Ed – Page 250 – The Smell of Molten Projects in the Morning

Monthly Science: Weight

Weight Chart 2019-06 - Ed — Weight Chart 2019-06 – Ed

On the other paw, the eyeballometric trend line since mid-April slopes at -1 lb/month and arrives at just over 150 lb in December, so progress continues apace.

2019-07-01

American Standard Kitchen Faucet: Valve Shaft Mystery

The latest in a continuing series of annoyances from our American Standard kitchen faucet: it became increasingly hard to turn it on with the handle all the way to the left in the “hot” position. Bear in mind this valve is less than a year old and I replaced its predecessor two years before that, after maybe a decade of service from the OEM valve.

Pulling it apart revealed the problem, which requires a close inspection.

The view from the “cold” side:

American Standard faucet cartridge - cold side — American Standard faucet cartridge – cold side

And from the “hot” side:

American Standard faucet cartridge - hot side — American Standard faucet cartridge – hot side

See it?

The valve handle stem pivots on the 4 mm shaft passing through the black “engineering plastic” shape inside the red hot-limit ring. This top view shows the overall layout:

American Standard faucet - hot limit ring — American Standard faucet – hot limit ring

The shaft has worked its way leftward, toward the “hot” side, until it bumped into the limit ring. The right end of the shaft hasn’t come completely out of the inside of its pivot, but it’s apparently gone far enough to stop pivoting freely.

This may also explain how the previous hot-limit ring worked loose: the misplaced shaft applies torque to the limit ring as we move the lever to the “cold” side. I don’t know how the ring worked its way upward from its positioning notches. Overall, it seem plausible.

Installing a new valve isn’t going to get us a better design, so I must figure out how to keep the shaft in the middle of its travel. Perhaps replacing it with a slightly longer shaft will work around the problem, because it simply can’t slide in either direction.

Loosening the three screws holding the cartridge down (and applying pressure against the seals) reduces the force required to move the faucet, even with the shaft in the wrong position. This suggests the valve body distorts slightly, so I loosened all three and (roughly) equalized their torque; the valve isn’t leaking and we’ll see what happens next.

2019-06-30

Walkway Over The Hudson: Privileged Parking

Walkway West - Privileged Parking — Walkway West – Privileged Parking

Although different rules apply to the Park staff, so they can drive back & forth across a crowded Walkway with impunity, it’d be courteous if they didn’t block the bike rack with their vehicles. After we parked our bikes in the rack, the woman riding the third bike couldn’t get out and two other riders simply leaned their bikes against the Welcome Center.
Privilege is one thing, flaunting it seems entirely unnecessary.
I’ve yet to understand why the staff must drive over the Walkway at any time, not just park on the pedestrian plaza, as there’s a perfectly serviceable bridge designed specifically for motor vehicles barely half a mile to the south. Heck, on a clear day, you can even see it from the Walkway. [grin]
Our bikes get us from one end to the other in under ten minutes, about as fast as the Park staff can drive, so using a car doesn’t provide any speed advantage. I can carry a week’s worth of groceries in my bike trailer and rarely see the staff carrying anything bigger in the car, so a “we must haul stuff” excuse seems self-serving.
Every “unintended acceleration” mass-casualty incident involves a vehicle, a bunch of pedestrians, and a driver who never thought it could happen. Proactively eliminating vehicle traffic from the Walkway seems much easier than explaining why you didn’t.
Parking vehicles in appropriate places doesn’t require any explanation.
Thanks …
Email to Walkway Over the Hudson

I should have sent it to the sprawling NYS Office of Parks, Recreation, and Historic Preservation, but I hoped the Walkway staff could forward it to the right person. Haven’t heard anything back; I should have saved the electrons.

2019-06-29

MPCNC Diamond Engraver: LM3UU Bearings, Second Pass

Having a single spring and a fixed upper plate works much better than the first version:

Diamond Scribe - LM3UU Rev 2 - overview — Diamond Scribe – LM3UU Rev 2 – overview

The (lubricated!) nyloc nuts under the plate provide a little friction and stabilize the whole affair.

