Improvements – Page 58 – The Smell of Molten Projects in the Morning

ShopVac Nozzle Caddy

Shortly after acquiring the Greatest ShopVac, I zip-tied half a foot of cardboard tube to the handle to corral the nozzle and keep the ungainly hose from sprawling across the floor. While disembowling the Ottlite into a mini-lathe light, the plastic trim joining the baseplate to the vertical tube cried out to become a nozzle caddy:

It was exactly the right size and shape (by my admittedly slack standards) to hold the nozzle, plus being destined for the trash, so all it needed was a pair of clamp brackets conjured from the vasty digital deep:

ShopVac Nozzle Caddy - solid model — ShopVac Nozzle Caddy – solid model

The bosses fit into a tapered slot along what was the rear side, with a pair of 4 mm holes at each end for screws into threaded brass inserts epoxied into the brackets:

ShopVac Nozzle Caddy - clamps mounted — ShopVac Nozzle Caddy – clamps mounted

They obviously descend from the many clamp mounts I’ve made for everything from garden hoses to bike running lights. A pair of 4 mm SHCS squish the clamp around the handle, with a strip of electrical tape improving plastic-to-metal griptivity:

ShopVac Nozzle Caddy - side view — ShopVac Nozzle Caddy – side view

The clearance just barely allows a nylock nut atop a washer and you’ll want to trim those 40 mm screws to an exact fit, but it came out pretty well.

The original dimension doodle with some modeling ideas that didn’t survive more thinking:

ShopVac Nozzle Caddy - Dimension Doodle 1 — ShopVac Nozzle Caddy – Dimension Doodle 1

A more detailed doodle with brass inserts instead of the nylock nuts and an aluminum spreader plate that was obviously not necessary:

ShopVac Nozzle Caddy - Dimension Doodle 2 — ShopVac Nozzle Caddy – Dimension Doodle 2

In retrospect, the inserts would make more sense.

The angle doodles convinced me not to bother modeling either the slot’s taper along its length or its mold draft.

Kinda looks like it grew there and makes one wonder why they don’t include a caddy as a standard option.

The OpenSCAD source code as a GitHub Gist:

	// ShopVac Nozzle Caddy
	// Ed Nisley KE4ZNU 2022-02

	Layout = "Show"; // [Handle,Block,Show,Build]

	HandleOD = 20.0;

	//- 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);

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

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

	Handle = [200,HandleOD,HandleOD]; // X = longer than anything else

	WallThick = 5.0; // Thinnest printed wall

	Screw = [4.0,7.0,25.0]; // M4 socket head cap screw
	Washer = [4.5,9.0,0.8]; // M4 washer
	Insert = [4.0,5.9,10.0]; // M4 brass insert

	Block = [15.0,Handle.y + 4WallThick + 2Screw[ID],HandleOD + 2*WallThick]; // overall clamp block
	echo(str("Block: ",Block));

	Bosses = [[Block.x,9.5,13.0],[Block.x,15.0,9.0]];

	ScrewOC = Handle.y + 2*WallThick + Screw[ID];

	Kerf = 1.0; // cut through middle to apply compression

	Gap = 1.25;

	CornerRadius = Washer[OD]/2;

	//———————-
	// 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);
	}

	// Shopvac handle

	module Handle() {

	rotate([0,90,0])
	translate([0,0,-Handle.x/2])
	rotate(180/(4*8))
	PolyCyl(Handle.y,Handle.x,4*8);
	}



	// Clamp block

	module ClampBlock(BossID=0) {

	difference() {
	union() {
	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=8);
	translate([0,0,-(Block.z/2 + Bosses[BossID].z/2 – Protrusion)])
	cube(Bosses[BossID],center=true);
	}

	for (j = [-1,1]) // screw holes
	translate([0,j*ScrewOC/2,-(Block.z/2 + Protrusion)])
	rotate(180/6)
	PolyCyl(Screw[ID],Block.z + 2*Protrusion,6);

	cube([2Block.x,2Block.y,Kerf],center=true);

