With such a busy month I almost forgot to post this. The R2 Builders Club was featured in Servo Magazine and Nuts and Volts. Can you believe it, two great articles!
For Servo Magazine, Kate Stiles Howard cover the history of the club, plus a interviews with members and the story behind R2-KT.
And Vern Graner in his “Personal Robotics†column for Nuts and Volts talks about crafting an all-aluminum astromech droid with photos of hand-milled robot parts. There’s even a photo or two of my droid in there 😀
I made a bit of progress tonight getting the center foot ball casters replaced with regular wheel casters.
One of the issues with using wheel casters is finding one’s that will fit. Many builders opt to use smaller 2″ or sometimes 2.5″ casters, but I really wanted to maximize the size to help with difficult terrain. I was lucky to get some of the magical 3″ casters from the Ace Hardware store down in So Cal with the help of a friend.
At first I thought they weren’t going to fit, so I double checked with Victor to confirm that he and Mike really are using 3 inchers. He assured me that they were and sent me some current photos to prove it, along with a few suggestions and tweaks they used to get them to work.
My plan is that any mods I make will not interfere with me going back and installing the original ball casters – just in case the new one’s do not work. e.g. I’ll be using the same mounting plate but will drill some new mounting holes.
I knew I had to remove some of the lip on the front and back of the JAG center foot shell – which I did with the Dremel and a file.
I also had to remove some of the casters mounting plate to allow it to sit closer to the edge of the foot shell.
It wasn’t important to keep the mounting holes as I’d planned on drilling new one’s to match the original mounting plate used with the ball casters.
Here’s the first real test fitting before any holes were drilled
Like an idiot I forgot to take photos of the new casters bolted into place, but I did shoot this short video showing them in action
As I show in the video, ground clearance is now 1.5″ as opposed to the 1″ I had with the ball casters. But this maybe a good thing as I plan on adding an extra “skirt” at the bottom of the foot shell to mimic the center foot as seen some of the movies.
It was getting late, but I did get the foot mounted and a quick test run highlighted a problem with the rear caster not spinning fully. I’m really not sure why it’s not keeping up with the front. It spins freely when I move it by hand but when I run the droid it seems to stick to one side and drag. If I spin him enough it’ll rights itself and sometimes it does keep up.
Here’s quick shot of it sticking – I was trying to do a right turn when this happened.
I suspect it might be something to do with the fixed angle in the outer feet/legs, using wedges, which should be an easy test to see if it’s the problem.
I also need to add some wedges to the front foot to stop it tipping. With the three original ball casters located in the extreme corners of the foot this rarely happened – but now with the casters closer to the center it tips/drags very easily.
Posted by Chris on May 27th, 2008 in Feet, Legs|Comments Off on New Wheel Casters
I finally got time today to do some overdue maintenance.
I started off with the biggest issue that would most likely stop me going out again anytime soon – The center foot. At the museum event last week I’d noticed it was jittering way to much – it was probably the cobble stones that finally pushed the casters over the edge.
On the bench – I was surprised to find the two rear casters still in good condition and span fine, but the front one was in sad shape and would not move without some force. It has several gashes, dents and cracks – which isn’t a surprise really considering how hard I’ve been driving him this last year on all sort of surfaces.
I opened up the housing and on closer inspection it was obvious why it wouldn’t turn. It had developed a bulge and become pear shaped.
I could just replace it with another ball caster, but it would fail again. I’ve been planning on trying out some regular swivel casters for sometime, so later this week I’m going to try and get them mounted. The issue will be trying to get them to fit in the foot shell and maintaining the same clearance as before.
We had another successful event at the San Jose Museum of Art this last Tuesday. A few days earlier I’d read on Laughing Squid that there was going to be a party for the current exhibit “Robots: Evolution of a Cultural Icon“. Given that Artoo is such an icon I had to do my duty and take him along.
The only real issues we had at the event was the two city blocks of cobbled stones Artoo had to endure to get there, and having to sit in the droid mobile all day suffering temperatures in excess of 100 degrees – which cause some problems with parts expanding – resulting in dome drive problems, but I’m not sure if it was the heat or the cobble stones that did it. He definitely needs a tune up at this point.
Big thanks to Chinh, Steve and his family for support that night.
I’ve done enough all day events to now know that downtime and space is a good thing. It’s especially difficult when you’re the only one minding the shop. People sometimes just can’t seem respect that you’re on a break or trying to fix something – and just have to get close to Artoo for a photo.
To help with crowd control I bought some second hand retractable belt stanchions. I picked them up from a local airline for $20 a piece via an ad on Craigslist.
With 6 of these I can create a 7×14 space which should be plenty big enough to hold the fans at bay 🙂
I’d almost bought some the other day, but they’re super expensive to ship due to the weight and can run anywhere from $70-100 ea. for the really cheap variety, to over $400 for the top of the line models similar to what I got from the airline.
Now all I need is an event to use them at – maybe I can create a ticket line on the driveway for the local kids to come visit Artoo 🙂
