OpenSCAD source code: Generator for 3D printed hex, triangle, and half-triangle quilting templates

Quilting Hex Template.scad

// Quilting - Hexagon Templates
// Ed Nisley KE4ZNU - July 2020
// Reverse-engineered to repair a not-quite-standard hexagon quilt
// Useful geometry:
//  https://en.wikipedia.org/wiki/Hexagon

/* [Layout Options] */

Layout = "Build";                    // [Build, HexBuild, HexPlate, TriBuild, TriPlate, EndBuild, EndPlate]

//-------
//- Extrusion parameters must match reality!
//  Print with 2 shells

/* [Hidden] */

ThreadThick = 0.25;
ThreadWidth = 0.40;

HoleFinagle = 0.2;
HoleFudge = 1.00;

function HoleAdjust(Diameter) = HoleFudge*Diameter + HoleFinagle;

Protrusion = 0.1;           // make holes end cleanly

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

inch = 25.4;

//-------
// Dimensions

/* [Layout Options] */

FinishedWidthInch = 2.75;
FinishedWidth = FinishedWidthInch * inch;

SeamAllowanceInch = 0.25;
SeamAllowance = SeamAllowanceInch * inch;

TemplateThick = 3.0;

TriKnob = true;
EndKnob = false;

/* [Hidden] */

FinishedSideInch = FinishedWidthInch/sqrt(3);
FinishedSide = FinishedSideInch * inch;

echo(str("Finished side: ",FinishedSideInch," inch"));

CutWidth = FinishedWidth + 2*SeamAllowance;

CutSide = CutWidth/sqrt(3);
echo(str("Cut side: ",CutSide / inch," inch"));

// Make polygon-circles circumscribe the target widths

TemplateID = FinishedWidth / cos(180/6);
TemplateOD = CutWidth / cos(180/6);

/* [Hidden] */

TriRadius = FinishedSide/sqrt(3);

TriPoints = [[TriRadius,0],
             [TriRadius*cos(120),TriRadius*sin(120)],
             [TriRadius*cos(240),TriRadius*sin(240)]
            ];
echo(str("TriPoints: ",TriPoints));

EndPoints = [[TriRadius,0],
             [TriRadius*cos(120),TriRadius*sin(120)],
             [TriRadius*cos(120),0]
            ];
echo(str("EndPoints: ",EndPoints));

TipCutRadius = 2*(TriRadius + SeamAllowance);       // circumscribing radius of tip cutter
TipPoints = [[TipCutRadius,0],
             [TipCutRadius*cos(120),TipCutRadius*sin(120)],
             [TipCutRadius*cos(240),TipCutRadius*sin(240)]
            ];

HandleHeight = 1 * inch;
HandleLength = (TemplateID + TemplateOD)/2;
HandleThick = IntegerMultiple(3.0,ThreadWidth);
HandleSides = 12*4;

StringDia = 4.0;
StringHeight = 0.6*HandleHeight;

DentDepth = HandleThick/4;
DentDia = 15 * DentDepth;
DentSphereRadius = (pow(DentDepth,2) + pow(DentDia,2)/4)/(2*DentDepth);

KnobOD = 15.0;    // Triangle handle
KnobHeight = 20.0;

//-------

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=HoleAdjust(FixDia)/2,h=Height,$fn=Sides);
}


//-------
// Hex template

module HexPlate() {

  difference() {
    cylinder(r=TemplateOD/2,h=TemplateThick,$fn=6);
    translate([0,0,-Protrusion])
      cylinder(r=TemplateID/2,h=(TemplateThick + 2*Protrusion),$fn=6);
  }

  for (i=[1:6/2])
    rotate(i*60)
      translate([0,0,TemplateThick/2])
        cube([HandleLength,HandleThick,TemplateThick],center=true);
}

module HexHandle() {

	difference() {
		rotate([90,0,0])
			scale([1,HandleHeight/(TemplateOD/2),1])
				rotate(180/HandleSides)
					cylinder(d=HandleLength,h=HandleThick,center=true,$fn=HandleSides);
		translate([0,0,-HandleHeight])
			cube([2*TemplateOD,2*TemplateOD,2*HandleHeight],center=true);
		translate([0,HandleThick,StringHeight])
			rotate([90,090,0])
				rotate(180/8)
					PolyCyl(StringDia,2*HandleThick,8);
		for (j=[-1,1]) {
			translate([0,j*(DentSphereRadius + HandleThick/2 - DentDepth),StringHeight])
        rotate(180/48)
				sphere(r=DentSphereRadius,$fn=48);
		}
	}

}

module HexTemplate() {
	HexPlate();
  HexHandle();
}

//-------
// Triangle template

module TriPlate() {

  linear_extrude(height=TemplateThick)
    intersection() {
      offset(delta=SeamAllowance)     // basic cutting outline
        polygon(points=TriPoints);
      rotate(180)
        polygon(points=TipPoints);
    }
}


module TriTemplate() {

  union() {
    if (TriKnob)
      cylinder(d=KnobOD,h=KnobHeight,$fn=HandleSides);
    TriPlate();
  }

}

//-------
// End piece template

module EndPlate() {

  linear_extrude(height=TemplateThick)
    intersection() {
      offset(delta=SeamAllowance)     // basic cutting outline
        polygon(points=EndPoints);
      rotate(180)
        polygon(points=TipPoints);
    }
}

module EndTemplate() {

  union() {
    if (EndKnob)
      translate([0,(TriRadius/2)*sin(30),0])
        cylinder(d=KnobOD,h=KnobHeight,$fn=HandleSides);
    EndPlate();
  }

}



//-------
// Build it!

if (Layout == "HexPlate")
	HexPlate();

if (Layout == "HexBuild")
	HexTemplate();

if (Layout == "TriPlate")
  TriPlate();

if (Layout == "TriBuild")
  TriTemplate();

if (Layout == "EndPlate")
  EndPlate();

if (Layout == "EndBuild")
  EndTemplate();

if (Layout == "Build") {
  translate([1.5*TriRadius,-TriRadius,0])
    rotate(180/6)
      TriTemplate();
  translate([-1.5*TriRadius,-TriRadius,0])
    rotate(180/6)
      EndTemplate();
  translate([0,TemplateOD/2,0])
    HexTemplate();
}

More details on my blog at https://wp.me/poZKh-9fL