Tag: CNC

Making parts with mathematics

Check Your Zero

A recent OpenSCAD mailing list discussion started with an observation that the dimensions of printed parts were wildly different from the numeric values used in the OpenSCAD program that created the STL. Various folks suggested possible errors, examined the source and STL files to no avail, and were generally baffled.

Finally, a photo conclusively demonstrating the problem arrived:

Caliper – digital vs. analog scale

Note the difference between the digital readout and the analog scale printed on the body.

Turns out it’s his first digital caliper: he simply didn’t realize you must close the jaws and press the ZERO button before making any measurements.

We’ve all been that guy. Right?

FWIW, our Larval Engineer can probably still hear me intoning “Check your zero” every time she picks up a caliper or turns on a multimeter. Perhaps she’ll think fondly of me, some day. [grin]

2017-03-18

Kenmore Progressive Vacuum Tool Adapters: Second Failure

Pretty much as expected, the dust brush nozzle failed again, adjacent to the epoxy repair:

Dust brush adapter - second break — Dust brush adapter – second break

A bit of rummaging turned up some ¾ inch Schedule 40 PVC pipe which, despite the fact that no plumbing measurement corresponds to any physical attribute, had about the right OD to fit inside the adapter’s ID:

Dust brush - PVC reinforcement — Dust brush – PVC reinforcement

The enlarged bore leaves just barely enough space for a few threads around the circumference. Fortunately, the pipe OD is a controlled dimension, because it must fit inside all the molded PVC elbows / tees / caps / whatever.

The pipe ID isn’t a controlled dimension and, given that the walls seemed far too thick for this purpose, I deployed the boring bar:

Dust brush adapter - reinforced tube - boring — Dust brush adapter – reinforced tube – boring

That’s probably too much sticking out of the chuck, but sissy cuts saved the day. The carriage stop keeps the boring bar 1 mm away from the whirling chuck.

Bandsaw it to length and face the ends:

Dust brush adapter - reinforcement — Dust brush adapter – reinforcement

The PVC tube extends from about halfway along the steep taper from the handle fitting out to the end, with the section closest to the handle making the most difference.

Ram it flush with the end:

Dust brush adapter - reinforced tube - detail — Dust brush adapter – reinforced tube – detail

I thought about gluing it in place, but it’s a sufficiently snug press fit that I’m sure it won’t go anywhere.

Natural PETG probably isn’t the right color:

Dust brush adapter - reinforced tube - installed — Dust brush adapter – reinforced tube – installed

Now, let’s see how long that repair lasts …

The OpenSCAD source code as a GitHub Gist:

	//——————-
	// eBay horsehair dusting brush
	// Hacked for 3/4" Schedule 40 PVC stiffening tube

	module DustBrush() {

	union() {
	translate([0,0,40.0])
	rotate([180,0,0])
	difference() {
	union() {
	cylinder(d1=EndStop[OD1],d2=31.8,h=10.0);
	translate([0,0,10.0 – Protrusion])
	cylinder(d1=32.0,d2=30.0,h=30.0 + Protrusion);
	}
	translate([0,0,-Protrusion])
	cylinder(d1=26.0,d2=24.0,h=100);
	translate([0,0,-Protrusion]) // 3/4 inch Sch 40 PVC
	PolyCyl(27.0,100);
	}
	translate([0,0,40.0 – Protrusion])
	MaleFitting();
	}
	}

view raw Kenmore Wand Bushings – Reinforced Dust Brush Adapter.scad hosted with ❤ by GitHub

2016-11-29

TCRT5000 Proximity Sensor Mount

Having a few TCRT5000 proximity sensors lying around, I used one for the Color Mixer so folks could just wave a finger to flip the LED colors, rather than pound relentlessly on the top plate:

Color mixer - controls — Color mixer – controls

The stem fits into a slot made with a 3/8 inch end mill:

Prox Sensor Bezel - Slic3r preview — Prox Sensor Bezel – Slic3r preview

You move the cutter by the length of the sensor (10.0 mm will work) to make the slot. In practical terms, drill a hole at the midpoint, insert the cutter, then move ±5.0 mm from the center:

A bead of epoxy around the stem on the bottom of the panel should hold it in place forevermore.

The rectangular inner hole came out a tight push fit for the TCRT5000 sensor, so I didn’t bother gluing it in place and, surprisingly, it survived the day unscathed!

The OpenSCAD source code as a GitHub Gist:

	// TCRT5000 Proximity switch sensor mount
	// Ed Nisley KE4ZNU – October 2016

	Layout = "Build"; // Show Build

	//- Extrusion parameters must match reality!

	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

	Sensor = [5.9,10.0,7.0];

	SensorHoleCutter = 3/8 * inch;

	echo(str("Cutter dia: ",SensorHoleCutter," mm"));
	echo(str("Cutter motion: ",Sensor[1]," mm"));

	PanelThick = 5.0;

	StemLength = PanelThick + 6*ThreadThick;

	FlangeThick = 3 * ThreadThick;

	//———————-
	// Flange model

	module ProxFlange() {

	difference() {
	union() {
	linear_extrude(height=FlangeThick)
	hull()
	for (i=[-1,1], j=[-1,1])
	translate([iSensor[0],jSensor[1]])
	circle(r=Sensor[0]/2,$fn=8*4);
	translate([0,0,-StemLength])
	linear_extrude(height=StemLength)
	hull()
	for (j=[-1,1])
	translate([0,j*Sensor[1]/2])
	circle(d=SensorHoleCutter,$fn=8*4);
	}
	translate([0,0,-Protrusion])
	cube(Sensor + [HoleWindage,HoleWindage,2*(PanelThick + Protrusion)],center=true);
	}

