Tag: Sherline

Sherline CNC mill

Improved Octal Tube Base Clamp

In order to clamp the tube in a V-block, the clamp must position the tube’s centerline so the envelope will clear the V groove, thusly:

OD3 Octal - V-block clamp — OD3 Octal – V-block clamp

The clamp now extends into the V-block and surrounds the entire Bakelite tube base:

Octal base compression clamp - Slic3r preview — Octal base compression clamp – Slic3r preview

The little divot captures the clamp screw and the slot lets the whole affair compress just enough to firmly squeeze the entire tube base.

The tube data table now includes columns for the envelope OD and the base OD, although only the 0D3 (and similar) Octal tubes in my collection have a bulging envelope and a smaller base. You can build clamps for cylindrical glass tubes if you like; I don’t vouch for the accuracy of the table contents.

For whatever it’s worth, the 6SN7GTB tube I started with has a 32 mm Bakelite base and the 0D3 tube has a 29 mm base. That should probably justify two separate entries in the table, but I’m making this up as I go along.

The OpenSCAD source code as a GitHub Gist:

	// 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 PlatterParts
	DefaultSocket = "Octal";

	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_BASEOD = 7; // base OD
	T_BULBOD = 8; // glass envelope OD
	T_PIPEOD = 9; // light pipe from LED to tube base (clear evac tip / spigot)
	T_SCREWOC = 10; // mounting screw holes
	T_PLATECAP = 11; // nonzero to print a plate cap

	// Name pins BCD dia length hole punch base bulb pipe screw cap
	TubeData = [
	["Mini7", 8, 9.53, 1.016, 7.0, 16.0, 25.0, 18.0, 18.0, 5.0, 35.0, 0], // punch 11/16, screw 22.5 OC
	// ["Octal", 8, 17.45, 2.36, 11.0, 36.2, (8 + 1)/8 * inch, 32.0, 38.1, 11.5, 47.0, 1], // screw 39.0 OC, base 32 or 39
	["Octal", 8, 17.45, 2.36, 11.0, 36.2, 25.0, 29.0, 38.1, 11.5, 42.0, 1], // platter + 4 mm screws
	["Noval", 10, 11.89, 1.1016, 7.0, 22.0, 25.0, 21.0, 21.0, 7.5, 35.0, 0], // punch 7/8, screw 28.0 OC
	["Magnoval", 10, 17.45, 1.27, 9.0, 29.7, (4 + 1)/4 * inch, 46.0, 46.0, 12.4, 38.2, 0], // similar to Novar
	// ["Duodecar", 13, 19.10, 1.05, 9.0, 32.0, (4 + 1)/4 * inch, 38.0, 38.0, 12.5, 47.0, 1], // screw was 39.0 OC
	["Duodecar", 13, 19.10, 1.05, 9.0, 25.0, 25.0, 38.0, 38.0, 12.5, 42.0, 1], // 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
	PixelRecessHeight = 1.55*Pixel[LENGTH]; // enough of a recess to allow for tube top curvature

	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
	PlatterSides = 8*4; // polygon approximation

	//———————-
	// 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] + 2.0*Pixel[LENGTH])];
	CapSides = 8*4;

	SkirtOD = CapSize[OD] + 4*ThreadWidth;

	CapTubeHeight = (CapSize[LENGTH] + PixelRecessHeight)/2;
	CapTubeBossOD = 1ThreadWidth + 2(CapTubeHeight – PixelRecessHeight)/cos(180/8);

	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=SkirtOD,d2=CapSize[OD],h=PixelRecessHeight,$fn=CapSides); // skirt
	translate([0,-SkirtOD/2,CapTubeHeight]) // boss around brass tube
	rotate([-90,0,0])
	rotate(180/8)
	cylinder(d=CapTubeBossOD,h=CapTube[LENGTH],$fn=8);
	}

	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],(PixelRecessHeight + Protrusion),CapSides);

	translate([0,0,(PixelRecessHeight – 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,CapTubeHeight]) // 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],(PixelRecessHeight + 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
	[3.7,5.0,8.0] // 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[OD] – Stud[OD]/cos(180/StudSides));
	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])
	difference() {
	rotate(180/(2*StudSides))
	cylinder(d=Stud[OD],h=Stud[LENGTH],$fn=2*StudSides);
	translate([0,0,Bottom])
	rotate(180/StudSides)
	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;

	AlignOffset = 100;
	AlignBar = [3ThreadWidth,10.0,3ThreadThick];