	Handle();

	translate([0,0,-Block.z])
	rotate(180/6)
	PolyCyl(Screw[ID],Block.z,6);

	translate([0,0,-(Handle.z/2 + Insert[LENGTH])])
	rotate(180/6)
	PolyCyl(Insert[OD],Handle.y,6);
	}
	}

	// Splice block less handle bore

	module ShapedBlock() {
	difference() {
	ClampBlock();
	Handle();
	}
	}




	//———-
	// Build them

	if (Layout == "Handle")
	Handle();

	if (Layout == "Block")
	ClampBlock(BossID=0);

	if (Layout == "Show") {
	color("Green",0.25)
	Handle();
	xofs = -((len(Bosses) – 1)/2 * Gap*Block.x);
	for (i=[0:len(Bosses) – 1])
	translate([xofs + iGapBlock.x,0,0])
	ClampBlock(i);
	}

	if (Layout == "Build") {
	yofs = -((len(Bosses) – 1)/2 * Gap*Block.y);
	for (j=[0:len(Bosses) – 1])
	translate([0,yofs + jGapBlock.y,0])
	translate([0,0,Block.x/2])
	rotate([0,90,0])
	ClampBlock(j);
	}

view raw ShopVac Nozzle Caddy.scad hosted with ❤ by GitHub

2022-02-25

Fluorescent Shop Light Ballast Caps

It never ceases to amaze me that these capacitors appear in the AC power line circuits inside old-school fluorescent shop lights:

It really is a capacitor:

Shop light ballast cap A - test — Shop light ballast cap A – test

Its sibling from the other end of the fixture had more ESR:

Shop light ballast cap B - test — Shop light ballast cap B – test

Both were likely within spec, whatever that means.

I have no idea what’s lurking inside the tidy LED tubes now living in that same fixture, of course.

2022-02-24

Underwriter’s Knot

Found inside a fluorescent desk lamp being salvaged for possible use as an LED task lamp:

It’s one of the few Underwriter’s Knots I’ve ever seen in the wild. Many recent (i.e., built in the last half-century) lamps pass the cords through a plastic clamp or depend on simple bushings, with some just ignoring the problem.

This anonymous lamp sports the usual Made in China sticker, but also features a genuine-looking UL sticker complete with elaborate holograms, so it may well have been sold by a reputable company. IIRC, it came from a trash can in a Vassar College hallway, back when in-person meetings were a thing; perhaps Vassar required known-good electrical hardware.

2022-02-11

CNC-3018XL: Improved X-Axis Home Switch Mount

A few months of inactivity left the CNC-3018XL table parked in its homed position where the gentle-but-inexorable pressure of the switch lever displaced the foam holding the plastic actuator tab on the X-axis bearing enough that it would no longer operate reliably:

3018 CNC - Y axis endstop — 3018 CNC – Y axis endstop

Putting foam tape in a highly leveraged position produces the same poor results as in finance.

The fix requires reorienting the switch so a solid block on the bearing can push directly on the actuator lever:

CNC-3018 X Home Switch - bottom view — CNC-3018 X Home Switch – bottom view

The block must curve around the bearing to give the tape enough surface area for a good grip:

CNC-3018 X Home Switch - oblique view — CNC-3018 X Home Switch – oblique view

The solid model for the new X-axis mount looks about like you’d expect:

CNC-3018 X Home Switch Mount - solid model — CNC-3018 X Home Switch Mount – solid model

I increased the home switch pulloff to 2 mm, although it’s not clear that will make any difference in the current orientation.

