The Big Think

April 25, 2016

R2 Ankle Breakthrough!

Filed under: The R2 Project — jasony @ 8:57 pm

After sitting and pondering and sitting and thinking and sitting and staring off into the distance for far too long I think I have finally cracked the center ankle problem. This whole time I’ve been trying to figure out how to make this shape:

PART PHOTO ANKLE Center Ankle 2

from either a solid billet of aluminum (expensive and hard with many chances to break bits), or by forming/welding a rectangular bit of channel and then welding onto a solid hunk of aluminum for the curvy bits. The problem with the second approach is that aluminum is such a good conductor of heat that the thin walled channel will overheat and melt before the solid hunk even gets up to melting temp. A true welding pro can do it, but me? Not even close.

So what to do, what to do? More sitting and staring off into the distance, and then a long, slow walk around Techshop. I do my best 3D thinking while moving.

Then I looked at the layered horseshoe assembly I’ve been working on and thought OF COURSE! Could I adapt that idea to the center ankle?

So I used Fusion 360 to design the two different layer shapes, exported them as .dxf files into Illustrator, checked the geometries, did a little bit of redesign on the interior of the foot, and then dropped them onto the laser cutter with some 1/4″ plywood for a proof of concept. The plywood was being stubborn and didn’t cut too well (and there was a guy waiting to use the laser anyway), so unfortunately I had to finish the cut on the bandsaw. It turned out very rough but I was more worried about seeing it prototyped than seeing it neat.

Here’s the Illustrator file of the layers:

Screen Shot 2016 04 25 at 9 23 54 PM

With the layers (badly) cut, I quickly glued them together, trying my best to keep the layers aligned. For the aluminum version I might cut a couple of alignment holes and then tap threads so that I can run some permanent alignment screws. That way they’ll be nice and tight and aligned before welding.

Once the stack dried I took them into the wood shop and hit them with the big stationary belt sander to clean up the edges and sides.

So if you’re keeping track, I had a brainstorm and was able to use the following process to go from idea to physical prototype:

Fusion360 CAD software
Illustrator
Trotec Laser Cutter
Band Saw
Glue
Belt Sander

All in the course of about two hours (a little more if you count drying time). The end result?

IMG 2084

You can see the inside lip that the corresponding mounting block will rest against. This means that the weight isn’t being borne by the screws (as in the blueprints), but by the structure itself. That was my little idea. Yay me.
IMG 2085

And here it is on the upside-down frame. It works! It works GREAT! I’ll double check the measurements tomorrow but it looks great! I’ll just have to make sure that the layers are perfectly aligned before I weld them together since there is literally maybe .001 of slop in that inside joint. If I mess up the alignment it’ll be a whole lot of filing to get it to fit together. Lining up the screw holes isn’t going to be fun either. But hey, if there’s one thing I can do, it’s the slow and steady thing. I might not be the most talented guy around, but I’m stubborner and mule-headeder than anybody.

IMG 2086

My prototype isn’t pretty, but it does the job and I think it’s exactly the right way to go about this. I’ll make the curved outer part out of 16ga (.063″) 5052 and bend it on the slip roller, then cut and weld the curved part with the slot in it last (and probably file and sand for hours).

I’ll still have to TIG weld the edges of the aluminum once they’re cut on the Water Jet and ground down to make the little “V” shaped edges. But since I’m working in consistent 1/4″ layers, uneven heat build up shouldn’t be a problem. That’s the beauty of this design and I’m actually rather proud of my solution. I’m fairly certain that I’ll be able to use the same procedure to make the outer feet with just a few alterations for a slightly different geometry. The best news? If I bought these feet online from a builder they’d run around $900 (!!!!).

Doing them this way will be about a quarter of that.

Take that!

I feel really good about my progress lately. I had been feeling stuck lately what with the horseshoes. But all the thinking and staring off into space finally got things unjammed. I feel like I have some momentum now.

