DAY 20 - Has it really been two weeks ???

Missed working last weekend - something about a red-eye return on Saturday Morning and leaving on Sunday makes for short time at home.

I certainly made up for it in new "stuff".  I find it difficult to think about anything but what I want to work on next as I sit in some random hotel room during the week.  This is good and bad - I play out all of the options in my head - my inner dialog argues the good and bad points about what I want to do.

Bad : as I think of something - I usually get online and order parts.  Two days later, I think of / read about something different, and decide to go in a different direction.  Admittedly, this has slowed down the progress of the build, but it has also offered me insights on the advantages and disadvantages of certain building methods.

Good : When I do get home, I have a host of stuff to tear into.  Most times, I do remember everything I have ordered.  More important, I remember what I was thinking when I ordered it.

At any given time on  the Astromech boards, members offer parts for sale.  These parts are either from a Builder's Council approved "run" or they are members selling extras that they don't need.  Typically, the official runs of parts require you to get on a list and wait until the parts are made.  This can take a couple of weeks to a few months to complete.  When a member offers parts for sale from their private stock, it is sometimes funny to watch how quickly the parts are scooped up.  I have seen parts sell 30 seconds after they are posted "for sale".  This is especially true when aluminum details become available.  I have been fortunate to grab a good number of pieces second hand along the way.  The members are always excellent with their communication, and I have no qualms about sending money for parts listed on the forums.

I thank Mom and Dad for all of the effort they have put in on this project - between monitoring and receiving nearly daily visits from the USPS to dealing with the random bits of aluminum dust floating about the basement.

Mom likes to inform me of just how many packages arrived on any given week.  I believe this week (In my defense, it was actually 2 weeks) the count was 19.  Nylon Lock nuts, Captive Studs, Motor Mount Tensioners... and.... uhhhhh, I don't know what else.  That said, here is the pile of goodies I came home to this weekend:

In earlier posts, I had talked about my concern about the long-term resilience of some of the styrene / ABS / Acrylic parts on my oh so weight-unconscious friend.  One of the main concerns was (and to some point is) the legs and feet.  When it all breaks down, the entire weight of the droid is supported at three points: The two outer ankles and center leg.  There are 1/2" bolts on the outer legs and a 3/8" bolt in the center leg that attaches the motor mount and caster assemblies to the bottom of the leg.  That is a lot of weight on these three points.

Steele and Ted, two outstanding members of the Atlanta-based R2 Builders Club, are a couple of guys that like to make parts available to members of the Astromech community.  Steele and Ted are the ones who put together the run of the blue anodized dome base plates a couple of months back.  The really cool thing about the boards is when a member comes up with a new solution, you can either A: try to recreate it with your own modifications or B: Pray that the member turns it into a "run".  Ted had mentioned this run becoming a possibility a couple of months ago.  I toyed with the idea of making my own motor mounts out of 3" x 4" square aluminum tube.  "Toyed" meaning, actually bought the tube on eBay.... then decided that I like sound of "Water Jet Cut Aluminum Plates - All hardware included" that was offered when the run became a reality.  

Here is what the kit looks like out of the box.  I think my favorite part is the "Hardware Burrito Pack".  This had all of the nuts, bolts and spacers individually bagged and labeled for easy reference along with the 20 page instruction manual.  The bag of bolts did look like a burrito, enough to make Chipotle jealous.  I imagine consuming this burrito would be slightly more kind to your stomach then those that come wrapped in aluminum foil.

As with most of the photos I take, they are of the complete project... no time for fancy picture takin' when you are working.  Dad and I sat down with one foot each and got to task. 

What are the advantages of these mounts ?

     - Aluminum (duh) no worries about strength

     - Axle tensioner that pulls on Aluminum plate

     - The moter mounts directly to the aluminum plate - no play or wiggles to worry about.

     - Aluminum center channel mount.  The ankle bolt is threaded into the channel....awesome. 

     - Swivel casters.  Although I really like the Uniball casters, I have seen too many reports of other
       members swapping them out for traditional swivel casters.  The Uniballs are not cheap and are
       only available from a supplier in the U.K.