	}

	//———————-
	// Build it

	if (Layout == "Show")
	ProxFlange();

	if (Layout == "Build")
	translate([0,0,FlangeThick])
	rotate([180,0,0])
	ProxFlange();

view raw Prox Switch Mount.scad hosted with ❤ by GitHub

2016-11-14

Reticle Guide for Ruler Quilting

I made the pencil guides to help Mary design ruler quilting patterns, but sometimes she must line up the ruler with a feature on an existing pattern. To that end, we now have a reticle guide:

Ruler Adapters - pencil guide and reticle — Ruler Adapters – pencil guide and reticle

The general idea is that it’s easier to see the pattern on paper through the crosshair than through a small hole. You put the button over a feature, align the reticle, put the ruler against the button, replace it with pencil guide, and away you go.

The solid model looks much more lively than you’d expect:

Ruler Adapter - reticle - Slic3r preview — Ruler Adapter – reticle – Slic3r preview

Printing up a pair of each button produces the same surface finish as before; life is good!

The OpenSCAD source code as a GitHub Gist:

	// Quilting Ruler Adapters
	// Ed Nisley KE4ZNU October 2016

	//- Extrusion parameters must match reality!

	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

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

	Offset = 0.25 * inch;

	Template = [2.0,2*Offset,3.0];

	NumSides = 16*4;
	HoleSides = 8;

	//———————-
	// 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);
	}


	//———-
	// Build them

	translate([-Template[OD],0,0])
	difference() {
	cylinder(d=Template[OD],h=Template[LENGTH],$fn=NumSides);
	translate([0,0,-Template[LENGTH]])
	PolyCyl(Template[ID],3*Template[LENGTH],HoleSides);
	translate([0,0,-Protrusion])
	cylinder(d1=2*Template[ID],d2=Template[ID],h=Template[LENGTH]/3 + Protrusion,$fn=HoleSides);
	translate([0,0,Template[LENGTH] + Protrusion])
	mirror([0,0,1])
	cylinder(d1=2*Template[ID],d2=Template[ID],h=Template[LENGTH]/3 + Protrusion,$fn=HoleSides);
	}

	translate([Template[OD],0,0])
	difference() {
	cylinder(d=Template[OD],h=Template[LENGTH],$fn=NumSides);
	for (a=[45,135])
	rotate(a)
	cube([0.70Template[OD],0.15Template[OD],3*Template[LENGTH]],center=true);
	}

view raw Ruler Adapters.scad hosted with ❤ by GitHub

2016-10-17

Octal Tube Base Clamp

One of the octal tubes in my collection has a broken spigot / key post that lets some light in through the bottom of the normally opaque Bakelite base:

Octal socket in CD - LED diffraction — Octal socket in CD – LED diffraction

Perhaps drilling out the base would let more light pass around the evacuation tip, but that requires a shell drill to clear the tip. Some doodling suggested a drill with 12 mm OD and 8 mm ID, which was close enough to one of the smaller homebrew drills in my collection that I decided to see how it worked:

You (well, I) can’t freehand such a hole, particularly with a glass tip in the middle, so I needed a way to clamp the tube in either the drill press or the Sherline. A pad for the clamp screw in a V-block seemed appropriate:

Vacuum Tube Lights - Octal base clamp - Slic3r preview — Vacuum Tube Lights – Octal base clamp – Slic3r preview

The screw hole sits at the 1/3 point to put more pressure near the pin end of the base. Maybe that matters.

The setup looks like this, with a small red laser dot near the front of the base:

The tube rests on a random scrap of plastic, with the hope that the drill won’t apply enough pressure to break the glass envelope.

In normal use, the V-block would be oriented the other way to let you cross-drill the cylinder. In this end-on orientation, drilling torque can rotate the tube; compliant padding for more traction may be in order.

The OpenSCAD source code as a GitHub Gist now includes a module that spits out the clamp:

	// Vacuum Tube LED Lights
	// Ed Nisley KE4ZNU February … September 2016

	Layout = "TubeClamp"; // Cap LampBase USBPort Bushings
	// Socket(s) Cap (Build)FinCap Platter[Base\|Fixture]
	// TubeClamp
	DefaultSocket = "Mini7";

	Section = false; // cross-section the object

	Support = true;

	//- Extrusion parameters must match reality!

	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
	// https://en.wikipedia.org/wiki/Tube_socket#Summary_of_Base_Details
	// punch & screw OC modified for drive platter chassis plate
	// platter = 25 mm ID
	// CD = 15 mm ID with raised ring at 37 mm, needs screw head clearance

	T_NAME = 0; // common name
	T_NUMPINS = 1; // total, with no allowance for keying
	T_PINBCD = 2; // tube pin circle diameter
	T_PINOD = 3; // … diameter
	T_PINLEN = 4; // … length (must also clear evacuation tip / spigot)
	T_HOLEOD = 5; // nominal panel hole from various sources
	T_PUNCHOD = 6; // panel hole optimized for inch-size Greenlee punches
	T_TUBEOD = 7; // envelope or base diameter
	T_PIPEOD = 8; // light pipe from LED to tube base (clear evac tip / spigot)
	T_SCREWOC = 9; // mounting screw holes