After the ankles will come the feet (a huge multi-month job) and then the motor mounts but those are both on the far side of 40 hours of TIG welding practice. But that’s basically Year 2: Legs in a nutshell. I can’t see the end of this particular tunnel but I feel like I finally have a map that makes sense.

This morning (really early… insomnia) I also bought some aluminum prep cleaner (called, naturally enough, “Alumiprep 33”) that should make the TIG learning a lot less painful. Dirty aluminum is a pain to weld and this stuff cleans it right up. Wasn’t too expensive either.

So yeah…. Center ankle!

New Electromagnetic Space Drive?

Filed under: Space,Technology — jasony @ 7:57 am

An interesting article about a potential space drive breakthrough that nobody can explain. This story is cropping up in the more respectable tech press and has been around a while so I’m intrigued. It looks like there might actually be something to it.

The Curious Link Between the Fly-By Anomaly and the “Impossible” EmDrive Thruster

April 24, 2016

The Smug Style

Filed under: Politics — jasony @ 10:00 pm

When even a (very left-leaning) Vox writer notices it, you know something has gone badly wrong in political discourse. My hope is that the people who need this the most will read it with consideration. My fear is that they will and not see themselves therein.

Read the (long) article. Worth it.

April 23, 2016

More R2

Filed under: The R2 Project — jasony @ 9:38 pm

It’s been a busy R2 week! Feels good to get some serious time in on the build. Tonight, after spending 8 hours at Techshop (four of which were teaching a water jet class), Erin and I went out to dinner. While leaving dinner I said “I kinda feel like going to Techshop”. It’s nice that the place has such a good hold on me and I don’t get tired of it.

Now that it looks like I have a handle on the horseshoe I went ahead and cut the rest of the layers (six of them) for the other side. Then I filed off the tabs and ground down the v-grooves on the edges of each. So now I have a second stack of horseshoes all ready to weld! I might hit up Keith again to walk me through it, but this time maybe he’ll let me weld while he advises from the sidelines. I’m about ready to get started TIG welding parts.

Side story: tonight my water jet class had two people in it. Normally it has four. I really like two person classes since I can help the students more and I don’t feel as rushed. One of the men in the class was about 70 years old with a great sense of humor. Funny stories (he was a pilot as well so we could talk endlessly about planes and flying), great sense of humor, and — unusual for someone of that generation — was heavily involved in programming and microcontroller technology. We hit if off immediately and I had a great time teaching him. The only issue was that it was sometimes rather difficult to understand him on account of the fact that half of his face was missing. And one whole eye.

You see, this funny, lighthearted, intelligent septuagenarian is fighting a long battle with cancer. 8 years ago he had a tooth that wouldn’t heal and here, eight years later, he’s had one eye removed, he’s missing the teeth on one side of his head, the entire left side of his face is nearly gone from the cancer, he’s wearing two hearing aids, jokes about his lack of depth perception, and says the hardest part of his life comes every four months when he goes in for his MRI to see if the cancer has returned yet again (it keeps coming back). The hardest wait is between the MRI and waiting to see the doorknob turn and see if his doctor’s face is smiling or ashen. He calls it “getting his ticket punched for another four months”.

And now this guy chooses to spend four hours of his remaining time in my classroom learning how to use the water jet because he wants to be a Techshop member and he wants to use the tools to build cool stuff. He’s not sure if he’ll be here next year, or even six months from now. But with the time he has left he’s going to make stuff, and try to make it well. And I can’t tell you how much I enjoyed getting to know him.

R2 Horseshoe Weld Success!

Filed under: The R2 Project — jasony @ 9:20 am

Some good success today. I coated the horseshoes in JB Weld and LabMetal to fill in the little V-grooves that I ground in each side layer. It was ugly once it dried:

 

IMG 2060

Next I clamped the part in the vice with some wooden shims:

IMG 2062

Then I ground the welds and filler down with an aluminum grinding disk that Keith gave me the other night (thanks, Keith!) They looked really good after I was done. Nice and smooth and flush with the surface. Since I was using a disk and not a belt, though, it was easy to make little divots and gouges in the soft aluminum. There’s a bit of waviness on the edge of the part in this photo:

IMG 2066

So I’m ordering some Rage Gold body filler from Amazon (the same stuff I used to make the Tri Delt clamshell prop about five years ago). I’ll do a few layers of filler on the outside so I can cover up the metal edges. But before that I still need to drill out that broken screw (you can see it in that top photo). 

