M2 – Page 2 – The Smell of Molten Projects in the Morning

Anker LC-40 Flashlight Switch Repair

The switch on the Anker LC-40 flashlight serving as a running light on my Tour Easy became slightly intermittent before I replaced it with a 1 W amber LED, but it was still good enough to become the troubleshooting flashlight in the tray next to the Prusa Mk 4 printer. Eventually, of course, it failed completely and Something Had To Be Done.

Although I knew an exact replacement switch had to be available from the usual sources, I could not come up with a set of keywords capable of pulling them out of the chaff.

That was not a problem, because the assortment of SMD switches I used to replace the handlebar control caps on Mary’s Handi-Quilter HQ Sixteen contained push-on / push-off switches that were almost the right size:

Anker LC-40 Flashlight - switches and caps — Anker LC-40 Flashlight – switches and caps

Having recently convinced the MakerGear M2 3D printer to use TPU filament, all I had to do was produce a suitable cap to fit over the new switch in the flashlight’s tail:

Anker LC-40 Flashlight Button - TPU PrusaSlicer — Anker LC-40 Flashlight Button – TPU PrusaSlicer

Which turned into a multi-dimensional search over cap geometry, TPU extrusion speeds & feeds, and various impossible-to-directly-measure sizes:

Anker LC-40 Flashlight - TPU cap iterations — Anker LC-40 Flashlight – TPU cap iterations

The squarish block over on the left is PrusaSlicer’s version of a support structure wrapped around the first cap version; if human lives depended on it, I could surely extract the cap, but it would take a while.

The remaining ~~debris~~ samples occured while discovering:

An extruder temperature of 230 °C, not 250 °C, works well
A conical shape of the lip around the open end to eliminate the support structure
TPU doesn’t bridge well, so the closed end must be down
Length of the central pillar to barely touch the switch stem when released
Cap length and wall thickness so the TPU shell can collapse enough to actuate and release the switch stem
And so on and so on and scooby dooby dooby

Eventually I came up with a suitable combination:

Anker LC-40 Flashlight - switch caps — Anker LC-40 Flashlight – switch caps

Because I expected this would be an easy job, I used snap ring pliers to unscrew and rescrew the threaded retaining ring holding the switch PCB in place. Because the pliers didn’t have a stable grip on the ring, the threads eventually became just a bit goobered.

This was not a problem, because I have a(nother) 3D printer:

Anker LC-40 Flashlight Retainer - show view — Anker LC-40 Flashlight Retainer – show view

The gray thing on the right is a simple pin wrench fitting both the original and the replacement retaining rings, so I can orient the rings properly while unscrewing & rescrewing:

Anker LC-40 Flashlight - pin wrench in place — Anker LC-40 Flashlight – pin wrench in place

The threads have a 0.75 mm pitch and, while it’s possible to print screw threads, even a tedious 0.1 mm layer height would define each turn of the thread with only 7-½ layers.

This was not a problem, because I have a mini-lathe:

Anker LC-40 Flashlight - thread cutting — Anker LC-40 Flashlight – thread cutting

The yellow & green things on the left of those solid models are the fixture holding a retaining ring for threading and the washer applying pressure to keep the ring in place:

Anker LC-40 Flashlight - lathe fixture - detail — Anker LC-40 Flashlight – lathe fixture – detail

The alert reader will note that washer lacks holes for the alignment pins I added after seeing the washer sit not quite concentric on the fixture. I could call it continuous product improvement, although I doubt I’ll print another one.

Setting up the lathe involved finding the proper set of change gears, including the vital 42-50 stacked gear I made a while ago to print metric threads on a hard-inch lathe:

Anker LC-40 Flashlight - lathe change gear train — Anker LC-40 Flashlight – lathe change gear train

Although you’re supposed to measure the thread spacing on a skim pass, I find it’s easier to just measure the carriage movement for one spindle rotation:

Anker LC-40 Flashlight - lathe gear check — Anker LC-40 Flashlight – lathe gear check

A few passes produced a fine retaining ring:

Anker LC-40 Flashlight - pin wrench - detail — Anker LC-40 Flashlight – OEM vs lathe-cut threads

Sporting much nicer looking threads than the goobered original:

Anker LC-40 Flashlight - OEM vs lathe-cut threads — Anker LC-40 Flashlight – OEM vs lathe-cut threads

The original switch had a stabilizing ring around the body to prevent it from wobbling under the original rubber cap.

