R5 Dome Work and Pixar Roach at Mike's

We'll get to the Pixar roach in a minute. :)

After a few weeks away from work on the R5 dome, Mike kindly had me back at his place to finish the prep work needed to fit the dome onto the Rockler bearing.

Here's where we left off: Dome, Rockler bearing, several segments of steel bar with holes drilled, some screws, and Gorilla Glue (so we can glue gorillas).



The first step was to rough-up the dome screw heads on the bench grinder, so they could be JB Welded securely to their holes in the steel bar segments.





After securing the dome screws to the Rocker bearing with #10-32 nuts, it was time to apply Gorilla Glue to the underside of each steel bar segment.




We then centered the bearing with the steel bar segments attached to it into the dome using washers, all the while making sure the bearing was oriented so that the "front" of the circular bearing (chosen arbitrarily long ago) was pointing toward the front of the dome.



We clamped bearing to the dome, to help secure the glue on the steel bar segments to the lip on the dome that I had routed out a few weeks ago.




While the Gorilla Glue cured, we took on a detour project.

Remember the cockroach in Pixar's WALL•E?



Mike made the roach out of MDF, and then made a silicone mold of that. From there, he poured a few resin roaches for Maker's Faire that he attended last weekend with Michael McMaster. Mike offered to help make me a roach of my own (just what I always wanted!).




Besides the resin body, the only other essential ingredients are some pieces of solid wire that need to be cut to the proper length and bent to the correct shape. Mike had templates for these.



Mike showed me how to get started with bending the wire. I did my best to bend the wire segments to the proper shapes, but inevitably he had to make a few corrections along the way.



Once the bends were in proper order, Mike drilled some holes in the resin body and glued the wire segments in place.



Ready for paint!



Rustoleum Cinnamon does the job.



Next, into the oven it goes to bake to a delicious golden brown.



While the roach was drying, we checked on the dome and the Gorilla Glue. It had cured sufficiently that we were able to remove the clamps and the Rockler bearing.



I will clean up the excess ooze from the expanding Gorilla Glue, and further secure the steel bar segments with a pair of #10 1/2" wood screws for each segment. I also need to cut down the dome screws to the proper length, once I've determined how tall they should be. Hopefully I'll get to that soon.

In the meantime, Bon Appetit!

More R5 Dome Work

Today I returned to Mike's house to continue work on the R5 dome, while Mike and Michael McMaster continued their WALL•E work.

Yesterday, I left off having routed the lower portion of the inside of the dome base ring to allow room for the Rockler bearing. Today I raised the router bit to allow for full vertical clearance of the bearing into the dome (and then some).



As was the case yesterday, this was an iterative exercise, where I reused the peg stop positions to route out a little more material at a time. The peg positions were chosen on a best-guess basis, with no real measurements taken.



The first stair step is from yesterday's work, with the router bit set to a lower position. The second stair step is from the first pass of the router from today's work, with the bit set at the higher position.



After six passes with the router bit raised to its new, higher position, the entire Rockler bearing fit into the dome vertically, with room to spare.




As luck would have it though, there is a problem. Normally the screws that slide through the dome ring fit just fine on an R2 dome. However, on this R5 dome, the screws don't have a good dome ring to fit through.



What to do?? Building a dome ring won't be of much help, as half of the screw would poke down into the neck area, and possibly poke through the outer surface of the dome.

Mike came up with the idea of securing the screws to the dome itself, and have them point down, rather than have the the screws pointing up from the Rockler bearing. I think I've seen this idea used before, and I'll have to use it here.

So, how to secure the screws to the dome? Mike suggested attaching segments of steel bar to the dome with screws and glue, and have the #10 screws that will point down be attached to the segments of steel bar. Here is a preview of a loose-fit of what I'm talking about.



Time for another episode of "Cutting Lots of Steel with a Hacksaw," my least favorite form of entertainment.

First, I cut six segments of steel bar stock to a semi-arbitrary length. Mainly we're looking for a decent amount of surface area for when it will be bonded and screwed onto the dome.



I traced the arc of the bearing onto the steel segment, so I'd know where I needed to do more trimming.



