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.
On the drive side, of course:
I’d noticed some brake drag on our last few rides, but forgot to check until I saw the rim wobble while extracting images from the rear camera.
It’s a lot easier to fix in the Basement Shop than on the road. After nigh onto a decade since replacing the last broken spoke, perhaps this is a harbinger of doom to come.
Memo to Self: spoke tension is now 20-ish on the drive side, 15-ish on the left.
The cover for Mary’s favorite seam ripper cracked long ago, has been repaired several times, and now needs a replacement:
The first pass (at the top) matched the interior and exterior shapes, but was entirely too rigid. Unlike the Clover seam ripper, the handle has too much taper for a thick-walled piece of plastic.
The flexy thinwall cover on the ripper comes from a model of the interior shape:
It’s not conspicuously tapered, but OpenSCAD’s perspective view makes the taper hard to see. The wedge on top helps the slicer bridge the opening; it’s not perfect, just close enough to work.
A similar model of the outer surface is one thread width wider on all sides, so subtracting the handle model from the interior produces a single-thread shell with a wedge-shaped interior invisible in this Slic3r preview:
The brim around the bottom improves platform griptivity. The rounded top (because pretty) precludes building it upside-down, but if you could tolerate a square-ish top, that’s the way to go.
Both models consist of hulls around eight strategically placed spheres, with the wedge on the top of the handle due to the intersection of the hull and a suitable cube. This view shows the situation without the hull:
The spheres overlap, with the top set barely distinguishable, to produce the proper taper. I measured the handle and cover’s wall thicknesses, then guesstimated the cover’s interior dimensions from its outer size.
The handle’s spheres have a radius matching its curvature. The cover’s spheres have a radius exactly one thread width larger, so the difference produces the one-thread-wide shell.
Came out pretty nicely, if I do say so myself: the cover seats fully with an easy push-on fit and stays firmly in place. Best of all, should it get lost (despite the retina-burn orange PETG plastic), I can make another with nearly zero effort.
The Basement Laboratory remains winter-cool, so I taped a paper shield over the platform as insulation from the fan cooling the PETG:
The shield goes on after the nozzle finishes the first layer. The masking tape adhesive turned into loathesome goo and required acetone to get it off the platform; fortunately, the borosilicate glass didn’t mind.
The OpenSCAD source code as a GitHub Gist:
| // Cover for old seam ripper | |
| // Ed Nisley – KE4ZNU | |
| // 2019-03 | |
| /* [Layout Options] */ | |
| Layout = "Build"; // [Show,Build] | |
| Part = "Handle"; // [Handle,CoverSolid,Cover] | |
| /* [Extrusion Parameters] */ | |
| ThreadWidth = 0.40; | |
| ThreadThick = 0.25; | |
| HoleWindage = 0.2; | |
| Protrusion = 0.1; | |
| //—– | |
| // Dimensions | |
| /* [Dimensions] */ | |
| WallThick = 1*ThreadWidth; | |
| CapInsideLength = 48.0; | |
| CornerRadius = 2.0; // handle at base | |
| Base = [11.0,5.5,0.0]; // handle at base | |
| Tip = [8.2,3.7,CapInsideLength]; // inferred at tip | |
| HandleOC = [Base – 2*[CornerRadius,CornerRadius,0.0], | |
| Tip – 2*[CornerRadius,CornerRadius,CornerRadius/2] | |
| ]; | |
| NumSides = 2*3*4; | |
| //—– | |
| // Useful pieces | |
| // Handle is basically the interior of the cover | |
| module Handle() { | |
| intersection() { | |
| hull() | |
| for (i=[-1,1], j=[-1,1], k=[0,1]) | |
| translate([i*HandleOC[k].x/2,j*HandleOC[k].y/2,k*HandleOC[k].z]) | |
| sphere(r=CornerRadius,$fn=NumSides); | |
| translate([0,0,-CornerRadius/2]) // chop tip for better bridging | |
| rotate([45,0,0]) | |
| cube([2*Base.x,CapInsideLength*sqrt(2),CapInsideLength*sqrt(2)],center=true); | |
| } | |
| } | |