This was not a problem, because I have a laser cutter:

Anker LC-40 Flashlight - new switch in stabilizer — Anker LC-40 Flashlight – new switch in stabilizer

Those came from a scrap of fluorescent acrylic.

The wave washer behind the acrylic stabilizer improves the contact between the PCB trace around the rim and the flashlight tailcap, with the current passing through the body to the “light engine” up front. The retaining ring provides enough pressure to compress the wave washer, which is why it’s so easily goobered without a close-fitting pin wrench.

With everything assembled in reverse order, the flashlight worked pretty much as it did back when it was new:

Anker LC-40 Flashlight - TPU cap installed — Anker LC-40 Flashlight – TPU cap installed

However, after describing this during a recent SquidWrench meeting, I discovered that adding “latching” to my keywords surfaced a bodacious assortment of flashlight switches, so (a few days later) I removed the not-quite-right switch and replaced it with an identical twin of the OEM switch requiring just a little lead forming to fit the PCB.

Even better, using the 3D printed pin wrench to screw the original retaining ring into the flashlight’s aluminum threads a few times re-formed (unrelated to recent electrolytic capacitor reforming) its goobered threads well enough to fit and work perfectly again.

So I have:

… reassembled the flashlight with more-or-less original components
… a repair tool kit ready when another LC-40 fails
… re-learned the lesson that any time spent making a fixture or a special tool is not deducted from one’s allotment

And I loves me a happy ending or two!

The OpenSCAD source code as a GitHub Gist:

	// Anker LC-40 flashlight switch retainer
	// Ed Nisley – KE4ZNU
	// 2025-05-05

	include <BOSL2/std.scad>

	Layout = "Show"; // [Show,Build,Retainer,Fixture,Washer,Wrench]

	Gap = 5; // [0:10]

	/* [Hidden] */

	HoleWindage = 0.2;
	Protrusion = 0.1;
	NumSides = 334;

	ID = 0;
	OD = 1;
	LENGTH = 2;

	$fn=334;

	Plate = [16.8,20.0,3.0]; // retainer plate, OD allows for lathe threading
	PlateRecessDepth = 1.6;
	PlateInnerThick = Plate[LENGTH] – PlateRecessDepth;
	ClearID = 11.0;

	PinOD = 3.0;
	PinOC = 12.0;

	WrenchLength = 25.0; // handle on wrench
	JawLength = 22.0; // lathe jaw
	ThreaderOverrun = 10.0; // stick-out for threading tool clearance
	ThreadAllowance = 2*1.0; // clearance for thread depth

	//———-
	// Define Shapes

	module Retainer() {

	difference() {
	tube(Plate[LENGTH],od=Plate[OD],id=ClearID,anchor=BOTTOM);
	up(Plate[LENGTH] + Protrusion)
	cyl(PlateRecessDepth + Protrusion,d=Plate[ID],anchor=TOP);
	down(Protrusion)
	hull()
	for (i = [-1,1])
	right(i*PinOC/2) down(Protrusion)
	cyl(Plate[LENGTH] + Protrusion,d=PinOD,anchor=BOTTOM);
	}

	}

	module Fixture() {

	difference() {
	regular_prism(6,h=JawLength,d=1.2*Plate[OD],anchor=BOTTOM) position(TOP) {
	cyl(PlateRecessDepth + ThreaderOverrun,d=Plate[ID],anchor=BOTTOM);
	cyl(Plate[LENGTH] + ThreaderOverrun,d=ClearID,anchor=BOTTOM);
	// hull()
	for (i = [-1,1])
	right(i*PinOC/2)
	cyl(Plate[LENGTH] + ThreaderOverrun + Plate[LENGTH]/2,d=PinOD,anchor=BOTTOM);
	cyl(ThreaderOverrun,d=Plate[OD] – ThreadAllowance,anchor=BOTTOM);
	}
	up(JawLength + ThreaderOverrun + Plate[LENGTH] + Protrusion) // M4 burly insert
	cyl(10.0 + 5,d=5.5,anchor=TOP);
	}
	}

