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.
Things around the home & hearth
After five years, I figured it’d be a Good Idea™ to replace the Forester’s wiper blades. Being in the Walmart at the time, I tried to use their helpful Wiper Selector gadget:
You’d think whoever is responsible for updating / replacing such things would have done so several times during the last eight years.
Back in the day, bathtubs had a porcelain coating over a cast-iron carcass, so embedding little magnets in shower curtains worked perfectly to keep the loose ends from billowing out of the tub. Surprisingly, even here in the future, with plastic bathtubs ruling the land, some shower curtains still have magnets. The mud-job tile walls of shower stall in the Black Bathroom have nary a trace of iron, but we though I could add ferrous targets for a new shower curtain, thusly:
The magnet lives inside a heat-sealed disk, so it’s (more-or-less) isolated from the water. As you’d expect, it’s a cheap ceramic magnet, not a high-performance neodymium super magnet, with no more strength than absolutely necessary to work under the most ideal of conditions.
My anchors must also be waterproof, firmly attached, non-marking, easily removable, and no more ugly than absolutely necessary. The general idea is to slice the bottom from a pill bottle, entomb a thin steel disk in epoxy, and attach to the tile with a patch of outdoor-rated foam tape.
So, we begin …
Cutting a narrow ring from a pill bottle requires a collet around the whole circumference, which started life as some sort of stout aluminum pole:
Bore out the inside, with a small step to locate the bottle:
Clean up the outside, just for pretty:
Slit the fixture to let it collapse around the bottle, then chuck up the first victim with support from a conveniently sized drill chuck in the tailstock:
I did a better job of cutting the second bottle to the proper length:
Nibble disks from sheet metal, half-fill the bottle bottoms with steel-filled (and, thus, magnetic!) JB Weld epoxy, insert disks, add sufficient epoxy to cover the evidence:
Fast-forward to the next day, punch out two disks of double-sided foam tape:
Affix, install, and it’s all good.
Actually, it’s not. The ceramic magnets are so weak they don’t hold the curtain nearly well enough to satisfy me. The next anchor iteration should have embedded neodymium magnets to attract the curtain’s crappy ceramic magnets, but this is Good Enough™ for now.
For reasons not relevant here, the lawn mower suffered some Foreign Object Damage:
I’m sure the hard stop loosened the tolerances along the shaft, but the mower fired right up (with that new blade!) and has no more vibration than usual, despite the seriously bent blade mount.
I no longer have a deep emotional attachment to lawn mowers, which is apparently common, as the label advises me there’s no need to change the oil:
Drive it ’til it drops …
The ancient utility pole on the north side of our property fell over a few hours after a thunderstorm rolled through:
Fortunately, the wire clamps were upward and it just lay there without sparks or excitement. It feeds the vacant house out back, so restoring power wasn’t urgent.
Unfortunately, the lines neatly bisected Mary’s garden:
The utility crew arrived a few hours later, disconnected the triplex at the fallen pole, rolled it up, secured it to the source pole out front, and promised a different crew would replace the pole in a while:
We agreed restoring service to other folks who needed it should take priority.
Mary’s been ducking the various cable TV / phone / FiOS cables ever since.
The pole has been God’s own toothpick for quite some time, as shown by this picture from 2001:
Fortunately for us, its pole tag hadn’t fallen off in all those years:
That little tag may save us ten large during this exquisite little inconvenience …
A pair of Step2 rolling garden seats (they have a new version) served in Mary’s gardens long enough to give their seat panels precarious cracks:
The underside was giving way, too:
We agreed the new seat could be much simpler, although it must still hinge upward, so I conjured a pair of hinges from the vasty digital deep:
The woodpile disgorged a slab of 1/4 inch = 6 mm plywood (used in a defunct project) of just about the right size and we agreed a few holes wouldn’t be a problem for its projected ahem use case:
The screw holes on the hinge tops will let me run machine screws all the way through, should that be necessary. So far, a quartet of self-tapping sheet metal (!) screws are holding firm.
A closer look at the hinges in real life:
The solid model now caps the holes; I can drill them out should the need arise.
