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.
Who’d’a thunk it?
One of the price scanners at Stop & Shop was already lit up when I arrived:
Let’s take a closer look:
Can it be that S&S, having outsourced the scanning & bagging operations to its customers, now expects sysadmin skills?
Given our previous experience, I didn’t even think of fiddling with it…
And, yes, I know that “baud rate” is an oxymoron.
Back in 1998, we bought this house “with contents” and spent the next year sorting the heap. Among the treasures was a half-size clipboard with a black Dymo label on the clamp:
And what’s obviously an airplane checklist on the back:
I looked up N9991W back then and didn’t find anything useful; it was early on with the Internet, so perhaps the records weren’t so readily available. Time passed, our daughter grew up using the clipboard for this-and-that, and it accumulated the usual scuffs and doodles.
Searching for N9991W now produces a plethora of information, including the fact that N9991W belongs to the Lehigh Valley Flying Club:
It’s a Piper Cherokee 140 built in 1967 and, after nigh onto half a century, it looks just fine, doesn’t it?
There’s no way to know how that clipboard came to rest in what was to become our basement, probably no later than the mid-1980s, but it’s good to know they’re both still around.
May it continue to land with the shiny side up and the rubber side down…
After removing the AC motor from the sewing machine, I wondered if a NEMA 23 stepper motor would fit:
Huh. Who’d’a thunk it? That’s just too good to pass up…
Although you wouldn’t use PLA for the real motor mount, this was easy:
And the whole affair fits pretty much like you’d expect:
The NEMA 23 motor doesn’t have the same end profile as the AC motor and the adapter plate gets in the way of the pulley, but flipping the pulley end-for-end perfectly aligned the belt.
For whatever it’s worth, here’s how I removed the pressed-on gear from the shaft:
I’m pretty sure I have a little gear puller somewhere, but it’s not where I expected to find it, which means it could be anywhere.
Much to my astonishment, the shafts on both motors are exactly 1/4″ inch. I filed a flat on the shaft to avoid having the setscrew goober the poor thing.
A stepper isn’t the right hammer for this job, because it can’t possibly reach 8000 rpm, but it’ll be good enough to explore the parameter space and weed out the truly stupid mistakes. A brushless DC motor from halfway around the planet would fit in the same spot.
The OpenSCAD source code:
// NEMA 23 Stepper Mounting Plate
// Ed Nisley - KE4ZNU - June 2014
Layout = "Build"; // Build Show
//- Extrusion parameters must match reality!
// Print with 4 shells and 3 solid layers
ThreadThick = 0.20;
ThreadWidth = 0.40;
HoleWindage = 0.2; // extra clearance
Protrusion = 0.1; // make holes end cleanly
AlignPinOD = 1.70; // assembly alignment pins: filament dia
inch = 25.4;
function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);
//----------------------
// Dimensions
// Origin at bottom front corner of plate as mounted on machine
// motor mounted on rear surface, so recess is on that side
PlateThick = 4.0; // overall plate thickness
SlotOffset = [10.0,13.0,0]; // center nearest origin, motor in X+,Y+ direction
SlotSize = [8.0,25.0]; // diameter of mounting screw , overall end-to-end length
CutoutOffset = [0.0,40.0,0]; // cutout around machine casting
CutoutSize = [18.0,18.0];
MotorBase = 58.0; // square base plate side
MotorHoleOC = 47.2; // hole center-to-center spacing
MotorHoleOffset = MotorHoleOC/2;
MotorHoleDia = 5.0;
MotorBaseCornerRadius = (MotorBase - MotorHoleOC)/2;
FlangeWidth = 20.0; // mounting flange
MotorCenter = [(FlangeWidth + MotorBase/2),(MotorBase/2),0]; // XY of shaft centerline
MotorShaftDia = 7.0; // allow some clearance
HubDia = 38.5; // allow some clearance
HubHeight = 1.8;
//----------------------
// Useful routines
module PolyCyl(Dia,Height,ForceSides=0) { // based on nophead's polyholes
Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);
FixDia = Dia / cos(180/Sides);
cylinder(r=(FixDia + HoleWindage)/2,
h=Height,
$fn=Sides);
}
module ShowPegGrid(Space = 10.0,Size = 1.0) {
RangeX = floor(100 / Space);
RangeY = floor(125 / Space);
for (x=[-RangeX:RangeX])
for (y=[-RangeY:RangeY])
translate([x*Space,y*Space,Size/2])
%cube(Size,center=true);
}
//----------------------
// Build it!
