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.
Hawks lack waterproofing, which means devoting the morning after a torrential downpour to drying out:
The dark bar across its back comes from an overhead utility line.
The male sparrow of the pair nesting in that box wasn’t pleased about the situation:
Not much he could do about it, though …
The power switch on Mary’s “embroidery” Kenmore Model 158 sewing machine became exceedingly stiff, to the extent she said it was painful to push. Buying a shiny new switch seemed iffy, because a cursory search through the usual reputable electronic suppliers suggested there’s no way to specify how stiff the button might be, nor how that might feel in actual practice.
The switch harvested from the pulse-drive machine felt somewhat less stiff, so I decided to (try to) loosen it up and, if that worked, swap it for the stubborn one.
A pair of rivets hold the two halves of the switch together, obviously intended as a permanent solution. A carbide burr in the Dremel tool dealt with them easily enough:
Inside, the actuator drives a rotating brass contact:
Two stationary brass contacts are spot-welded to the wires:
The actuator under the button consists of a helix-twisted steel rod, a rather stiff spring, and a four-vaned phenolic blade that engages those two little flaps on the rotor. The rivet holes exactly fit plain old 1-72 screws:
Not seeing anything obviously fix-able inside, I wiped the excess oil off and reassembled it in reverse order:
Astonishingly, that bit of attention loosened it up: the button now presses easily!
I swapped it with the too-stiff switch and declared victory…
Mostly as an excuse to use the mini-lathe’s MT3 headstock collets, I made a cover for a tuning whistle (it’s an A, if that matters) case that’s been rolling around on the bench for far too long:
Yeah, it needs a bit more polishing and maybe a fancy 3D printed wrapper…
By some small miracle, one of the cutoffs in the brass tubing heap was exactly the right diameter and length, needing only a cap.
A cap looks a lot like a random piece of brass shimstock held in place with silver solder:
Fire the propane torch:
I trimmed the shimstock around the tube with scissors, grabbed it in a collet, and laid into it:
That’s just before the last few passes bringing the shimstock and solder fillet down to the tube OD, which sat nicely concentric in the collet. The carbide insert worked surprisingly well and produced shavings resembling stringy dust.
The collet drawbar, a.k.a. a hardened 3/8-15 bolt and washer, requires a distressing amount of effort to clamp the collet around the workpiece. I think it wants a Delrin / UHMW washer or some such to reduce the friction; a full-on thrust bearing seems uncalled for.
T=0.000 s – The dot just below the lower tree branch extending over the middle of the road doesn’t look like much:
T=0.600 s – It’s fluttering, which means I’ve noticed it:
T=1.317 s – Rolling at just under 20 mph:
T=2.117 s – I know exactly what’s going to happen:
T=2.850 s – The camera lens is seven inches above my eye level:
T=2.867 s – The air stream over the fairing begins tilting the leaf:
T=2.883 s – Collision alarm!
T=2.900 s – Perfect alignment:
T=2.917 s – I’m now riding with an oak leaf plastered over my entire face:
I wear big lab-grade splash-resistant goggles over my prescription sunglasses to keep dust out of my eyes: the leaf covers the googles, I can’t see out of my left eye (and, thus, the mirror), and most of my right-eye vision has gone green. Although I managed to not inhale during the impact, the leaf forms a good seal over my nose and mouth.
T=3.683 s – Glancing to the left doesn’t dislodge the leaf:
Did you notice the oncoming car?
T=7.483 s – Four seconds later, I’m off the bridge and past the bushes overhanging the guide rail, so I can finally spare a hand:
The view to the rear, showing the car that’s been trailing 1 second = 25 feet behind me during this entire adventure:
I caught another oak leaf the same way on the rail trail a few weeks earlier at a much lower speed in much less stressful surroundings; I figured that wouldn’t happen again for quite a while.
Ya never know what’s going to happen out there on the road…
A chunk of 1/2 inch = 12.7 mm brass hex rod looks pretty good as an ersatz heatsink serving as an ersatz plate cap on a halogen bulb standing in for a vacuum tube:
The knockoff Neopixels measure just over 10 mm at their widest points, but some judicious filing rounded it off and brought it down to fit in the 3/8 inch = 0.375 = 9.52 mm hole I drilled in the hex:
I let it run for a day like that to make sure the thing wasn’t going to crap out, then epoxied everything in place. If the WS2812B controller fails, the repair will require drilling out all the electronics and wiring, then rebuilding it in place.
The fins come from the same HSS cutoff tool I used for the Bowl o’ Fire cap, cut at 2.5 mm intervals to produce 0.9 mm fins that IMO better suit the smaller diameter. I stopped cutting when the tool got through the hex flats to produce a continuous ring, cut the hex off a bit above the top fin, rounded the end with a carbide insert cutting tool, then sanded the flats to shine ’em up a bit:
It turns out that 12 inches of wire inside PET braid barely reaches from the cap to the Arduino Pro Mini in the base:
Next time, I’m going to add half a foot more wire than I think it can possibly require, with PET braid to suit.
A thin ring of clear epoxy holds the “heatsink” at the dead center of the bulb. It lights up a bit more than I expected, so opaque epoxy may be in order:
It’s still too big to suit even the big 21HB5A tubes, but brass definitely wins over plastic!
That blue PETG base has become the least-attractive part of the lamp, but it’s survivable for now.
It runs the same TubeMood firmware as the Bowl o’ Fire.
Just for the record, heating four 500 g bags of silica gel at 230 °F for 12 hours overnight works exactly the way it should. Two of the bags baked down to 490 g, another was at 509 g, and the fourth had bulldog clips (rather than staples); given that they started with a measured 500 g of beads, that’s entirely good enough.
Memo to Self: don’t try to cut corners: heat the silica gel packs above water’s boiling point, let them cook overnight, don’t worry about wrecking the weird ground-cloth landscaping bags, and be done with it.
This resembles nothing so much as a “developing country” shipbreaking operation:
For all I know, the ants haul the carcass into position, blow the scuttling charges to loosen the armor, and sink it in a convenient spot on the driveway:
The hulk vanished later in the day.
This is the season for staghorn beetles; the one we spotted a few years ago was in much better condition.
The Smell of Molten Projects in the Morning 