So in spite of the expected (and unexpected) little snags it appears that I have a clear way forward on the shoes! Really happy with the way it’s turning out.

I spent about 3 hours at TechShop this afternoon and in addition to the grinding I also did some thinking about the center leg ankle. The finished part should look like this:

Centerankle5

with this inside (I’ve already made the rectangular part):

PBLCenterFootMount01

 I had what I thought was a shoe-in idea for this and spent some time at TechShop designing a file in Fusion 360 (what a great program), but now that I look at it in the first picture above I’m not so sure it’ll work. More thought needed.

A lot of this thinking is due to the fact that I can’t TIG weld (yet). I really should get off my butt and just do it. I’ll probably ask some advice and start that process next week. So much would be easier about this project if I could just TIG. Even badly. Grinding down that aluminum results in an amazingly clean joint (see the post-ground horseshoe pics above). But the process kind of scares me.

 

April 20, 2016

Horseshoe Update

Filed under: The R2 Project — jasony @ 10:11 pm

In the great-news, slightly annoying news department, I went to Techshop today and bumped into the welding instructor (a super guy named Keith Wojcik who is one of the best welders in Austin). Great guy, great teacher, great welder.

IMG 2055

I showed him the part and asked him if it was even possible to weld it and he said “come here” and wandered back to the welding room. Back there he set up the TIG welder, described what needed to happen, and then just welded it for me right there. I couldn’t believe it. The aluminum was pretty dirty so the welds ended up a little messy (absolutely not Keith’s fault), but at the end all seven layers were securely welded together. Success (so far).

IMG 2056

It’s a tack weld job and will be ground down and cleaned up, but the layers are connected. I’ll also put a coating of Lab Metal between the welds to cover the layers and then grind/sand it down until it’s smooth.

Unfortunately (you knew this was coming), I think the screws were overheated when the aluminum got hot — and it got stupendously hot. It took more than 45 minutes for the aluminum to even be movable, and even then I had to wear leather gloves. Anyway, the screws got bound in the holes. I also think that the act of clamping the parts together compressed the threads in the holes and made the screws bind even tighter.

Sooooo… when I went to take the screws out they were extremely difficult to turn. Two of them came out with a little bit of effort. But that third one? The screw head just snapped right off. Nooooo!!!! Luckily there was still a little bit of thread showing so I got some Vice Grips after the little threaded leftover…… and promptly snapped that off as well, completely flush with the surface.

Well poop.

So I have to figure out how to remove that bloody screw. That stinking #$@#@^ screw. It’s so completely stuck in there that a normal screw remover probably won’t do the trick (though I have nothing to lose by trying). What I think I’ll end up having to do is slowly destroy the screw by drilling it out with progressively larger bits. I might have to enlarge the hole and put a #10 screw in there instead of the #8 that’s stuck, but that means enlarging the mating keyhole, which introduces alignment issues (which I’ll have to figure out a solution for). There’s also the risk of breaking the welds when I clamp it on the mill to remove the screw. UGH

But hey! One of the horseshoes is welded. Better yet, Keith told me that he’d weld whatever I need. He’s also going to teach me TIG. I took his MIG class again tonight and had fun. TIG is a whole different story. I get to learn from the master.

When I left the shop tonight one of the Techshop employees said “that’s why they call it a Herculean effort”. Every step has something go wrong.

Every. Single. Step.

R2 Update

Filed under: The R2 Project — jasony @ 8:38 am

It’s been a while since an R2 update. I probably need to write a lot more but I don’t have time right now (I’m actually building instead of writing about it).

