Monday, July 30, 2012

Test fitting booster pieces and battery boxes attached

After all the work I've done on these aluminum pieces, I wanted to do a test fit to make sure they would work out alright.

Everything went together very smoothly.   One complication I can see is that the rocket booster will be tricky to properly align when extended.  Note to self on that!

I also tested out the fit for the swing arms.

I don't quite have the right shoulder screw for the piece to smoothly articulate.  But, with some minor bending here and there, it all fits.

Next up was to get out the fine files and shave away and bumpy spots from the CNC cutting.

After a few minutes of filing, a much smoother surface.
Next up was to finish attaching the detail pieces to the outer feet and then attaching the battery boxes.

The battery boxes hang from a keyhole cut out in the feet.  It takes a few moments to line up the box, mark the spots and drill/tap a hole.  The battery boxes hang from a 10-24 thread pan-head screw.

One foot down, on to the next...

Next up for these guys will be the battery harnesses and ankle details, which need to have the R2 blue paint applied.  Both pieces are resin copies of the aluminum pieces.  With this R2-D2, I am striving to cut down weight where I can, so every little savings adds up!


Sunday, July 29, 2012

Pivot mounts, swing arm hinge and mountnig blocks

Today we continued the progress on the booster rocket pieces.

In the previous entry, I explained that due to these pieces being structural pieces, I wanted to re-do them in aluminum where possible.

My friend Fred, from East Coast Sign Pro, had some good suggestions and since his CNC machine is up and running, we had a chance to use it to fabricate the pivot mounts and the swing arm hinges.

With the help of a welding friend, the swing arm was welded together, filed and ready to go home.

With those pieces done for now, it was time to drill and tap holes into the pivot and mounting blocks that the swing arms will attach to.

In the upper left is the resin version we used to model the aluminum ones and fabricate.  It was a little tricky drilling  the hole in the bottom of this piece, a small vice is your friend!

These are the swing arm mounting arms which will serve as guides for it.
While seeing a bunch of small aluminum pieces with tapped holes may not look that exciting, they do take a lot of work to do! 

Next time, its time to drill the holes into the swing arm where it will bolt into the top of the booster cover.  We're slowly getting to the point we can install structures into the leg...then look at getting servos to work with it.

Friday, July 27, 2012

More Leg work

In my last entry, we got the rockets assembled and fitted inside the leg.  Now it was time to remove everything, inspect the pieces again and paint the leg.

As I have done in the past with the white parts, the legs got primed with etching primer and three coats of Satin White Rustoleum spray paint.  Since some of the inside of the leg will be visible when the rocket boosters are extended, I waited until I had the cut outs and holes drilled to do this.

Multiple light coats is the secret to priming with the etching primer.  You're natural inclination is to get a complete coating but resist it or face running paint lines!

First coat is on

Second and third!

I used painter's tape to cover the area for the under shoulder details.

These newer JAG legs have a hole already drilled out for attaching the under shoulder detail piece.

I replaced the 10-24 thread screw with a hex head since getting a screwdriver, or ANY tool in that small space difficult.

The leg cut out makes this awkward but if you take your time (and play good music in the background), you eventually get it installed.
Under shoulder detail piece installed.  The hex head allows me to really torque it in since I know R2 will rattle these guys loose otherwise!

Since I had painted the shoulders the previous week, I installed the detail pieces back into them and installed them onto the leg.

Legs with shoulder horseshoes cat "Mokey" looking on.

While the resin pieces will obviously work, there are some that I would like to replace with aluminum version.  Why?  Namely reliability.  There aren't many resin parts I have used that move around.  After two years of watching my first R2-D2 shake, rattle and roll things loose, I wanted to beef up those structural areas.

A $4 piece of aluminum from my local metal supply store, Lane Supply.  Foreground is the resin piece we are going to replace.

My friend Fred from East Coast Sign Pro was kind enough to cut these pieces down for me.  Straight cuts are essential!