Without these extra cuts, the steel segments would bump into the inside perimeter of the dome, thereby forcing the inside edge of the bar into the dome drive wheel, and we don't want that.



Some barely visible sparks on the grinder help clean things up. That looks like Michael McMaster's reflection in the glass, with the camera.



With 18 total cuts of steel out of the way, it was time to start drilling holes for the #10 dome screws.




Followed by countersinking.



Next, I drilled two more holes on each of the steel segments and countersunk them on the opposite side of the center hole, for the screws that will be used to help secure the segments to the dome. The plan is to use #10 1/2" wood screws, and glue.



And that's all I had time for today. Here are the six steel segments, loose-fitted.



Returning to the picture I previewed earlier, the two holes on the left and right will have the #10 1/2" wood screws in them, while the center hole is home to the #10 screws that will slip through the Rockler bearing holes, with the bearing secured to the frame, but absent the usual screws that face upward.



Mike is busy getting his WALL•E ready for Maker Faire in the San Francisco Bay Area in a couple of weeks, so I'm planning to pause on this effort until he's done with that. Next steps will be to use the Rockler bearing itself as a template for where each of the six steel segments should be secured to the dome. We'll get there eventually.

R2LA Build Day - May 2012

Droid #2 was head over heels for today's R2LA Build Day.



Mike Senna hosted a build day at his house, and I had two things I wanted to work on.

First, I needed to route out some material in the base of the new R5-D4 dome I recently ordered and received.  Second, I wanted to work on finishing up the drivetrains for droid #2 (hence the reason he was upside down; I needed to remove the feet and partially finished drivetrains to attach the motor mounts).  The R5 dome's base needs routing to allow clearance for the Rockler bearing, upon which it will spin.

At least 20 builders and a few droids were in attendance.  Marc Verdiell demonstrated his impressive droid, including the 2-3-2 transition.



In the meantime, my first order of business was to work on the R5 dome. Since none of us were sure if the base of the R5 dome was hollow, or what even it was made of, I took a "core sample" with a thin drill bit.

We're still not sure exactly what the base ring is made from, but it was solid, and possibly a resin or epoxy material. The key fact it is that it is flat, wide, and needs to be trimmed down so the Rockler bearing can fit inside the dome.



William Miyamoto worked out a way to use Mike's router to trim material from the base ring. In involved drilling three holes in a sheet of 3/4" plywood - one hole for the router bit, and the other two for a couple of segments of 1/2" diameter scrap steel rods that are used as stops. (William and I actually went shopping for a trim router, but Harbor Freight was out of stock on the cheapies, and I didn't feel like spending $140.00 at OSH.)



The stops are inserted like pegs into the 3/4" plywood. To make sure they don't lean or topple over, they are backed by some scrap wood that is clamped down.



Finally, the dome is put down, with the router bit hiding underneath. Initially the router bit is toward the middle of the inside of the dome, but as I slide the dome away from me and up against the posts, the router bit starts routing out material from the base ring as I spin the dome in place. The key is to locate the two steel posts in the proper location. The array of builders films and photographs my potential disaster.



So far, so good on the first pass. The router took out a small amount of material, which is good for the first pass



With a lot more help from William, I made five more passes with the router. We moved one of the steel stops back a little farther for each pass by drilling a new hole location for it, until the circle was routed large enough for the Rockler bearing to fit inside.



However, I'm not quite done. I need to go back to Mike's again tomorrow and repeat today's steps, with the router bit raised a little higher. This will allow vertical clearance for the Rockler bearing.

It turns out that if we raised the bit high enough for vertical clearance for the Rockler bearing on the first set of passes, bottom of the router bit cleared the bottom of the R5 dome's base, leaving a lip of material at the bottom. So another set of passes needs to be done with the router bit slightly higher, now that the bottom part of the base ring has been routed out. That should go a lot more quickly.

I never did have time to work on the drivetrain. Hopefully I can get to that in the not-too-distant future.

CHOC Spring 2012 Visit

Today R2 made his quarterly visit to Childrens Hospital Orange County.



As usual, no pictures from the room-to-room stops with the many patients he visited, but there are plenty with the staff.






The kids always amaze me with their smiles and positive attitudes, they are real troopers!