	// Name pins BCD dia length hole punch tube pipe screw
	TubeData = [
	["Mini7", 8, 9.53, 1.016, 7.0, 16.0, 25.0, 18.0, 5.0, 35.0], // punch 11/16, screw 22.5 OC
	// ["Octal", 8, 17.45, 2.36, 11.0, 36.2, (8 + 1)/8 * inch, 32.0, 11.5, 47.0], // screw 39.0 OC
	["Octal", 8, 17.45, 2.36, 11.0, 36.2, 25.0, 32.0, 11.5, 42.0], // platter + 4 mm screws
	["Noval", 10, 11.89, 1.1016, 7.0, 22.0, 25.0, 21.0, 7.5, 35.0], // punch 7/8, screw 28.0 OC
	["Magnoval", 10, 17.45, 1.27, 9.0, 29.7, (4 + 1)/4 * inch, 46.0, 12.4, 38.2], // similar to Novar
	// ["Duodecar", 13, 19.10, 1.05, 9.0, 32.0, (4 + 1)/4 * inch, 38.0, 12.5, 47.0], // screw was 39.0 OC
	["Duodecar", 13, 19.10, 1.05, 9.0, 25.0, 25.0, 38.0, 12.5, 42.0], // fit un-punched drive platter
	];

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

	Pixel = [7.0,10.0,3.0]; // ID = contact patch, OD = PCB dia, LENGTH = overall thickness

	SocketNut = // socket mounting: threaded insert or nut recess
	// [3.5,5.2,7.2] // 6-32 insert
	[4.0,6.0,5.9] // 4 mm short insert
	;
	NutSides = 8;

	SocketShim = 2*ThreadThick; // between pin holes and pixel top
	SocketFlange = 1.5; // rim around socket below punchout
	PanelThick = 1.5; // socket extension through punchout

	FinCutterOD = 1/8 * inch;
	FinCapSize = [(Pixel[OD] + 2FinCutterOD),30.0,(10.0 + 2Pixel[LENGTH])];

	USBPCB =
	// [28,16,6.5] // small Sparkfun knockoff
	[36,18 + 1,5.8 + 0.4] // Deek-Robot fake FTDI with ISP header
	;

	Platter = [25.0,95.0,1.26]; // hard drive platter dimensions

	//———————-
	// 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);
	}

	//———————-
	// Tube cap

	CapTube = [4.0,3/16 * inch,10.0]; // brass tube for flying lead to cap LED

	CapSize = [Pixel[ID],(Pixel[OD] + 2.0),(CapTube[OD] + 2*Pixel[LENGTH])];

	CapSides = 8*4;

	module Cap() {

	difference() {
	union() {
	cylinder(d=CapSize[OD],h=(CapSize[LENGTH]),$fn=CapSides); // main cap body
	translate([0,0,CapSize[LENGTH]]) // rounded top
	scale([1.0,1.0,0.65])
	sphere(d=CapSize[OD]/cos(180/CapSides),$fn=CapSides); // cos() fixes slight undersize vs cylinder
	cylinder(d1=(CapSize[OD] + 23ThreadWidth),d2=CapSize[OD],h=1.5*Pixel[LENGTH],$fn=CapSides); // skirt
	}

	translate([0,0,-Protrusion]) // bore for wiring to LED
	PolyCyl(CapSize[ID],(CapSize[LENGTH] + 3*ThreadThick + Protrusion),CapSides);

	translate([0,0,-Protrusion]) // PCB recess with clearance for tube dome
	PolyCyl(Pixel[OD],(1.5*Pixel[LENGTH] + Protrusion),CapSides);

	translate([0,0,(1.5*Pixel[LENGTH] – Protrusion)]) // small step + cone to retain PCB
	cylinder(d1=(Pixel[OD]/cos(180/CapSides) + HoleWindage),d2=Pixel[ID],h=(Pixel[LENGTH] + Protrusion),$fn=CapSides);

	translate([0,0,(CapSize[LENGTH] – CapTube[OD]/(2*cos(180/8)))]) // hole for brass tube holding wire loom
	rotate([90,0,0]) rotate(180/8)
	PolyCyl(CapTube[OD],CapSize[OD],8);
	}

	}

	//———————-
	// Heatsink tube cap

	module FinCap() {

	CableOD = 3.5; // cable + braid diameter
	BulbOD = 3.75 * inch; // bulb OD; use 10 inches for flat

	echo(str("Fin Cutter: ",FinCutterOD));
	FinSides = 2*4;

	BulbRadius = BulbOD / 2;
	BulbDepth = BulbRadius – sqrt(pow(BulbRadius,2) – pow(FinCapSize[OD],2)/4);
	echo(str("Bulb OD: ",BulbOD," recess: ",BulbDepth));

	NumFins = floor(PIFinCapSize[ID] / (2FinCutterOD));
	FinAngle = 360 / NumFins;
	echo(str("NumFins: ",NumFins," angle: ",FinAngle," deg"));

	difference() {
	union() {
	cylinder(d=FinCapSize[ID],h=FinCapSize[LENGTH],$fn=2*NumFins); // main body

	for (i = [0:NumFins – 1]) // fins
	rotate(i * FinAngle)
	hull() {
	translate([FinCapSize[ID]/2,0,0])
	rotate(180/FinSides)
	cylinder(d=FinCutterOD,h=FinCapSize[LENGTH],$fn=FinSides);
	translate([(FinCapSize[OD] – FinCutterOD)/2,0,0])
	rotate(180/FinSides)
	cylinder(d=FinCutterOD,h=FinCapSize[LENGTH],$fn=FinSides);
	}

	rotate(FinAngle/2) // cable entry boss
	translate([FinCapSize[ID]/2,0,FinCapSize[LENGTH]/2])
	cube([FinCapSize[OD]/4,FinCapSize[OD]/4,FinCapSize[LENGTH]],center=true);
	}

	for (i = [1:NumFins – 1]) // fin inner gullets, omit cable entry side
	rotate(i * FinAngle + FinAngle/2) // joint isn't quite perfect, but OK
	translate([FinCapSize[ID]/2,0,-Protrusion])
	rotate(0*180/FinSides)
	cylinder(d=FinCutterOD/cos(180/FinSides),h=(FinCapSize[LENGTH] + 2*Protrusion),$fn=FinSides);

	translate([0,0,-Protrusion]) // PCB recess
	PolyCyl(Pixel[OD],(1.5*Pixel[LENGTH] + Protrusion),FinSides);

