OpenSCAD source code: Felt feet for Pride lift chairs

Lift Chair Feet.scad

// Feet for Pride lift chair
// Ed Nisley KE4ZNU 2020-05

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

Support = true;

//- Extrusion parameters must match reality!
//  Print with 2 shells and 3 solid layers

/* [Hidden] */

ThreadThick = 0.25;
ThreadWidth = 0.40;

HoleWindage = 0.2;

Protrusion = 0.1;			// make holes end cleanly

inch = 25.4;

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

/* [Dimensions] */

ChairFootOD = 33.0;
ChairFootRecess = 5.0;

FeltOD = 39.0;
FeltRecess = 2.5;

FootPlate = 6*ThreadThick;
FootWall = 4*ThreadWidth;

FootOD = 2*FootWall + max(ChairFootOD,FeltOD);
echo(str("Foot OD: ",FootOD));

FootTall = ChairFootRecess + FootPlate + FeltRecess;
echo(str(" ... height: "),FootTall);

NumSides = 9*4;


//----------------------
// Useful routines

module FootPad() {

	difference() {

		cylinder(r=FootOD/2,h=FootTall,$fn=NumSides);

		translate([0,0,FeltRecess + FootPlate])
			cylinder(d=ChairFootOD,h=2*ChairFootRecess,$fn=NumSides);

		translate([0,0,-Protrusion])
			cylinder(d=FeltOD,h=(FeltRecess + Protrusion),$fn=NumSides);

	}
}


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


if (Layout == "Show")
	FootPad();

if (Layout == "Build") {
	translate([0,0,FootTall])
		rotate([180,0,0])
			FootPad();
	if (Support)
		color("Yellow") {
			for (Seg=[0:5])
				rotate(30 + 360*Seg/6)
				translate([0,0,(ChairFootRecess - ThreadThick)/2])
					cube([(ChairFootOD - 3*ThreadWidth),
						  2*ThreadWidth,
						  (ChairFootRecess - ThreadThick)],
						  center=true);
      rotate(180/6)
        cylinder(d=0.5*ChairFootOD,h=ThreadThick,$fn=6);
    }
}

More details on my blog at https://wp.me/poZKh-93H