The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Author: Ed

  • Belt Pack Zipper Pull Re-Repair

    In our last episode, the zipper tab on my belt pack had worn through:

    Eroded YKK Zipper Tab
    Eroded YKK Zipper Tab

    I “fixed” that by the simple expedient of running a key ring through the latch that used to hold the tab. That held for half a year, which isn’t to be sniffed at for a zero-cost repair.

    A few days ago, the abused latch popped off the slider, leaving the NSA tag and ring in my hand:

    Belt Pack Zipper - missing tab and latch
    Belt Pack Zipper – missing tab and latch

    I scuffed up the surface with a file to provide a bit more grip for the inevitable epoxy, then clamped a brass tube athwart the slider:

    Belt Pack Zipper - wired brass tube
    Belt Pack Zipper – wired brass tube

    The tube ID passes the ring with enough clearance to make it work out. The general idea is that the tube provides rigidity for the ring, the wires hold the tube against the pull, and the epoxy holds the wires in place. I fully expect the sharp edges around the tube’s ID will gradually wear away.

    Threading 14 mil stainless steel wire through the slider’s pivot hole:

    Belt Pack Zipper - wire opened end
    Belt Pack Zipper – wire opened end

    … and under the latch guide:

    Belt Pack Zipper - wire closed end
    Belt Pack Zipper – wire closed end

    … required a few tries and produced some nasty puncture wounds, but eventually it all hung together long enough to let me tuck some JB Kwik epoxy into all the nooks and crannies:

    Belt Pack Zipper - epoxy curing
    Belt Pack Zipper – epoxy curing

    That’s wide masking tape covering the work area. As it turned out, good preparation like that meant I didn’t slobber epoxy anywhere it shouldn’t go; had I omitted the tape, there’d be a smear down the side of the pack.

    Fast-forward to the next morning and it’s all good:

    Belt Pack Zipper - repaired
    Belt Pack Zipper – repaired

    The missing latch locked the slider in place, but I think I can eke out a miserable existence with a loose slider…

  • American Optical Microscope Illuminator: New Bulb!

    A classic American Optical microscope illuminator emerged from a box, minus its bulb. Some rummaging turned up a reference for AO bulbs, so I knew I needed a GE 1460 prefocused bulb. Those seem to be a bit rare these days, with 1460X bulbs sharing the same base with a slightly different glass envelope shape. As nearly as I can tell, as long as the filament sits in the same location relative to the base, it’s all good. Five bucks and a few days brought a new 1460X bulb to the bench, a few drops of Caig DeoxIT slicked the holder’s rather gritty contact patches, and the new bulb fit perfectly:

    Microscope Illuminator - 1460X bulb - detail
    Microscope Illuminator – 1460X bulb – detail

    And it lit up just fine, too:

    Microscope Illuminator - 1460X bulb - turned on
    Microscope Illuminator – 1460X bulb – turned on

    That’s running at the lowest of three selectable voltages: 5, 6, and 7.5 VAC, respectively. Given that the bulb spec says 6.5 V (at 2.75 A!), you best have a spare bulb on hand if you need the highest setting. At the nominal 6.5 V, it’s good for 100 hours; 6 V should eke out many more hours.

    A generously articulated arm holds the illuminator for desk work:

    American Optical Model 651 Microscope Illuminator - on base
    American Optical Model 651 Microscope Illuminator – on base

    That long snout fits into the pair of holes in the arm of my stereo zoom microscope to cast a bright light directly on the subject. The LED ring light makes that less necessary than before, although sometimes distinct shadows help pick out the details:

    Microscope Illuminator Test
    Microscope Illuminator Test

    That’s the failed WS2812B LED from the Noval tube, which again shows I need a USB camera with better resolution …

    The data plate on the bottom of the illuminator, should someone need it:

    American Optical Model 651 Microscope Illuminator - data plate
    American Optical Model 651 Microscope Illuminator – data plate

    The optics cast an image of that white-hot filament out into space, so I think the diffuse active area of a white LED wouldn’t produce the same amount of light on the target. I have some Pirhana LEDs, though, so (when this bulb fails) I’ll see about that.

  • Discrete LED Aging

    We all know that LED brightness decreases with age. An exit sign in Vassar’s Skinner Hall shows what that looks like in real life:

    Exit Sign - LED aging
    Exit Sign – LED aging

    The LEDs on the other side of the sign look about the same: a few very bright spots, a few very dim ones, and a whole bunch in the middle.

