OpenSCAD source code: Prototype board holder with mounting holes and selectable board sizes

Proto Board Holder.scad

// Test support frame for proto boards
// Ed Nisley KE4ZNU - Jan 2017
// June 2017 - Add side-mount bracket, inserts into bottom
// 2017-11 - Selectable board sizes, chassis mounting holes

/* [Options] */

PCBSelect = "ArdUno";    // ["20x80","40x60","30x70","50x70","70x90","80x120","ArdDuemil","ArdMega","ArdPro","ArdUno","ProtoneerCNC"]

Layout = "Frame";       // [Frame, Bracket]

ClampFlange = true;     // external flange

Mounts = true;          // frame to chassis screw holes

Channel = false;        // wiring channel cutout

WasherRecess = false;   // cutout around screw head

/* [Extrusion parameters] */

ThreadThick = 0.25;     // [0.15, 0.20, 0.25]
ThreadWidth = 0.40;

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

/* [Hidden] */

Protrusion = 0.1;

HoleWindage = 0.2;

inch = 25.4;

Tap4_40 = 0.089 * inch;
Clear4_40 = 0.110 * inch;
Head4_40 = 0.211 * inch;
Head4_40Thick = 0.065 * inch;
Nut4_40Dia = 0.228 * inch;
Nut4_40Thick = 0.086 * inch;
Washer4_40OD = 0.270 * inch;
Washer4_40ID = 0.123 * inch;

Tap6_32 = 0.106 * inch;
Clear6_32 = 0.166 * inch;
Head6_32 = 0.251 * inch;
Head6_32Thick = 0.097 * inch;
Nut6_32Dia = 0.312 * inch;
Nut6_32Thick = 0.109 * inch;
Washer6_32OD = 0.361 * inch;
Washer6_32ID = 0.156 * inch;

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

//- PCB sizes
// the list must contain all the selection names as above

//* [Hidden] */
PCB_NAME = 0;
PCB_DIMENSION = 1;

PCBSizes = [
  ["40x60",[40,60,1.6]],
  ["30x70",[30,70,1.6]],
  ["50x70",[50,70,1.6]],
  ["20x80",[20,80,1.6]],
  ["70x90",[70,90,1.6]],
  ["80x120",[80,120,1.6]],
  ["ArdDuemil",[69,84,1.6]],
  ["ArdMega",[102,53.5,1.6]],
  ["ArdPro",[53,53.5,1.6]],
  ["ArdUno",[69,53.1,1.6]],
  ["ProtoneerCNC",[69,53.1,1.6]],
];

PCBIndex = search([PCBSelect],PCBSizes)[0];
PCBSize = PCBSizes[PCBIndex][PCB_DIMENSION];

//echo(str("PCB Size Table: ",PCBSizes));
//echo(str("PCB Select: ",PCBSelect));
//echo(str("PCB Index: ",PCBIndex));
echo(str("PCB Size: ",PCBSize));

/* [Sizes] */

WallThick = 4.0;                                  // basic frame structure

FrameHeight = 10.0;

/* [Hidden] */

Insert = [3.9,4.6,5.8];

PCBShelf = 1.0;                                   // width of support rim under PCB

Clearance = 1*[ThreadWidth,ThreadWidth,0];        // around PCB on all sides

ScrewOffset = ThreadWidth + Insert[OD]/2;         // beyond PCB edges
echo(str("Screw offset: ",ScrewOffset));

/* [Screw Selectors] */

// ij selectors for PCB clamp screw holes: -1/0/1 = left/center/right , bottom/center/top

ScrewSites = [
//  [-1,1],[1,1],[1,-1],[-1,-1],        // corners
//  [-1,0],[1,0],[0,1],[0,-1]           // middles
  [-1,1],[-1,-1],[1,0]                  // Arduinos
];

// ij selectors for frame mounting holes

MountSites = [
    [0,-1],[0,1],
//  [-1,0],[1,0]
];

function ScrewAngle(ij) = (ij[0]*ij[1]) ? ij[0]*ij[1]*15 : ((!ij[1]) ? 30 : 0);    // align screw sides

OAHeight = FrameHeight + Clearance[2] + PCBSize[2];   // total frame height
echo(str("OAH: ",OAHeight));

BossOD = 2*Washer4_40OD;              // make bosses oversized for washers

FlangeExtension = 4.0 + Washer6_32OD/2 - WallThick;   // beyond frame structure

FlangeThick = IntegerMultiple(2.0,ThreadThick);       // plate under frame

Flange = PCBSize
      + 2*[ScrewOffset,ScrewOffset,0]
      + [BossOD,BossOD,0]
      + [2*FlangeExtension,2*FlangeExtension,(FlangeThick - PCBSize[2])]
;