	module Washer() {

	difference() {
	tube(Plate[LENGTH],od=Plate[OD] – ThreadAllowance,id=4.5,anchor=BOTTOM);
	down(Protrusion)
	for (i = [-1,1])
	right(i*PinOC/2)
	cyl(2*Plate[LENGTH],d=PinOD,anchor=BOTTOM);
	}
	}

	module Wrench() {

	difference() {
	union() {
	cyl(WrenchLength,d=Plate[ID],anchor=BOTTOM);
	for (i = [-1,1])
	right(i*PinOC/2)
	cyl(WrenchLength + Plate[LENGTH],d=PinOD,anchor=BOTTOM);
	}
	down(Protrusion)
	cyl(2*WrenchLength,d=ClearID – 2.0,anchor=BOTTOM);
	}
	}

	//———-
	// Build things

	if (Layout == "Retainer")
	Retainer();

	if (Layout == "Fixture")
	Fixture();

	if (Layout == "Washer")
	Washer();

	if (Layout == "Wrench")
	Wrench();

	if (Layout == "Show") {
	color("Gold")
	Fixture();
	up(JawLength + ThreaderOverrun + Gap)
	zflip(z=Plate[LENGTH]/2)
	Retainer();
	color("Green")
	up(JawLength + ThreaderOverrun + Plate[LENGTH] + 2*Gap)
	Washer();

	right(40) {
	zflip(z=Plate[LENGTH]/2)
	Retainer();
	color("Silver")
	up(Plate[LENGTH] + Gap)
	zflip(z=WrenchLength/2)
	Wrench();
	}
	}

	if (Layout == "Build") {
	Fixture();
	right(1.5*Plate[OD]) {
	Retainer();
	fwd(1.5*Plate[OD])
	Retainer();
	}
	left(1.5*Plate[OD])
	Washer();
	fwd(1.5*Plate[OD])
	Wrench();
	}

view raw Anker LC-40 Flashlight Retainer.scad hosted with ❤ by GitHub

2025-05-12

Metal Spring Clamp: TPU Jaw Pads

Setting up the Makergear M2 to print TPU (eSun 95A) involved a cold pull to get the remaining PETG out of the nozzle, some manual flushing, then printing test cubes to figure out a reasonable speed / temperature combination:

Makergear M2 - first TPU test cube — Makergear M2 – first TPU test cube

A 10 mm solid cube came out overstuffed and the first 20 mm cube lacked enough infill to hold its top up, but the third cube looked surprisingly good at 230 °C and 30 mm/s with 15% 3D Honeycomb infill:

Makergear M2 - TPU test cubes — Makergear M2 – TPU test cubes

With that settled, I conjured pairs of soft (-ish) jaw pads for the far-too-many metal spring clamps having worn out their vinyl pads:

Spring clamp jaws - installed — Spring clamp jaws – installed

Those were the first attempt and worked well enough to suggest nicely rounded endcaps instead of flat cylinders:

Spring Clamp Jaws - show view — Spring Clamp Jaws – show view

Unlike the first version, they now build standing on their rectangular clamp jaw opening:

Spring Clamp Jaws - slicer preview — Spring Clamp Jaws – show view

Those two groups have different lengths (1 inch and 1-⅛ inch) with PrusaSlicer combining the OpenSCAD program’s output.

The as-built pads are essentially un-photographable:

Spring clamp jaws - group build — Spring clamp jaws – group build

TPU is tough enough to make the single-layer brim un-tearable, but they’re easy enough to separate & trim with scissors. Even the 5 mm brim has a tenuous grip on glass + Suave hair “spray” applied from a dropper bottle, so I should try a BuildTak sheet that’s been on the to-do pile for far too many years.

Similarly, TPU is flexy enough to make a precise fit unnecessary: push firmly to force the pads onto the jaws and you’re done.