module BasePlate() {
difference() {
// cube([(MotorCenter[0] + MotorBase/2),MotorBase,PlateThick],center=false);
linear_extrude(height = PlateThick) {
hull() {
translate([MotorBaseCornerRadius,MotorBaseCornerRadius])
circle(r=MotorBaseCornerRadius);
translate([MotorBaseCornerRadius,MotorBase - MotorBaseCornerRadius])
circle(r=MotorBaseCornerRadius);
translate([FlangeWidth + MotorBase - MotorBaseCornerRadius,MotorBase - MotorBaseCornerRadius])
circle(r=MotorBaseCornerRadius);
translate([FlangeWidth + MotorBase - MotorBaseCornerRadius,MotorBaseCornerRadius])
circle(r=MotorBaseCornerRadius);
}
}
translate(MotorCenter - [0,0,Protrusion]) {
rotate(180/8)
PolyCyl(MotorShaftDia,(PlateThick + 2*Protrusion),8); // shaft hole
PolyCyl(HubDia,(HubHeight + Protrusion)); // hub recess
for (x=[-1,1] , y=[-1,1]) {
translate([x*MotorHoleOffset,y*MotorHoleOffset,0])
rotate(180/8)
PolyCyl(MotorHoleDia,(PlateThick + 2*Protrusion),8);
}
}
translate(SlotOffset - [0,0,Protrusion]) { // adjustment slot
linear_extrude(height = (PlateThick + 2*Protrusion))
hull() {
circle(d=SlotSize[0]);
translate([0,(SlotSize[1] - SlotSize[0])])
circle(d=SlotSize[0]);
}
}
translate(CutoutOffset - [Protrusion,0,Protrusion])
linear_extrude(height = (PlateThick + 2*Protrusion))
square(CutoutSize + [Protrusion,Protrusion]);
}
}
ShowPegGrid();
if (Layout == "Show") {
BasePlate();
}
if (Layout == "Build") {
translate([-(SlotOffset[0] + MotorBase/2),MotorBase/2,PlateThick])
rotate([180,0,0])
BasePlate();
}
It was not, however, a pleasant turtle:
That’s a fairly large snapping turtle in the middle of the Dutchess Rail Trail, between Morgan Lake and the Violet Avenue tunnel.
Snappers can move just under the speed of light for about a foot in order to latch onto you, but they’re not quite as fast while turning around: always pass to their rear. You do not attempt to save them from their folly at being in the middle of the road / trail / driveway: they have absolutely no patience with meddlers.
Turtles lay eggs around this time of year, which means they’re on the move, which means they cross roads, which means they get mashed. We’ve seen maybe half a dozen smashed turtles on our usual routes.
Quite some years ago, we found one of its relations in the flower garden beside our house, where it climbed at least 18 inches of vertical concrete block to see what was inside. It was about two feet long, jaws to tail, and obviously a survivor:
Those missing plates probably didn’t help its attitude in the least.
It eventually klonked down to the driveway without our assistance:
After a pause for gimbal unlocking and compass recalibration, it ambled off toward the Mighty Wappingers Creek. The wall gets much shorter to the right, which is likely where it climbed up.
We wished it good hunting …
Neither turtle was radio-active.
These seem to be ordinary birch logs, cut into short chunks, sporting a top crosscut loaded with fire starter:
The front of the label makes them seem wonderfully eco-friendly, but the fine print on the back shows that they’re from the Old World:
There’s surely a universe where shipping heat-treated firewood from Estonia to Poughkeepsie makes perfect sense. I just didn’t realize I was living in it.
Our Forester has three knobs that control air direction / speed / temperature. Knobs are much better than buttons, because you can adjust them without looking. At least, that’s the ideal situation.
Here’s the setting for airflow to the footwell:
Here’s what it looks like with airflow to the cabin:
The knob has no tactile position indicator. That greenish rectangle, located in one of seven symmetric dimples that camouflage its position, is barely visible in normal light, invisible with sunglasses, and not apparent to the touch.
Well, if conspicuous is what you want, I can fix that:
Fluorescent tape will fade quickly, but it’ll last until something better comes along. Perhaps a small pointer epoxied onto the knurled surface, extending around to the indicator?
I finally figured out why the Forester feels so slow:
Here in the Northeast US, the maximum legal speed anywhere is 65 mph, less than half-scale, and typical around-town speeds hit 40 mph, barely 1/4 of full scale.
For all practical purposes, that needle barely moves during our usual trips.
I like analog gauges to represent smoothly varying quantities that you must read at a glance, but a big digital display would actually be more useful than that thing.
A 150 mph speedometer scale makes no sense in what’s basically a shrunken all-wheel-drive SUV, even with minimal off-road capabilities. Yes, perhaps the Forester could hit 150 mph, but why not have the scale top out around, say, 100 mph? Above that, you shouldn’t be paying much attention to the speedo, anyway.
The Sienna’s speedo went to 110 and, to the best of my knowledge, that needle never passed 85 mph, tops. However, ordinary (and legal) driving speeds filled the lower half of the scale, with the highest useful speeds in the next quadrant beyond vertical.
Yes, I know why the speedos sport such absurd numbers. I don’t have to like it.
There’s a servo motor (or some such) driving the needle; calibration has been a simple matter of software for a long, long time.
For whatever it’s worth, the Forester and the Sienna have both tachometers and automatic transmissions, a combination that converts shifting into a spectator sport. The Forester’s continuously variable transmission moves the tach needle in smooth glides, rather than abrupt jumps.
The Smell of Molten Projects in the Morning 