The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Tag: M2

Using and tweaking a Makergear M2 3D printer

  • Vacuum Tube LEDs: 5U4GB Vacuum Rectifier with Sidelight

    A larger version of the V-block clamp accommodates the 35 mm = 1-3/8 inch octal base of a 5U4GB Full-Wave Vacuum Rectifier tube:

    5U4GB - spigot milling
    5U4GB – spigot milling

    The evacuation tip nearly touched the inside end of the base spigot!

    I had to cut the shaft and half the body off the shell drill in order to fit it into the space above the tube base and below the chuck:

    5U4GB - base shell drilling
    5U4GB – base shell drilling

    A slightly larger shell drill would still fit within the pin circle, but the maximum possible hole diameter in the base really isn’t all that much larger:

    5U4GB - base opening
    5U4GB – base opening

    The getter flash covers the entire top of this tube, so I conjured a side light for a rectangular knockoff Neopixel:

    Vacuum Tube Lights - side light - solid model
    Vacuum Tube Lights – side light – solid model

    There’s no orientation that doesn’t require support:

    Vacuum Tube Lights - side light support - Slic3r preview
    Vacuum Tube Lights – side light support – Slic3r preview

    A little prying with a small screwdriver and some pulling with a needlenose pliers extracted those blobs. All the visible surfaces remained undamaged and I cleaned up the curved side with a big rat-tail file.

    I wired the Arduino and Neopixels, masked a spot on the side of the tube (to improve both alignment and provide protection from slobbered epoxy), applied epoxy, and taped it in place until it cured:

    5U4GB - sidelight epoxy curing
    5U4GB – sidelight epoxy curing

    The end result looks great:

    5U4GB Full-wave vacuum rectifier - side and base illumination
    5U4GB Full-wave vacuum rectifier – side and base illumination

     

    It currently sends Morse code through the base LED, but it’s much too stately for that.

  • 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([0.70*Template[OD],0.15*Template[OD],3*Template[LENGTH]],center=true);
    }
    view raw Ruler Adapters.scad hosted with ❤ by GitHub

  • Pencil Guides for Ruler Quilting

    Mary has been doing Ruler Quilting and wanted a pencil guide (similar to the machine’s ruler foot) to let her sketch layouts before committing stitches to fabric. The general idea is to offset the pencil by 1/4 inch from the edge of the ruler:

    Ruler Adapter - solid model
    Ruler Adapter – solid model

    That was easy.

    Print three to provide a bit of cooling time and let her pass ’em around at her next quilting bee:

    Ruler Adapter - Slic3r preview
    Ruler Adapter – Slic3r preview

    Her favorite doodling pencil shoves a 0.9 mm lead through a 2 mm ferrule, so ream the center hole with a #44 drill (86 mil = 2.1 mm) to suit:

    Ruler quilting pencil guides
    Ruler quilting pencil guides

    The outer perimeters have 64 facets, an unusually high number for my models, so they’re nice & smooth on the ruler. Even though I didn’t build them sequentially, they had zero perimeter zits and the OD came out 0.500 inch on the dot.

    The chamfers guide the pencil point into the hole and provide a bit of relief for the pencil’s snout.

    If I had a laser cutter, I could make special rulers for her, too …

    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,$fn=Sides);
    }
    //———-
    // Build it
    difference() {
    cylinder(d=Template[OD],h=Template[LENGTH],$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);
    }
    view raw Ruler Adapters.scad hosted with ❤ by GitHub

  • Makergear M2: Spring-Loaded Extruder Feed Gear

    When I installed the new fine-tooth filament drive gear (wheel, whatever) in the M2, I ran some numbers that suggested replacing the fixed-position screw with a (more-or-less-)constant-force spring. Some recent discussions on the M2 forum suggest, at least to me, that the drive gear is, indeed, less forgiving of filament diameter variations, drive housing wear, and suchlike than the chunkier old gear.

    Having recently bought an assortment of longer M4 screws, I finally got around to installing an appropriate spring from the Big Box o’ Springs and another washer to capture it:

    Makergear M2 - spring-loaded filament drive
    Makergear M2 – spring-loaded filament drive

    Before doing anything, I measured the gap between the filament drive body (on the left) and the lever arm (on the right) holding the idler bearing: 21 mil = 0.53 mm.

    I don’t have a number for the spring constant; it’s rather stiff.

    After installing the spring, I cranked the screw to restore the same gap as before, which should mean the spring is exerting roughly the same force on the arm as the fixed-position screw.

    The general idea: the spring allows the flexible arm to move as the filament diameter changes, while maintaining roughly the same pressure on the drive gear, thus producing nearly the same depth-of-engagement grooves in the filament. Maintaining “the same pressure” requires the motion to be relatively small compared to the spring preload distance, which seems reasonable with ±0.1 mm diameter variations and maybe 5 mm of preload.

