did not allow me to be able to secure the dowel into the tubing without having a large amount of excess glue running out. I cut the inserted dowel piece in half and after brushing the inside of half the tube with gorilla glue I inserted one half into the tubing so that it goes in partially leaving the excess inch to hang out. Using the open end of the tube I spread more glue into the tube making sure to get it down on top of the other dowel already in the tube and then inserted the other half of the dowel. Again, about 1" of the dowel stuck out the end. This process allowed a large area the glue to adhere itself to the tube while also fastening the 2 dowel halves together.
Once the glue was dry, I used the table saw to make the grooves in the cylinders. I did practice cutting the grooves on several scratch pieces of PVC to make sure the depth looked good and I could get a nice straight groove out of it. I do realize that the grooves are slightly larger than spec but that was something I just accepted..
Next, after cutting the grooves, I needed to determine how to notch out some material on the bottom of the cylinder so that it will sit nicely on my legs ankle. The problem I could foresee is being able to keep the cylinder from turning while cutting. After some thought, I ended up gluing a piece of wood on each end of the dowels so the pvc tube would stay still. Without a pic it's hard to explain but I guess the best way to say it is it kind of looked like a TIE Fighter in the the sides were flat with the cylinder going between them. Anyway, I then used the dado blade on my table saw and slowly cut away the unnecessary material. It took a long time to get the depth correct on the blade and then twice as long to remove the 5" of material .25" at a time. It proved to be worth it and I ended up with a nice fit when putting it on the leg.
The last part that remained was trimming the ends of the dowel to look like a trapezoid. Once again I created a jig to keep the cylinder/dowel combination from moving and I used the dado blade on the saw to remove the unnecessary material. This needed to be done from both the top and bottom and the left and right. Once I got the correct length I needed, I used my band saw to make the angled cuts for the trapezoidal shape and hooray, I was done. I still need to do some sanding, fill some gaps, and paint but the hard part was done. And they turned out pretty well. I will post another set of pics when they are fully painted.
Once the glue was dry, I used the table saw to make the grooves in the cylinders. I did practice cutting the grooves on several scratch pieces of PVC to make sure the depth looked good and I could get a nice straight groove out of it. I do realize that the grooves are slightly larger than spec but that was something I just accepted..
Next, after cutting the grooves, I needed to determine how to notch out some material on the bottom of the cylinder so that it will sit nicely on my legs ankle. The problem I could foresee is being able to keep the cylinder from turning while cutting. After some thought, I ended up gluing a piece of wood on each end of the dowels so the pvc tube would stay still. Without a pic it's hard to explain but I guess the best way to say it is it kind of looked like a TIE Fighter in the the sides were flat with the cylinder going between them. Anyway, I then used the dado blade on my table saw and slowly cut away the unnecessary material. It took a long time to get the depth correct on the blade and then twice as long to remove the 5" of material .25" at a time. It proved to be worth it and I ended up with a nice fit when putting it on the leg.
The last part that remained was trimming the ends of the dowel to look like a trapezoid. Once again I created a jig to keep the cylinder/dowel combination from moving and I used the dado blade on the saw to remove the unnecessary material. This needed to be done from both the top and bottom and the left and right. Once I got the correct length I needed, I used my band saw to make the angled cuts for the trapezoidal shape and hooray, I was done. I still need to do some sanding, fill some gaps, and paint but the hard part was done. And they turned out pretty well. I will post another set of pics when they are fully painted.
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| Completed Ankle Cylinder |
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| Trapezoidal Outcropping on the end of the ankle cylinder |
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| Cylinder showing the notched area |
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