| module CoverSolid() { | |
| hull() | |
| for (i=[-1,1], j=[-1,1], k=[0,1]) | |
| translate([i*HandleOC[k].x/2,j*HandleOC[k].y/2,k*HandleOC[k].z]) | |
| sphere(r=CornerRadius + WallThick,$fn=NumSides); | |
| } | |
| module Cover() { | |
| difference() { | |
| CoverSolid(); | |
| Handle(); | |
| translate([0,0,-CornerRadius]) | |
| cube(2*Base + [0,0,2*CornerRadius],center=true); | |
| } | |
| } | |
| //—– | |
| // Build things | |
| if (Layout == "Build") { | |
| Cover(); | |
| } | |
| if (Layout == "Show") | |
| if (Part == "Handle") | |
| Handle(); | |
| else if (Part == "CoverSolid") | |
| CoverSolid(); | |
| else if (Part == "Cover") | |
| Cover(); | |
Having an ancient flip phone in need of a battery, I ordered a Kyocera TXBAT10133 battery from eBay. Described as “new” (which, according to the Ebay listing, means “New: A brand-new, unused, unopened, undamaged item in its original packaging”), I was somewhat surprised to see this emerging from the box:
It obviously led a rather hard life before being harvested from somebody else’s obsolete flip phone and is definitely not “new”.
Not yet having a deep emotional attachment to the thing, I set it up for a capacity test:
Given a very light 100 mA load, it shows about the same capacity as the original battery in our phone:
Given the precarious contact arrangement, the glitches near the right end aren’t surprising.
The battery label claims a 900 mA·h rating, so both have nearly their nominal capacity at such a reduced load. In actual use, the phone has a low battery after a few hours of power-on time, far less than when it was new.
The seller promises a replacement. For all I know, there are no genuinely “new” batteries available for these phones.
Somewhat to my surprise, Aneng AN8008/AN8009 multimeter PCBS sport what looks like a reasonably accurate current sense resistor on the 10 A input:
The legend says 0.01R and the conductor doesn’t look quite like pure copper:
The indentations look like clamp marks from the bending jig, rather than “calibration” notches made while squeezing the wire with diagonal cutters and watching the resistance on another meter.
One might quibble about the overall soldering quality, but one would also be splitting hairs. I doubt the meter leads could withstand 10 A for more than a few seconds, anyhow.
If you buy enough of something, you can buy pretty nearly anything you want, even cheap precision resistors!
Having recently acquired a pair of photo lights and desirous of eliminating some desktop clutter, I decided this ancient incandescent (!) magnifying desk lamp had outlived its usefulness:
The styrene plastic shell isn’t quite so yellowed in real life, but it’s close.
Stripping off the frippery reveals the tilt stem on the arm:
The photo lights have a tilt-pan mount intended for a camera’s cold (or hot) shoe, so I conjured an adapter from the vasty digital deep:
Printing with a brim improved platform griptivity:
Fortunately, the photo lights aren’t very heavy and shouldn’t apply too much stress to the layers across the joint between the stem and the cold shoe. Enlarging the stem perpendicular to the shoe probably didn’t make much difference, but it was easy enough.
Of course, you (well, I) always forget a detail in the first solid model, so I had to mill recesses around the screw hole to clear the centering bosses in the metal arm plates:
Which let it fit perfectly into the arm:
The grody threads on the upper surface around the end of the slot came from poor bridging across a hexagon, so the new version has a simple and tity flat end. The slot is mostly invisible with the tilt-pan adapter in place, anyway.
There being no need for a quick-disconnect fitting, a 1/4-20 button head screw locks the adapter in place:
I stripped the line cord from inside the arm struts and zip-tied the photo lamp’s wall wart cable to the outside:
And then It Just Works™:
The lens and its retaining clips now live in the Big Box o’ Optical parts, where it may come in handy some day.
