Today I brought home my first R2-D2 from my parent's place. I couldn't resist taking some pictures of both droids side by side.
I did some test fitting of the skins on droid 2 and there are a small areas where the Goop adhesive needs some trimming. The excess that dried up on one side is making it difficult for the door to close completely. Easy fix.
As you can see, I have the droid back in 2-leg mode and as such, sitting on top of a milk crate so it will not fall over. The ankles and shoulders have free movement.
Tonight I worked on attaching the feet to the ankle & legs. I was eager to see how everything looked all together.
The first step was to install the round brass pivot piece into the ankle.
Having installed these before on the first droid, I used a file to take the edges down and working the file all around the surface. You want to take some of the material off but not too much.
With the first portion able to fit inside, I used a piece of wood under the ankle. I used another piece of wood and lightly tapped with a hammer, slowly putting the piece in place.
Go slow because you may have to wiggle the brass barrel a bit to correctly line up with the other side.
With the ankles ready, I found that the ankle fit into the foot groove with ease. On the other droid, it was a lot of grunt work to get them in the groove, then trying to line up the foot so the bolt could pass thru. On this droid, it went very easy. Despite being bolted in as tight as I could make it, the ankle pivots with ease.
With this "uber" version, linear actuators and ball-screw drives, under computer control, will actuate the ankle and shoulders, allowing them to pivot into 2-leg or 3-leg mode.
I do not have the "stop plate" used in the shoulders installed to lock the shoulders into the 2 or 3 leg position, so everything moves rather freely.
While trying to get R2 into a stable 2 leg position, I had to work hard on finding a good balance for the picture. As I was grabbing the camera to take the picture, R2 fell forward, breaking both utility arms. No biggie, those were old resin ones I was testing paint color on. But that's the last time I want to hear the THUD of the Jawa-face-plant.
Here's how it looks in two-leg mode.
With R2 being so unstable in 2 leg mode, in quickly put the center ankle and foot together and installed it inside. Here's R2 in 3 leg mode...
That's it for tonight!
Today the JAG steel feet for my second R2 arrived. I was able to purchase a set from another R2 Builder who was willing to part with them (pun intended).
These are identical to what I have on my first R2-D2. The gentleman I bought them from had already cleaned and primed them, so that saves me some time!
With the exception of some detail pieces, I have both legs, ankles and feet for the droid.
Now I can start doing some prototype work with some ideas I have for locking and pivoting the ankles for R2 to go from 3-leg mode to 2-leg mode (known as 2-3-2 in the building world).
In a few weeks, the foot drives should arrive, which is what R2 #1 has been using with great success.
I am also looking to make this droid lighter than the first. Things like using resin detail pieces instead of aluminum is one area I am looking to try.
As I start to think about the next few steps ahead, one thing I am considering doing is using micro-servos for all the dome's hinged panels.
I've used them before but wasn't happy with the flimsy plastic horns they came with. Too much flex when attached to the metal push rods.
However upon doing some research, I have found both metal mini-servo brackets and aluminum servo horns. For me, this makes the idea of using a micro-servo much more appealing. Plus, there will be some weight savings using these versus the regular sized servos.
With the lower panels I have chosen to hinge, I will need 6 of these and the top, pie panels, 5 more.
It'll take a while to get these as the R2 building fund is pretty low lately! But, for now, I can at least plot out what I will need.
Tonight I took some time to file the dome panels a bit more uniform and then cleaned up the excess slag from that. Again the dremel made quick work of this with the sanding bit.
I wanted to do a test run with one of the dome panels and try attaching one. I was curious what spacers, screw length and such I would need to get a good fit.
First I used one of the backs of the hinge and lined it up even with the edge of the panel.
Once I had the holes marked, I tried to find my center punch. I couldn't locate it so as a result, one of the holes I drilled wandered up a bit.
With the holes drilled with a 1/8 inch drill bit, I countersunk the hole so the 4-40 screws would fit flush. I screwed the bolt and nut together and could tell I would need something behind the hinge to accommodate for the curvature of the dome. I think a very small, rubber washer will be ideal.