    The new filament drive gear hasn’t ever stripped out (after that initial finger fumble), so this will be more of a test to verify that the spring doesn’t make the situation worse.

  • Vacuum Tube LEDs: Improved Sockets

    All the sockets now sport channels in the bottom to capture the braid to the plate cap (whether or not the tube has a plate cap) and the wiring from the Arduino:

    Vacuum Tube Lights - Octal Socket - solid model
    Vacuum Tube Lights – Octal Socket – solid model

    The Slic3r preview shows the detail a bit better:

    Vaccum Tube Lights - Octal Socket - Slic3r preview
    Vaccum Tube Lights – Octal Socket – Slic3r preview

    The boss around the pins is now 25 mm OD and snaps neatly into the unpunched hub hole of a hard drive platter:

    0D3 Octal - 25 mm socket OD in platter
    0D3 Octal – 25 mm socket OD in platter

    I moved the mounting holes to 42 mm OC to give the button heads on those screws a bit more clearance from the base.

    Moving the knockoff Neopixel up to the top of the pipe leading to the tube base dramatically increases the amount of light going into the tube envelope:

    0D3 Octal - 25 mm socket - raised LED
    0D3 Octal – 25 mm socket – raised LED

    You can just barely see a strip of foam tape holding the LED PCB (loosely) into the too-large hole.

    The OpenSCAD source code also produces the improved base clamp; to get a socket, just set Layout = "Socket" and away you go. It doesn’t yet have the reduced-diameter hole down the middle; that’s in the nature of fine tuning.

  • Vacuum Tube LEDs: Milling a 0D3 Spigot the Right Way

    Now, with the 0D3 tube properly clamped and aligned in the Sherline mill:

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

    I can slowly run an end mill down onto the spigot:

    0D3 Octal - milling spigot
    0D3 Octal – milling spigot

    Eventually converting the whole post into black dust in the vacuum cleaner:

    0D3 Octal - milled spigot
    0D3 Octal – milled spigot

    That was completely uneventful, which is pretty much the whole point of good fixturing, isn’t it?

    Applying the vacuum cleaner while milling seems to have kept the dust out of the base, although I’m not sure I can pull that trick off every time.