From the bottom:
Three coats of white exterior paint make it blindingly bright in the sun, although we expect a week or two in the garden will knock the shine right off:
After the first coat, I conjured a drying rack from a bamboo skewer, a cardboard flap, and some hot-melt glue:
Three small scars on the seat bottom were deemed acceptable.
The OpenSCAD source code as a GitHub Gist:
| // Hinge brackets for rolling garden stool | |
| // Ed Nisley – KE4ZNU – 2019-06 | |
| Layout = "Build"; // [Block,Build,Show] | |
| Support = true; | |
| /* [Hidden] */ | |
| ThreadThick = 0.20; | |
| ThreadWidth = 0.40; | |
| HoleWindage = 0.2; | |
| Protrusion = 0.1; // make holes end cleanly | |
| ID = 0; | |
| OD = 1; | |
| LENGTH = 2; | |
| //———————- | |
| // Dimensions | |
| SeatThick = 6.0; // seat panel above cart body | |
| HingePin = [11.5,12.0,7.0]; // ID = tip OD = base | |
| HingeOffset = 8.0; // hinge axis above cart body (larger than radius!) | |
| HingeBolster = [5.0,24.0,SeatThick]; // backing block below hinge | |
| Block = [25.0,HingeOffset + 30.0,23.0]; // Z = above cart body | |
| Screw = [3.8,11.0,2.5]; // self-tapping #8 OD=head LENGTH=head thickness | |
| ScrewOC = 15.0; // spacing > greater than head OD | |
| ScrewOffset = Block.y/2 – (ScrewOC/2 + Screw[OD]/2 + HingeOffset); // space for head behind hinge | |
| BlockRadius = 7.0; // corner rounding | |
| //———————- | |
| // 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, | |
| $fn=Sides); | |
| } | |
| // Basic block shape | |
| // X axis collinear with hinge axes, hinge base at X=0 | |
| module HingeBlock() { | |
| PinSides = 3*4; | |
| PinSupport = [HingePin[LENGTH] – 2*ThreadWidth,0.6*HingeOffset,HingePin[OD]]; // pre-rotated | |
| union() { | |
| translate([Protrusion,Block.y/2 – HingeOffset,HingeOffset]) | |
| rotate([0,-90,0]) | |
| rotate(180/PinSides) | |
| cylinder(d=HingePin[OD],h=HingePin[LENGTH] + Protrusion,$fn=PinSides); | |
| difference() { | |
| hull() { | |
| translate([Block.x – BlockRadius,-(Block.y/2 – BlockRadius),Block.z – BlockRadius]) | |
| rotate(180/PinSides) | |
| sphere(r=BlockRadius/cos(180/PinSides),$fn=PinSides); | |
| translate([0,-(Block.y/2 – BlockRadius),Block.z – BlockRadius]) | |
| rotate([0,90,0]) rotate(180/PinSides) | |
| cylinder(r=BlockRadius/cos(180/PinSides),h=Block.x/2,$fn=PinSides); | |
| translate([Block.x – BlockRadius,(Block.y/2 – BlockRadius),Block.z – BlockRadius]) | |
| sphere(r=BlockRadius/cos(180/PinSides),$fn=PinSides); | |
| translate([0,(Block.y/2 – BlockRadius),Block.z – BlockRadius]) | |
| rotate([0,90,0]) rotate(180/PinSides) | |
| cylinder(r=BlockRadius/cos(180/PinSides),h=Block.x/2,$fn=PinSides); | |
| translate([0,-Block.y/2,0]) | |
| cube([Block.x,Block.y – HingeOffset,Block.z/2],center=false); | |
| translate([0,Block.y/2 – HingeOffset,HingeOffset]) | |
| rotate([0,90,0]) rotate(180/PinSides) | |
| cylinder(r=HingeOffset/cos(180/PinSides),h=Block.x,$fn=PinSides); | |
| } | |
| translate([Block.x/2 + HingeBolster.x,0,(SeatThick – Protrusion)/2]) | |
| cube([Block.x,2*Block.y,SeatThick + Protrusion],center=true); | |
| translate([0,-HingeBolster.y,(SeatThick – Protrusion)/2]) | |
| cube([3*Block.x,Block.y,SeatThick + Protrusion],center=true); | |
| for (j=[-1,1]) | |
| translate([Block.x/2,j*ScrewOC/2 + ScrewOffset,-4*ThreadThick]) | |
| rotate(180/8) | |
