OpenSCAD source code: replacement clips for fake muntin grille

Window Muntin Clips.scad

// Window Muntin Clips
// Ed Nisley KE4ZNU June 2022

Layout = "Show";       // [Build, Show]

/* [Hidden] */

ThreadThick = 0.25;
ThreadWidth = 0.40;

HoleWindage = 0.2;

Protrusion = 0.1;           // make holes end cleanly

inch = 25.4;

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

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

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

ClipOA = [13.0,18.7,8.0];

TongueAngle = 70;

TongueOA = [14.0,10.0,1.8 - 0.2];       // minus Z windage for angular slices

BuildGap = 5.0;

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

//----------------------
// Pieces


module Shell() {

// Clip base as 2D polygon
// Magic numbers from measurements

cx = ClipOA.x;
cy = ClipOA.y;
cz = ClipOA.z;

ClipPts = [
[0,0],[0,cz],[0.3,cz],
[1.0,cz-1.0],[2.0,cz-2.3],[2.0,cz-3.0],[1.3,cz-3.5],
[1.3,1.6],[17.4,1.6],
[17.4,cz-3.5],[16.7,cz-3.0],[16.7,cz-2.3],[17.7,cz-1.0],
[18.4,cz],[18.7,cz],[18.7,0.0],[0,0]
];

    difference() {
        translate([-ClipOA.x,-ClipOA.y/2,0])
            rotate([90,0,90])
                linear_extrude(height=ClipOA.x,convexity=3)
                    polygon(convexity=3,points=ClipPts);
        translate([-(ClipOA.x - 3.0/2 + Protrusion),0,0])
            cube([3.0 + Protrusion,ClipOA.y - 2*1.3,4*1.6],center=true);
    }
}

module Tongue() {

tx = TongueOA.x;
ty = TongueOA.y;
tz = TongueOA.z;

tt = ty - 2*sqrt(2)*tz;         // width at top of tapers
td = ThreadWidth;               // min size of features

    intersection() {

        rotate([0,-TongueAngle,0]) {

            difference() {

                union() {
                    hull() {
                        for (j=[-1,1]) {
                            translate([td/2,j*(ty - td)/2,td/2])
                                cube(td,center=true);
                            translate([td/2,j*(tt - td)/2,tz - td/2])
                                cube(td,center=true);
                        }
                        translate([10.0,0,0])
                            rotate(180/12)
                                cylinder(d=ty,h=td,center=false,$fn=12);
                        translate([10.0,0,tz - td/2])
                            rotate(180/12)
                                cylinder(d=tt,h=td,center=false,$fn=12);
                    };

                    translate([10.0,0,-5.2])
                        rotate(180/12)
                            cylinder(d=5.0,h=5.2,center=false,$fn=12);

                    translate([10.0,0,-5.2])
                        rotate(180/12)
                            resize([0,0,2.0])
                                sphere(d=5.0/cos(180/12),$fn=12);

                }

                if (false)
                    translate([10.0,0,-10])     // stiffening hole
                        rotate(180/6)
                            PolyCyl(0.1,20,6);

            }


        }

        cube([2*ClipOA.x,2*ClipOA.y,2*IntegerMultiple(13.0,ThreadThick)],center=true);
    }


}

module Clip() {
    Shell();
    Tongue();
}

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


if (Layout == "Show") {
    Clip();
}

if (Layout == "Build") {
    Clip();
}

More details on my blog at https://wp.me/poZKh-b2J