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.
Making the world a better place, one piece at a time
The last time around, this involved silver soldering the boom wire directly to the mic housing. This time, I filed a fishmouth in the smaller tube and epoxied it to the tube that’ll hold the mic capsule:
The smaller tube is a loose slip fit for #10 copper wire, but that’s really too heavy for the boom. I’ll probably nestle #12 wire inside another tube and epoxy that whole affair in place.
The mic capsule tube needs a rounded notch filed in one end to accommodate the wire.
Even though it’s really hard to damage a trailer hitch made of 5/16 inch welded steel plate, that hitch made a mess out of the cardboard box:
It’s a Class III hitch with specs (3500 pound max, 525 pound tongue weight) that greatly exceed the Forester’s ratings (1500/150 pound), but it seems to be the only way to get a 2 inch receiver socket. I have no intention whatsoever of towing anything I can’t see over and around.
This is part of the “how to haul the recumbents” solution. Trailer hitch racks require a receiver with a tongue rating of twice the static load; a pair of Tour Easy ‘bents and most of the racks weigh in pretty close to the Subaru OEM 150 pound rating.
It turns out that the clever idea of moving the swap partition to a USB flash drive had no effect whatsoever; the UI continued to freeze up during OpenSCAD compiles and suchlike, with the drive activity light on solid and not much in the way of swap activity. Sooo, I wondered what would happen with the /tmp directory on non-rotating memory.
Then I spotted a sale on a Samsung 840 EVO 120 GB solid state drive, which seemed like it might improve almost everything in one swell foop. That’s a tiny drive, at least by contemporary standards, but all my data files live downstairs on the file server, so the desktop drive holds just the Xubuntu installation.
It’s worth noting that SSDs tend to fail suddenly and catastrophically, so that if the only copy of your data is on that drive, there is no recovery. In this case, I’d lose some configuration that changes with every installation, a few locally installed / compiled-from-source programs, and little else.
The nice thing about transferring a Linux installation: boot a live CD image (I used Ubuntu 14.04LTS, the same as the desktop box), copy the files to the new drive, set up Grub, and you’re back on the air. That recipe worked fine, although I used rsync -au to copy the files and then updated /etc/fstab with the SSD’s new UUID (rather than duplicate a supposedly unique ID).
The Grub recipe does require a bit of delicate surgery, so I removed the OEM hard drive and rebooted the live CD image before doing this. If the SSD fell victim to a finger fumble, I could just start over again:
sudo mount /dev/sda1 /mnt for f in dev proc sys usr ; do sudo mount --bind /$f /mnt/$f ; done sudo chroot /mnt sudo update-grub sudo grub-install /dev/sda sudo grub-install --recheck /dev/sda exit for f in dev proc sys usr ; do sudo umount /mnt/$f ; done sudo umount /mnt
Then reboot from the SSD and It Just Worked.
Dropbox and DigiKam noticed the UUID change and asked for advice; there’s no need for re-registration, re-activation, or re-authorization.
The overall time from boot to login isn’t much shorter, because of the tedious delay while the network and the NFS shares get up & running, but the desktop UI startup zips right along.
The same OpenSCAD compile that previously brought the UI to a halt has no effect, so I hereby declare victory. I think the complex solid models that used to take forever will see much the same speedup.
The Dell hard drive (an ordinary 7200 RPM 3.5 inch brick) lies abandoned in place under the fancy black shroud; the Optiplex 980 layout butts the drive’s right-angle SATA connectors hard against the CPU heatsink and offers no spare SATA power connectors. There was just enough room to wedge the SSD above the PCI connectors, where it won’t get into any trouble:
The hard drive contains the never-used Windows 7 partition and the corresponding recovery / diagnostic partitions; keeping the drive with the Optiplex chassis seems like a Good Idea.
In what’s surely a change intended to better meet the needs of their customers, the newspaper changed the crossword layout just a little teeny bit, so my previous script needed a tweak:
#!/bin/bash echo Scanning... scanimage --mode Gray --opt_emulategray=yes --resolution 300 -l 5 -t 0 -x 105 -y 195 --format=pnm > /tmp/scan.pnm echo Converting... convert /tmp/scan.pnm -level 45%,60% -resize 2400x3150 +repage -unsharp 0 /tmp/trim.png convert -density 300 -size 2550x3300 canvas:white /tmp/trim.png -gravity center -composite /tmp/page.pdf echo Printing... lp -n 2 /tmp/page.pdf echo Done!
It now spits out two large-print copies, to better meet their actual needs, at least for two of their customers.
The entire Kenmore Model 158 sewing machine tilts on a pair of pivots extending from the rear of the base, just below the top surface. Mary’s slightly more recent machine has all-steel pivots:
The older crash test dummy machine has two-part pivots, with a plastic housing molded around a steel pin:
Obviously, plastic was the wrong material for the cross pins that rest in the base, leading to the all-steel redesign. Sears no longer stocks replacement parts for those pins, sooo …
Both machines have a large plastic base that’s gradually disintegrating. The plan is to embed the machine frames in countertops, with those cross pins resting on plastic plugs set flush with the surface.
The frame sockets aren’t quite 1/4 inch in diameter; the rest of the hardware uses hard metric sizes, so they’re most likely 6 mm. A 15/64 inch (5.95 mm) drill bit fits snugly and a length of 0.228 inch (5.79 mm) drill rod fits loosely. The round pins are 18 mm long from the shoulder.
The square section is 8.5 mm wide, 9.5 mm tall, and 16 mm long. I have no idea what that mysterious tab on the end is supposed to do.
The cross pins are 5 mm diameter, a scant 15 mm end-to-end, stand 3 mm proud of the central block, and are centered 11 mm out from the edge of the block. I’d make them longer, to distribute the machine’s weight over more of the plugs in the countertop when it’s tilted back.
I can’t duplicate the newer forged steel pins and, for sure, they’re not good candidates for 3D printing. Perhaps:
For the moment, the crash test dummy sits happily on the three legs that the designers thoughtfully cast into its frame.
After doing the second batch of quilting pin caps, I dropped the newly opened silicone caulk tube into a jar with some desiccant, which worked wonderfully well. Unlike the usual situation where the caulk under the cap hardens into a plug after a few weeks, the tube emerged in perfect condition. In fact, even the caulk in the middle of the conical nozzle was in good shape, with just a small cured plug on either end; it had been sitting inside a cloth wrap with no sealing at all.
Here’s what it looked like after finishing the last of the most recent caps:
The indicator card says the humidity remains under 10%, low enough to keep the caulk happy and uncured. Well worth the nuisance of having a big jar on the top shelf instead of a little tube next to the epoxy.
Although I thought the desiccant was silica gel, it’s most likely one of the clay or calcium desiccants.
Pinning the top of Mary’s latest quilt used more than 1600 pins: three boxes of specialized quilting safety pins, plus straight quilting pins tucked into all the 3D printed / silicone filled caps. Less than a quarter of the quilt top fits on the table:
Although Mary doesn’t need them right now, I made another batch of 100 caps for her next project:
I tweaked the OpenSCAD source to build a 10×10 array:
But it turns out that a 5×5 array of caps, duplicated four times, works out better:
Slic3r takes far longer to process the larger array than to make four copies of the smaller array.
Half an hour later, they’re ready for silicone fill. In retrospect, natural PLA wasn’t a good choice for this job: there’s no way (for me) to take a picture of translucent silicone in crystalline PLA atop waxed paper on a white cutting board under fluorescent light…
On the upside, however, you can see exactly how far the pin goes into the cap:
The Smell of Molten Projects in the Morning 