The other side.  Mmmmmmmm - water jet cut aluminum......

Top view of the motor mount.  After these were all assembled - Dad and I were congratulating each other on a fine job.... then we tried to put them in the foot shells.  

The center channel on the motor mount was too narrow to fit inside the foot.  This was rectified by placing spacers in the center channel to widen the gap.  Dad said something about "tight tolerances" - yeah you bet.  These things fit together one way and one way only - not much room for creativity here.

Hmmmm... last post, nephew Kaden was "helping" Uncle Dott.  Here is Daddy-O HELPING his boy. It was a good day, and R2 has new insoles that I trust in supporting his weight.

Yet another left turn in the build.  More Aluminum stuff bought second-hand from a member of the Astromech boards.  Below is what is known as a 300mm aluminum dome.   These come with an inner dome that is uncut and an outer dome that is LASER cut.   Pffffffft... water jet..... we gots LASERS !  Both methods produce excellent precision cuts.  The outer dome is a thing of beauty.  All of the details cut with excellent precision, all you need to do is use a hack-saw and cut off 1/16" tabs that hold the panels in place.

Cutting the panels off took a total of about 10 minutes.  Then it came time to address the inner dome.  I started with what I thought was going to be the difficult part - cutting the holes for the holo-projectors.  Turns out this was the easy part.

First, mark the hole and drill a series of holes around the perimeter of the hole.  (Not sure if I could have used the word "hole" one more time in that sentence)

I had read a number of posts about scoring pizza like pie cuts in the center of the hole and then snapping the parts out.  I opted to try using the Roto-Zip bit on these.  Here is a short video showing the process.

A shot of the dome with the holo-ports cut in the inner dome.

Next came the rather difficult process of cutting the access windows for the top pie panels.  Who knew that cutting a circle would be infinitely easier than cutting a number of straight lines ?  Not this guy, until it was done.  

I ended up using a combination of techniques to achieve my goal.  What I found to work the best was to score the dome alone the cut line with a metal cutting disk on the Dremel.  Then I drilled a couple of holes in the score line.

Next, I switched back to the Dremel metal cut-off disk and cut through the area where I drilled the holes.  (Less material - easier cut).  Finally, I used a Skil-saw to saw the final line.  Unfortunately, I developed this successful technique on the second to last pie panel, so I had a TON of filing to do on the other cuts to make then straight.

The interesting thing about the Aluminum Domes is that the inner and outer domes do not seat perfectly together.  Some members report "getting lucky" and receiving domes that seat together perfectly, but from what I understand, they are few and far between.   When the inner and outer dome were set together, there was about a 1/8" gap at the pie panels and 1/4" gap at the bottom.  This is not good, as the inner dome needs to sit flush against the outer dome in order for the panels and doors to sit properly.

A quick search on the boards let me know how to resolve this issue.  Cut the inner dome.  Just the thought of this made my lower region pucker a bit.  Well, the Lord hates a coward, so off to the chopping block, inner dome.  I decided that a better fit would be achieved by cutting the top portion and bottom portion separately.

Once this was done, it made me feel much better about the surgery I just performed.  You can see the split in the upper left hand corner in the top and bottom sections of the inner dome.  Note the gap near the holo-projector hole in the upper left.  There was just too much play in the dome without resulting to these cuts.  The top pie panels sit perfectly now (although there are no photos) and once the inner and outer domes are bonded together, the recesses for the doors will be perfect all the way around.

Sunday at around 5:00, my hands finally gave out, I was finding it difficult to grasp a file.  A combination of cramping and metal shavings finally put this builder to rest.  

More on the dome progress in upcoming installments.  I am very excited to get this in place on R2's head !

Oh, and another goody that arrived this week.  Electromagnetic charge arm for zapping Buzz-Droids !  This photo is courtesy of Astromech member Rotopod's post, mine will be assembled soon.  Apparently, you can "age" the bronze piece by soaking it in vinegar and placing it in the oven at 475 degrees for 15 minutes.  I am sure Mom will be happy to let me do that in her new oven.  Heck - there are 2 - if it ruins one, there is a spare.... right ?!?!?