The solid model has the same stylin’ tapered snout as the LM12UU drag knife mount:

Diamond Scribe - LM3UU bearings — Diamond Scribe – LM3UU bearings

The spring seats in the plate recess, with the 3 mm shank passing through the hole as the tool holder presses the tip against the workpiece.

I diamond-filed a broken carbide end mill to make a slotting tool:

Diamond Scribe - LM3UU - Rev 2 - carbide notch tool — Diamond Scribe – LM3UU – Rev 2 – carbide notch tool

Lacking any better method (“a tiny clip spreader tool”), I rammed the Jesus clip the length of the shank with a (loose-fitting) chuck in the tailstock:

Diamond Scribe - LM3UU - Rev 2 - clip installation — Diamond Scribe – LM3UU – Rev 2 – clip installation

Even without nyloc nuts, the first test worked fine:

Diamond Scribe - LM3UU - Rev 2 - first light — Diamond Scribe – LM3UU – Rev 2 – first light

The 53 g/mm spring rate may be too low for serious engraving, but it suffices for subtle Guilloché patterns on scrap platters.

The OpenSCAD source code as a GitHub Gist:

	// Drag Knife Holder using LM12UU linear bearing
	// Ed Nisley KE4ZNU – 2019-04-26
	// 2019-05-09 LM3UU for diamond scribe
	// 2019-05-28 taper end, single spring around shaft

	Layout = "Build"; // [Build, Show, Puck, Mount, Plate]

	/* [Extrusion] */

	ThreadThick = 0.25; // [0.20, 0.25]
	ThreadWidth = 0.40; // [0.40, 0.40]

	/* [Hidden] */

	Protrusion = 0.1; // [0.01, 0.1]

	HoleWindage = 0.2;

	inch = 25.4;

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

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

	//- Adjust hole diameter to make the size come out right

	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);
	}

	//- Dimensions

	// Knife holder & suchlike

	KnifeBody = [3.0,9.0,2.0]; // washer epoxied to diamond shaft, with epoxy fillet

	Spring = [9.5,10.0,3*ThreadThick]; // compression spring around shaft, LENGTH = socket depth

	WallThick = 4.0; // minimum thickness / width

	Screw = [4.0,8.5,8.0]; // holding it all together, OD = washer

	Insert = [4.0,6.0,10.0]; // brass insert

	Bearing = [3.0,7.0,2*10.0 + WallThick]; // linear bearing body (pair + small gap)

	// Basic shape of DW660 snout fitting into the holder
	// Lip goes upward to lock into MPCNC mount

	Snout = [44.6,50.0,9.6]; // LENGTH = ID height
	Lip = 4.0; // height of lip at end of snout

	Plate = [KnifeBody[ID],Snout[OD] – WallThick,WallThick]; // spring reaction plate

	PuckOAL = max(Bearing[LENGTH],(Snout[LENGTH] + Lip)); // total height of DW660 fitting
	echo(str("PuckOAL: ",PuckOAL));
	Key = [Snout[ID],25.7,(Snout[LENGTH] + Lip)]; // rectangular key

	NumScrews = 3;

	ScrewBCD = 2.5*(Bearing[OD]/2 + Insert[OD]/2 + WallThick);

	NumSides = 9*4; // cylinder facets (multiple of 3 for lathe trimming)

	module DW660Puck() {

	translate([0,0,PuckOAL])
	rotate([180,0,0]) {
	cylinder(d=Snout[OD],h=Lip/2,$fn=NumSides);
	translate([0,0,Lip/2])
	cylinder(d1=Snout[OD],d2=Snout[ID],h=Lip/2,$fn=NumSides);
	cylinder(d=Snout[ID],h=(Snout[LENGTH] + Lip),$fn=NumSides);
	translate([0,0,(Snout[LENGTH] + Lip) – Protrusion])
	cylinder(d1=Snout[ID],d2=2*WallThick + Bearing[OD],h=PuckOAL – (Snout[LENGTH] + Lip),$fn=NumSides);
	intersection() {
	translate([0,0,0*Lip + Key.z/2])
	cube(Key,center=true);
	cylinder(d=Snout[OD],h=Lip + Key.z,$fn=NumSides);
	}
	}
	}

