The Big Think

May 10, 2016

R2 Outer Ankles

Filed under: The R2 Project — jasony @ 9:19 pm

I’ve spent the last few days (post concussion) designing and tweaking the design for Artoo’s Outer Ankles. The water jetted layered .25″ aluminum trick is working nicely. I still have to TIG weld everything but Keith was able to TIG the .125″ horse shoes a few weeks ago and it worked well.

Today I checked out the water jet and spent four hours cutting 21 parts for the outer ankles. I had to remake one part since I didn’t clamp down the metal well enough and the edges were really jagged and messed up. I could have maybe dealt with it while welding but I decided to spend the extra three bucks and just cut another one. Total price for the outer ankles was just over $50 for the water jet time. The reason it took so long (4 hours!) was because I cobbled together a bunch of scrap aluminum that I’d used on other parts. I got all the parts in on scrap! This saved me probably $50 extra dollars in aluminum and let me clear some cruft out of my locker. Keep in mind that I’ve now done all three ankles (one center and two outer) for about $120. If I bought these over the internet from one of the suppliers they’d have cost me over $900!

In fact, I just looked at my master budget sheet and if I just look at Year 2: Legs I can get a sense of just how much I’m saving making the parts myself. Here’s the going price on the internet if I just bought the aluminum leg parts that I’ve made so far:

Leg boxes: $900
Horseshoes: $450
Ankles: $900
Ankle Bracelets: $30

So if I’d have just laid down the dough I’d be looking at almost $2500. I’ve spent less than a fifth on the legs. From here I still have to do the feet and the drive mechanisms, which would add another $1800 if I bought them…. and which I’ll get for an even better fraction.

So yeah… building it yourself is definitely the way to go, and the skills you pick up can’t be beat.

Speaking of which, I’m into my TIG welding practice. I’ve spent 8 hours at the TIG and can just now barely succeed (sometimes) at not embarrassing myself. But if I can just break through to reliably making two or three inches of halfway decent welds then I’m home free. I’m saving a bunch of offcuts and scraps of aluminum in various thicknesses to practice on. My plan is to make all the parts for the legs– horseshoes, ankles, leg boxes, feet, etc– but not weld any of them. Once the parts are made I’ll then dig in for several weeks of slow and methodical welding on each part. All I have to do is one or two inches at a time, let things cool, then repeat. I figure I probably have 200 feet of welds to do. It’s gonna take a while.

But slow and steady wins this race.

I may not be the most talented guy at any particular thing, but what I lack in ability I make up for in sheer stamina. I figure if I can stay with this R2 build for a half decade then really nothing is outside of my grasp.

Onward.

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