Squarestruder

October 25, 2013

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What’s worse than this dog’s breakfast is the fact that I thought I had blown out the stepper motor in the previous extruder after weeks of running it way too hot, but after I’d gone too far with this version to unwind my hot-end modifications, I found I hadn’t.  It’s a really bad design, but it was what I could do without being able to print up any new parts. Probably my most serious mistake  is the idler, which is a skate bearing in a bent-aluminum frame being pushed against the old makerbot drive pulley by those three torsion springs, which were the strongest things I could find at the local hardware store. All the pivoting designs have a serious mechanical advantage, but this has none. The springs acquire a permanent bend and stop working after a few hours, so I am ordering some stamping-machine compression springs from McMaster-Carr that max out at about 200 pounds. With luck, it will last long enough for me to print a lever-action extruder and maybe even some herringbone gears.

 

I found myself thinking a lot about the kind of design you do when bodging pre-existing parts into shape versus printing pieces from scratch. I can go to the drill press and put a new hole in my piece of old aluminum extrusion in a few minutes, or bend a piece of flat stock to the right shape and drill and tap it. But once I’ve done that, especially with the extrusion body, I’m pretty much stuck with it, unless I want to chop up another piece and start from the beginning. If I print something, it will be a few hours (at least), but if I have a completely different idea I can just discard the old piece and print up the new. It’s a very different style, sorta like the difference between writing software at a REPL or in a really fast IDE versus old-fashioned edit-compile-make-run-curse. But also sorta not. Anyone else have thoughts about that?

Oh, and I also learned that the mini-hyena drive gear is brilliant for an extrude that’s well tuned, but once you start slipping  you’re going to need acetone or fire or who knows what to get the ground-up filament out of those sharp little grooves.

Copyright is dead

May 4, 2012

At least if you’re a big company and you want to violate it.

How OpenStreetMap Got Apple To Give It Due Credit | TPM Idea Lab

“The OSM Foundation has made informal contact with staff at Apple and, in addition, one of our volunteer mappers who is an iOS developer spoke to people at Apple. We believe it was the latter that precipitated adding the attribution – it’s great to have such an active and engaged community!

Completely ignored in all of this back-and-forth has been the fact that the CC attribution license is a license for things that are copyrighted, and that if you make copies without following it, you are infringing. Depending on the way Apple has parceled up the data when developing iphoto and the mood of a court, that would be statutory damages anywhere from the low millions to the high tens of billions.

Oh, and distribution of copyrighted material worth more than $2000? Check. For personal gain? Check. In interstate commerce? Check. Apple management and the engineers involved in the project have pretty clearly met the predicates for the criminal law involving piracy for profit.

But none of that matters these days unless you’re some dweeb downloading songs or your favorite movie.

Why TPM sucks slightly less than the New York Times

April 18, 2012

Republicans Give Up The Game: It Was Never About Deficits | TPMDC

Republicans are still running on deficit reduction, but as the election nears, their governing agenda reveals something that close observers recognized all along: Deficit reduction was never the point.

The front-page headline on this story is “How Republicans Threw In The Towel On Deficit Reduction.” Only in the third or fourth graf do you get the fact that the GOP never had any allegiance to deficit reduction, and was only using it as cover for cutting spending they didn’t like. None of the GOP numbers on spending (much less taxes) have ever made any sense this cycle, but “Republican Lies on Deficit Reduction Become More Transparent” is not the kind of headline you’re going to see on a publication that wants to become mainstream, and that does much of its business covering Washington.

Which is sort of sad, if predictable. Insofar as enterprises like TPM grow, they need a continuing flow of stories, and if you’re covering politics that means a continuing practice of not calling bullsh*t on your sources too loudly.

For thee but not for me

April 5, 2012

http://tpmdc.talkingpointsmemo.com/2012/04/steve-king-on-sexual-orientation-in-workplace-dont-ask-dont-tell.php?ref=fpblg

Of course from Rep. King’s biography on his House web page:

Steve King grew up in a law enforcement family in Storm Lake, Iowa. He attended Denison Community High School, where he met Marilyn Kelly, whom he married in 1972. They have lived in Kiron for 38 years and are members of St. Martin’s Church in Odebolt. Steve and Marilyn have three grown sons and·five grandchildren.