	module MountBase() {

	difference() {
	DW660Puck();

	translate([0,0,-Protrusion]) // bearing
	PolyCyl(Bearing[OD],2*PuckOAL,NumSides);

	for (i=[0:NumScrews – 1]) // clamp screws
	rotate(i*360/NumScrews)
	translate([ScrewBCD/2,0,-Protrusion])
	rotate(180/8)
	PolyCyl(Insert[OD],2*PuckOAL,8);
	}
	}

	module SpringPlate() {
	difference() {
	cylinder(d=Plate[OD],h=Plate[LENGTH],$fn=NumSides);

	translate([0,0,-Protrusion]) // ample shaft clearance
	PolyCyl(1.5KnifeBody[ID],2PuckOAL,NumSides);

	// translate([0,0,Plate[LENGTH] – KnifeBody[LENGTH]]) // flange, snug fit
	// PolyCyl(KnifeBody[OD],KnifeBody[LENGTH] + Protrusion,NumSides);

	translate([0,0,Plate[LENGTH] – Spring[LENGTH]]) // spring retainer
	PolyCyl(Spring[OD],Spring[LENGTH] + Protrusion,NumSides);

	for (i=[0:NumScrews – 1]) // clamp screws
	rotate(i*360/NumScrews)
	translate([ScrewBCD/2,0,-Protrusion])
	rotate(180/8)
	PolyCyl(Screw[ID],2*PuckOAL,8);
	}
	}

	//—–
	// Build it

	if (Layout == "Puck")
	DW660Puck();

	if (Layout == "Plate")
	SpringPlate();

	if (Layout == "Mount")
	MountBase();

	if (Layout == "Show") {
	MountBase();
	translate([0,0,1.5*PuckOAL])
	rotate([180,0,0])
	SpringPlate();
	}

	if (Layout == "Build") {
	translate([0,Snout[OD]/2,PuckOAL])
	rotate([180,0,0])
	MountBase();
	translate([0,-Snout[OD]/2,0])
	SpringPlate();
	}

view raw Diamond Scribe – LM3UU bearings.scad hosted with ❤ by GitHub

2019-06-28

Garden Soaker Hose Connector Repair

Two of Mary’s garden soaker hoses failed their pre-installation checks with leaks from around their connectors. The problem seemed to be a break in the hose inside the connector, with water spewing out of the connector around the hose. Having previously fixed a gash in another hose, I figured I might have some success at fixing these leaks.

The general idea is to squish enough silicone rubber inside the connector to seal around the hose, then clamp the hose and connector snugly enough to hold the rubber in place:

Soaker Hose Connector Clamp - Show view — Soaker Hose Connector Clamp – Show view

The enlarged recess fits around the brass connector shell, which is squashed loosely around the hose and from which the leaking water emerges. Of course, because this is a different hose, the previous model didn’t quite fit and I had to doodle up new geometry:

Soaker Hose Connector repair - Dimension doodle — Soaker Hose Connector repair – Dimension doodle

As before, I bandsawed aluminum backing plates to ensure the plastic didn’t get all bendy in the middle:

The hose clamp (!) around the connector on the far right ensures a split in the brass shell doesn’t get any larger.

They’ll spend the rest of their lives under the garden mulch, where nobody will ever see those bulky lumps. Life is good!

The OpenSCAD source code as a GitHub Gist:

	// Rubber Soaker Hose End Connector Clamp
	// Helps hold silicone rubber in connector
	// Ed Nisley KE4ZNU June 2019

	Layout = "Build"; // [Hose,Connector,Block,Show,Build]

	//- Extrusion parameters must match reality!

