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
Got one of those painful, bloodless slices:
From, believe it or not, the razor-sharp edge of a fillet of cured green Loctite:
Of course, it didn’t stay bloodless for long: every time I put pressure on the ball of my thumb, the split gets longer.
I hate it when there’s blood all over the workpiece…
Although that fix continues to work, the second pin failed pretty much as expected:
I glued the pin to rebuild the base, sheared the pin off, extracted the matching screw from the Tiny Vial of Teensy Screws, drilled a hole, and forced it in. This shot of the underside of the pitcher lid clearly shows that drilling the hole perpendicular to the edge doesn’t produce the proper alignment, but it works well enough:
The “Smart Pitcher” LCD panel in the lid that counts down six weeks until filter replacement didn’t survive its most recent trip through the dishwasher, so we’re reduced to marking the calendar. How 20th century…
Mary has been quilting up a storm lately and is growing dissatisfied with the special safety pins she’s been using to hold the layers together. Long straight pins are ideal, except that maneuvering a large quilt through her sewing machine resembles stuffing a porcupine into a keyhole. A commercial solution costs nearly half a buck per pin, which seems unreasonably spendy for something you need by the hundreds.
We kicked around some finger- and quilt-friendly dimensions and I cobbled up a solid model:
Which turned into an array of small octagons that won’t roll off the table:
We figured 25 would be enough to decide if this is workable and whether the dimensions fit fingers, pins, and quilts.
Filling them with silicone rubber required one squirt each:
The trick with the silicone rubber is to cut the snout so it fits flat on the cylinder top. Put the cylinders on a piece of non-stick paper (I used the back of the carrier for some double-sided tape, but wax paper would be better), hold one with tweezers, squirt in enough rubber to fill the cylinder solidly from bottom to top, then slide the snout sideways to smooth the surface.
Wait for a day, pop them off, and remove any drool:
It’s garden planting time right now, so it’ll take a while before I tweak the design and run off the next batch.
I don’t know how to compute an actual cost for each of those things. I regard the entire Thing-O-Matic as fully depreciated and pretty much a sunk cost, which means the expense boils down to the incremental cost of plastic and silicone. All the Quality Shop Time is, of course, free… and maybe even therapeutic.
The (trivially simple) OpenSCAD source code:
// Quilting pin caps
// Ed Nisley KE4ZNU April 2012
//- Extrusion parameters must match reality!
// Print with +1 shells and 3 solid layers
ThreadThick = 0.25;
ThreadWidth = 2.0 * ThreadThick;
HoleWindage = 0.2;
function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);
Protrusion = 0.1; // make holes end cleanly
//----------------------
// Dimensions
ID = 5.0;
OD = ID + 2*ThreadWidth;
Length = 5.0;
Sides = 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) {
Range = floor(50 / Space);
for (x=[-Range:Range])
for (y=[-Range:Range])
translate([x*Space,y*Space,Size/2])
%cube(Size,center=true);
}
//----------------------
// Build them!
ShowPegGrid();
rotate(180/Sides) {
difference() {
PolyCyl(OD,Length,8);
translate([0,0,-Protrusion])
PolyCyl(ID,(Length + 2*Protrusion),8);
}
}
One of the oven drawer supports in our Sears Kenmore gas range cracked and I finally got around to replacing it:
I originally thought the drawer slid on the large, blocky, well-supported lump. Nope, that delicate little tab must support half the weight of the drawer; the lump might support the drawer in another oven. Perhaps we shouldn’t store the Lesser and Least Cast Iron Pans in that drawer, but that’s where they fit best. The Greater Cast Iron Pan lives atop the stove, because it get used so often there’s no point in putting it away.
One could, of course, Fire the Thing-O-Matic! to print brightly colored plastic bits (after the usual tedious 3D modeling & trial fitting), but replacement parts cost a buck each from RepairPartsDirect. I bought three, so as to have a complete backup set, and most of the $9 total went to postage & handling.
Done!
Our story so far:
So here’s the Rest of the Story, reconstructed from my notes…
Having already torn the thing apart and discovered that the repair would include both the drum+spider assembly (not available separately, which may actually make sense given high-speed spin balancing) and the front half of the plastic tub, I priced them at RepairClinic and Sears Parts Direct. In round numbers, this adventure would cost $300-400 just for the parts, a bit less than half the cost of the washer.
As I recall, the Sears price for the drum was roughly twice that for RepairClinic, while the tub was about the same. I suspect Sears deliberately inflates the drum price to make sure nobody actually buys the thing and to pad out the tech’s time to replace it.
The warranty in the front of the Owner’s Manual seemed promising:
So I called the Sears Parts & Warranty line, walked the menu tree, explained the situation, asked for a new drum, and was told that they must dispatch a tech to diagnose the problem. Despite the warranty, there would be a labor fee and an additional fee to process the parts order. There was no way to determine those fees before dispatching the tech.
I pointed out that I’d already dismantled the washer, knew exactly what the problem was, and just needed the replacement drum as described in the warranty. I was put on hold to “process my request”, eventually being transferred to a “tech specialist department for further assistance”.
The “tech specialist” was willing to spend as much time as required to convince me that the Lifetime Warranty had expired, based on a deliberate misreading of the terms. As far as they were concerned, the sentence “After the first year, you will be charged for labor” meant that the warranty had expired on a five-year-old washer and that the drum was no longer covered. They would not, under any circumstances, send me the drum. Yes, I asked for a supervisor and, no, I doubt that she really was one; handing the call to the next cubicle is standard call-center subterfuge to placate irate customers.