The OpenSCAD source code as a GitHub Gist:

	// 3018-Pro Mount for Makerbot Endstop PCB
	// Ed Nisley KE4ZNU – 2019-07 (using OEM machine axes)
	// 2022-02-02 rotate X block (after renaming axes to match new layout)

	/* [Build Options] */

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

	/* [Hidden] */

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

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

	Protrusion = 0.01; // [0.01, 0.1]

	HoleWindage = 0.2;

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

	//- Shapes

	// Basic PCB with hole for switch pins
	// origin at switch actuator corner, as seen looking at component side

	SwitchClear = [15.0,5.0,2.0]; // clearance around switch pins
	SwitchOffset = [12.5,9.0,0.0]; // center of switch pins from actuator corner

	PCB = [26.0,16.4,2*SwitchClear.z]; // switch PCB beyond connector, pin height

	//XBlock = [PCB.x + 10.0,PCB.y,20.0];
	XBlock = [PCB.x,PCB.y,10.0];
	XBearing = [10.0,26.5,28.5];
	XPin = [10.0,20.0,10.0];

	module XMount() {

	if (false) // side-push switch tended to slip
	difference() {
	translate([-10.0,0,0])
	cube(XBlock,center=false);
	translate([0,-Protrusion,10.0])
	cube(XBlock + [0,2*Protrusion,0],center=false);
	translate(SwitchOffset + [0,0,10.0 – SwitchClear.z/2])
	cube(SwitchClear + [0,0,Protrusion],center=true);
	}
	else {
	difference() {
	cube(XBlock,center=false);
	translate(SwitchOffset + [0,0,XBlock.z – SwitchClear.z/2])
	cube(SwitchClear + [0,0,Protrusion],center=true);
	}

	translate([1.25*XBlock.x,0,0])
	difference() {
	cube(XPin + [0,0,XBearing[OD]/4],center=false);
	translate([-Protrusion,XPin.y/2,XPin.z + XBearing[OD]/2])
	rotate([0,90,0])
	cylinder(d=XBearing[OD],h=XPin.x + 2*Protrusion,center=false);
	translate([-Protrusion,-XPin.y/2,XPin.z])
	cube(XPin + [2*Protrusion,0,0],center=false);
	}
	}
	}

	YBlock = [PCB.x,PCB.y,5.0];

	module YMount() {

	difference() {
	cube(YBlock,center=false);
	translate(SwitchOffset + [0,0,YBlock.z – SwitchClear.z/2])
	cube(SwitchClear + [0,0,Protrusion],center=true);
	}

	}

	ZBlock = [PCB.x,PCB.y,6.0];
	ZPin = [20.0,10.0,5.5];


	module ZMount() {

	difference() {
	cube(ZBlock,center=false);
	translate(SwitchOffset + [0,0,ZBlock.z – SwitchClear.z/2])
	cube(SwitchClear + [0,0,Protrusion],center=true);
	}

	translate([1.25*ZBlock.x,0,0])
	difference() {
	cube(ZPin,center=false);
	translate([ZPin.x/2,-Protrusion,4.0])
	cube(ZPin + [0,2*Protrusion,0],center=false);
	}
	}

	//- Build things

	if (Layout == "Show") {
	translate([0,XBlock.y,0])
	YMount();
	translate([0,-XBlock.y/2])
	XMount();
	translate([0,-(ZBlock.y + XBlock.y)])
	ZMount();
	}

view raw Home Switch Mounts.scad hosted with ❤ by GitHub

2022-02-10

Inkjet Refilling: End of an Era

Just before the turn of the millennium, I bought what turned out to be a never-sufficiently-to-be-damned HP 2000C inkjet printer that served as my introduction to refilling inkjet cartridges. A few years later, a Canon S630 printer joined the stable and worked fine for perhaps five years before succumbing to a printhead death. An Epson R380 that might have cost fifteen bucks after rebate took over, drank maybe a gallon of knockoff ink through a continuous ink supply system during the next thirteen years, and finally suffered progressive printhead failure during the last year.

Something recently changed in the inkjet market: Epson (among others) now touts their “Ecotank” printers featuring large internal reservoirs refilled by 70 ml bottles of color ink priced at perhaps 20¢/ml, obtained direct from Epson via Amazon. They proudly note you can save 90% off the cost of cartridges (“Kiss Expensive Cartridges Goodbye”), without mentioning how their previous extortionate cartridge business made that possible. Of course, Ecotank printers cost far more than cartridge-based printers, but that seems reasonable to me.