	PolyCyl(Pixel[ID],(FinCapSize[LENGTH] – 3*ThreadThick),FinSides); // bore for LED wiring

	translate([0,0,(FinCapSize[LENGTH] – 3ThreadThick – 2CableOD/(2*cos(180/8)))]) // cable inlet
	rotate(FinAngle/2) rotate([0,90,0]) rotate(180/8)
	PolyCyl(CableOD,FinCapSize[OD],8);

	if (BulbOD <= 10.0 * inch) // curve for top of bulb
	translate([0,0,-(BulbRadius – BulbDepth + 2*ThreadThick)]) // … slightly flatten tips
	sphere(d=BulbOD,$fn=16*FinSides);
	}

	}


	//———————-
	// Aperture for USB-to-serial adapter snout
	// These are all magic numbers, of course

	module USBPort() {

	translate([0,USBPCB[0]])
	rotate([90,0,0])
	linear_extrude(height=USBPCB[0])
	polygon(points=[
	[0,0],
	[USBPCB[1]/2,0],
	[USBPCB[1]/2,0.5*USBPCB[2]],
	[USBPCB[1]/3,USBPCB[2]],
	[-USBPCB[1]/3,USBPCB[2]],
	[-USBPCB[1]/2,0.5*USBPCB[2]],
	[-USBPCB[1]/2,0],
	]);
	}


	//———————-
	// Box for Leviton ceramic lamp base

	module LampBase() {

	Insert = [3.5,5.2,7.2]; // 6-32 brass insert to match standard electrical screws

	Bottom = 3.0;
	Base = [4.0inch,4.5inch,20.0 + Bottom];
	Sides = 12*4;

	Retainer = [3.5,11.0,1.0]; // flat fiber washer holding lamp base screws in place

	StudSides = 8;
	StudOC = 3.5 * inch;
	Stud = [Insert[OD], // insert for socket screws
	min(15.0,1.5*(Base[ID] – StudOC)/cos(180/StudSides)), // OD = big enough to merge with walls
	(Base[LENGTH] – Retainer[LENGTH])]; // leave room for retainer


	union() {
	difference() {
	rotate(180/Sides)
	cylinder(d=Base[OD],h=Base[LENGTH],$fn=Sides);
	rotate(180/Sides)
	translate([0,0,Bottom])
	cylinder(d=Base[ID],h=Base[LENGTH],$fn=Sides);
	translate([0,-Base[OD]/2,Bottom + 1.2]) // mount on double-sided foam tape
	rotate(0)
	USBPort();
	}
	for (i = [-1,1])
	translate([i*StudOC/2,0,0])
	rotate(180/StudSides)
	difference() {
	cylinder(d=Stud[OD],h=Stud[LENGTH],$fn=StudSides);
	translate([0,0,Bottom])
	PolyCyl(Stud[ID],(Stud[LENGTH] – (Bottom – Protrusion)),6);
	}
	}
	}

	//———————-
	// Base for hard drive platters

	module PlatterBase(TubeName = DefaultSocket) {

	PCB =
	[36,18,3] // Arduino Pro Mini
	;

	Tube = search([TubeName],TubeData,1,0)[0];
	SocketHeight = Pixel[LENGTH] + SocketShim + TubeData[Tube][T_PINLEN] – PanelThick;

	echo(str("Base for ",TubeData[Tube][0]," socket"));

	Overhang = 5.5; // platter overhangs base by this much

	Bottom = 4*ThreadThick;
	Base = [(Platter[OD] – 3*Overhang), // smaller than 3.5 inch Sch 40 PVC pipe…
	(Platter[OD] – 2*Overhang),
	2.0 + max(PCB[1],(2.0 + SocketHeight + USBPCB[2])) + Bottom];
	Sides = 24*4;

	echo(str(" Height: ",Base[2]," mm"));

	Insert = // platter mounting: threaded insert or nut recess
	// [3.5,5.2,7.2] // 6-32 insert
	[3.9,5.0,8.0] // 3 mm – long insert
	;

	NumStuds = 4;
	StudSides = 8;
	Stud = [Insert[OD], // insert for socket screws
	2*Insert[OD], // OD = big enough to merge with walls
	Base[LENGTH]]; // leave room for retainer
	StudBCD = floor(Base[ID] – Stud[OD] + (Stud[OD] – Stud[ID])/2);
	echo(str("Platter screw BCD: ",StudBCD," mm"));