	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([iAlignOffset/2,jAlignOffset/2,BasePlate[2] – 2*ThreadThick])
	cylinder(d=1.5,h=1,$fn=6);

	for (i=[-1,1])
	translate([i*(AlignOffset + AlignBar[0])/2,0,(BasePlate[2] – AlignBar[2]/2 + Protrusion/2)])
	cube(AlignBar + [0,0,Protrusion],center=true);

	for (j=[-1,1])
	translate([0,j*(AlignOffset + AlignBar[0])/2,(BasePlate[2] – AlignBar[2]/2 + Protrusion/2)])
	rotate(90)
	cube(AlignBar + [0,0,Protrusion],center=true);

	for (a=[0:90:270])
	rotate(a)
	translate([(AlignBar[1]/2 + AlignBar[0]/2),0,(BasePlate[2] – AlignBar[2]/2 + Protrusion/2)])
	cube(AlignBar + [0,-Protrusion,Protrusion],center=true);

	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
	rotate(180/PlatterSides)
	linear_extrude(height=(Platter[LENGTH] + Protrusion),convexity=2)
	difference() {
	circle(d=(Platter[OD] + 1),$fn=PlatterSides);
	circle(d=Platter[ID],$fn=PlatterSides);
	}

	translate([0,0,BasePlate[2] – 4.0]) // drilling recess
	rotate(180/PlatterSides)
	linear_extrude(height=(4.0 + Protrusion),convexity=2)
	difference() {
	circle(d=(Platter[OD] – 10),$fn=PlatterSides);
	circle(d=(Platter[ID] + 10),$fn=PlatterSides);
	}
	}

	}

	//———————-
	// 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

	ClampBlock = [4*ThreadWidth + TubeData[Tube][T_BULBOD],
	4*ThreadWidth + TubeData[Tube][T_BULBOD],
	ClampLength];

	difference() {
	union() {
	intersection() {
	translate([0,0,ClampBlock[2]/2])
	rotate(45)
	cube(ClampBlock,center=true); // V-block sides
	translate([0,-ClampWidth/2,ClampBlock[2]/2])
	cube([ClampWidth,ClampWidth,ClampBlock[2]],center=true); // clamp sides
	}
	intersection() {
	cylinder(d=ClampWidth,h=ClampBlock[2]);
	translate([0,ClampWidth/4,ClampBlock[2]/2])
	cube([ClampWidth,ClampWidth/2,ClampBlock[2]],center=true); // clamp sides
	}
	}
	translate([0,0,-Protrusion]) // remove tube base (remains centered)
	cylinder(d=TubeData[Tube][T_BASEOD],h=(ClampLength + 2*Protrusion));
	translate([0,(ClampWidth/2 + TubeData[Tube][T_BASEOD]/2)/2,ClampBlock[LENGTH]/3])
	rotate([-90,0,0])
	PolyCyl(ClampScrew[ID],1*ClampScrew[LENGTH],6); // clamp screw recess
	translate([0,-(6*ThreadWidth)/2,-Protrusion])
	cube([ClampWidth,6ThreadWidth,(ClampLength + 2Protrusion)]); // clamp relief slot
	}

	}

	//———————-
	// 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 == "PlatterParts") {
	Tube = search([DefaultSocket],TubeData,1,0)[0];
	echo(str("Parts for ",TubeData[Tube][T_NAME]," assembly"));
	PlatterBase();
	translate([0.25Platter[OD],-0.6Platter[OD],0])
	rotate(0)
	Socket();
	if (TubeData[Tube][T_PLATECAP])
	for (i=[-1,1])
	translate([(-0.25Platter[OD] – iPixel[OD]),-0.6*Platter[OD],0])
	rotate(i*90)
	Cap();
	}

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

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

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

	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

2016-10-04

Vacuum Tube LEDs: Grinding Off a 0D3 Base Spigot

Rummaging in the Hollow State Electronics box produced the shapely 0D3 regulator tube with an intact spigot / key post in its base:

0D3 voltage regulator tube in socket

Because the glass envelope (1.5 inch = 38.1 mm OD) extends beyond the base (1.125 inch = 28.6 mm OD), the simple base clamp must let the tube extend over the workbench:

0D3 Octal tube – V-block clamp

There’s no way to clamp that mess in the Sherline, so, rather than freehanding the shell drill, I misused a Dremel slitting wheel to grind away the end of the spigot, which normally extends a bit beyond the pins so you can’t possibly insert the tube into the socket the wrong way:

0D3 Octal tube – ground-off spigot tip

The missing end exposed the hole in the middle of the post and showed this tube’s evacuation tip didn’t extend into the spigot. Emboldened by that, I continued the mission until the wheel wouldn’t reach any further:

0D3 Octal tube – Dremel grinding

That didn’t work well, but at least I didn’t break anything and nobody will ever see those mauled pin tips.

Obviously, the only way to do this right is to clamp the tube properly and mill the spigot flush with the socket; it’s time for more 3D printing…

2016-10-03
Vacuum Tube LEDs: Octal Tube Base Drilling

Clamping the octal tube into the Sherline let me set the XY=0 origin to the center of the base with the laser dot (visible near the front):

Octal tube clamped on Sherline mill

Find the edges, touch off the half the 32.2 mm diameter, then align the drill at XY=0 directly over the exposed evacuation tip:

Octal Tube – drill alignment

Make a very shallow cut to verify the alignment:

Octal Tube – drill first touch

Just inside the scuffed ring from the drill, you can see the fractured ring where the original one-piece Bakelite spigot / key / post broke off.