About two weeks ago I decided to mill up the little leg “cups” that hold the leg hubs. It’s an easy part to overlook. Fortunately, I was able to find some aluminum tubing with an inside diameter (I.D.) that was close. I got a 12″ piece, chopped off a 5″ piece, and proceeded to very slowly mill out the I.D. on the lathe.

IMG 2003

IMG 2004

That wall is less than .125″ thick. It’s really delicate and I was worried about milling through it so this cut took me about 2 hours. I’m slow on the lathe but the tool scares me so I play it as safely as I can.

Once I got the I.D. correct I just cut off a piece that was the right length (two, actually). The part separated early before the cutting tool had cut completely through, which I was initially upset about (oh no! sanding a delicate part!)

IMG 2005

but it turns out that the little edge you can see on the left was pushed in a few thousandths of an inch and so it fits perfectly inside the mating hole and acts as a guide! I’ll have to chamfer off a tiny amount on the inside of the hub when the time comes so the hub will clear it, but since it’s inside the leg you’ll never see it. And besides, the little guide ring makes alignment and gluing MUCH easier. So an unintended mistake turns into a win! Happy accident.

In the past week I’ve worked about 20 hours at Techshop on the Horseshoe parts. Well, one horseshoe. I water jet cut out the 8 layers (out of .125″ aluminum 6061) and test fit them together.

Here’s a pic of the sheet of 6061 before and after water jetting

IMG 2007

IMG 2014

And here are the layers stacked up on the leg (which is itself just stacked precariously and not welded yet):

IMG 2015

Great fit. I had to file the tab from the water jet off of each layer (2 tabs actually)

IMG 2053

IMG 2052

I bought a set of files from Lowes since so many of the TechShop files are corrupted with steel or not in good shape. Add it to the budget.

IMG 2054

Once I’d filed away the tabs I sandblasted each part to give each layer a bit of “bite”. My idea here was to lay down a coating of aluminum epoxy to bond the layers together. However, once I got the epoxy and did a test run on some scrap, the scrap debonded (it broke) with very little pressure. So instead I VERY carefully aligned the eight layers and clamped them together, then spent the next three hours in the machine shop drilling and tapping some holes so the layers could be held together with screws. Somewhere during this process (power washing after the sandblasting, I think) some of the layers got very slightly bent. So now my perfectly flat horseshoe ends are flayed out. Ugh. I’m going to TechShop tonight to talk to a professional welder to see if it’s possible to clamp the layers together and tack weld them. In preparation for that I spent a few hours grinding a bevel on each layer so that when they’re stacked up there’s a little “V” shaped groove on the edges between layers. Hopefully if the layers can be welded this will give the aluminum rod enough “bite” to hold the layers together after grinding off the excess material.

Keep in mind that I’ve worked about 40 hours on just this one horseshoe. I haven’t even cut the parts for the second one yet. I’ll give the welding thing a try and if it works I’ll go ahead and commit to the second one. If, however, the welding is a total bomb then I’ll step back and rethink how I’m doing the horseshoes. I really really want aluminum shoes but if it’ll delay me too much I’ll do MDF now so that I can move on. Those parts are easy to replace in the future if/when I choose to revisit them. It’s been so long since I’ve seen forward momentum that it’s easy to get discouraged. So I’m considering making some temp parts and replacing them in the future if I get stuck at a certain point. Droid building is the Everest of Nerddom, as I’ve said. So there will be some parts of the journey that feel like you’re stuck. But I don’t want to get so mired up in one part that I get discouraged and wash out.

I’m frankly terrified to weld these things. I’ve spent a lot of time (and not inconsiderable money) getting the horseshoes to this point and if they warp under the heat (something I’ve been warned about) then it’s back to square one. But if I’m so nervous about messing them up that I don’t move forward then I’ll be stuck here forever. So I guess I have to do something. Hope I don’t screw it up. I might hire a pro to do these particular parts, or at least to just tack them in five or six places so that I can come back and Lab Metal them and sand them down.

