The New Hotness

Although I’d put the same knob on the half-triangle end piece template as on the equilateral triangle template for piecing hexagons into strips, Mary decided a flat chip would be easier to use:

Quilting Hex Template - family - knobless half-triangle — Quilting Hex Template – family – knobless half-triangle

Bonus: you can now flip it over to cut the other half-triangles, if you haven’t already figured out how to cut two layers of fabric folded wrong sides together.

While I was at it, the knob on the triangle became optional, too. Flipping that one doesn’t buy you much, though.

The OpenSCAD source as a GitHub Gist has been ever so slightly tweaked:

	// 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],
	[TriRadiuscos(120),TriRadiussin(120)],
	[TriRadiuscos(240),TriRadiussin(240)]
	];
	echo(str("TriPoints: ",TriPoints));

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

	TipCutRadius = 2*(TriRadius + SeamAllowance); // circumscribing radius of tip cutter
	TipPoints = [[TipCutRadius,0],
	[TipCutRadiuscos(120),TipCutRadiussin(120)],
	[TipCutRadiuscos(240),TipCutRadiussin(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,$fn=HandleSides);
	translate([0,0,-HandleHeight])
	cube([2TemplateOD,2TemplateOD,2*HandleHeight],center=true);
	translate([0,HandleThick,StringHeight])
	rotate([90,090,0])
	rotate(180/8)
	PolyCyl(StringDia,2*HandleThick,8);
	for (j=[-1,1]) {
	translate([0,j*(DentSphereRadius + HandleThick/2 – DentDepth),StringHeight])
	rotate(180/48)
	sphere(r=DentSphereRadius,$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();
	}

view raw Quilting Hex Template.scad hosted with ❤ by GitHub

The New Hotness

Quilting Hexagon Template Generator: Knobless Half-Triangle