Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Tag: Improvements
Making the world a better place, one piece at a time
A discussion there reminded me to mention a good habit taught by my buddy Eks: when you must look something up, write the information where you’ll see it the next time you need it.
So, for example, each of the van wheels sports its own tire-rotation schedule inside the cover. When it’s time to swap tires in early spring and late autumn, I pry the cover off, read where the tire should go, and do the deed. I write ’em down four or five years at a time, so there’s not much thinking involved.
The engine compartment has all the most-often-used wrench sizes and capacities.
I write the oil change & inspection info in the maintenance schedule booklet that came with the van, although after a decade that’s pretty much full up.
Just chopped up a 5-lb lump of Provolone into 2-oz chunks for pizza, which brings this simple shop project to mind: a cheese garrotte.
It’s about a foot of 0.011-inch (call it 0.25 mm) stainless steel wire with the ends wrapped around some aluminum rod, neatly tied off with heatshrink tubing.
Usage is about what you’d expect: it cuts cheese like nothing else on earth. The only trick is maintaining a straight line, which is easier (for me, at least) when I cut vertically downward.
It’s difficult to cut all the way to the bottom and that wire is rough on the fingertips, so I tend to flip the cheese over and pull sideways for the last inch or two. Maybe not a perfect cut, but good enough.
Cheese Garrotte Handle Detail
Construction nuance: loop the wire around the handle once or twice, pass it through the hole, then do another loop before twisting the end. If you run the wire directly through the hole, it’ll break on the far-side sharp edge after a while, even when you countersink the hole.
I put a shallow groove around the handle, but that’s likely not needed. You can certainly get fancier with the handles if you like. This one is dishwasher safe, which makes up for a lot.
You really, really need heatshrink tubing over the bare wire ends, as the tip of a 11-mil stainless wire is indistinguishable from a needle.
I just figured out how to use the WordPress “sourcecode” formatting and applied it to my software-related posts. It produces much nicer results than the manual formatting I was using, mostly by preventing long lines from jamming into the right column.
The catch: WordPress imposes a round trip from my original text to the screen encoding and back, which sometimes randomly mangles special symbols. Angle brackets and double-quotes, in particular, take serious damage.
If you happen to remember a favorite chunk of code in a previous post, please take a look at it and see if I missed any of the obvious text-replacement errors. Trawling through the Software category should turn up most of the posts.
As is always the case with program listings, the errors will be really obvious to everyone except me.
Just refilled the continuous-flow ink tanks on my Epson R380 for the first time this year.
In milliliters:
Yellow 35
Light Magenta 40
Magenta 40
Light Cyan 40
Cyan 40
Black 50
Done in that order, the whole process requires only three syringe cleanings.
I haven’t checked lately, but the last time I worked it out, printer ink cost $1.80/ml. Let’s call it $2 nowadays, which means I just squirted nigh onto 500 bucks worth of ink into those tanks.
Much of that seems to go into head cleaning, as I don’t print that many photo-quality images on it. Nevertheless, they don’t charge you any less for ink that winds up in the diaper inside the printer.
I don’t keep track of the ink going into the refillable tanks on my Canon S630, but it’s the same order of magnitude. I have four trios of color tanks and six black tanks for that printer and refill them all when the last set runs low. I’ve been doing that for years with no printhead issues.
Sooo, for not spending a kilobuck a year on ink cartridges, I’m willing to spend 100 bucks for bulk ink, undergo some hassle, and endure the occasional oddly colored thumb…
Mary has been quilting up a storm lately and wanted a larger surface to handle a bed-sized quilt. A table in the basement was big enough, but she wanted a larger flat surface around the sewing machine adjacent to the table.
I converted the typing return (*) from her upstairs desk into a table, then cut a piece of aluminum-clad 1-inch foam insulation board to fit. It’s 4 feet long, a convenient length to cut from the 4×8-foot insulation board, and slightly narrower than the typing return. Cutting it required a long X-Acto knife blade, but a really sharp utility knife would work as well.
Some stainless-steel tape finished off the edges. The tape itself is lethally sharp-edged, but it’s perfectly harmless if you do a good job of smoothing it against the foam board…
A pair of closed-cell rigid foam blocks held one end of the board at the proper height around the sewing machine, while a pair of cutoffs from the wood pile were just the right thickness & length to extend under the other end. It turns out that precise height isn’t nearly as vital as we expected; close enough is fine.