Because the ink bottles fit neatly into the printer through a push-to-flow valve interlock, I can finally retire this relic:

That’s maybe fifteen years of accumulated splotches.

I hope my refusal to buy their cartridges helped immanentize their eschaton, just a little.

Good riddance.

2022-02-09

Raspberry Pi: WLAN to Wired Network

The CNC-3018XL and MPCNC machines each have a Raspberry Pi feeding G-Code into an Arduino clone controlling the stepper motors. The former grew a USB WiFi interface in place of its internal WiFi hardware when it seemed to have difficulty connecting to the house router, while the latter pretty much worked. Of late, however, I’ve been trying to reduce the number of WiFi devices cluttering the airwaves, with the result of wiring both machines to an old Ethernet switch from the Box o’ Network Stuff:

The blue puck is the KVM button to select one of the machines for the keyboard / mouse / monitor on the bench.

One key point I generally screw up: the WiFi IP address cannot become the wired IP address without rebooting everything else on the network. Instead, just change the IP addresses and be done with it.

Collecting all the pieces in one place:

Disable the both internal WiFi hardware and Bluetooth in /boot/config.txt, thereby eliminating the need to force the WiFi down in /etc/rc.local:

dtoverlay=pi3-disable-wifi
dtoverlay=pi3-disable-bt

Define the static IP address in /etc/dhcpcd.conf:

interface eth0
static ip_address=192.168.1.34/24
static routers=192.168.1.1
static domain_name_servers=192.168.1.2

Kill IPV6 activity in /etc/sysctl.conf:

net.ipv6.conf.all.disable_ipv6=1

I very much doubt this information is either complete or correct, but it serves the purpose as of early 2022.

2022-02-08

Floor Lamp Shortening

A new floor lamp similar to the one I adjusted to suit my chair appeared next to Mary’s chair. It was, as I expected, much too tall, but shortening it required just removing one of the vertical tube sections (exactly one foot long!), as Mary was content with the flexy arm’s reach. Perhaps as a nod to the current chip shortage, this version of the lamp has a control consisting of a mechanical knob in a lump just under the flexy arm: push to turn on, rotate for intensity, tap for color, push-and-hold for off. This is much more usable than the finicky proximity pads on my lamp (and the slightly more expensive version of this one), which is why I picked it.

Because the coaxial power connector doesn’t fit through the bushing in the base of the vertical tubes and didn’t have a connector at the control lump, I had to dismantle the lump to disconnect the power cable to remove the pipe section, an operation deep in warranty violation territory.

So, we begin.

Loosen the screw clamping the power cord to the tube just below the control lump:

LED Floor Lamp - DC wire clamp — LED Floor Lamp – DC wire clamp

Remove the two screws holding the control lump together:

LED Floor Lamp - control case — LED Floor Lamp – control case

Pull the front of the lump off the tube and peel off a protective foam sheet to expose the circuitry:

LED Floor Lamp - PCB silkscreen — LED Floor Lamp – PCB silkscreen

Power comes from a 12 VDC 400 mA wall wart, so note the wire markings:

LED Floor Lamp - DC wire marking — LED Floor Lamp – DC wire marking

In this case, the marked wire (with the dashed lines) is the positive conductor:

LED Floor Lamp - DC polarity PCB marking — LED Floor Lamp – DC polarity PCB marking

Unsolder the cable and pull it out of the entire collection of tubing. The topmost section has two inner threads, so remove one of the other sections (with inner and outer threads) and reassemble the rest. Poke the cable through the tubes, solder to PCB, tighten clamp screw, reassemble lump in reverse order, then declare victory:

LED Floor Lamp - shortened — LED Floor Lamp – shortened

The business end now hovers 39 inches (a neat 1 m) over the floor, just below her eye level, where it belongs.

2022-02-07