    It’s hard to judge by eye, but the brightest LEDs look much more than a factor of two brighter than the dimmest ones.

    An LED with a 50,000 hour lifetime will have 50% of its initial brightness at EOL and a year has 8,766 hours, so the LEDs will reach half-brightness in a bit under six years. I think discrete LEDs went out of style around the turn of the millennium, so it’s three half-lives old: the dimmer LEDs must be around 1/8 brightness.

    In case of an actual emergency, just follow me out the door, OK?

  • Demolition Card GTA 5-10-9

    So I found two copies of the US Army’s Demolition Card GTA 5-10-9 tucked under a row of completely unrelated books in the Basement Laboratory (clicky for more dots):

    Demolition Card GTA 5-10-9 - 1
    Demolition Card GTA 5-10-9 – 1
    Demolition Card GTA 5-10-9 - 2
    Demolition Card GTA 5-10-9 – 2
    Demolition Card GTA 5-10-9 - 3
    Demolition Card GTA 5-10-9 – 3
    Demolition Card GTA 5-10-9 - 4
    Demolition Card GTA 5-10-9 – 4

    All four images wrapped up in a convenient PDF for your printing amusement:
    Demolition Card GTA 5-10-9

    One can only hope it’s slightly more useful than the Calculator Set, Nuclear, M28 — FSN 6665-897-8697 on another shelf. It dates back to the era when you could get ammonium nitrate that went blam when prompted; rumor has it that retail fertilizer now comes with built-in detonation inhibitors.

    Essentially all adult human males have a story including the phrase “but for an (inch | second), I wouldn’t be here” … it’s a survivor bias thing.

  • Phil Wood Rear Hub Internal Bearing

    As part of replacing the entire drivetrain on my Tour Easy, I finally got around to replacing the bearings in the Phil Wood rear hub. The rear axle supports four bearings, with the innermost one captured between the end of the freehub and the aluminum retainer:

    Phil Wood hub - internal bearing
    Phil Wood hub – internal bearing

    The three small screws secure the retaining ring (sitting off to the right) against the bearing. If you don’t know what’s inside, you’d think they hold the freehub in place. Removing them doesn’t do anything useful unless you’re replacing the bearings and, if the retainer rotates even slightly inside the hub, you’re faced with taking the whole damn thing apart.

    That bearing is lightly loaded, well-protected on all sides, and felt just fine, so I slathered more grease around it and left it in place. The other three bearings hit the trash can with a resounding clang…

  • Opening a Dell Inspiron Mini 10 Case

    I volunteered to update an old Inspiron Mini 10 netbook (or whatever they called the things) with Mint Linux and wanted to see what replacing the dead-slow 5400 rpm hard drive with an SSD would do for the struggling Intel Atom Inside. Dell provides a Service Manual showing how to remove the three screws on the bottom of the case, then gently remove the keyboard (!) to get access to the innards.

    You start by covering the screen with some low-tack plastic film that you’ve been saving for this very purpose, sticking a small screwdriver into the center screw hole, and pushing the keyboard firmly away from the case. This bends the keyboard enough to get your fingernails underneath, after which you can pull / pry it away from the latches on each side.

    The left side of the keyboard (as seen from the normal vantage point) comes out first, after clearing a small latch just over the single left-side USB port:

    Dell Inspiron Mini 10 - left keyboard latch
    Dell Inspiron Mini 10 – left keyboard latch

    The right side pops free from its latch over the HMDI port when you push the keyboard firmly to the left:

    Dell Inspiron Mini 10 - right keyboard latch
    Dell Inspiron Mini 10 – right keyboard latch

    Then release the keyboard’s ribbon cable clamp, pull the cable out, remove the keyboard, remove the single screw holding the hard drive carrier in place, and swap drives in the obvious manner.

    Conclusion: an SSD helps a lot, but Firefox on an Atom CPU remains pretty slow off the starting blocks …

  • Monthly Image: April Snow

    An unusually late two-day snowstorm laid down half a foot of snow starting in the evening of April 3:

    Norway Spruce with April snow
    Norway Spruce with April snow

    Up until then, the weather had been running a bit warmer than usual, which seems to be the new normal, and this snowfall put more snow on the ground than we’d seen all winter.

    The snow took some critters by surprise:

    Sparrow - nest box in April snow
    Sparrow – nest box in April snow

    Most of the snow melted during the sunny 40 °F day after the storm, but overnight lows in the teens wiped out most of the spring flowers and buds.