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sprockets, sockets, grommets & gaskets

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(no subject) [Apr. 24th, 2017|09:02 pm]
sprockets, sockets, grommets & gaskets
This morning I got up, hopped in the shower, and fainted.
I faint a lot, but usually what that means is I stand up, get dizzy, grab the wall, and have to sit down for several seconds.
This was a complete blackout, fall through the shower curtain, and stay on the floor for quite a while until N had pulled the curtain off me and started checking for a pulse.
It may be the same low blood pressure problems I've had for years: standing in a really hot shower is the sort of thing that leads to fainting.
Nevertheless I'm going back to the doctor.

Anyway, I took the day off because I had an awful headache. Apparently I hit my head pretty hard.
So I did a bunch of housework, got the new DSL modem FINALLY hooked up and functioning, cut down a bunch of stupid elm trees that keep coming back every year, watered all the plants, walked the dog several kilometers. Not much involving power tools.

Greyhound legs look particularly alien.
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I went over to the junkyard to get steel for the deck railing and found some drillbits that were more than two meters long. I kind of want one.
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Some newspaper blew into the yard. It's had a long journey.
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I set up the foundry and did some more casting, just scrap processing.
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In doing so I found the last bits of the Subaru engine block I broke up and mostly melted down years ago.
20170424_192017

Whilst organizing the workshop I got out the old glass annealing oven. I recently bought a fancy PID controller for it, that'll replace the kind of scary triac-based control system I built for it many years ago. That's the last step I need for the 3d-print-to-aluminum-casting toolchain.

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(no subject) [Apr. 23rd, 2017|11:14 pm]
sprockets, sockets, grommets & gaskets
We went to the Ingress cross-faction awards ceremony for the Colorado area on Saturday. They hold it in a kind of divey artist gallery on Santa Fe, but there are usually at least a couple of good sculptures.
Both these were basically 2 meters tall.
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Two of my coworkers have bought the same model of 3d printer that I have. One printed a tiny crossbow, that is almost entirely a single print: all the moving parts (and there are several) were printed in one go, assembled, relying on flex to enable it to work.
20170421_142509

I think it's funny that so far he has printed a fidgeter (a weighted spinny thing) and the plastic equivalent of brass knuckles and a crossbow and a skull. I have printed a testbed for one of my circuit boards, an enclosure for another circuit board, an intake manifold, and motor hold-down brackets. The other guy has printed a klein bottle and another mathematical oddity, related to a moebius strip. We all seem to be quite consistent in our choices, although they are all quite different.

I bought a pipe nipple and cap, intending to weld them together to make a small heavy-duty crucible for melting and casting brass, insofar as my aluminum one is intended for much larger volumes and much lower temperatures. The nipple and cap both claimed to be galvanized steel. I sat them in hydrochloric acid for about 20 minutes and then went to weld them. The HCl did not sufficiently strip off the zinc in 20 minutes: I should have left it in there for an hour.
This is what it looks like when you try to weld something galvanized.
20170423_191742
Zinc fumes are bad for you. Avoid doing this.
As it turns out, even though they both claimed to be galvanized steel, the cap was in fact cast iron. I should have tested it before trying to weld it.
This is what happens when you use standard welding rod to try to attach steel to cast iron.
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See that big old crack horizontally right down the center of the weld? The cast iron has melted and run up to that point, but because it is brittle, when it cools it contracts and cracks. (Steel is ductile enough to stretch just a little as it cools.)
This is definitely not going to hold liquid brass without leaking everywhere.
I'll fabricate another one later.

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(no subject) [Apr. 22nd, 2017|11:00 pm]
sprockets, sockets, grommets & gaskets
[personal profile] threemeninaboat says there's this song that includes the words "Hakuna matata" that everyone in the world knows except me.
Is she right?