I would like to also replace the 4-40 nuts with larger, 4-40 lock nuts with nylon inserts.
With that attached, here's how it looks from outside...
I think the process will work well. I just need to accommodate for the dome curvature with the hinge mount....and of course, find that center punch! No more wandering drill bits!
This evening I continued work on the inner dome.
First I had to assemble the JAG hinges I would need a bit later on.
My assistant then stole my chair as I prepared to work on the inner dome...
While Mokey took over my chair, I had all kinds of slag to file from the cuts I made yesterday.
Being in a curved surface, I decided to go with the Dremel flap sander bit I have. Make sure you have eye protection, breathing protection and long sleeves when you do this. Using the 120 grit flap wheel, I was able to make quick work of all the rough edges.
I placed the outer dome on the inner to see how the panels looked. It wouldn't fit just right since I still have some more filing to do. However, with the outer dome on, I can see just how much filing I need to do to "square up" some of the cutouts.
That's it for tonight. More work tomorrow!
Today I did some cutting of the inner dome panels I had previously marked out.
A few weeks ago, while removing the head of a screw, my 7 year old Dremel made a POP sound and died. Now I have replaced the Dremel with the latest and greatest model. This also means the better cutting wheels will work on this model.
The goal is to cut the panels out, file them, then I will use the JAG hinges to bolt them into position. I'll counter-sink the screw holes so that the end result will be perfectly flush. My thinking is that by using the inner dome pieces, I will not have to mess with the troubles other builders have had. Some have had difficulty getting the panels to close or open completely, more notably in the dome pie-panels. Since all of these panels will be attached to servos for quick opening and closing, I want to make sure they all close flush.
First I wanted to make the cut lines more pronounced, so I took a flexible metal ruler and pencil to them.
The vertical lines were easy, the horizontal, due to the curvature of the dome, were a bit tricky.
Speaking of tricky...how to cut the dome panels was my next hurdle. Since the panels are all near the bottom, I would need to find some way to cut them safely. What I came up with wasn't exactly ideal...but worked!
With that, it was time to start cutting...
Next up is to file the pieces.
However there was one boo-boo. I cut through the bottom so I mixed up some JB Weld, put it in the overcut and set it so I can sand smooth tomorrow...
More tomorrow!
Today, the aluminum center ankle that Jerry Greene's machine shop produces, arrived on my door step.
The list of needed items for the second R2-D2 is slowly getting shorter!
David Shaw from Australia just finished doing a part run of the front and rear logic displays. My set arrived a few days ago...
These go in R2's dome and will eventually have the lighting mounted to them.
This is all new to me...cleaning up the inner dome pieces I cut out for use on the outer "pie" panels. Like I did for the skin panels and doors, the material from the inner layer will make hinging the piece easier. The hinges will attach to the inner material and allow for a flush fit for the finished product.
Or...so I hope!
As you may recall from a previous posting, cutting the dome pie panels out was a challenge, going through many cutting bits in the process. That made for a lot of filing work to clean up the not-so-great cuts on the inner dome cut outs. And...as you can see, the pieces removed need a good deal of work too.....
As you can see from above, I pulled out my reference blue print I used to label all the panels. I do NOT do this while cutting the panels out, so I had to line up each piece and see what went where. (One of the FEW times spin lines are useful!). I used a pencil to label the outside of the panels since those will be covered up by the outer dome panels in the future.
And once I had those all labeled, I did the same to the inner dome as a reference. I made these marks low on the dome where they will not be visible when the outer dome is placed on it.
Then there was the filing. Lots and lots of filing. I just kicked on the TV downstairs and took my time.
The top and bottom have the curved edges which require a little finesse when filing into a smoother curve. The sides are straight lines so this is pretty easier to take care of.
Here's the finished results...
Next up is to clean up the inner dome with some more filing...then on to cutting out the the panels on the lower part of the dome.
Next up on the list of dome pieces to get prepped was the dome ring.