	PCBInset = Base[ID]/2 – sqrt(pow(Base[ID]/2,2) – pow(PCB[0],2)/4);

	union() {
	difference() {
	rotate(180/Sides)
	cylinder(d=Base[OD],h=Base[LENGTH],$fn=Sides);
	rotate(180/Sides)
	translate([0,0,Bottom])
	cylinder(d=Base[ID],h=Base[LENGTH],$fn=Sides);
	translate([0,-Base[OD]/2,Bottom + 1.2]) // mount PCB on foam tape
	rotate(0)
	USBPort();
	}

	for (a = [0:(NumStuds – 1)]) // platter mounting studs
	rotate(180/NumStuds + a*360/(NumStuds))
	translate([StudBCD/2,0,0])
	rotate(180/StudSides)
	difference() {
	cylinder(d=Stud[OD],h=Stud[LENGTH],$fn=2*StudSides);
	translate([0,0,Bottom])
	PolyCyl(Stud[ID],(Stud[LENGTH] – (Bottom – Protrusion)),StudSides);
	}

	intersection() { // microcontroller PCB mounting plate
	rotate(180/Sides)
	cylinder(d=Base[OD],h=Base[LENGTH],$fn=Sides);
	translate([-PCB[0]/2,(Base[ID]/2 – PCBInset),0])
	cube([PCB[0],Base[OD]/2,Base[LENGTH]],center=false);
	}

	difference() {
	intersection() { // totally ad-hoc bridge around USB opening
	rotate(180/Sides)
	cylinder(d=Base[OD],h=Base[LENGTH],$fn=Sides);
	translate([-1.25*USBPCB[1]/2,-(Base[ID]/2),0])
	cube([1.25*USBPCB[1],2.0,Base[LENGTH]],center=false);
	}
	translate([0,-Base[OD]/2,Bottom + 1.2]) // mount PCB on foam tape
	rotate(0)
	USBPort();

	translate([0,-(Base[ID]/2 – 2.0 + 1ThreadWidth),Bottom – 3ThreadThick]) // legend
	rotate([90,0,180])
	linear_extrude(height=1*ThreadWidth + Protrusion) {
	translate([0,(Base[LENGTH] – 5.5),0])
	text(text=TubeName,size=4,font="Arial:style=Bold",halign="center");
	// translate([0,(Base[LENGTH] – 8.5),0])
	// text(text=str("BCD ",StudBCD),size=2,font="Arial",halign="center");
	translate([0,(Base[LENGTH] – 11),0])
	text(text="KE4ZNU",size=3,font="Arial",halign="center");
	}

	}
	}
	}


	//———————-
	// Drilling fixture for disk platters

	module PlatterFixture() {

	StudOC = [1.16inch,1.16inch]; // Sherline tooling plate screw spacing
	StudClear = 5.0;

	BasePlate = [(20 + StudOC[0]*ceil(Platter[OD] / StudOC[0])),(Platter[OD] + 10),7.0];
	PlateRound = 10.0; // corner radius

	difference() {
	hull() // basic block
	for (i=[-1,1], j=[-1,1])
	translate([i(BasePlate[0]/2 – PlateRound),j(BasePlate[1]/2 – PlateRound),0])
	cylinder(r=PlateRound,h=BasePlate[2],$fn=4*4);

	for (i=[-1:1], j=[-1:1]) // index marks
	translate([i100/2,j100/2,BasePlate[2] – 2*ThreadThick])
	cylinder(d=1.5,h=1,$fn=6);

	for (i=[-1,1], j=[-1,0,1]) // holes for tooling plate studs
	translate([iStudOC[0]ceil(Platter[OD] / StudOC[0])/2,j*StudOC[0],-Protrusion])
	PolyCyl(StudClear,BasePlate[2] + 2*Protrusion,6);

	translate([0,0,-Protrusion]) // center clamp hole
	PolyCyl(StudClear,BasePlate[2] + 2*Protrusion,6);

	translate([0,0,BasePlate[2] – Platter[LENGTH]]) // disk locating recess
	linear_extrude(height=(Platter[LENGTH] + Protrusion),convexity=2)
	difference() {
	circle(d=(Platter[OD] + 1),$fn=8*4);
	circle(d=Platter[ID],$fn=8*4);
	}

	translate([0,0,BasePlate[2] – 4.0]) // drilling recess
	linear_extrude(height=(4.0 + Protrusion),convexity=2)
	difference() {
	circle(d=(Platter[OD] – 10),$fn=8*4);
	circle(d=(Platter[ID] + 10),$fn=8*4);
	}
	}

	}

	//———————-
	// Tube Socket

	module Socket(Name = DefaultSocket) {

	NumSides = 6*4;

	Tube = search([Name],TubeData,1,0)[0];
	echo(str("Building ",TubeData[Tube][0]," socket"));
	echo(str(" Punch: ",TubeData[Tube][T_PUNCHOD]," mm = ",TubeData[Tube][T_PUNCHOD]/inch," inch"));
	echo(str(" Screws: ",TubeData[Tube][T_SCREWOC]," mm =",TubeData[Tube][T_SCREWOC]/inch," inch OC"));

	OAH = Pixel[LENGTH] + SocketShim + TubeData[Tube][T_PINLEN];
	BaseHeight = OAH – PanelThick;

	difference() {
	union() {
	linear_extrude(height=BaseHeight) // base outline
	hull() {
	circle(d=(TubeData[Tube][T_PUNCHOD] + 2*SocketFlange),$fn=NumSides);
	for (i=[-1,1])
	translate([i*TubeData[Tube][T_SCREWOC]/2,0])
	circle(d=2.0*SocketNut[OD],$fn=NumSides);
	}
	cylinder(d=TubeData[Tube][T_PUNCHOD],h=OAH,$fn=NumSides); // boss in chassis punch hole
	}

	for (i=[0:(TubeData[Tube][T_NUMPINS] – 1)]) // tube pins
	rotate(i*360/TubeData[Tube][T_NUMPINS])
	translate([TubeData[Tube][T_PINBCD]/2,0,(OAH – TubeData[Tube][T_PINLEN])])
	rotate(180/4)
	PolyCyl(TubeData[Tube][T_PINOD],(TubeData[Tube][T_PINLEN] + Protrusion),4);