	/* [Hidden] */

	ThreadThick = 0.25;
	ThreadWidth = 0.40;

	HoleWindage = 0.2;

	Protrusion = 0.1; // make holes end cleanly

	inch = 25.4;

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

	//———-
	// Dimensions
	// Hose lies along X axis

	Hose = [200,26.5,11.6]; // X=very long, Y=width, Z=overall height

	RimThick = 10.3; // outer sections
	RimOD = RimThick;
	RimFlatRecess = 1.0; // recess to front flat surface

	OuterOC = Hose.y – RimOD; // outer tube centers

	RecessM = 0.8; // back recess chord
	RecessC = OuterOC;
	RecessR = (pow(RecessM,2) + pow(RecessC,2)/4) / (2*RecessM);

	RidgeM = 1.6; // front ridge chord
	RidgeC = 7.5;
	RidgeR = (pow(RidgeM,2) + pow(RidgeC,2)/4) / (2*RidgeM);

	HoseSides = 12*4;

	Connector = [5.0,33.0,13.0]; // oval brass: X=snout Y=width Z=dia

	Block = [20.0,50.0,4.0 + Hose.z]; // overall splice block size
	echo(str("Block: ",Block));

	Kerf = 0.5; // cut through middle to apply compression

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

	// 8-32 stainless screws
	Screw = [4.1,8.0,3.0]; // OD = head LENGTH = head thickness
	Washer = [4.4,9.5,1.0];
	Nut = [4.1,9.7,6.0];

	CornerRadius = Washer[OD]/2;

	ScrewOC = Block.y – 2*CornerRadius;

	echo(str("Screw OC: x=",ScrewOC.x," y=",ScrewOC.y));

	//———————-
	// 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(d=(FixDia + HoleWindage),h=Height,$fn=Sides);
	}

	// Hose shape
	// This includes magic numbers measured from reality

	module HoseProfile() {

	rotate([0,-90,0])
	translate([0,0,-Hose.x/2])
	linear_extrude(height=Hose.x,convexity=4)
	difference() {
	union() {
	for (j=[-1,1]) // outer channels
	translate([0,j*OuterOC/2])
	circle(d=RimOD,$fn=HoseSides);
	translate([-RimOD/4,0]) // rear flat fill
	square([RimOD/2,OuterOC],center=true);
	translate([(RimOD/4 – RimFlatRecess),0]) // front flat fill
	square([RimOD/2,OuterOC],center=true);
	intersection() {
	translate([Hose.z/2,0])
	square([Hose.z,OuterOC],center=true);
	translate([-RidgeR + RimOD/2 – RimFlatRecess + RidgeM,0])
	circle(r=RidgeR,$fn=HoseSides);
	}
	}
	translate([-(RecessR + RimOD/2 – RecessM),0])
	circle(r=RecessR,$fn=2*HoseSides);
	}
	}

	// Outside shape of splice Block
	// Z centered on hose rim circles, not overall thickness through center ridge

	module SpliceBlock() {
	difference() {
	hull()
	for (i=[-1,1], j=[-1,1]) // rounded block
	translate([i(Block.x/2 – CornerRadius),j(Block.y/2 – CornerRadius),-Block.z/2])
	cylinder(r=CornerRadius,h=Block.z,$fn=4*8);
	for (j=[-1,1]) // screw holes
	translate([0,
	j*ScrewOC/2,
	-(Block.z/2 + Protrusion)])
	PolyCyl(Screw[ID],Block.z + 2*Protrusion,6);
	cube([2Block.x,2Block.y,Kerf],center=true); // slice through center
	}
	}

	// Splice block less hose

	module ShapedBlock() {
	difference() {
	SpliceBlock();
	HoseProfile();
	Connector();
	}
	}