Unlike my first R2-D2, which has a 300mm dome, the blue ring does not come off. With this dome, you need to carefully tape up and paint it.
The dome ring has the spot to be painted already pre-etched into it. The tricky part is carefully putting the painter's tape on the lip/edge of each side. If you go slow and use your fingernail, its not too hard to sufficiently cover up the areas that need to stay unpainted.
Just for good measure, I went around a second time and double-checked. It sure beats trying to remove paint from a tiny crevice.
With that done, I took advantage of the great weather today and used Duplicolor Etching Primer on the dome ring.
And....I also put the etching primer on the pieces I treated with filler primer and sanded smooth the other night....
The pieces will get some light sanding (400 grit) and be ready for the blue formula anytime.
Today I collected up all the dome pieces and started the process of cleaning them up.
First I had to finish filing off all the laser slag residue from the laser cutting process. Then I had to file down the tabs. I used a double-cut file to do this, which removes more material than a single cut one. You just have to be careful not to over do it, since aluminum is a soft metal.
Then, all the pieces were done!
Since the dome has been polished in the past, I had to rough up the surface for better adhesion with the primer. Using a mouse sander and some 220 grit paper made pretty quick work of this.
After a short break, it was time to take the pieces outside and use some Filler-Primer. This will fill in those spots that still have some un-even surfaces or spin lines in them.
The filler sander sat outside in the sun for 2 hours to dry completely.
Next up was to sand the pieces with the mouse sander again, this time using 120 grit paper. 120 grit is for medium to light removal, which is all we want. The goal is a level surface.
After the sanding...
There's a few spots with primer still on the surface, which is fine.
Tomorrow we'll put a coat of etching primer on the pieces, which gives the paint a solid foundation to bite into the surface. Once that dries, sand smooth with some 400 grit sandpaper....then its on to the Krider Blue formula.
Today I went thru 7 more Dremel cutting wheels but made some more progress on the inner dome...
Today I started tracing and cutting the inner dome.
First was to add a 1/8th inch "lip" for the pie panel to lay on. The easiest way I found to do this was with 2 pop-sickle sticks. I just went slow and steady, making many small marks.
Once I had the pie panels done, I checked my Star Wars reference pictures to see which lower panels I wanted to hinge. I want to be able to duplicate R2-D2 having all of the panels popped open, much like when R2 shorted out when shot in "Return of the Jedi
...
With that as a reference, I traced out the panels....
With that done, it was time to connect the dots for cut lines. The vertical lines were pretty easy, just using a flexible ruler. For the horizontal ones, I used the pie panels that were cut out of the outer dome to trace the curvature correctly.
Then came the nerve-wracking part...cutting. I had two options....drill a large hole and try cutting with a bulky jigsaw. Or...use the Dremel with a reinforced cutting disc. I opted for the Dremel.
The Dremel could do it but it required the RPMs to be pretty high. Going slow and steady I managed to stay within my lines. However, the Dremel was getting very, very hot so it wasn't very fun to handle, even with workgloves on.
Here's the first panel cutout!
One down, about 10 more to go!
While I was down in New Hampshire, I was able to pick up some parts from my friend Jerry Greene. Jerry had some spare electronics tray/doors for the frames he designed. He also had a shelf piece that he had made that he wasn't going to use.
The electronics tray is identical to what I installed in my first R2-D2. It required a bit of tweaking to make fit but I has worked out great. For the second R2, with the newer frame, its just a matter of bolting it in!
The shelf piece required a bit more modification since the door bread pans in each tall door interfere.
After some diligent cutting with a reinforced cutting disc on the Dremel, I was able to trim them down to fit.
Here's the finished product installed....
Originally this piece was going to be used for a 2-3-2 center ankle mechanism using a NPC 2212 motor, the same motors that propel the foot drives. As such, each side is trimmed away for a swing arm and pre-cut holes to attach the NPC motor. However it never went beyond the experimentation stage.
For my uses, first and foremost, its a place for R2's netbook to sit! As for anything beyond that, its too early to tell.
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