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.
Having had the only two working knurled planetary gear bearings “roll away” at a recent show-n-tell session, I made a few more:
The top looks slightly understuffed, but it’s solid:
They’re a nearly perfect fondletoy, so I can understand why they rolled away…
With the Sony HDR-AS30V camera Gorilla Taped to the Sienna’s dashboard, we drove it to Rochester with a bank shot off Saratoga:
I then converted nearly 5000 images into Yet Another Crappy Youtube Movie that is, mercifully, only 00:02:43 long.
The key steps:
mkdir /tmp/Video cd /tmp/Video sn=1 ; for f in /mnt/backup/Video/2014-05-29/* ; do printf -v dn 'dsc%05d.jpg' "$(( sn++ ))" ; cp -a $f $dn ; done avconv -r 30 -i dsc%05d.jpg -q 5 Pok-Saratoga-Rochester.mp4
I tossed out a few images you didn’t need to see, then renumbered the remainder:
sn=1 ; for f in * ; do printf -v dn 'dsc%05d.jpg' "$(( sn++ ))" ; mv $f $dn ; done
The point of this exercise was to find out how Youtube treats “HD” movies. The original 1920×1080 MP4 file weighed in at nearly 500 MB with very good quality (due to the -q 5), but the Youtube “HD” result exhibits terrible compression artifacts; the black cloth crawls with huge checkerboard squares. Because the relatively slow-moving sequences at traffic signals and rest stops have excellent quality, I’d say Youtube’s video bit rate just doesn’t support images that change completely from frame to frame. Makes sense; nobody could watch such a thing, so why allocate that many bits?
Now I have another Youtube movie-making data point …
Back when the New York Central Railroad built the overpass at North Clinton Avenue, likely around the late 1800s, they had no idea the I-beams under the tracks would eventually look like this:
The longitudinal I beams have more iron and haven’t corroded through:
But the footing under that beam doesn’t look very good at all:
I think that Lego brick is a nice touch …
We drove the van along I-90 to Rochester and passed many bridge repair operations. The NY Thruway isn’t all that old and the rebar has been corroding out of the concrete pylons for years.
Nowadays, we use exactly enough material to carry the anticipated loads and not one gram more; fast forward a century and our structures won’t be around.
Those pictures were taken from the platform just west of the covered section.
Back in early May, I swapped in a new bag of silica gel, which (as always) immediately punched the humidity down to the Hobo datalogger’s 15%RH minimum reading:
A closer look at the very beginning of that data shows the humidity dropping for an hour after the door closes:
The logger is on the bottom of the safe, with the desiccant bag on the shelf above it, and there’s no mechanical air circulation: it’s all done by air currents, driven by whatever drives them. I have no idea what that bump in the middle means.
My first thought was that you can’t make this stuff up:
That’s taken through one of the windows over Track 3 at the Poughkeepsie railroad station, so it’s a bit blurrier than usual.
It turns out a “Dry Water” pipe delivers ordinary water, but normally contains pressurized air to prevent freezing. An intricate valve in a heated room balances air pressure in the pipe against the supply water pressure; when the air pressure drops, water flows through the valve to the outlet.
Normally, you’d use a Dry Water pipe in a fire suppression system, but it makes perfect sense for an outdoor hose bib (or whatever you call that quick disconnect fitting) on the top level of the Poughkeepsie Railroad Station.
There’s (almost certainly) an automatic drain valve that removes water from the dry pipe: otherwise, it’d remain full after use and pop the pipe during the next freeze.
It turns out that an array of Cart Coins and Cart Releasers make a fine thickness test pattern and become useful tchotchkes when you’re done:
They’re a bit easier to see in the digital realm:
The trick is that they’re both eight layers thick at 0.20 mm/layer. With the platform aligned exactly right, all the objects should measure exactly 1.60 mm thick.
The blue numbers give the thickness measured across the stem, just above the hole, on each object:
The green numbers are the skirt thickness: 22 = 0.22 mm.
The platform has a tilt of 0.20 mm from +Y to -Y and is just about perfect from -X to +X.
The M3x0.5 adjusting screws under the (improved) platform, seen from the front (-Y) end of the platform:
The silicone plugs inside the springs are slightly compressed, so the springs are only decorative. The platform is rigidly mounted on the plugs, with only very slight compliance, and I haven’t leveled the platform in a few months.
Tightening the “north” adjusting screw by 1/6 turn lowered the +Y end of the plate by about 0.05 mm and tilted the +X side slightly higher:
The skirt thicknesses are now in blue, too.
Tightening the “north” screw an additional 1/6 turn and tightening the “east” screw 1/6 turn produced an almost perfect result:
The thicknesses don’t vary quite randomly, but I think further adjustments won’t make much difference: the total range is only 0.12 mm = 1.53 to 1.65 mm. That’s pretty close to the limit of my measurement ability on the plastic pieces.
Notice that the skirt thread, which should be exactly 0.2 mm thick all around, really isn’t. I’m going to see whether a two-layer-thick skirt measures a more consistent 0.40 mm.
While scrubbing a hard drive and decommissioning an old Dell Dimension 2300, I spotted a failed capacitor:
And another:
The board sported many of those little caps, well over half showing signs of distress.
A progression of victims, from I’m-not-dead-yet to phew:
According to its Service Tag, this Dimension 2300 came off the line in late November 2002. All of the other caps on the board seemed OK, so apparently the plague affected just this lot of Hermei 470 µF 6.3 V capacitors.
Or, hey, they’re not supposed to last a dozen years and this is perfectly normal …
The Smell of Molten Projects in the Morning 