Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
I read these reassuring instructions in the elevator of a different building:
Elevator power failure instructions
I’d be mildly unsurprised to discover the elevator controls also handle the interior lighting, invariably putting me in the dark while the thing reboots. At least the paper would remain readable, because phones can become flashlights under duress.
Our Young Engineer knits during rare moments of downtime and sketched an idea for stitch counters to mark progress between those moments. There being nothing like a new project to take one’s mind off all of one’s previous projects:
Stitch Counters – overview
These are more along the lines of feasibility / material tests than finished products, so you’ll see plenty of rough edges.
Prior to doing this, we agreed that 3 mm material was probably too thick, particularly given the small scale: the hexagons are 10 mm edge-to-edge with a 1.5 mm hole for the jump ring.
The jump rings are (mostly) 8 mm OD, which may or may not be the right diameter for all possible knitting needles.
The count sequence goes 10 20 10 40 50 10 with alternating colors:
Stitch Counters – red and blue
Those came from 3 mm red and blue transparent acrylic, looking entirely too much like candy. Cutting two identical layouts from two different materials, then swapping a few counters, gives me two related-but-different sets. This idea is also subject to revision.
I like the set of 3 mm acrylic mirror counters colored with Sharpie:
Stitch Counters – mirror
Alas, the unprotected mirror backing won’t survive long in the real world and Sharpie ink tends to stress-crack the acrylic. Bonding a thin colored sheet / gel filter to the back with an adhesive sheet in between would work, although I don’t look forward to the fiddly alignment. Bonus: sticky edges are a nonstarter in this application.
A setup error produced a set of unmarked counters that might still come in handy for something:
PXL_20230507_150124595 – Stitch Counters – blue blank
Trolase acrylic 1/16 inch = 1.5 mm sheets produce the most visible legends, in a relentlessly industrial sort of way:
Stitch Counters – Trolase
Those have a single thin layer atop a white or black base sheet, but three-layer 1.5 mm Trolase sheets with matching top and bottom colors (cladding on a white core) would look better.
If you can’t decide on a color, go clear:
Stitch Counters – clear
All of those appear on a background of some thin DIY plywood:
Stitch Counters – veneer plywood sheets
The bottom sheet is very pale veneer that came with a layer of genuine 3M 468 transfer tape with 200MP adhesive. I stuck three different veneers on three 100×50 mm rectangles of the stuff to make 1.5 mm thick “plywood”. The adhesive sheet provides lateral strength, not the wood fibers, so it’s not quite as easy to tear as the broken fragment would suggest.
The results look passable, although there’s room for improvement:
Stitch Counters – veneer plywood
After engraving & cutting, I slathered them with clear polyurethane finish and hung them up to dry:
Stitch Counters – wood finish curing
I like the effect, but using the pale veneer for the bottom layer made them look identical from that side. Worse, two of the three top layer veneers had nearly identical colors (one has more grain) after the finish cured.
More thought seems in order, but at least I’ve explored some of the solution space.
The knuckle joint on the Dirt Devil stick vacuum failed, so it followed us home instead of leaping into the trash:
Dirt Devil – broken swivel joint
Although the fitting seems to be made of ABS, it’s now missing major chunks of plastic in the high-stress areas, so rebuilding it seems not worth the effort.
Because we don’t have any carpets and this one will never leave the basement, I extracted the carpet beater brush and its motor, only to find Yet Another Example of poor assembly practices:
Dirt Devil – stray strands
It’s a 12 V (-ish, I didn’t measure whatever comes out of the vacuum head) DC motor and those errant strands aren’t quite long enough to meet in the middle. The yellow rectangle is a thermal fuse that would be shorted out if the strands were a bit longer.
The broken joint lets the head swivel from side to side, but the elevation joint is still good. If I don’t expect too much, the thing might still suffice for extracting dust from under the benches:
Dirt Devil – taped joint
Worst case, I can swap in a classic floor brush using one of the adapters I made a while ago:
Dirt Devil adapters – assembled
That was easy, if only because I skipped the hard part …
It’s more properly called a “chain guide” and is basically a shifter cage minus the mechanism:
Chain Catcher – side view
Because the Tour Easy frame has a 25 mm tube where the guide’s clamp expects a minimum 31.8 mm tube, a 3D printed adapter fills the gap:
Chain Catcher adapter ring – solid model
The hole is off-center because it seemed like a good idea, although it’s not strictly necessary. The flange helps align the pieces while tightening the clamp screw.
The guide cage clears the chain on all sides while up on the work stand, but there’s nothing like getting out on the road to find out why something doesn’t work as you expect.
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When the chain falls off the top of the chainring toward the motor, the part remaining engaged with the chainring will inevitably drag the rest into the gap between the motor and the chainring spider, whereupon it will jam firmly in place and be almost impossible to extract. Preventing this means filling the gap, which required several iterations:
Bafang motor gap filler – prototypes
The Bafang motor has a cover held in place by seven M3 flat-head screws, shown here below a test filler using pan head screws:
Bafang motor gap filler – installed
Contrary to what you might think, the five screws that obviously sit on five points of a hexagon do not in fact sit 60° apart. How you find this out is by making the obvious layout, including the two screws bracketing the pinion gear in the lower right, then applying windage:
Bafang motor housing gap filler – hole adjustments
That’s one of the paper templates seen above, with laser-cut holes 60° apart and ugly holes punched at the actual screw locations. Then you scan and overlay that image with the LightBurn layout and twiddle the hole locations to make the answer come out right:
Bafang motor housing gap filler – hole adjustments – LB overlay
With that in hand, I cut a 1 mm acrylic shape to measure the clearance between the motor + filler and the chainring spider, with pan-head screws replacing the original flat-head screws:
Bafang motor gap filler – top view
That’s a single piece of 2.5 mm acrylic I used after discovering a pair of the 1 mm acrylic shapes fit with space to spare: hooray for rapid prototyping.
A test chain drop suggested it might suffice:
Bafang motor gap filler – test
If I were so inclined, 3 mm acrylic with countersunk holes and slightly longer flat-head screws would probably work, but I’ll use this until it fails to prevent a chain snag.
The careful observer will have noted the stress crack extending radially inward from the upper-right screw, which I am carefully avoiding doing anything about, pending the aforementioned failure.
Although these passed the annual New York State safety inspection, I thought they needed replacing:
HB3 9005 Bulbs – bulged glass
A closer look:
HB3 9005 Bulbs – bulged glass – detail
The bulge was upward, of course.
The Forester’s manual says they’re HB3 bulbs, but the rest of the world knows them as 9005 bulbs. At full power they draw 60 W = 5 A each, although we rarely drive at night and then rarely have the opportunity for much high-beam use. I assume the blackening comes from nine years of running at half-ish power as the Forester’s daytime running lights.
The low beam headlights seem to be in fine shape.
These two went into the tray under the floor of the rear cargo area, because the crappy bulb you have is better than the one that just burned out on the road.
The Smell of Molten Projects in the Morning 