I guess it’s fine for him to tell other people about his sexual orientation, just not the other way round.

Abortion arguments and the kidney theft legend

February 18, 2012

Bear with me here.

Back in the 60s and 70s, when moral arguments about abortion were still about something more than tribal identity, one of the standard hypotheticals was the Violinist Argument: a worl-famous violinist, who has brought joy to millions and done no harm, finds himself (by no personal fault) suddenly without the use of a kidney, a liver or some other vital organ. He could recover, but needs to be hooked up to another person’s circulatory system for 6 months or so in order to survive. Someone with just the irght blood and tissue type. So, the question went, is it OK for a particularly zealous music lover, having learned of your fortuitous match, to jump out from behind a tree, knock you down and hook up your veins? Conversely, is it OK, once you wake up and find yourself entangled in tubing with a violinist staring at you with his artistic, deeply soulful eyes, to pull the IVs out and condemn him to death?  Remember that this will only last 6 months or so, and you’ll only face a certain amount of discomfort, and the risks of getting a septic IV connection are minimal.

The points of analogy are obvious, as are some of the points where the analogy breaks down. Mostly they have to do with consent and “culpability”. (And some with the character of the risks involved.)

So I was reading about the whole contraceptive-coverage fake controversy and it came to me that the kidney-theft UL is really a much better analogy, especially since the violinist version has pretty much been overtaken by advance in medical science. So, to review: Guy on vacation or business trip, lured to a hotel room by apparently-willing member of the appropriate gender, wakes up neatly incised, short one kidney that is no doubt going to a desperately needy recipient. Temporarily acute body modification that might have serious longterm consequences, check. In the cause of a deserving recipient, check. Motivated by lust, check. Consented to the lustful part, didn’t consent to the body modification, although “obviously” should have seen it coming, check. Would it be OK to go tearing through town to the nearest hospital and demand your kidney back?

The devil is in the details, and the body modification is loaded differently, oh, yeah, and the protagonist in one case is a man while the protagonist in the other is a woman. And yet the urge to differentiate these two hypotheticals seems so visceral.

I had wondered whether the popularity of the kidney-theft legend might even be a sort of sign of anxiety about legalized abortion (because other than slasher movies, there aren’t that many ways for illicit sex to go so horribly wrong for men’s bodies — well, yeah , HIV, but that has its own set of urban legends), but it turns out from snopes that the original germ of the story was probably the testimony of a guy who sold a kidney to an organ broker and had regrets. Um.

 

Most annoying component ever

February 8, 2012

The other day I put a new battery in an old digital tire gauge, hoping to revive it Nope. So just for the heck of it I took it apart and found that it didn’t matter whether the batter was dead or that gauge circuitry was still working, because there was no connection between the display and the rest of the thing.

Instead of wires or flex or something sensible, the designer used a piece of rubber with a zillion embedded parallel conductors. The idea, I guess, is to carry signals from a bunch of goldplated bumps on the main circuit board to a bunch of contacts on the display. As long as those two are properly aligned, it doesn’t matter whether the rubber bit is in exactly the right place, because it conducts across the piece but not lengthwise.

Until the rubber shrinks a little. Or the ends of the embedded conductors develop an oxide coating. Or moisture condenses anywhere near it. I’ve lost count of how many cheapjack little devices I’ve taken apart that might have been working fine, except that they couldn’t display anything because of one of those stupid little rubber bits. And each time (hope springs eternal) I’m pissed off again. I should really have learned by now.

For the manufacturers I guess it makes sense. Not only do they lower parts and manufacturing costs (no fancy soldering, no super-precise alignment fixtures), but they guarantee a steady stream of replacement purchases. And sure, I’ll never buy something with that particular brand name on it again, but the factory doesn’t care.

