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.
Mechanical widgetry
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…
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.
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.
Mary (not the spammer) uses a stirrup hoe for most of what little weeding she does, so it spends much of its life outdoors in the Vassar Farms plot. The bottom of the handle disintegrated and she brought the business end home for repair:
That was easy: a suitable handle lay on the top of the rods-and-tubes rack; I’d harvested it from a defunct rake a while back. Although the wood is weathered, we think of it as well-seasoned. The errant hole marks came from a first pass, before I realized there was no point in having the handle extend beyond the outward-bending part of the brackets.
The bolts and locking nuts are original!
Ya gotta have stuff…
(And not a trace of 3D printing anywhere to be seen. Imagine that!)
More than five hours of stand-up comedy condensed into two minutes of frenzied video showing activity like this:
The Sony HDR-AS30V perched atop a tripod behind the table, where only one errant Scout bumped it, recording one image every 5 seconds. The non-adjustable focus seems biased for selfies, but the compression definitely produces softer images in subdued lighting conditions, so it’s hard to say.
Each NP-BX1 battery lasts about 2.5 hr in that mode and I brought all three, but simply forgot to install the third one. As a result, we don’t get to see the last 2+ hours… it was a long day.
The “image processing” behind the movie went a little something like this, modulo a few edits to elide my blundering around:
sudo mount /dev/sdb1 /mnt/backup sudo mount -o uid=ed /dev/sdd1 /mnt/part mkdir /mnt/backup/Video/2014-05-17 rsync -au /mnt/part/DCIM/100MSDCF/ /mnt/backup/Video/2014-05-17 rsync -au /mnt/part/DCIM/101MSDCF/ /mnt/backup/Video/2014-05-17 cd /tmp mkdir Video cd Video sn=1 ; for f in /mnt/backup/Video/2014-05-17/*JPG ; do printf -v dn 'dsc%05d.jpg' "$(( sn++ ))" ; cp -a $f $dn ; done mkdir Shrink for f in *jpg ; do convert $f -resize 50% Shrink/$f ; done cd Shrink/ avconv -r 30 -i dsc%05d.jpg -q 5 3DPrinting-q5.mp4 mv 3DPrinting-q5.mp4 "3D Printing Demo - HV Scout CamporALL 2104.mp4"
One could, of course, do all that in fewer steps, if one knew the answers ahead of time, which should may apply when I refer back to this post.
Using rsync -au to copy the files from the camera to the 2 TB backup drive neatly solves the problems that occur when the camera’s USB port abruptly disconnects itself during the copy: rsync can recover without losing or trashing any files. Alas, after the camera disconnects, it requires a power cycle to recover its wits.
The USB camera connection reads data at 6 MB/s. Removing the MicroSD card and jamming it in the card-reader slot on my monitor runs at 18 MB/s. Apart from the fact that the MicroSD card seems so flimsy, I wonder how long the spring-detent latch inside the camera will continue working. On the other paw, when the USB port finally breaks, it’ll take the GPS assist data path along with it.
Not shown: the rename 'y/A-Z/a-z/' *JPG that converts the original filenames to lowercase, which I did after the fact. Because blundering around, OK?
The 3964 original 1920×1080 images, hot from the camera, weigh in at 2.2 GB and the half-size video emerged at 118 MB. The default avconv quality setting produces surprisingly crappy results, so I used -q 5. Some after-the-fact fiddling showed that -qscale 5 produces the same file size with about the same apparent quality.
None of that matters, because Youtube set the maximum resolution to 480 and applied ruthless compression. Now I know better…
The humidity in the basement safe has been on the rise for the last few months:
So I dumped all three bags of spent silica gel onto cookie sheets and baked them at 250 °F for a bit less than 12 hours overnight. As the (gas) oven temperature isn’t all that well regulated, I set it to 230 °F and hoped for the best. I have no way of knowing what the actual temperature was during the night.
The silica gel inside the bag from the safe weighed 583 g and the two bags that had been sitting in the basement air weighed 663 g. After baking, all three trays of beads weighed 496 g, slightly less than the 500 g direct from the factory-sealed cans.
The beads looked undamaged from their ordeal.
Two dozen scattered beads collected from the countertop and floor weighed 0.4 g, for an average weight of 0.017 g each. I definitely didn’t lose 12 g of beads during this adventure!
The translucent white beads vanish against an off-white laminate kitchen floor under ordinary lighting. They’re retroreflective enough that peering along the side of an LED flashlight lights them up; I’m pretty sure I got most of ’em.
Memo to Self: Next time, try 6 hours starting in the morning.
The Smell of Molten Projects in the Morning 