  • 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] + 2*FinCutterOD),30.0,(10.0 + 2*Pixel[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,$fn=Sides);
    }
    //———————-
    // Tube cap
    CapTube = [4.0,3/16 * inch,10.0]; // brass tube for flying lead to cap LED
    CapSize = [Pixel[ID],(Pixel[OD] + 2.0),(CapTube[OD] + 2.0*Pixel[LENGTH])];
    CapSides = 8*4;
    SkirtOD = CapSize[OD] + 4*ThreadWidth;
    CapTubeHeight = (CapSize[LENGTH] + PixelRecessHeight)/2;
    CapTubeBossOD = 1*ThreadWidth + 2*(CapTubeHeight – PixelRecessHeight)/cos(180/8);
    module Cap() {
    difference() {
    union() {
    cylinder(d=CapSize[OD],h=(CapSize[LENGTH]),$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(PI*FinCapSize[ID] / (2*FinCutterOD));
    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] – 3*ThreadThick – 2*CableOD/(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,$fn=16*FinSides);
    }
    }
    //———————-
    // Aperture for USB-to-serial adapter snout
    // These are all magic numbers, of course
    module USBPort() {
    translate([0,USBPCB[0]])
    rotate([90,0,0])
    linear_extrude(height=USBPCB[0])
    polygon(points=[
    [0,0],
    [USBPCB[1]/2,0],
    [USBPCB[1]/2,0.5*USBPCB[2]],
    [USBPCB[1]/3,USBPCB[2]],
    [-USBPCB[1]/3,USBPCB[2]],
    [-USBPCB[1]/2,0.5*USBPCB[2]],
    [-USBPCB[1]/2,0],
    ]);
    }
    //———————-
    // Box for Leviton ceramic lamp base
    module LampBase() {
    Insert = [3.5,5.2,7.2]; // 6-32 brass insert to match standard electrical screws
    Bottom = 3.0;
    Base = [4.0*inch,4.5*inch,20.0 + Bottom];
    Sides = 12*4;
    Retainer = [3.5,11.0,1.0]; // flat fiber washer holding lamp base screws in place
    StudSides = 8;
    StudOC = 3.5 * inch;
    Stud = [Insert[OD], // insert for socket screws
    min(15.0,1.5*(Base[ID] – StudOC)/cos(180/StudSides)), // OD = big enough to merge with walls
    (Base[LENGTH] – Retainer[LENGTH])]; // leave room for retainer
    union() {
    difference() {
    rotate(180/Sides)
    cylinder(d=Base[OD],h=Base[LENGTH],$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],$fn=Sides);
    translate([-1.25*USBPCB[1]/2,-(Base[ID]/2),0])
    cube([1.25*USBPCB[1],2.0,Base[LENGTH]],center=false);
    }
    translate([0,-Base[OD]/2,Bottom + 1.2]) // mount PCB on foam tape
    rotate(0)
    USBPort();
    translate([0,-(Base[ID]/2 – 2.0 + 1*ThreadWidth),Bottom – 3*ThreadThick]) // legend
    rotate([90,0,180])
    linear_extrude(height=1*ThreadWidth + Protrusion) {
    translate([0,(Base[LENGTH] – 5.5),0])
    text(text=TubeName,size=4,font="Arial:style=Bold",halign="center");
    // translate([0,(Base[LENGTH] – 8.5),0])
    // text(text=str("BCD ",StudBCD),size=2,font="Arial",halign="center");
    translate([0,(Base[LENGTH] – 11),0])
    text(text="KE4ZNU",size=3,font="Arial",halign="center");
    }
    }
    }
    }
    //———————-
    // Drilling fixture for disk platters
    module PlatterFixture() {
    StudOC = [1.16*inch,1.16*inch]; // Sherline tooling plate screw spacing
    StudClear = 5.0;
    AlignOffset = 100;
    AlignBar = [3*ThreadWidth,10.0,3*ThreadThick];
    BasePlate = [(20 + StudOC[0]*ceil(Platter[OD] / StudOC[0])),(Platter[OD] + 10),7.0];
    PlateRound = 10.0; // corner radius
    difference() {
    hull() // basic block
    for (i=[-1,1], j=[-1,1])
    translate([i*(BasePlate[0]/2 – PlateRound),j*(BasePlate[1]/2 – PlateRound),0])
    cylinder(r=PlateRound,h=BasePlate[2],$fn=4*4);
    for (i=[-1,1], j=[-1,1]) // index marks
    translate([i*AlignOffset/2,j*AlignOffset/2,BasePlate[2] – 2*ThreadThick])
    cylinder(d=1.5,h=1,$fn=6);
    for (i=[-1,1])
    translate([i*(AlignOffset + AlignBar[0])/2,0,(BasePlate[2] – AlignBar[2]/2 + Protrusion/2)])
    cube(AlignBar + [0,0,Protrusion],center=true);
    for (j=[-1,1])
    translate([0,j*(AlignOffset + AlignBar[0])/2,(BasePlate[2] – AlignBar[2]/2 + Protrusion/2)])
    rotate(90)
    cube(AlignBar + [0,0,Protrusion],center=true);
    for (a=[0:90:270])
    rotate(a)
    translate([(AlignBar[1]/2 + AlignBar[0]/2),0,(BasePlate[2] – AlignBar[2]/2 + Protrusion/2)])
    cube(AlignBar + [0,-Protrusion,Protrusion],center=true);
    for (i=[-1,1], j=[-1,0,1]) // holes for tooling plate studs
    translate([i*StudOC[0]*ceil(Platter[OD] / StudOC[0])/2,j*StudOC[0],-Protrusion])
    PolyCyl(StudClear,BasePlate[2] + 2*Protrusion,6);
    translate([0,0,-Protrusion]) // center clamp hole
    PolyCyl(StudClear,BasePlate[2] + 2*Protrusion,6);
    translate([0,0,BasePlate[2] – Platter[LENGTH]]) // disk locating recess
    rotate(180/PlatterSides)
    linear_extrude(height=(Platter[LENGTH] + Protrusion),convexity=2)
    difference() {
    circle(d=(Platter[OD] + 1),$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([2*ThreadWidth,0.9*SocketNut[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([2*ThreadWidth,0.9*Pixel[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,6*ThreadWidth,(ClampLength + 2*Protrusion)]); // clamp relief slot
    }
    }
    //———————-
    // Build it
    if (Layout == "Cap") {
    if (Section)
    difference() {
    Cap();
    translate([-CapSize[OD],0,CapSize[LENGTH]])
    cube([2*CapSize[OD],2*CapSize[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([2*FinCapSize[OD],2*FinCapSize[OD],3*FinCapSize[LENGTH]],center=true);
    translate([-FinCapSize[OD],0,FinCapSize[LENGTH]])
    cube([2*FinCapSize[OD],2*FinCapSize[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([0.25*Platter[OD],-0.6*Platter[OD],0])
    rotate(0)
    Socket();
    if (TubeData[Tube][T_PLATECAP])
    for (i=[-1,1])
    translate([(-0.25*Platter[OD] – i*Pixel[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");}
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