	for (i=[-1,1]) // mounting screw holes & nut traps / threaded inserts
	translate([i*TubeData[Tube][T_SCREWOC]/2,0,-Protrusion]) {
	PolyCyl(SocketNut[OD],(SocketNut[LENGTH] + Protrusion),NutSides);
	PolyCyl(SocketNut[ID],(OAH + 2*Protrusion),NutSides);
	}

	translate([0,0,-Protrusion]) { // LED recess
	PolyCyl(Pixel[OD],(Pixel[LENGTH] + Protrusion),8);
	}

	translate([0,0,(Pixel[LENGTH] – Protrusion)]) { // light pipe
	rotate(180/TubeData[Tube][T_NUMPINS])
	PolyCyl(TubeData[Tube][T_PIPEOD],(OAH + 2*Protrusion),TubeData[Tube][T_NUMPINS]);
	}

	for (i=[-1,1]) // cable retaining slots
	translate([i*(Pixel[OD] + TubeData[Tube][T_SCREWOC])/4,0,(Pixel[LENGTH] – Protrusion)/2])
	cube([Pixel[LENGTH],TubeData[Tube][T_SCREWOC],(Pixel[LENGTH] + Protrusion)],center=true);
	}

	// Totally ad-hoc support structures …

	if (Support) {
	color("Yellow") {
	for (i=[-1,1]) // nut traps
	translate([i*TubeData[Tube][T_SCREWOC]/2,0,(SocketNut[LENGTH] – ThreadThick)/2])
	for (a=[0:5])
	rotate(a*30 + 15)
	cube([2ThreadWidth,0.9SocketNut[OD],(SocketNut[LENGTH] – ThreadThick)],center=true);

	if (Pixel[OD] > TubeData[Tube][T_PIPEOD]) // support pipe only if needed
	translate([0,0,(Pixel[LENGTH] – ThreadThick)/2])
	for (a=[0:7])
	rotate(a*22.5)
	cube([2ThreadWidth,0.9Pixel[OD],(Pixel[LENGTH] – ThreadThick)],center=true);
	}
	}
	}


	//———————-
	// Greenlee punch bushings

	module PunchBushing(Name = DefaultSocket) {

	PunchScrew = 9.5;
	BushingThick = 3.0;

	Tube = search([Name],TubeData,1,0)[0];
	echo(str("Building ",TubeData[Tube][0]," bushing"));

	NumSides = 6*4;

	difference() {
	union() {
	cylinder(d=Platter[ID],h=BushingThick,$fn=NumSides);
	cylinder(d=TubeData[Tube][T_PUNCHOD],h=(BushingThick – Platter[LENGTH]),$fn=NumSides);
	}
	translate([0,0,-Protrusion])
	PolyCyl(PunchScrew,5.0,8);
	}
	}

	//———————-
	// Tube clamp

	module TubeClamp(Name = DefaultSocket) {

	Tube = search([Name],TubeData,1,0)[0];
	echo(str("Building ",TubeData[Tube][0]," clamp"));

	ClampWidth = 37.0; // inside of clamp arch
	ClampLength = 20; // along tube base

	ClampScrew = [6.0,7.8,6.0]; // nose of clamp screw
	ClampArc = 3*45; // angle subtended by block bottom

	ClampChordWidth = 2 * (TubeData[Tube][T_TUBEOD]/2) * sin(ClampArc/2);
	ClampChordDepth = (ClampChordWidth / 2) * tan(ClampArc/4);
	echo(str("Chord width: ",ClampChordWidth," depth: ",ClampChordDepth));

	ClampBlock = [ClampWidth,(ClampChordDepth + 2*ClampScrew[LENGTH]),ClampLength];

	difference() {
	translate([0,(ClampBlock[1]/2 + TubeData[Tube][T_TUBEOD]/2 – ClampChordDepth),0])
	intersection() {
	translate([0,0,ClampLength/2])
	cube(ClampBlock,center=true);
	translate([0,(ClampBlock[1]/2 – ClampWidth/2),0])
	cylinder(d=ClampWidth,h=ClampLength);
	}
	translate([0,0,-Protrusion]) // remove tube base (remains centered)
	cylinder(d=TubeData[Tube][T_TUBEOD],h=(ClampLength + 2*Protrusion));
	translate([0,(TubeData[Tube][T_TUBEOD]/2 + ClampScrew[LENGTH]),ClampBlock[LENGTH]/3])
	rotate([-90,0,0])
	PolyCyl(ClampScrew[ID],2*ClampScrew[LENGTH],6);
	}

	}

	//———————-
	// Build it

	if (Layout == "Cap") {
	if (Section)
	difference() {
	Cap();
	translate([-CapSize[OD],0,CapSize[LENGTH]])
	cube([2CapSize[OD],2CapSize[OD],3*CapSize[LENGTH]],center=true);
	}
	else
	Cap();
	}

	if (Layout == "FinCap") {
	if (Section) render(convexity=5)
	difference() {
	FinCap();
	// translate([0,-FinCapSize[OD],FinCapSize[LENGTH]])
	// cube([2FinCapSize[OD],2FinCapSize[OD],3*FinCapSize[LENGTH]],center=true);
	translate([-FinCapSize[OD],0,FinCapSize[LENGTH]])
	cube([2FinCapSize[OD],2FinCapSize[OD],3*FinCapSize[LENGTH]],center=true);
	}
	else
	FinCap();
	}