The OpenSCAD source code as a GitHub Gist:

	// Spring clamp replacement jaw pad
	// Ed Nisley – KE4ZNU
	// 2025-04-26

	include <BOSL2/std.scad>

	Layout = "Show"; // [Show,Build,Clamp]

	Ends = "Round"; // [Flat,Round]

	Sets = 1;

	/* [Hidden] */

	HoleWindage = 0.2;
	Protrusion = 0.1;
	NumSides = 234;

	WallThick = 2.0;

	CushionOD = 10.0;
	CushionStem = 10.0;

	JawAngle = 60/2; // just for Show

	JawWidth = 1.000*INCH; // clamps are hard-inch sizes: 1.0 and 1.125

	Jaw = [1.5,50,JawWidth]; // roughly one jaw

	Gap = 2.0;

	$fn = 234;

	//———-
	// Define objects

	//—–
	// Clamp jaw

	module Clamp() {

	up(WallThick)
	cuboid(Jaw,anchor=BOTTOM+BACK);

	}

	module Pad() {

	difference() {
	union() {
	cyl(d=CushionOD,h=Jaw.z + 2*WallThick,anchor=BOTTOM,
	rounding = (Ends == "Flat") ? 0 : CushionOD/2);
	cuboid([Jaw.x + 2WallThick,CushionStem,Jaw.z + 2WallThick],
	rounding=WallThick/2,anchor=BOTTOM+BACK);
	}
	Clamp();
	}
	}

	//———-
	// Build things

	if (Layout == "Clamp") {
	Clamp();
	}

	if (Layout == "Show") {
	for (i = [-1,1])
	right(i*(CushionOD + Gap)/2)
	zrot(i*JawAngle) {
	Pad();
	color("Silver",0.5)
	Clamp();
	}
	}

	if (Layout == "Build") {
	for (n = [0:(Sets – 1)])
	for (i = [-1,1])
	right(i((CushionOD + Gap)/2 + n(CushionOD + Gap)))
	up(CushionStem) back(Jaw.z/2) xrot(90)
	Pad();
	}

view raw Spring Clamp Jaw Pads.scad hosted with ❤ by GitHub

2025-04-30

Champion Hose Nozzle: TPU Washer

There being nothing like a good new problem to take one’s mInd off one’s old problems, I set the Makergear M2 to printing TPU and made a washer for the Champion Hose Nozzle:

Champion hose nozzle - TPU vs rubber washers — Champion hose nozzle – TPU vs rubber washers

It turns out PrusaSlicer can produce models for simple shapes using the Shape Gallery. Subtracting a 7.5 mm cylinder (as a “negative shape”) from a 12.7 mm = ½ inch cylinder does the trick, with the washer all of 2.5 mm thick.

The ID of the thread inside the nozzle is slightly smaller than 12.7 mm, but TPU is bendy enough to let me push it through sideways and reorient it against the front of the nozzle.

The conical part of the nozzle seals against the washer, leaving only a very slight ooze of water, and opens far enough to produce a jet. The TPU is solid enough to not vibrate in the flow and the nozzle no longer howls at low flow rates.

None of the other nozzles in the box have a washer up in there, so they all depend on a much better machined fit than I achieved.

At least the Champion nozzle is once again usable, should it ever emerge from the bottom of the box.

2025-04-29

Planetary Gear Bearing Fondletoy: M2 vs MK4

It’s been about a decade since I made a batch of planetary gear fondletoys:

Planetary Gear Bearing - black red natural — Planetary Gear Bearing – black red natural

So I loaded up the same STL in Prusaslicer and made three more:

Planetary Gear Bearing - M2 vs MK4 — Planetary Gear Bearing – M2 vs MK4

Both pictures show the same red bearing, done in PLA on the Makergear M2. The other bearings are PETG and PETG-CF on the Prusa MK4 + MMU3.

The blue bearing has about 5 mm of axial play, a bit more than the red.

The gray bearing is PETG-CF and has maybe 1 mm of axial play, which agrees with my original observation that an Extrusion Multiplier of 1.0 results in slightly overstuffed carbon fiber parts. It’s not much and, frankly, produces a better fit in this case, but it’s different than pure PETG. Which should come as no surprise, of course, given that it’s 15% carbon.