The OpenSCAD source code as a GitHub Gist:
| // Photo light mount for desk lamp arm | |
| // Ed Nisley – KE4ZNU | |
| // 2019-03 | |
| /* [Layout Options] */ | |
| Layout = "Build"; // [Show,Build] | |
| Part = "Mount"; // [LampArm,ShoeSocket,Mount] | |
| /* [Extrusion Parameters] */ | |
| ThreadWidth = 0.40; | |
| ThreadThick = 0.25; | |
| HoleWindage = 0.2; | |
| Protrusion = 0.1; | |
| //—– | |
| // Dimensions | |
| /* [Hidden] */ | |
| ID = 0; | |
| OD = 1; | |
| LENGTH = 2; | |
| /* [Dimensions] */ | |
| FrictionDisk = [4.0,16.5,11.0]; // squashed inside desk lamp arm frame | |
| Divots = [4.0,9.5,0.75]; // recesses for frame alignment bumps | |
| ArmLength = 30.0; // attached to disk | |
| ShoeWheelOD = 32.0; // lock wheel on photo lamp | |
| ShoeBase = [18.5,18.5,2.0] + [HoleWindage,HoleWindage,2*ThreadWidth]; // square base on photo lamp gimbal | |
| ShoeStem = [6.3,12.0,1.5]; // top slide clearance, ID = 1/4 inch screw | |
| ShoeBlock = [ShoeWheelOD,ShoeWheelOD,2*(ShoeBase.z + ShoeStem.z)]; // overall shoe block | |
| NumSides = 3*4; | |
| //—– | |
| // Useful routines | |
| function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit); | |
| module PolyCyl(Dia,Height,ForceSides=0,Center=false) { // based on nophead's polyholes | |
| Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2); | |
| FixDia = Dia / cos(180/Sides); | |
| cylinder(r=(FixDia + HoleWindage)/2,h=Height,$fn=Sides,center=Center); | |
| } | |
| //—– | |
| // Various Parts | |
| // Arm captured in disk lamp | |
| module LampArm() { | |
| difference() { | |
| union() { | |
| cylinder(d=FrictionDisk[OD],h=FrictionDisk[LENGTH],$fn=NumSides,center=true); | |
| hull() | |
| for (j=[-1,1]) | |
| translate([0,j*(FrictionDisk[OD]/2 – FrictionDisk[LENGTH]/2),0]) { | |
| rotate([0,90,0]) rotate(180/NumSides) | |
| cylinder(d=FrictionDisk[LENGTH]/cos(180/NumSides),h=ArmLength/2,$fn=NumSides); | |
| translate([ArmLength – FrictionDisk[LENGTH]/2,0,0]) | |
| sphere(d=FrictionDisk[LENGTH],$fn=NumSides); | |
| } | |
| } | |
| rotate(180/6) { | |
| PolyCyl(FrictionDisk[ID],FrictionDisk[LENGTH] + 2*Protrusion,6,Center=true); | |
| for (k=[-1,1]) | |
| translate([0,0,k*(FrictionDisk[LENGTH]/2 – Divots[LENGTH]/2)]) | |
| PolyCyl(Divots[OD],Divots[LENGTH] + Protrusion,6,Center=true); | |
| } | |
| } | |
| } | |
| // Basic hot shoe socket | |
| module ShoeSocket() { | |
| difference() { | |
| union() { | |
| cube(ShoeBlock,center=true); // overall blocky retainer | |
| translate([-ShoeBlock.x/2,0,0]) | |
| cylinder(d=ShoeBlock.x,h=ShoeBlock.z,$fn=NumSides,center=true); | |
| } | |
| translate([0,0,-2*ShoeBlock.z]) // screw hole throughout | |
| rotate(180/6) | |
| PolyCyl(ShoeStem[ID],4*ShoeBlock.z,6); | |
| translate([0,0,ShoeBase.z/2]) // base slot under pillar | |
| cube([ShoeBase.x,ShoeBase.y,ShoeBase.z],center=true); | |
| translate([ShoeBase.x/2,0,ShoeBase.z/2]) // base slot opening | |
| cube([ShoeBase.x,ShoeBase.y,ShoeBase.z],center=true); | |
| translate([ShoeStem[OD]/2,0,ShoeBase.z/2 + ShoeStem[LENGTH]]) // stem slot | |
| cube([2*ShoeStem[OD],ShoeStem[OD],2*ShoeStem[LENGTH]],center=true); | |
| } | |
| } | |
| // Stick parts together | |
| module Mount() { | |
| rotate([90,0,0]) | |
| LampArm(); | |
| translate([ArmLength + ShoeBlock.x/2 – Protrusion,0,0]) | |
| ShoeSocket(); | |
| } | |
| //—– | |
| // Build things | |
