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

  • Harbor Freight Bar Clamp Failure

    The squeeze handle that tightens the bar clamp cracked exactly where you’d expect: directly across the pivot hole where the miracle engineering plastic thins down to a precarious ridge. The end of the handle is still inside the clamp:

    Bar clamp with broken handle
    Bar clamp with broken handle

    Nothing bonds that plastic, so, in the nature of a quick fix, I cut a steel strap to wrap around the perimeter of the broken section and epoxied the whole mess together:

    Reinforced bar clamp handle
    Reinforced bar clamp handle

    That lasted for exactly 2.5 squeezes and then pulled apart; the epoxy doesn’t really have anything to grab.

    ABS isn’t a good substitute for engineering plastic, so this will require a bit of CNC work on the Sherline. I’ll probably carve the first one from polycarbonate, just because I have a sheet of the right thickness, but it really cries out for aluminum, doesn’t it?

    Why CNC? Well, I’m going to make a handful of handles and get proactive on the other clamps.

    My other bar clamps have much heavier sections in that area, so perhaps the folks supplying Harbor Freight could take a hint? Yeah, but the clamp was cheap, which always conflicts with good. On the other paw, I’ve seen exactly this same clamp priced at not cheap elsewhere.

  • Glass Chip Flat

    Having had trouble with tire liners eroding the rear tube, I went with just a tube and a Kevlar belted Marathon tire. Somewhat to my surprise, that lasted for most of the riding season, but a recent trip had a protracted rest stop:

    Glass chip in tire
    Glass chip in tire

    The puncture came from a knife-edged glass chip that avoided most of the Kevlar belt inside the tire:

    Glass chip - detail
    Glass chip – detail

    I think even a tire liner wouldn’t help with this one.

    Other than that, the tube was in fine shape, so I’ll probably patch it and toss it back in the bike pack. Tire liners prevent most flats from gashes along the midline of the tire, but …

  • LTSpice IV: Simulation Run Hotkey

    For some odd reason, Linear Tech’s LTSpice IV simulator has a hotkey to stop a simulation (Ctrl-H), but not one to start the run.

    Add one:

    • Control Panel
    • Drafting Options
    • Hot Keys button
    • Click in Run Simulation slot
    • Tap the ~ key
    • Back out of everything
    LTSPice Run key binding
    LTSPice Run key binding

    Done!

  • Window Strike: Swainson’s Thrush

    Birds flow through the Hudson River Valley during spring and fall migratory seasons, leading to tragedies such as this:

    Dead Swainsons Thrush - ventral
    Dead Swainsons Thrush – ventral

    We think it’s a Swainson’s Thrush that mistook our bedroom window for open sky:

    Dead Swainsons Thrush - left side
    Dead Swainsons Thrush – left side

    We’ve tried several techniques to prevent birds from making that mistake, but to no avail.

    It weighed 38 grams, a bit heavier than the typical 30-ish grams reported in our bird books. If I were flying to Mexico I’d want a little extra padding, too.

    I put it out for recycling in the back yard; in Nature, nothing goes to waste…

  • Monthly Aphorism: On Right Behavior

    • Do what’s right and sleep well at night

    Father Vaughn taught that precept to everybody he managed: he expected complete technical and personal honesty. That meant you did your best, reported the facts, and didn’t tell different versions of the same story to different people.

    It was painful to watch him in meetings with his manager who had, shall we say, a tendency to skew the truth in certain situations.

    Dilbert is a documentary of what happens when you don’t live by that rule…

  • Expedient Handlebar Mirror Repair

    We frequently host touring bicyclists who need a campsite in the Mid-Hudson Valley. The most recent couple has been riding for two years, starting eastward from Paris shortly after their wedding. Yeah, it’s a honeymoon trip.

    After riding through Western and Eastern Europe, the Middle East, and several of the ‘Stans, JeanMarc’s handlebar mirror broke in Kazakhstan. Marie toted the carcass out of the ‘Stans, across India, through China, and then from Montreal to here. They’re biking to Houston, where they’ll fly to Peru, ride south and across the Andes, and work their way across the Atlantic on a cargo ship that eventually docks in Germany. Then, a year from now, they’ll just bike back to Paris.

    Makes you feel like sludge, too, doesn’t it?

    With that as prologue, JeanMarc wondered if I could fix the mirror mount. It started as a 10 mm plastic ball on a molded plastic fitting with an integral worm screw and strap; of course, the ball stem snapped off during a hard landing or some such event that comes naturally during long-distance riding. We kicked around some ideas, rummaged through the heap, and came up with a workable, albeit hideous solution.

    I applied a Dremel slitting wheel to a pair of Zerk grease fittings, sliced off the inlet valve, extracted the valve spring, and cleaned up the residue to leave a somewhat misshapen 9.3 mm (really a scant 3/8 inch) ball-like end. A bit of lathe work converted a chunk of PVC pipe into a sleeve grooved for a metal hose clamp. I drilled two #3 holes, tapped them 1/4-28 (which, believe it or not, is the correct thread for a Zerk), bandsawed the pipe in half, introduced the pieces to Mr Belt Sander to round the edges, screwed Zerks into holes, and wound up with a pair of these:

    Handlebar Mirror Mount - detail
    Handlebar Mirror Mount – detail

    Which looks awful on the handlebars, but we’re pretty sure it won’t break and he has a spare if the mirror on Marie’s bike snaps off:

    Handlebar Mirror Mount - fixed
    Handlebar Mirror Mount – fixed

    The Zerk fitting could unscrew, but the threads aren’t exactly in pristine condition after all that fussing and seem to be jammed firmly in place. If we had more time, I’d have heated the PVC and molded it around the handlebars, but we decided that wasn’t really necessary.

    They rode off into the distance this morning… may you have smooth roads and a tailwind, JeanMarc and Marie!

    JeanMarc and Marie
    JeanMarc and Marie

  • Praying Mantis

    Praying Mantis on bike rack
    Praying Mantis on bike rack

    We met this Praying Mantis on the bike rack outside Skinner Hall at Vassar College. Even knowing they’re harmless, I’d have trouble picking it up; we parked on the other end of the rack.

    If these things were any bigger, they’d be terrifying…