Looking forward, there are so many aluminum parts that need to be welded that I’m almost certain I’ll have to learn to TIG weld. This project is about learning new skills but TIG is extremely difficult to master and represents a major detour while I develop the skill. Probably about 40-60 hours running a mile of bead to get good. In the meantime nothing will get planned, designed, or built. But there are so many parts to weld that hiring someone to do it doesn’t make much sense. My Techshop friend Bill May gave me a pep talk the other night that helped a lot. I was getting a bit discouraged thinking about the ridiculous challenge this project represents. Bill had some really kind and encouraging words for me and encouraged me to learn to TIG and keep moving forward. Frankly, I kind of needed it and appreciated it more than I think he realized.

It seems like at every single point in this project, from major design decisions down to where to clamp a part on the mill, there is some sort of little issue that crops up. For example, while tapping the holes in the horseshoe stack I discovered that my tap was about 1/16th too short. But since the stack was already clamped and the hole drilled I had to solve the problem right then. No coming back to it later since I couldn’t take it off the mill until the holes were drilled and tapped. I managed to figure out a solution but it took a lot of seat-of-the-pants thinking. The entire project is like that: nothing easy, everything fights you. So Bill’s words were really helpful. Keep pushing ahead. Eat the elephant one bite at a time. Don’t look at the summit– just look at the next step to be taken. This will take another three or four years (if I’m lucky!) and if I think of the whole project at once I’ll just get discouraged.

Okay, onward.

April 18, 2016

College Kids Say the Darndest Things

Filed under: Uncategorized — jasony @ 8:48 am


Link


“It shouldn’t be hard to tell a 5’9” white guy that he’s not a 6’5” tall Chinese woman, but clearly it is. Why?

And what does that say about our culture?

And what does that say about our ability to answer the questions that actually are difficult?”

Watch the video (sorry if the link is small. Working on an issue with MarsEdit).

April 12, 2016

Class I – Loose Fit Tolerance Chart for Holes and Bolts – Engineers Edge

Filed under: The R2 Project — jasony @ 4:07 pm

I was referring to the following chart for R2D2 aluminum fit tolerances. I was just looking at one of the engineering drawings that I have to reproduce in a year or so and inadvertently started giggling like a crazy person. What am I doing? I’m insane. I’m insane. Not until one of the other members at Techshop looked at me funny did I realize that I had just said everything out loud at full voice.

Oh, R2. You’re going to be the end of me.

Class I – Loose Fit Tolerance Chart for Holes and Bolts – Engineers Edge: “”

April 9, 2016

Argument

Filed under: Politics — jasony @ 3:05 pm

Here is a carefully thought-through argument I have spent years forming.

YOU’RE HATEFUL!

But I don’t hate anybody. I just have this calm, cogent argument that addressing the issues in what I view as a proper historical and cultural context.

WHY ARE YOU SO FULL OF HATE!?!? IT IS MY DUTY TO SHAME YOU PUBLICLY TO SHUT YOU UP.

Wait, wait, wait, wait… you haven’t even heard me out. I think if people just stop for a minute and…

YOU MAKE ME SICK. HATEFUL HATER.

Sigh.

True story: our old pastor, one of the most caring and compassionate people you’ll ever meet, who has decades of service and pastoral experience, was told that he was “full of hate” because of his (equally compassionate and nuanced) political opinions (which he, significantly, went to great pains to avoid expressing). The exact comment was “I can’t believe someone like you could have so much hate in his heart”.

Hate has become the new weapon, to be wielded by the emotional to shut down arguments they disagree with. This is what passes for argument among a significant portion of our society (both on and off of Facebook). We’ve become such a bumper-sticker culture that the feeling seems to be if you can’t zing your opponent or get your argument out in five seconds then the other side doesn’t have to make an effort to understand you and has a right to shut you up. And if they shout louder, they win.

It’s going to be a long year.

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