Using the breadpan piece as a temple to line up and mark the holes to be drilled.

For a 10-24 sized thread we use a 5/32 drill bit.  Small piece can be tricky to drill out...and they get VERY warm so use a guide, wear gloves, mask and eye protection.  Use a chisel or punch to pre-mark the holes to drill to prevent the drill head from wandering.

All the pieces drilled and tapped.  I used a file to remove the sharp edges on the corners.

 I mentioned to Fred that there were a few pieces that I wasn't exactly sure what to do about...keep as resin and take my changes, or see about crafting a metal version.  Fred was already assisting me with the hinge piece and suggested letting him take a try with his new CNC machine that he built himself.  I left the piece with him and caught up with him the next day.

Watching the CNC machine work do its thing was amazing.  Fred made multiple measurements of the resin piece and crafted it up in his software he uses for sign making and engraving.

Due to how the piece get molded, it was a tad too wide, so Fred changed the measurements in the computer software, imported the file into the CNC machine and just like that, the bit went to work removing a very small amount of material around the entire post.

The final result.  Nice!  Now I have to drill and tap a hole in the bottom, where it attaches to the leg.

Wayne ( was able to do something incredible, he made a resin copy of the metal hinge piece that actuates the top of the boosters.  Its extremely fragile but nothing beats having that piece in your hand to help figure out how to replicate it.  Fred took measurements on this and we started work on it on the CNC machine.

We ran out of time today but we'll resume working on this.  


Wednesday, July 18, 2012

Legs modified for resin booster rockets

It seems like I have a lot of things going at once, doesn't it?  Between the rear skin work, the booster rockets, paint work and so on....I'm just on a streak where I enjoy working on R2 #2 after I get home from work.

One of the things I was not looking forward to was making the cut outs in the aluminum legs.  I wanted the measurements to be right and I wanted to make sure the cuts were correct.  The aluminum legs are not inexpensive and are usually only available every 18 months, based on the demand for them.

I got really lucky and Jerry Green had extra "rocket breadpans", as I refer to them.  When the aluminum versions are shipped to buyers, the rockets are assembled on this tray.  This piece goes inside the leg opening, as you'll see along the way.

Digital caliper, a metal ruler and pencil....ready to go to work

Referring to the blueprints often, here I'm using the measurement from the base of the leg, to 5.1250 inches for the bottom area of the cutout.  Check, doublecheck!

I had to drill a hole so that the variable speed saw would have a way to get the blade in and start the cutout  I'll use a file to correct the rounded edge

A lot of very slow, meticulous work and the cut out is done

The breadpan is going to act as a template for what holes to drill.  On the far right, or bottom of leg, there are two holes that are used and already exist in these legs.

Just to make sure this is perfectly straight, I place the leg on a flat surface and use a level to make sure we are even.
Once leveled out, I use a fingernail to set the electrical tape to hold the template in place.

As I drill the holes out, everytime I drill a hole, I insert a 10-24 thread screw into it.  This way the breadpan will stay more stable and not wiggle loose.

As I get near the end, most of the holes have screws in them....time to remove....

 The resin pieces that act as mounting blocks need to be level and uniform, for everything to fit correctly that will attach to it.  Some have excess material from the molding process.

Now while each looks level, upon lining them all up, there aren't all the same size.  I line them up on a level surface and them place them in the vice to file them all down together

Now they are all the same size and I can start drilling the holes (5/32 drill bit for tapping to 10-24 thread)

Tapping the holes.
The bottom pieces need to be drilled and tapped to attach to the leg.  For the piece to fit into the slider, some filing needed to be done

Time to slide the breadpan into place and start mounting the pieces into it

Top pieces screwed into place

Booster Seating Block installed, slider attached to leg....

View of how the back of the leg looks with the pan head screws

With the booster cover piece that goes in the bottom

Exciting times!  A lot of work but great progress.  There are a few spots I would like to replace with an aluminum part, since I am not sure hot well taped holes in resin will stand up to all he bouncing around R2 does!