| if (Layout == "Build") { | |
| rotate([0,90,0]) | |
| translate([-(ArmLength + ShoeBlock.x),0,0]) | |
| Mount(); | |
| } | |
| if (Layout == "Show") | |
| if (Part == "LampArm") | |
| LampArm(); | |
| else if (Part == "ShoeSocket") | |
| ShoeSocket(); | |
| else if (Part == "Mount") | |
| Mount(); |
The original dimension doodles, made before I removed the stem and discovered the recesses around the screw hole:
We’d been eating a “healthy” high-carb / low-fat diet, which produced the more-or-less expected 1 lb/yr weight gain over the course of three decades. Given that we eat about 106 Cal/yr, being off by a mere 0.3% seemed fixable, but we were always hungry while trying to cut out calories.
In April 2016, we decided our tummies had come between us, so we switched to a mostly ketogenic diet (clicky for more dots):
Having a Master Gardener in the family complicates dietary choices along the ketogenic axis, but Mary raised more green-and-leafy veggies, less squash-and-corn, and we keto-ized our meals reasonably well. Moderation in all things works fine for us, so losing 25 pounds at about 1 lb/week wasn’t particularly stressful.
Continuing through 2017, you can see how regular bike riding season affects winter bloat:
Our cycling vacation in July 2018 produced a blip, but the rest of the riding season worked as expected:
It’s straightforward to crash-diet two dozen pounds, but maintaining a more-or-less stable weight for the next two years suggests we’ve gotten the annual calorie count about right. FWIW, my bloodwork numbers sit in the Just Fine range, apart from the somewhat elevated cholesterol level typical of a keto-ized diet.
Starting in late 2018, however, a stressful situation of a non-bloggable nature (at least for a blog such as this) produced an unusually high number of road trips, motel stays, and generally poor dietary choices:
The situation now being over, our lives / exercise / diet will return to what passes for normal around here and my goal is to lose another 10% of my current body weight, ending at 150 pounds, by the end of the year. In round numbers, that requires losing half a pound = 1700 Cal/week, 250 Cal/day. Not power-noshing an ounce or two of nuts a day should do the trick.
If it makes you feel more science-y, you can use the NIH Body Weight Planner, but it produces about the same answer: knock off 300 Cal to lose weight, 250 Cal to maintain it, at essentially the same exercise level as before.
We’ve been recording our weights as dots on graph paper every Saturday evening for the last four decades, so I know for a fact I averaged 148 pounds when I wore a younger man’s clothes. I’ll re-post the 2019 chart, adding four dots every month, during the rest of the year.
This way, you can help keep me on track … [grin]
Spotted this in a lobby (clicky for more dots):
I know no more than you do about the situation, but I’d lay long, long odds Hannaford created the poster with a more recent version of Microsoft Word (or whatever) than the recipient organization has available, making the file essentially read-only.
Not casting shade on ’em; sometimes, you do what you gotta do.
FWIW, I’d expect LibreOffice and any Microsoft Word version other than the exact one used to create the poster to mangle the formatting differently. Been there, done that.
The Smell of Molten Projects in the Morning 