The gray-and-orange bearing looks spectacular in person and has about 3 mm of axial play, roughly the same as the red bearing, which you’d expect from overstuffed PETG-CF and pure PETG.

The single-color bearings print in about 1.5 hours and the two-color one weighed in over four hours. Multi-material objects are do-able, but you gotta want the results.

I told Prusaslicer to wipe the orange filament into the gray infill during color changes (per the Wipe Tower doc), but those two gray parts have so little infill as to make no difference:

Planetary Gear Bearing - PETG PETG-CF with wipe tower — Planetary Gear Bearing – PETG PETG-CF with wipe tower

The wipe tower in that posed photo has a nubbly texture because the filament just gets squirted without regard to anything other than maintaining the basic tower shape.

Seeing things appear on the platform never gets old!

2024-09-13

Glass-top Patio Table Leg Brackets: Hardfought

A glass-top patio table came with our house and, similar to one of the patio chairs, required some repair. The arched steel legs fit into plastic brackets / sockets around the steel table rim under the glass top:

Glass patio table - new brackets installed — Glass patio table – new brackets installed

The four glaringly obvious white blocks are the new brackets.

The original brackets had, over uncounted years, deteriorated:

Glass patio table - failed OEM bracket — Glass patio table – failed OEM bracket

Perhaps disintegrated would be a better description:

Glass patio table - crumbled OEM bracket — Glass patio table – crumbled OEM bracket

Each leg has a pair of rusted 1-½ inch ¼-20 screws holding it to the central ring. As expected, seven of the eight screws came out easily enough, with the last one requiring an overnight soak in Kroil penetrating oil plus percussive persuasion:

Glass patio table - jammed screw — Glass patio table – jammed screw

The four legs had three different screws holding them to the brackets, so I drilled out the holes and squished M5 rivnuts in place:

Glass patio table - M5 rivnut installed — Glass patio table – M5 rivnut installed

Although it’s not obvious, the end of that tube is beveled with respect to the centerline to put both the top and bottom edges on the table rim inside the bracket. In addition, the tube angles about 10° downward from horizontal, which I did not realize amid the wrecked fittings, so the first bracket model failed instantly as I inserted the leg:

Glass patio table - first bracket test — Glass patio table – first bracket test

The top & bottom walls of that poor thing were breathtakingly thin (to match the original bracket) and cracked when confronted with the angled tube. I could not measure all the sizes & angles without assembling the table on trial brackets, so getting it right required considerable rapid prototyping:

Glass patio table - failed brackets — Glass patio table – failed brackets

Some trigonometry produced a solid model with features rebuilding themselves around the various sizes / angles / offsets:

Glass Top Table - leg bracket - solid model — Glass Top Table – leg bracket – solid model

A sectioned view shows the angled tube position and end chamfer:

Glass Top Table - leg bracket - section view — Glass Top Table – leg bracket – section view

The OpenSCAD code can produce a sectioned midline slice useful for laser-cut MDF pieces to check the angle:

Glass patio table - chunky bracket installed - bottom — Glass patio table – chunky bracket installed – bottom

That eliminated several bad ideas & misconceptions, although trying to balance the leg on a 3 mm MDF snippet was trickier than I expected. In retrospect, gluing a few snippets together would be easier and still faster than trying to print a similar section from the model.

The slightly elongated slot for the M5 screw shows that the original screw holes were not precisely placed or that the tubes were not precisely cut, neither of which come as a surprise. I finally built some slop into the design to eliminate the need for four different blocks keyed to four different legs.

The outer rim, the notch on the bottom, and the tab on the top curve to match the four foot OD glass tabletop, with the inward side & ends remaining flat:

Glass patio table - chunky bracket installed - top — Glass patio table – chunky bracket installed – top

The sector’s difference from a straight line amounts to half a millimeter and improved the fit enough to justify the geometric exercise. The bracket snaps into position with the notch over the table rim and the tab locked in the gap between the glass disk & the rim, although I suspect the weight of the tabletop would keep everything aligned anyway.

