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DIY lathe
Monday, October 15 2007
At various points throughout the day I worked on lathing parts of brass fittings so they could serve as interfaces between the imperial-based plumbing of the solar deck and the metric plumbing in the new flat plate solar collector. I don't actually have a lathe, but I do have a drill press, and as long as I can find a way to attach something to the drill press's chuck, it can serve as a crude lathe. The brass fittings I wanted to lathe were designed to connect two garden hoses together at their female ends. Since I use what are essentially garden hoses to interconnect my solar panels, on each of the fittings I wanted to preserve one of the threaded ends and lathe the other one down to something less than 25 mm so I could solder it into one of the metric stubs of the new solar panel. These fittings are over an inch in diameter at their smallest cross-sections, so there was no way to get them into the drill press's chuck directly. Instead I used some smaller brass fittings and a steel bolt to make a tool that could be screwed into the center of the target fitting (where it luckily had threads) and then the chuck of the drill press could be clamped down around the bolt, capable of turning the whole thing as a unit.
The problem with this kind of lathe is that the turning piece is only supported at one end, and any pressure applied with a file will tend to stress the axis going into the drill press's chuck (in this case, that steel bolt). With too much pressure, the bolt begins to bend and is quickly destroyed as the piece rotates and the bolt is rapidly bent back and forth. The solution to this problem was to apply balanced grinding pressure simultaneously from two opposite directions using two files. It would have been better to have a tool capable of keeping the two files perfectly parallel, but I managed to do a reasonably-effective job by simply holding the files in my hand. During the course of the day I made four such fittings, one for each of the panel's stubs (though only two of these will actually connect to hoses).
From left to right: the fitting before lathing, the homemade lathing tool used to attach the fitting to the drill press for lathing, and the fitting after lathing. The steel bolt of the tool is placed in the chuck of the drill press, allowing it to turn the fitting to be lathed.
From left to right: The lathing tool inside a fitting before lathing, the fitting after lathing. The new solar panel can be seen leaning against the ceiling in the background.
The structure of the solar deck's south annex, which is cantilevered out over the house's roof, features a piece of inch-thick galvanized steel pipe serving as a brace angled in both horizontal and vertical planes simultaneously. I used pipe for this brace because I didn't want to do the mental work necessary to figure how to miter the ends. With pipe all of that can be adjusted during installation by rotating elbows and flanges. The new panel will sit on a part of the annex that I never finished building, a part that still needs its piece of inch-thick pipe brace. But the pipe I'd bought yesterday had been the wrong diameter, so I returned to the store today to get the right piece as well as other things I needed. I actually went to P&T Surplus first to see what fun things they had in stock, since (like in a dollar store) their stuff is always changing and often there are fun surprises. Today I picked up a pair of alligator-clip "helping hands" with a magnifying glass, two huge spring clamps, and an eight port Linksys workgroup switch all for just $13. I strongly considered a one gallon stainless steel pressure tank with two fluid ports as a possible storage solution for water heated to boiling by the sun, but then decided to put that project off for later.
I was on the phone for over an hour with my colleague in California going over a mind-numbingly dull functional spec for a future website. At some point in the call I became aware of a growing pain in my right temple. After about ten minutes it was excruciating and I started wondering whether I should say I'd taken ill and end the call so I could lie down and recover. Though the pain was in my temple, it seemed to be radiating from somewhere in my jaw. I massaged the side of my face and encountered a pain center near the inside of the joint where the right jaw hinges into my skull. Maybe one of my crumbling molars was spectacularly abscessing.
But then, during a pause in the call, I took the phone headphones off and reversed them so that the speaker part was in my right ear (instead of my left ear, where I always hold a phone). Almost immediately the headache began to fade away and within a couple minutes it had completely evaporated. This led me to suspect that the little bar of rubber that presses on my right temple to keep the headset in place had caused the headache, perhaps by uncomfortably pinching one of my cranial nerves.
This evening I read a fascinating series of articles about how American society evolves outside of its legal system, gradually consigning its laws to irrelevance either by increasing non-enforcement (as with porn laws), or by systematic legalized circumvention (as with drug laws). I hadn't realized that much of the modern pharmaceutical industry is in place to provide legalized versions of the "highs" traditionally provided by illegal drugs. What used to be recreational joy is now rebranded as "treatment," and doctors are given broad latitude to chemically satisfy customers who complain of depression, anxiety, distractedness, or even boredom. As an ardent do-it-yourselfer, though, I find society's insistence on the participation of a doctor to be infantilizing. If we're given the freedom not to have health insurance, why can't we also have the freedom to alter our minds in the same way we can freely alter our living rooms?
For linking purposes this article's URL is:
http://asecular.com/blog.php?071015 feedback
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