	if (Layout == "BuildFinCap")
	translate([0,0,FinCapSize[LENGTH]])
	rotate([180,0,0])
	FinCap();

	if (Layout == "LampBase")
	LampBase();

	if (Layout == "PlatterBase")
	PlatterBase();

	if (Layout == "PlatterFixture")
	PlatterFixture();

	if (Layout == "USBPort")
	USBPort();

	if (Layout == "TubeClamp")
	TubeClamp("Octal");

	if (Layout == "Bushings")
	PunchBushing();

	if (Layout == "Socket")
	if (Section) {
	difference() {
	Socket();
	translate([-100/2,0,-Protrusion])
	cube([100,50,50],center=false);
	}
	}
	else
	Socket();

	if (Layout == "Sockets") {
	translate([0,50,0])
	Socket("Mini7");
	translate([0,20,0])
	Socket("Octal");
	translate([0,-15,0])
	Socket("Duodecar");
	translate([0,-50,0])
	Socket("Noval");
	translate([0,-85,0])
	Socket("Magnoval");}

view raw Vacuum Tube Lights.scad hosted with ❤ by GitHub

2016-09-26

Kenmore Progressive Vacuum Tool Adapters: First Failure

I picked up a horsehair dust brush from eBay as a lightweight substitute for the Electrolux aluminum ball, discovered that an adapter I’d already made fit perfectly, did the happy dance, and printed one for the brush. That worked perfectly for half a year, whereupon:

Dust Brush Adapter - broken parts — Dust Brush Adapter – broken parts

It broke about where I expected, along the layer lines at the cross section where the snout joins the fitting. You can see the three perimeter shells I hoped would strengthen the part:

Dust Brush Adapter - layer separation — Dust Brush Adapter – layer separation

That has the usual 15% 3D Honeycomb infill, although there’s not a lot area for infill.

There’s obviously a stress concentration there and making the wall somewhat thicker (to get more plastic-to-plastic area) might suffice. I’m not convinced the layer bonding would be good enough, even with more wall area, to resist the stress; that’s pretty much a textbook example of how & where 3D printed parts fail.

That cross section should look like this:

Dust Brush Adapter - Snout infill - Slic3r preview — Dust Brush Adapter – Snout infill – Slic3r preview

Anyhow, I buttered the snout’s broken end with JB Kwik epoxy, aligned the parts, and clamped them overnight:

Dust Brush Adapter - clamping — Dust Brush Adapter – clamping

The source code now has a separate solid model for the dust brush featuring a slightly shorter snout; if when the epoxy fails, we’ll see how that changes the results. I could add ribs and suchlike along the outside, none of which seem worth the effort right now. Fairing the joint between those two straight sections would achieve the same end, with even more effort, because OpenSCAD.

The OpenSCAD source code as a GitHub Gist:

	// Kenmore vacuum cleaner nozzle adapters
	// Ed Nisley KE4ZNU August 2016

	// Layout options

	Layout = "DustBrush"; // MaleFitting CoilWand FloorBrush CreviceTool ScrubbyTool LuxBrush DustBrush

	//- Extrusion parameters must match reality!
	// Print with +1 shells and 3 solid layers

	ThreadThick = 0.25;
	ThreadWidth = 0.40;

	HoleWindage = 0.2;

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

	Protrusion = 0.1; // make holes end cleanly

	//———————-
	// Dimensions

	ID1 = 0; // for tapered tubes
	ID2 = 1;
	OD1 = 2;
	OD2 = 3;
	LENGTH = 4;

	OEMTube = [35.0,35.0,41.7,40.5,30.0]; // main fitting tube
	EndStop = [OEMTube[ID1],OEMTube[ID2],47.5,47.5,6.5]; // flange at end of main tube

	FittingOAL = OEMTube[LENGTH] + EndStop[LENGTH];

	$fn = 12*4;

	//———————-
	// 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);
	}


	//——————-
	// Male fitting on end of Kenmore tools
	// This slides into the end of the handle or wand and latches firmly in place

	module MaleFitting() {

	Latch = [40,11.5,5.0]; // rectangle latch opening
	EntryAngle = 45; // latch entry ramp
	EntrySides = 16;
	EntryHeight = 15.0; // lower edge on inside of fitting

	KeyRadius = 1.0;

	translate([0,0,6.5])
	difference() {
	union() {
	cylinder(d1=OEMTube[OD1],d2=OEMTube[OD2],h=OEMTube[LENGTH]); // main tube

	hull() // insertion guide
	for (i=[-(6.0/2 – KeyRadius),(6.0/2 – KeyRadius)],
	j=[-(28.0/2 – KeyRadius),(28.0/2 – KeyRadius)],
	k=[-(26.0/2 – KeyRadius),(26.0/2 – KeyRadius)])
	translate([(i – (OEMTube[ID1]/2 + OEMTube[OD1]/2)/2 + 6.0/2),j,(k + 26.0/2 – 1.0)])
	sphere(r=KeyRadius,$fn=8);

	translate([0,0,-EndStop[LENGTH]]) // wand tube butts against this
	cylinder(d=EndStop[OD1],h=EndStop[LENGTH] + Protrusion);
	}

	translate([0,0,-OEMTube[LENGTH]]) // main bore
	cylinder(d=OEMTube[ID1],h=2OEMTube[LENGTH] + 2Protrusion);

	translate([0,-11.5/2,23.0 – 5.0]) // latch opening
	cube(Latch);

	translate([OEMTube[ID1]/2 + EntryHeight/tan(90-EntryAngle),0,0]) // latch ramp
	translate([(Latch[1]/cos(180/EntrySides))cos(EntryAngle)/2,0,(Latch[1]/cos(180/EntrySides))sin(EntryAngle)/2])
	rotate([0,-EntryAngle,0])
	intersection() {
	rotate(180/EntrySides)
	PolyCyl(Latch[1],Latch[0],EntrySides);
	translate([-(2*Latch[0])/2,0,-Protrusion])
	cube(2*Latch[0],center=true);
	}
	}
	}

