Monday, October 27, 2008

Cutting the Dome

Today I did some of the final cutting on my dome. Its been a while since I started the task. You can see me cutting my HP and PSI holes in a previous post. Cutting panels has been a completely different task. The previous work was done with Chris James hole cutter but for the panels I used my dremel tool.

Being nervous about cutting the curves of the pie panels and taking too much material off by accident, I hated the thought of attacking the job with a thick dremel in hand. I had also added a personal requirement that the scrap cut out be in one usable piece that I could attach to the bottom of the opening panels. So I tackled the problem in 2 ways.

First, I put the etching cable attachment on the tool but with the rotary blade. The cable slows things down a bit but that was ok because I did not want to witness the firepower of this fully operational tool.

After tracing my panels on to the dome and masking off the areas with some blue tape for a clearer guide line, I etched the lines on the dome at an extremely slow speed. Then I took another pass at slightly higher speed to form a groove.

Once I had the groove at a comfortable depth I turned the tool up near high and carved about a 1.5mm deep line that could be followed easily with a hack saw. After that I kept the dremel in one place long enough to create a starter hole for the other saw.

You can see the final dremel cuts in the pic below. I know my dome has several scratches and nicks that have come with constantly taking the outer dome on and off, but most of that wont matter once I clean it up with some sand paper.

With the lines nicely etched and the starter holes in place, cutting the panels out is super easy and clean. There is very little filing or sanding to do. I was confident enough with the ease of this last step that I even let my little apprentice to take a hand at it. Since she is interested in robotics and all things Star Wars she is very excited about this droid building process and is learning a great deal by helping out. So far, she has helped me mount the ankles and has cut several pie panels out of the dome.

For those wondering, she isn't leaning on the dome. I thought so at first, but she showed me that she was simply holding it in place. She already knows better than to mess with a delicate dome top. :)

Sunday, October 26, 2008

Radar Eye and Lens

I know that my previous post showed the Radar Eye attached to the dome, but it was just held there with tape. This week I have been working with the resin eye to get the curve just right for the 300mm dome.

In the process of working on that, my wife suddenly got up with an exclamation and went to the kitchen. I heard some terrible plastic noises and she returned with a clear radar eye lens for me to try out.

She had cut the lens from a Washington Apples carton from Costco. pictured below.

I tested the fit and it was pretty good. Im not an expert on the lens curve but this seems really close to perfect. It slightly protrudes from the front.

After a number of tests trying to heat the plastic with a hair dryer and mold a lip around the back I gave up on the idea. The plastic was too thin and warped badly. So I decided that I will have to cut the whole thing down once the resin piece is properly shaped.

To add strength to the eye I cut 2 pieces. I plan to paint the inner piece with black paint and then place the outer one on top to add the gloss. I have also considered filling the inner piece with some bondo to give it slightly more durability.

This is just a cheap fix for now. Later I will probably replace it with something better, but its one less thing I have to spend money on before WonderCOn.

Saturday, October 18, 2008

Standing Droid

This week Chris came over and we talked through a few of the problems that I was trying to work through on R2. He has challenged me to get the droid up and running for WonderCon at the end of Feb 09 which will be one year since I met him and discovered the group.

When he looked at my parts collection he recommended that I get everything that I have put together so that I know what I really need to deal with before the goal date.

I took his advice to heart, but it left me with some work to do.

First, I had to unpack all my feet that were still in grease and get them cleaned up. I filed down the area where the ankle connects until I got a decent fit and then put a few coats of primer on them.

Then I began the assembly of the legs-feet, finding out that I needed a run to Ace for some hardware. It turned out that the screws required by the threads in Ryan's legs were larger than the holes in the ankles so I had to drill the ankles out a bit.

All of that done, I was ready to mount the legs, but the bushings that I had for connecting to the frame were the wrong size. Rather than spending money for different ones (not even sure where they came from) I just used the grinding wheel and whittled them down to size.

Here is the result of all that work:

So now we have R2 standing in the living room. His center ankle is not attached to the base plate, nor is the center foot attached to the ankle. I don't have any of that hardware yet. Either way, he looks good standing there and my family was very excited to have something to see for all the work that has been put in this far.

Thursday, October 16, 2008

Front Logics

Its been a while since I have posted any progress. That's mostly due to a very slow collecting of parts and the need to replace some tools.

Now that I'm back to work on my dome, I finished sanding the HP holes and went to work on the Logic panels. When I finished cutting the front logic area, I put the surrounds in place only to find that they were not well adjusted to the thickness of my dome.

Apparently the thickness of the 300mm dome is greater than that of the C&J domes and others. Its a positive thing because the dome is more sturdy but when both inner and outer dome are put together, the thickness is great enough that the logic panel is recessed.

Not all of the pictures taken came out, but here is one that shows the logics looking perfectly placed. The problem is that what you are seeing is only the inner dome. The outer thickness hasnt been added yet. All in all I think its a couple of mm short.

I'm not sure how to handle the problem yet. I considered filing down the outside of the logics so that they would sit flush, but that runs the risk of messing up the perfect curve on the face. Another option would be to take a little off of the inner dome.

I'll post the results when I know what I'm going to do.