The walls are now at least 4 mm thick and, printed in PETG, came out strong enough to survive assembly and some gentle testing. They’re arranged to print on their side to eliminate support under those slight curves and to align the layers for best strength vertically in the finished bracket:

Glass Top Table - leg bracket - slicer preview — Glass Top Table – leg bracket – slicer preview

The leg cavity and screw hole built well enough without internal support.

They’re relentlessly rectangular and I’m not going to apologize one little bit.

Now to see how they survive out there on the screened porch.

The OpenSCAD source code as a GitHub Gist:

	// Glass patio table leg brackets
	// Ed Nisley – KE4ZNU
	// 2024-08

	/* [Layout] */

	Layout = "Show"; // [Section,Projection,Show,Build]

	Part = "Leg"; // [Leg, RimPlate, Block, Bracket]


	/* [Hidden] */

	ThreadWidth = 0.40;
	ThreadThick = 0.25;

	HoleWindage = 0.2;

	Protrusion = 0.1;

	//—–
	// Dimensions

	/* [Hidden] */

	GlassOD = 1230.0; // inner edge of upper tab
	GlassThick = 5.0;

	WallThick = 4.0;

	TOP = 0;
	BOT = 1;

	TabWidth = [3.0,3.0]; // locking tabs, top & bottom
	TabHeight = [0.5,3.0]; // … height

	LegOA = [16.0,36.5,23.0]; // X insertion, Y around glass, Z upward
	LegAngle = 10;

	ScrewOffset = [8.0,10.0]; // from socket bottom
	ScrewOD = 6.0; // clearance hole

	Plate = [1.0 + 2*max(TabWidth[TOP],TabWidth[BOT]),
	LegOA.y + 2*WallThick,
	25.5
	];
	echo(Plate=Plate);

	BlockOA = [LegOA.xcos(LegAngle) + (LegOA.z/2)sin(LegAngle) + WallThick,
	Plate.y,
	LegOA.z/cos(LegAngle) + 2LegOA.xsin(LegAngle) + 2*WallThick
	];
	echo(BlockOA=BlockOA);

	//—–
	// Useful routines

	function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);

	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);
	}


	//—–
	// Table Leg
	// Including screw slot
	// Additional length to allow use as difference

	module Leg() {

	union() {
	difference() {
	rotate([0,90,0])
	translate([0,0,-LegOA.x])
	linear_extrude(height=4*LegOA.x,convexity=5)
	hull()
	for (j=[-1,1])
	translate([0,j*(LegOA.y – LegOA.z)/2])
	circle(d=LegOA.z);
	rotate([0,-LegAngle,0])
	translate([-2*LegOA.x,0,0])
	cube(4*LegOA,center=true);
	}

	hull()
	for (c = ScrewOffset)
	translate([each c + (LegOA.z/2)*sin(LegAngle),0,-LegOA.z])
	//rotate(180/6)
	PolyCyl(ScrewOD,LegOA.z,6);
	}

	}

	// Rim Plate

	module RimPlate() {

	n = 1643;

	render(convexity=5)
	translate([-Plate.x,0,0])
	difference() {
	intersection() { // shape outer side to match table rim curve
	translate([0,-Plate.y/2,0])
	cube(Plate,center=false);
	translate([GlassOD/2 + TabWidth[TOP],0,0])
	cylinder(d=GlassOD + 2*TabWidth[TOP],h=Plate.z,center=false,$fn=n);
	}

	translate([GlassOD/2 + TabWidth[TOP],0,Plate.z – TabHeight[TOP]])
	cylinder(d=GlassOD,h=Plate.z,center=false,$fn=n);

	translate([GlassOD/2 + TabWidth[BOT],0,-(Plate.z – TabHeight[BOT])])
	difference() {
	cylinder(d=GlassOD,h=Plate.z,center=false,$fn=n);
	cylinder(d=GlassOD – 2*TabWidth[BOT],h=Plate.z,center=false,$fn=n);
	}
	}
	}

	// Block surrounding leg

	module Block() {

	intersection() {
	translate([BlockOA.x/2,0,0])
	cube(BlockOA,center=true);
	translate([0,0,BlockOA.x*sin(LegAngle) – BlockOA.z/2])
	rotate([0,LegAngle,0])
	translate([-2BlockOA.x,-2BlockOA.y,0])
	cube(4*BlockOA,center=false);
	}