I cannibalized a pair of table-saw feed roller stands for this project; they had just the right height adjustment and shape to support the typing return and the foam board.
The end result aligns the surface of the sewing machine with both the top of the table and the surface of the foam board. The quilt slides easily over the whole affair and doesn’t bunch up like it did before. Success!
Foam support blocks
(*) A “typing return” is the little table that sticks out from a desk, upon which you put a typewriter, back in the day when typewriters ruled the land. Nowadays, she uses it for her sewing machine, which normally lives at her desk, because there’s no practical way to type at right angles to one’s desk.
That’s the sort of item you can’t do web searches for, because all the terms are so heavily overloaded. Give it a try; you’ll find one or two useful hits. There’s a difference between syntax and semantics; we’re not in the semantic web yet by long yardage.
This is quick & easy. When you’re making a Powerpole connector, shrink a length of small heatshrink tubing over the end of the terminal after crimping.
Heatshrink tubing stress relief for Anderson Powerpole terminals
You can’t cover the entire crimped region, lest the terminal not snap into the housing, but halfway seems to work fine.
The goal is to keep the wires from flexing right at the end of the terminal, which is exactly where they’ll break.
I’ve also wrapped a length of self-vulcanizing rubber tape around the entire connector housing and the wire, which is appropriate for high-stress applications. Looks hideous, though, not that that matters much.
A new fast NiMH pack charger that uses a thermistor to detect the abrupt temperature rise at full charge just arrived on my Electronics Workbench. The instructions say to tape (“Use rubberized fabric …”) the thermistor to a cell in the middle of the pack, a process which loses its charm fairly quickly.
The intent is to have the thermistor bead in intimate thermal contact with the cell, but air is a rather crappy thermal conductor. We can do better than that.
Sooo, off to the Basement Laboratory Adhesives Division we go…
NiMH cells have a steel shell, so holding the sensor in place with a magnet makes at least some sense. I used a pair of teeny rare-earth magnets (Electronic Goldmine G16913) bridged by a snippet of steel strap. One magnet points up, the other points down, the strap provides a magnetic path, and the whole assembly sticks to the cell like glue.
First epoxy setup
I trimmed the heatshrink tubing surrounding the thermistor back a bit, then applied enough epoxy to secure the magnets to the strap and smooth out the edges, leaving the thermistor sticking out in mid-air.
Although it looks risky, the epoxy doesn’t bond well to the (sacrificial, dead) cell. Doing it this way produces a nearly perfect AA-cell-shaped contour in the epoxy on the bottom of the magnets.
It’s JB-Kwik fast-curing epoxy, not quite so runny as its slower-setting and much stronger JB-Weld relative.
Epoxy covering thermistor
After the epoxy cured, I bent the thermistor down to contact the cell and dabbed epoxy over the bead. This puts the thermistor in good thermal contact with the cell. Epoxy isn’t a great thermal conductor, but it’s a lot better than air.
The alert reader will note that I wrapped a layer of masking tape around the cell for this operation. I wasn’t convinced I could pop the epoxy off the cell without cracking the thermistor leads, but that turned out not to be a problem.
Trimming the edges of the epoxy around the bead gave it a certain geeky charm.
And it works like a champ: get the assembly close to a cell and it snaps right in place. I align the thermistor more-or-less in the middle of the cell, although I suspect the temperature gradient from the middle to either end isn’t all that large.
Magnetically attached thermal sensor
Now, one could argue that this lump increases the thermal mass surrounding the thermistor, thus slowing the charger’s reaction time. That might be true, but the pack’s end-of-charge temperature rise seems considerably subdued now; the charger used to cook the living piss right out of the cells (with the thermistor taped down): I couldn’t hold them in my hand, so they were well over 150 °F.
Now they become just uncomfortably warm, which says they’re closer to 130 °F.
The charger’s single page instructions (two pages if you count the sheet illustrating the rubberized fabric taping thing) cautions “Stop charging when [the cell’s surface temperature] is over 70C or it feels very hot”.
The Smell of Molten Projects in the Morning 