| PolyCyl(Screw[ID],Block.z,8); | |
| } | |
| } | |
| if (Support) { // totally ad-hoc | |
| color("Yellow") render(convexity=4) | |
| difference() { | |
| translate([-(PinSupport.x/2 + 2*ThreadWidth),Block.y/2 – PinSupport.y/2,HingeOffset]) | |
| cube(PinSupport,center=true); | |
| translate([Protrusion,Block.y/2 – HingeOffset,HingeOffset]) | |
| rotate([0,-90,0]) | |
| rotate(180/PinSides) | |
| cylinder(d=HingePin[OD] + 2*ThreadThick,h=2*HingePin[LENGTH],$fn=PinSides); | |
| for (i=[-1:1]) | |
| translate([i*4*ThreadWidth – HingePin[LENGTH]/2, | |
| Block.y/2 – (PinSupport.y + 1*ThreadThick), | |
| HingeOffset]) | |
| cube([2*ThreadWidth,2*PinSupport.y,2*PinSupport.z],center=true); | |
| } | |
| } | |
| } | |
| module Blocks(Hand = "Left") { | |
| if (Hand == "Left") | |
| HingeBlock(); | |
| else | |
| mirror([1,0,0]) | |
| HingeBlock(); | |
| } | |
| //- Build it | |
| if (Layout == "Block") | |
| HingeBlock(); | |
| if (Layout == "Show") { | |
| translate([1.5*HingePin[LENGTH],0,0]) | |
| Blocks("Left"); | |
| translate([-1.5*HingePin[LENGTH],0,0]) | |
| Blocks("Right"); | |
| } | |
| if (Layout == "Build") { | |
| translate([0,-Block.z/2,Block.y/2]) | |
| rotate([-90,0,0]) { | |
| translate([1.5*HingePin[LENGTH],0,0]) | |
| Blocks("Left"); | |
| translate([-1.5*HingePin[LENGTH],0,0]) | |
| Blocks("Right"); | |
| } | |
| } |
This original doodle gives the key dimensions, apart from the rounded rear edge required so the seat can pivot vertically upward:
The second seat looks just like this one, so life is good …
For reasons not relevant here, we have a power lift chair which has been shedding upholstery tufts since the day we got it. After realizing this wasn’t going to stop on its own, I spent a while poking around underneath and discovered the steel struts supporting the leg rest rub along the upholstery during their entire travel:
Apparently, the padding behind the upholstery pushes it a bit further out than the original design could accommodate, letting the raw edges on the steel struts shave off the fuzz.
I put relatively smooth stainless steel tape on all the protrusions and bent it around the rough edges:
Those steel folds are smoother than they appear.
It’s not obvious this will solve the problem, but the struts seems to be scraping off much less fuzz than before, so it’s a step in the right direction.
Why is it all of today’s consumer products require 10% more engineering to work in the real world?
The yard camera now resides outdoors and plugs into one of three outlets on the patio, all of which have weatherproof covers attached by a bead chain to the trim plate:
That’s the after-repair condition, as two of the three chains were broken when we bought the house.
Stipulated: the covers needed scrubbing, but sometimes ya gotta stay focused on the Main Goal.
Two feet of 3.4 mm brass bead chain (because spares: ya gotta have stuff) arrived from eBay, I dismounted all three covers, and discovered the bell-shaped brass caps on the old chains were perfectly serviceable after six decades:
The outlets are wired to circuit breaker 28, of course.
Having enough chain to go around, each cover now sports a slightly longer leash than before:
Reinstall in reverse order, the camera rebooted as it should, and it’s all good out there:
That was easy …
The Smell of Molten Projects in the Morning 