	// Brass connector end

	module Connector() {
	translate([-(Block.x/2 + Protrusion),0,0])
	rotate([0,90,0])
	linear_extrude(height=Connector.x + Protrusion)
	hull()
	for (i = [-1,1])
	translate([0,i*(Connector.y – Connector.z)/2])
	circle(d=Connector.z);
	}


	//———-
	// Build them

	if (Layout == "Hose")
	HoseProfile();

	if (Layout == "Block")
	SpliceBlock();

	if (Layout == "Connector")
	Connector();

	if (Layout == "Show") {
	ShapedBlock();
	color("Green",0.25)
	HoseProfile();
	}

	if (Layout == "Build") {
	SliceOffset = 0;
	intersection() {
	translate([SliceOffset,0,Block.z/4])
	cube([4Block.x,4Block.y,Block.z/2],center=true);
	union() {
	translate([0,0.6*Block.y,Block.z/2])
	ShapedBlock();
	translate([0,-0.6*Block.y,Block.z/2])
	rotate([0,180,0])
	ShapedBlock();
	}
	}
	}

view raw Soaker Hose Connector Clamp.scad hosted with ❤ by GitHub

2019-06-27

Ooma Telo 2: Speaker FAIL

The tiny voice inside our Ooma Telo 2 box died, although the VOIP phone service continued to work fine. A bit of searching showed the speaker seems to be the weak link.

Well, I can fix that.

Start by prying the recessed top panel off the case:

Ooma Telo 2 - upper case latches — Ooma Telo 2 – upper case latches

Remove the circuit board to expose the tiny speaker, taking care not to rip the tiny wires out of the tiny connector:

Ooma Telo 2 - OEM speaker to PCB — Ooma Telo 2 – OEM speaker to PCB

You can’t measure a dead speaker, but it seems to be an 8 Ω unit.

The speaker sits in a rubber surround, with a foam rubber cushion against the PCB, tucked into a walled garden stiffening the case:

Ooma Telo 2 - speaker port — Ooma Telo 2 – speaker port

I don’t happen to have a tiny 8 Ω speaker, but I do have a bunch of small speakers (Update: 28 mm OD), so I bulldozed those walls with a flush cutting pliers and a bit of cussing to make room:

Ooma Telo 2 - modified speaker port — Ooma Telo 2 – modified speaker port

Nibble an adapter ring to match the rim of the new speaker, thereby routing the sound out those little holes, and hot-melt glue it in place:

Ooma Telo 2 - speaker adapter — Ooma Telo 2 – speaker adapter

Hot-melt glue the new speaker in place atop the adapter, taking care to fill all the edges / cracks / crevices below it with an impenetrable wall of glop:

Ooma Telo 2 - replacement speaker installed — Ooma Telo 2 – replacement speaker installed

The sealing part turns out to be critical with these little speakers, because a leak from front to back will pretty much cancel all the sound from the cone.

Cut the wires off the old speaker, affix to the new one, replace the PCB, snap the case lid in place, and it sounds better than new.

Millions of transistors in those ICs, but Ooma can’t spec a good speaker? Maybe they should have used a bigger speaker to begin with; ya never know.

2019-06-26

Dell U2711 Monitor: FAIL

My landscape monitor, a six-year-old Dell U2711, died after a few days of flickering and failure-to-start. As you’d expect with any old electronics, particularly from Dell, it’s the electrolytic caps:

All of the black-cased caps on the board had bulged cases:

Dell U2711 Monitor - failed FOAI cap - detail — Dell U2711 Monitor – failed FOAI cap – detail

They’re (allegedly) made by FOAI, for whatever that’s worth.

They’re not really capacitors any more:

Dell U2711 Monitor - 100 uF 5 ohm cap — Dell U2711 Monitor – 100 uF 5 ohm cap

I replaced all of them with cheap eBay caps to no avail. Spot-checking the other (“brown”) caps on the logic board showed they were still good, but the power supply board is firmly glued in place and I can’t get to the HV cap.

A new monitor arrived two days later and it’s all good again.

2019-06-25