I eventually decided that this was not a language-barrier issue, but a carefully planned & executed part of their standard script: letting their Indian-subcontinent call center take the heat works wonderfully well for the purpose of getting rid of warranty claims.
So I looked up the phone number of the “interim CEO/President” (I assume he’s long gone by now) at Sears Holding Corporation and gave him a call. Of course, I didn’t expect to actually reach the CEO, but I figured I’d shake the dice a bit to see if a better combination came up.
It turns out that they expect this sort of behavior and immediately connected me to their “Executive Customer Service” department, which was described as “the highest they can go”. So I told my tale, asked her to ship me a drum, and was told that wasn’t possible. What she could do, as a “one time offer”, was to “waive the labor fee” when they dispatched the tech.
I asked if there were any other fees. She refused to answer that question. I asked if there was a charge to order the parts. She refused to answer that question. It being a Friday, I asked when the tech could arrive; she said that they would attempt to schedule it for Monday, but Tuesday was more likely. I asked if he’d arrive with the drum. She said the tech would assess the problem and order the necessary parts, requiring a second appointment later in the week.
I told her that it was obvious Sears had no intention of honoring their warranty. She repeated that this was a one-time offer. We did not part on good terms.
So I ordered the drum & tub from RepairClinic, two huge boxes arrived on Tuesday, I installed everything, buttoned up the machinery, and the washer has worked fine ever since.
Every time I looked at that big drum, I got mad all over again. I never mustered the enthusiasm to take the spider off the back for a post-mortem, which is why there’s no Part 2 after that post. Eventually I hauled the carcasses to the town’s disposal site and bid them good riddance.
Obviously, Sears won: they got rid of me without spending a dime on the warranty. It cost them maybe two hours of phone time, but I doubt the pleasant voice in the “Executive Customer Service” department makes much more than minimum wage and Indian-subcontinent personnel are basically free compared to that.
I’m doing a bunch of appliance repair right now and wonder just how much we’d be spending if we had to go through the Official Channels for repairs. I’m definitely earning my keep… and having much more fun than being jerked around by that corporate structure.
And that’s the end of that story…
The robust wire I used for the external battery connection required a bit of diagonal cutter work to enlarge the hole in the top plate, but eventually everything fit together and the GPS interface box latched neatly onto the radio:
The skein of cables:
All in all, it looks pretty good:
After a few rides to verify that this whole affair works, I must print up another case with slightly modified dimensions, add a plastic window over those cheerful LEDs on the TinyTrak3+ board, and mush an epoxy putty blob over the earphone and mic connections on that bright yellow plug plate. I’ve given up on the idea of having a cover for the top part of the battery compartment; there just isn’t enough space for such a thing and it’d be an impossibly delicate shell.
The radio seems happy enough being fed 9 V from a bench supply (to match the upconverted lithium packs I’ve been using on the bikes), rather than 7.4 V from its standard lithium pack. A freshly charged battery comes pretty close to 9 V, so they can’t be too fussy. It idles at about 100 mA, with periodic blips to 140 mA when (I think) the TinyTrak3+ tickles the GPS receiver, regardless of the supply voltage. Goosing it with 13.8 V surely wouldn’t have a happy outcome…
Lashed up like that on the bench, with the GPS receiver hanging out the basement window and the coax hitched to a bicone scanner antenna sitting inside the window, it generated APRS spots and the audio sounds OK, so the innards look good, too.
2012-04-11 20:09:08 EDT: KE4ZNU-9>APT311,WA2YSM-15,WIDE1*,WIDE2-1,qAR,K2MHV-6:>Ed - Bike PL100 UV3D
One downside: the TinyTrak3+ blurts its initial ID message instantly after being powered on, but the radio takes a few seconds to haul itself to its feet. As a result, the ID message never reaches the antenna. So it goes…
After considerable stalling, I filed the heads of two brass 4-40 screws down to about 1 mm, leaving just a hint of the slots in place. They’re a bit over 5 mm in diameter, smaller than the 7 mm I wanted to use, but have the compelling advantage of being Close Enough to get the rest of the hardware working. The gap between the interface PCB and the case is 3 mm, which turns out to be just about exactly the thickness of a 4-40 nut and flat washer, so I soldered a pair of them together as threaded spacers:
The soldering looks worse than it really is; they’re secured all the way around.
For the external battery connectors on the top, I ran a #33 drill through a pair of miniature crimp ring lugs to get a slip fit, then soldered them atop a pair of nickel-plated nuts. In normal use they’d be captured by the nuts, but I can’t figure out how to assemble them inside the case:
Those are stainless steel 4-40 screw cutoffs, which I used because solder doesn’t adhere to stainless… I tinned the nuts and connectors, clamped the screws in a small vise, heated the nuts with a soldering iron, and applied the contacts with a tweezer. They snapped right into place and the solder fillet wrapped neatly around the entire lug.
The heat from the soldering iron relaxed the insulator sleeves enough to remove nearly all trace of the crimping.
With all that in hand, I ran the brass screws through the case, into the spacer nut+washer combo, through the PCB, and into the battery contact nuts. A bit of tedious pliers work snugged the screws and got everything lined up, then I tightened the spacers against the PCB and battery nuts on the other side. That’s completely invisible inside the case, so there aren’t any pictures, but the idea is that the studs sit flush inside their case recesses and clamping the PCB between the nuts shouldn’t put any stress on the PCB. We shall see.
The slots became so shallow that a screwdriver doesn’t get any traction…
The Smell of Molten Projects in the Morning 