	//——————-
	// Refrigerator evaporator coil wand

	module CoilWand() {

	union() {
	translate([0,0,50.0])
	rotate([180,0,0])
	difference() {
	cylinder(d1=EndStop[OD1],d2=42.0,h=50.0);
	translate([0,0,-Protrusion])
	cylinder(d1=35.0,d2=35.8,h=100);
	}
	translate([0,0,50.0 – Protrusion])
	MaleFitting();
	}
	}


	//——————-
	// Samsung floor brush

	module FloorBrush() {

	union() {
	translate([0,0,60.0])
	rotate([180,0,0])
	difference() {
	union() {
	cylinder(d1=EndStop[OD1],d2=32.4,h=10.0);
	translate([0,0,10.0 – Protrusion])
	cylinder(d1=32.4,d2=30.7,h=50.0 + Protrusion);
	}
	translate([0,0,-Protrusion])
	cylinder(d1=28.0,d2=24.0,h=100);
	}
	translate([0,0,60.0 – Protrusion])
	MaleFitting();
	}
	}


	//——————-
	// Crevice tool

	module CreviceTool() {

	union() {
	translate([0,0,60.0])
	rotate([180,0,0])
	difference() {
	union() {
	cylinder(d1=EndStop[OD1],d2=32.0,h=10.0);
	translate([0,0,10.0 – Protrusion])
	cylinder(d1=32.0,d2=30.4,h=50.0 + Protrusion);
	}
	translate([0,0,-Protrusion])
	cylinder(d1=28.0,d2=24.0,h=100);
	}
	translate([0,0,60.0 – Protrusion])
	MaleFitting();
	}
	}

	//——————-
	// Mystery brush

	module ScrubbyTool() {

	union() {
	translate([0,0,60.0])
	rotate([180,0,0])
	difference() {
	union() {
	cylinder(d1=EndStop[OD1],d2=31.8,h=10.0);
	translate([0,0,10.0 – Protrusion])
	cylinder(d1=31.8,d2=31.0,h=50.0 + Protrusion);
	}
	translate([0,0,-Protrusion])
	cylinder(d1=26.0,d2=24.0,h=100);
	}
	translate([0,0,60.0 – Protrusion])
	MaleFitting();
	}
	}

	//——————-
	// eBay horsehair dusting brush

	module DustBrush() {

	union() {
	translate([0,0,40.0])
	rotate([180,0,0])
	difference() {
	union() {
	cylinder(d1=EndStop[OD1],d2=31.8,h=10.0);
	translate([0,0,10.0 – Protrusion])
	cylinder(d1=31.6,d2=31.8,h=30.0 + Protrusion);
	}
	translate([0,0,-Protrusion])
	cylinder(d1=26.0,d2=24.0,h=100);
	}
	translate([0,0,40.0 – Protrusion])
	MaleFitting();
	}
	}


	//——————-
	// Electrolux brush ball

	module LuxBrush() {

	union() {
	translate([0,0,30.0])
	rotate([180,0,0])
	difference() {
	union() {
	cylinder(d1=EndStop[OD1],d2=30.8,h=10.0);
	translate([0,0,10.0 – Protrusion])
	cylinder(d1=30.8,d2=30.0,h=20.0 + Protrusion);
	}
	translate([0,0,-Protrusion])
	cylinder(d1=25.0,d2=23.0,h=30 + 2*Protrusion);
	}
	translate([0,0,30.0 – Protrusion])
	MaleFitting();
	}
	}



	//———————-
	// Build it!

	if (Layout == "MaleFitting")
	MaleFitting();

	if (Layout == "CoilWand")
	CoilWand();

	if (Layout == "FloorBrush")
	FloorBrush();

	if (Layout == "CreviceTool")
	CreviceTool();

	if (Layout == "DustBrush")
	DustBrush();

	if (Layout == "ScrubbyTool")
	ScrubbyTool();

	if (Layout == "LuxBrush")
	LuxBrush();

view raw Kenmore Wand Bushings.scad hosted with ❤ by GitHub

2016-08-24

Inspiron Mini 10 as a 3D Printer Controller

It turns out that the dual-core Intel Atom Inside an old Dell Mini 10 isn’t up to the demands of rendering modern web design; disk I/O speed has nothing to do with the CPU’s (lack of) ability to chew through multiple layers of cruft adorning what used to be straightforward static HTML.

So, equipped with Linux Mint / XFCE, it’s now found a new purpose in life:

SnowWhite back in action

In truth, an Atom isn’t quite up to the demands of modern 3D printing, either, at least in terms of processing a huge G-Code file into a layer-by-layer path preview. Fortunately, Pronterface doesn’t generate the preview until you ask for it: arranging the UI to put the preview on a separate tab eliminates that problem.

The Mini 10 can dribble G-Code into the printer just fine and looks much cuter than the hulking laptop in the background.

2016-07-11

Tag: CNC

Check Your Zero

Kenmore Progressive Vacuum Tool Adapters: Second Failure

TCRT5000 Proximity Sensor Mount

Reticle Guide for Ruler Quilting

Octal Tube Base Clamp

Kenmore Progressive Vacuum Tool Adapters: First Failure

Inspiron Mini 10 as a 3D Printer Controller