FlangeRadius = BossOD/4;

echo(str("Flange: ",Flange));
NumSides = 4*5;

WireChannel = [Flange[0],15.0,3.0 + PCBSize[2]];        // ad-hoc wiring cutout
WireChannelOffset = [
  Flange[0]/2,0,(FrameHeight + PCBSize[2] - WireChannel[2]/2)
];

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

module PolyCyl(Dia,Height,ForceSides=0) {      // based on nophead's polyholes

  Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);

  FiiDia = Dia / cos(180/Sides);

  cylinder(r=(FiiDia + HoleWindage)/2,h=Height,$fn=Sides);
}

//- Build things

if (Layout == "Frame")
  difference() {
    union() {                                  // body block
      translate([0,0,OAHeight/2])
        cube(PCBSize + Clearance + [2*WallThick,2*WallThick,FrameHeight],center=true);

      for (ij = ScrewSites)                   // screw bosses
        if (ij[0] != 0 || ij[1] != 0)
          translate([ij[0]*(PCBSize[0]/2 + ScrewOffset),
                     ij[1]*(PCBSize[1]/2 + ScrewOffset),
                     0])
            cylinder(d=BossOD,h=OAHeight,$fn=NumSides);

      if (ClampFlange)                        // flange for work holder & mounting screw holes
        linear_extrude(height=Flange[2])
          hull()
            for (i=[-1,1], j=[-1,1]) {
              translate([i*(Flange[0]/2 - FlangeRadius),j*(Flange[1]/2 - FlangeRadius)])
                circle(r=FlangeRadius,$fn=NumSides);          // convenient rounding size
            }
    }

    for (ij = ScrewSites) {                                   // screw position indeies
        if (ij[0] != 0 || ij[1] != 0) {
          translate([ij[0]*(PCBSize[0]/2 + ScrewOffset),
                     ij[1]*(PCBSize[1]/2 + ScrewOffset),
                     -Protrusion])
            rotate(ScrewAngle(ij))
              PolyCyl(Clear4_40,(OAHeight + 2*Protrusion),6);      // screw clearance holes

          translate([ij[0]*(PCBSize[0]/2 + ScrewOffset),
                     ij[1]*(PCBSize[1]/2 + ScrewOffset),
                     -Protrusion])
            rotate(ScrewAngle(ij))
          PolyCyl(Insert[OD],OAHeight - PCBSize[2] - 3*ThreadThick + Protrusion,6);       // inserts

        if (WasherRecess)
          translate([ij[0]*(PCBSize[0]/2 + ScrewOffset),
                     ij[1]*(PCBSize[1]/2 + ScrewOffset),
                     OAHeight - PCBSize[2]])
            PolyCyl(1.2*Washer4_40OD,(PCBSize[2] + Protrusion),NumSides);  // optional washer recess
        }
    }

    if (Mounts)
      for (ij = MountSites)
        translate([ij[0]*(Flange[0]/2 - Washer6_32OD/2),ij[1]*(Flange[1]/2 - Washer6_32OD/2),-Protrusion])
          rotate(ScrewAngle(ij))
            PolyCyl(Clear6_32,(Flange[2] + 2*Protrusion),6);

    translate([0,0,OAHeight/2])                                   // through hole below PCB
      cube(PCBSize - 2*[PCBShelf,PCBShelf,0] + [0,0,2*OAHeight],center=true);

    translate([0,0,(OAHeight - (PCBSize[2] + Clearance[2])/2 + Protrusion/2)])  // PCB pocket on top
      cube(PCBSize + Clearance + [0,0,Protrusion],center=true);

    if (Channel)
      translate(WireChannelOffset)              // opening for wires from bottom side
        cube(WireChannel + [0,0,Protrusion],center=true);
  }

// Add-on bracket to hold smaller PCB upright at edge

PCB2Insert = [3.0,4.9,4.1];
PCB2OC = 45.0;

if (Layout == "Bracket")
  difference() {
    hull()                                   // frame body block
      for (i=[-1,1])                         // bosses around screws
        translate([i*(PCBSize[0]/2 + ScrewOffset),0,0])
          cylinder(r=Washer4_40OD,h=OAHeight,$fn=NumSides);

    for (i=[-1,1])                            // frame screw holes
        translate([i*(PCBSize[0]/2 + ScrewOffset),0,-Protrusion])
          rotate(i*180/(2*6))
            PolyCyl(Clear4_40,(OAHeight + 2*Protrusion),6);

    for (i=[-1,1])                            // PCB insert holes
        translate([i*PCB2OC/2,(Washer4_40OD + Protrusion),OAHeight/2])
          rotate([90,0,0])
            cylinder(d=PCB2Insert[OD],h=2*(Washer4_40OD + Protrusion),$fn=6);

  }

More details on my blog at https://wp.me/poZKh-7aC