	}

	// Complete bracket

	module Bracket() {

	difference() {
	union() {
	RimPlate();
	translate([0,0,Plate.z – BlockOA.z/2 – TabHeight[TOP] – 0*WallThick])
	Block();
	}
	translate([0,0,1Plate.z/2 – 1WallThick])
	rotate([0,LegAngle,0])
	translate([WallThick,0,0])
	Leg();
	}

	}

	//—–
	// Build things

	// Layouts for design & tweaking

	if (Layout == "Section")
	intersection() {
	Bracket();
	translate([0,BlockOA.y/2,0])
	cube([4BlockOA.x,BlockOA.y,3BlockOA.z],center=true);
	}

	if (Layout == "Projection")
	for (j = [1])
	translate([0,j2BlockOA.z])
	projection(cut=true)
	translate([0,0,j*5.0])
	rotate([90,0,0])
	Bracket();


	if (Layout == "Show")

	if (Part == "Leg")
	Leg();

	else if (Part == "RimPlate")
	RimPlate();

	else if (Part == "Bracket")
	Bracket();

	else if (Part == "Block")
	Block();


	// Build layouts for top-level parts

	if (Layout == "Build") {

	translate([0,0,Plate.y/2])
	rotate([90,0,0])
	Bracket();


	}

view raw Glass Top Table – leg brackets.scad hosted with ❤ by GitHub

Some dimension doodles, not all of which correspond to reality:

Glass patio table - dimension doodle A — Glass patio table – dimension doodle A

Glass patio table - dimension doodle B — Glass patio table – dimension doodle B

See? It’s not all slotted animals all the time around here …

2024-08-13

Tour Easy: Anker 20K V2 USB Power Bank

After five years, it’s time to replace the Anker 13000 mA·hr USB power banks / chargers I used with the M20 cameras and then the C100 cameras:

SJCAM M20 Mount - Tour Easy side view — SJCAM M20 Mount – Tour Easy side view

The Anker 325 20K V2 power bank is considerably chunkier, as befits its 20,000 mA·hr cell capacity (although the fine print says 12,500 mA·hr output):

Anker 20K V2 Power Bank - installed — Anker 20K V2 Power Bank – installed

The white tape stripe on the top marks the USB port on the end to reduce the fumbling involved in an out-of-sight socket. There’s also a USB-C port on that end for both charging the pack and powering other devices.

The new mounting cradle descends directly from the 13000 cradle:

Anker 325 20KV2 Power Bank - slicer preview — Anker 325 20KV2 Power Bank – slicer preview

The model includes a projection of the battery on the XY plane for export to an SVG file suitable for laser-cutting an EVA foam pad to cushion the bumps.

The OpenSCAD source code as a GitHub Gist:

2024-08-05

M5 Tee Nut: Test To Destruction

The mounting block under the electronics box for the new UPP battery has a recess for an M5 tee nut:

UPP Battery Mount - Block 5 Show View — UPP Battery Mount – Block 5 Show View

As with the Terry frame mounts, I glued the modified tee nut in place with JB Plastic Bonder urethane adhesive, did a test fit on the bike, discovered the whole affair had to sit about 10 mm forward, put the new frame measurement into the OpenSCAD code, and ran off a new block.

Which gave me the opportunity to perch the old block atop the bench vise with the tee nut aimed downward between the open jaws, run an M5 bolt into the nut, and give it a good thwack with a hammer:

UPP Battery Mount - M5 insert adhesive test — UPP Battery Mount – M5 insert adhesive test

Although the urethane adhesive didn’t bond uniformly across the tee nut, it had enough grip to tear the PETG layers apart and pull chunks out of the block.

As with the tee nuts on the Terry bike, this one will be loaded to pull into the block, so it will never endure any force tending to pull things apart, but it’s nice to know how well JB Plastic Bonder works.

I chiseled the PETG and adhesive debris off the tee nut, cleaned it up, slathered more Bonder on the new block, and squished the nut in place. After I get the electronics box sorted out, the whole affair will never come apart again!

2024-06-20

Tag: M2

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M5 Tee Nut: Test To Destruction