300mm dome for droid #2 arrives!

I was so impressed with the 300mm dome I bought for my first droid, I promised myself to purchase one for the second droid if they did another run.

Well, they did!

It arrived double-boxed and no damage.  Droid #2 is on track to be quite the improved droid!
 

JAG Foot Drives have arrived

We haven't had anything to post in a while but things are going to start changing!

Yesterday the JAG foot drives showed up.  These are designed to work with the popular NPC 2212 motor sold by NPC robotics.  Generating 1/4 horsepower, this drive system bolts right into the steel feet Jerry Green produces.

Both R2's have a lot of work planned for the next few weeks....keep checking in !
 

Test fitting the skins, legs...and then there was two!

 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.

Feet installed on R2

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!

R2-D2 #2 now has steel feet

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.

Pondering what to use inside the dome for servos

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.

Trying out the inner dome hinge process

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!