What’s missing from this story

February 7, 2012

Banks Paying Cash to Homeowners to Avoid Foreclosures (via eschaton)

Losses for lenders are about 15 percent lower on the sales than on foreclosures, which can take years to complete while taxes and legal, maintenance and other costs accumulate, according to Moody’s. The deals accounted for 33 percent of financially distressed transactions in November, up from 24 percent a year earlier, said CoreLogic Inc., a Santa Ana, California-based real estate information company.

Nowhere does anyone appear to mention the time value of money. As long as the real estate market is stagnant (or even falling) and the value of a house depends on things like maintenance and decorating, it makes enormous sense for a bank to take the money from a short sale now — and maybe even invest it in something that doesn’t go belly-up — rather than gamble that they will get a better price from a foreclosure sale a few years from now, or that the stones that are underwater householders will suddenly start bleeding green.

Say, for example, that the bank gets $200K out of a house now rather than the same $200K out of it in 18 months. That’s about $15K in profits that they could make (or $15K less interest they could pay whoever they’re borrowing from) even before the extra cost of the lawyers for foreclosure, the chance that the homeowner might walk away or even trash the place out, dropping the bank’s realized price substantially, or that the might fight the foreclosure and win because the bank doesn’t even properly hold the paper.

As long as the bank makes more money by getting a sale through now, it makes business sense for them to share that increment with the homeowner. So why haven’t banks been doing this all along? Some of them have — the article is reporting an increase in short sales from a quarter to a third of distressed transactions. But the answer, I think, is that the amount of money a bank is willing to offer a homeowner depends crucially on the power imbalances among the parties to the transaction. In previous years, at least according to reports, the power was mostly in the hands of mortgage-servicing companies, which made much more money by stringing out a loan and stringing out foreclosure. But servicers aren’t doing so hot, what with the criminal and civil liability for all those missing and falsified documents, so now the issue may be much more directly between the homeowner and the holder of the note.

Another possibility is that the economy is looking up enough that banks would like to have extra cash or borrowing capacity available on their balance sheets. That would be nice. But then again the bankers might be anticipating that prices will plummet further, and hoping to get out while they can…

Somewhere the ghost of Richard Whitney is laughing

November 1, 2011

What happened at MF Global | Felix Salmon

For traders, risk managers are always the enemy; Corzine was a poacher who was never going to be comfortable in a role as gamekeeper. The Goldman culture kept him in check, to some degree, before it pushed him out; on his own, he was — literally — out of control. And as a result, thousands of his employees are now out of jobs. It’s a truly ignominious end to Corzine’s career.

Before its time?

September 2, 2011

The Avrocar located in Dayton, Ohio, US | Atlas Obscura | Curious and Wondrous Travel Destinations

In flight-testing, the Avrocar proved to have unresolved thrust and stability problems. The saucer proved immensely difficult to fly with very sensitive controls, and one pilot likened flying it to “balancing on a beach ball.” Though the Avrocar was made to fly up to 190 km/h and it was believed with some modifications the project was salvageable, funding ran out and the project was canceled in September 1961.

Nowadays, when any geek who can follow directions can build a four-rotor helicopter with cheap microcontrollers that adjust the attitude 30 times a second, it seems that all those designs for flying stuff that was dangerously unstable would now be a piece of cake. Of course, I could be wrong.

Better late than never

August 10, 2011

Confessions of a Financial Deregulator – J. Bradford DeLong – Project Syndicate

Depression-era restrictions on risk seemed less urgent, given the US Federal Reserve’s proven ability to build firewalls between financial distress and aggregate demand. New ways to borrow and to spread risk seemed to have little downside. More competition for investment-banking oligarchs from commercial bankers and insurance companies with deep pockets seemed likely to reduce the investment banking industry’s unconscionable profits.

It seemed worth trying. It wasn’t.

Analytically, we are still picking through the wreckage of this experiment. Why were the risk controls at highly-leveraged money-center universal banks so lousy? Why weren’t central banks and governments willing and able to step up and maintain the flow of aggregate demand as the financial crisis and its aftermath choked off private investment and consumption spending?


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