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(no subject) [Apr. 18th, 2017|08:58 pm]
sprockets, sockets, grommets & gaskets
Apparently my style of decapsulating integrated circuits is so different we don't know how to take pictures of the results that show what we want to see. We have damaged chips. When we etch the top off with nitric acid there are spots that won't etch because they're a mixture of metals, epoxy, and silicon. The way I remove the top doesn't leave those spots, so we have to compare the pictures to pictures of a good chip and even then the evidence for damage is subtle: lines that aren't quite straight, for instance. I may have to come up with some way of producing contrast. But, generally, it's extremely successful save for our lack of ability to electrically connect to the die anymore, and we can even manage that with our probe station.

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(no subject) [Apr. 17th, 2017|10:09 pm]
sprockets, sockets, grommets & gaskets
Tonight I learned how to reliably, repeatably remove the top of an integrated circuit package and expose the silicon without damaging it much, and without using acid. I'll do a writeup on @smellsofbikes later in the week, when I have a chip for which posting pictures online is permissible. I made a tiny vise to hold the chip, then I cut off 98.5% of the packaging material, then I hold it up to the bottom-side of a sideways flame so it's as cool as possible and gently bake the remaining epoxy until it's brittle, then oh so carefully scrub it off with a fiber brush and careful compression to fracture larger pieces using the tip of a pair of tweezers. That last bit, the careful compression, is by far the hardest, most nitpicky part. I'm using a 20x microscope and wish I had a 50x.

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(no subject) [Apr. 16th, 2017|10:55 pm]
sprockets, sockets, grommets & gaskets
Two police officers showed up at our front door at 2200 tonight, and said they wanted to look in my back yard for a guy who might be wandering around through it. I think there was more to the story, because a plainclothes policeman showed up a minute later and two other cars a minute after that, and there were a fairly large number of people out looking through my back yard and my neighbor Ray's back yard (which are largely conterminous, though separated by a rather tall retaining wall.) That shot my interest in doing a bunch of work in the workshop.

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(no subject) [Apr. 15th, 2017|07:11 pm]
sprockets, sockets, grommets & gaskets
I need to remove the epoxy encapsulation, or at least most of it, from a whole bunch of chips, so I made a little de-encapsulation vise for my mill. This way the chip is supported across the bottom and at both ends. The vise height is the width of one human hair shorter than the chip, and the chip is the width of one human hair shorter than the vise length, so it fits in pretty solidly.
mechanical decap vise

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(no subject) [Apr. 14th, 2017|11:06 pm]
sprockets, sockets, grommets & gaskets
Lessee.
It's been windy lately.
20170409_170542
On this particular day it was gusting to over 70mph: 110 kph. Vroom. I was not out riding in that.

I had today off because I work for a Texas company. Nobody else in Colorado had today off, apparently, including schools. We went to City Park to bum around and play Pokemon Go and walk the dog. This is Cormorant Island. It looks like the place you end up when your ship has sunk and your lifeboat is just about out of supplies and you see a distant lump on the horizon and as you get closer you realize you really are doomed.
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The new 20 ton jack from Home Depot did what it was supposed to do.
I cut a weirdly shaped bit of wood.
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That was not in fact the right shape, but was close enough.
Then I stuck it in the corner between the front left shock tower, frame rails, and swaybar brackets and put a floor jack beneath it to hold the hydraulic jack in place, then put the hydraulic jack in with a bit of wood to protect the edges of the bumper.
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A few pumps later and the bumper-and-valence-spoiler-assembly made some truly horrible noises, followed by a pop as two bits of metal slid over each other and back into their correct alignment, and suddenly the car was symmetric.
I took it out for a spin and it now makes no grinding squealing crunchy noises.

Success is rarely so cheap, as the success dispensed by a 20 ton hydraulic press.