Then extract the drill from the chuck, file more relief behind the cutting edges so they actually cut, re-chuck, and continue the mission:

Octal Tube – drilling

Pick a nice Bakelite ring out of the drill:

Octal Tube – drilled ring

And eventually you can see all the way to the glass envelope:

Octal Tube – base opening

The (knockoff) Neopixel LED sits directly below the evacuation tip and is about the same diameter, so much of that enlarged opening will be in shadow. Despite that, the tube does seem noticeably brighter:

Octal Tube – drilled base opening

Drilling that tube was so harrowing that I can’t imagine similar surgery on an intact octal base.

Perhaps just slicing off the tip of the Bakelite spigot and gluing a single very bright red/orange LED in place, rather using than a (knockoff) Neopixel a few millimeters away, will suffice.

Or just give up, top-light these tubes, and move on?

2016-09-27

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

Hard Drive Platter Drilling Fixture

After drilling the platter for a Noval tube, I finally made a fixture to hold the platters firmly, but gently, in the proper position for drilling:

Hard drive platter – drilling fixture

The platter sits more-or-less flush with the surface, where credit-card plastic pads work fine. Thinner platters may require compliant padding.

The solid model has locating pips at ±50 mm from the center and airspace below the platter for the drill bit:

Vacuum Tube Lights – hard drive fixture – solid model

The 1.16 inch hole spacing matches the Sherline’s tooling plate. The center hole seemed like a Good Idea, although it has no purpose right now.

The OpenSCAD source code is the same as before; just set Layout = PlatterFixture; and it’ll produce the right thing.

2016-09-14
External Li-Ion Pack: More Sawing

Two of the external Li-Ion battery packs I’m using with the bike radios seemed to fail quickly after being charged, so I sawed them open to check the state of the cells. This time I used the fine-tooth cutoff blades, rather than a coarse slitting saw:

Li-Ion pack – sawing case

As before, a 2 mm depth-of-cut, done 0.25 mm per pass after the first millimeter, seems about right. I didn’t saw the front of the case near the jack, which proved to be a mistake; the interlocked case halves need cutting.

No cell trouble found, which leads me to suspect an intermittent short in the battery-to-radio cable that trips the battery protection circuit. The spare cables went into hiding during the shop cleanout, so I can’t swap in a known-good cable just yet; of course, the existing cable behaves perfectly on the bench. The suspect cable is now on my bike and, if the problem follows the cable, further surgery will be in order.

For the record, the insides look like this:

Li-Ion pack – interior

The cell label seems to show a 2004 date code:

Li-Ion pack – cell label

Given that I got them on closeout in early 2010, it definitely isn’t 2014.

Unlike some of the other cheap batteries around here, they’ve been spectacularly successful!

2016-08-17
Vacuum Tube LEDs: Brass Ersatz Heatsink

A chunk of 1/2 inch = 12.7 mm brass hex rod looks pretty good as an ersatz heatsink serving as an ersatz plate cap on a halogen bulb standing in for a vacuum tube:

Halogen bulb brass cap – overview

The knockoff Neopixels measure just over 10 mm at their widest points, but some judicious filing rounded it off and brought it down to fit in the 3/8 inch = 0.375 = 9.52 mm hole I drilled in the hex:

Halogen bulb brass cap – wiring

I let it run for a day like that to make sure the thing wasn’t going to crap out, then epoxied everything in place. If the WS2812B controller fails, the repair will require drilling out all the electronics and wiring, then rebuilding it in place.

The fins come from the same HSS cutoff tool I used for the Bowl o’ Fire cap, cut at 2.5 mm intervals to produce 0.9 mm fins that IMO better suit the smaller diameter. I stopped cutting when the tool got through the hex flats to produce a continuous ring, cut the hex off a bit above the top fin, rounded the end with a carbide insert cutting tool, then sanded the flats to shine ’em up a bit:

Halogen bulb brass cap – detail flash

It turns out that 12 inches of wire inside PET braid barely reaches from the cap to the Arduino Pro Mini in the base:

Halogen bulb brass cap – Arduino Pro Mini

Next time, I’m going to add half a foot more wire than I think it can possibly require, with PET braid to suit.

A thin ring of clear epoxy holds the “heatsink” at the dead center of the bulb. It lights up a bit more than I expected, so opaque epoxy may be in order:

Halogen bulb brass cap – detail red

It’s still too big to suit even the big 21HB5A tubes, but brass definitely wins over plastic!

That blue PETG base has become the least-attractive part of the lamp, but it’s survivable for now.

It runs the same TubeMood firmware as the Bowl o’ Fire.

2016-08-02