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(no subject) [Apr. 13th, 2017|07:37 pm]
sprockets, sockets, grommets & gaskets
Today I did commodities trading.
I traded about 25kg of lead, stuff I collected off the side of the road as a child, for about 15kg of brass.
I have several coworkers who shoot, a lot. They reload cartridges (and, I just found, buy bulk floor sweepings from local shooting ranges to reload those, too) and at some point the cartridges get metal fatigue and begin to bulge, at which point they go into buckets.
I now have one of those buckets.
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Cutting brass on the lathe is really enjoyable, and I can make all sorts of neat things, so now I get to find out if the foundry is capable of melting brass hot enough to pour.

Work is kind of stressful. My part isn't: I took over technical writing to free up time for people directly in the line of the stress, and spend my day merrily typing. Man, can I type a lot of words. The project I'm working on was up until quite recently our showpiece, because we're forecasting selling half a million of them before August. We run all our chips through a slew of physical tests, in addition to electrical ones: we freeze them, bake them, shock them, shake them (I just made that up but I'm totally gonna start using it at work.) In one of our tests, they're having issues in a particularly inexplicable manner. That's the most detail I can go into. But everyone is going crazy trying to figure out why. One of the ways we do this is by looking right at the silicon, which is inconveniently (for this situation) all nicely covered up in baked epoxy packaging intended to keep the silicon sealed against everything for at least a hundred years.
The traditional way of doing this is by dripping hot concentrated nitric acid onto the chip over a period of a few hours. The nontraditional way of doing this is called the Bic Decap: you take a cigarette lighter, hold the chip over it, and burn off the epoxy that way, leaving you with a somewhat battered piece of silicon. I volunteered a somewhat middle way: to chuck it up on my mill and cut off 99% of the epoxy, so that we can remove the last little bit at a reasonable rate with acetone.

On the way home, I stopped by Harbor Freight Tools on the theory that since I got one bum hydraulic jack there, why not get another? (To be fair, I bought the first one fifteen years ago and it did work for several years.) Our particular Harbor Freight seems to attract particularly dubious people. There was an extremely twitchy guy with face sores who spent the whole time cursing quietly at his wife, telling her that she was stupid and looked stupid and made him look stupid, while she doggedly picked out the things she needed. I feel very uncomfortable with situations where I feel like someone's being overtly abused but I also feel like if I even acknowledge the situation is happening I'm going to get stabbed.
There were two registers open. Both registers were occupied by customers who were, as far as I could tell, attempting fraudulent returns in hopes of getting cash: one had a return for which she had no receipt and said the credit card on which she'd purchased it had been cancelled, the other had some incredibly complex transaction involving buying multiple items in another state and trying to return one here after claiming he'd returned one at a third store and hadn't been properly credited for it, so had a wad of greasy receipts that he claimed showed the returns. I spent twenty minutes waiting for them to get their accounts settled, and after all that, I wouldn't be surprised if this hydraulic jack didn't work as advertised either. (But at least I can take it back, with a receipt, and the correct credit card.)

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(no subject) [Apr. 11th, 2017|10:51 pm]
sprockets, sockets, grommets & gaskets
Man, y'all, I went riding at lunch and felt just beat the whole time. I could not stay up with the fast people, and they were taking it easy because they had Crit Fight Club to go battle with in the evening. I have to up my game significantly.
Work is stressful. We're trying to get the project we've been doing for the last fourteen months wrapped up on time, and are desperately hoping the intended customer buys a million of them. (not even slightly an exaggeration, probably a significant underestimate.) That'll keep us afloat for two years, at least. But we are doing well enough we've hired two more of the people from the other department that was sharing our building, which has stopped new development and is now hemorrhaging good engineers.

I was talking to a friend last night about software security, and we got to talking specifically about trying to figure out if someone had screwed with binary blobs. I told her about setting up a prototype system years ago, where system 1 had hashes for all the main binary blobs on system 2's disc and would request that system 2 do hashes and send them over for comparison every now and then. My friend was on about how now the big challenge is handling software that patches running instances of interpreted code, rather than modifying binaries. That got me to thinking about how an operating system defines a memory space that contains executable code, so I spent some time reading about that today. Man, totally in over my head, but it was interesting reading.

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