SCAD (85 lines)
// Small butt hinge for furniture — open 180°
// Pin axis = Y axis (+Y), leaves lie in Z-normal plane
$fn = 64;
// ---------- parameters ----------
leaf_len = 30; // along Y (hinge axis)
leaf_w = 25; // along X (opening direction)
leaf_t = 2; // thickness (Z)
pin_d = 4;
pin_len = 32;
clearance = 0.3;
kn_od = 8;
kn_id = pin_d + clearance; // 4.6
kn_seg = leaf_len / 5; // 6 mm
hole_pitch = 8;
hole_d = 3.2;
csk_d = 6;
csk_depth = 1;
hole_x = 18; // distance from pin axis to screw line
// ---------- helpers ----------
module knuckle(y0, y1) {
// cylinder along Y from y0 to y1, centered on X=0, Z=0
translate([0, y0, 0])
rotate([-90, 0, 0])
cylinder(d = kn_od, h = y1 - y0);
}
module pin_bore() {
translate([0, -1, 0])
rotate([-90, 0, 0])
cylinder(d = kn_id, h = leaf_len + 2);
}
module screw_hole() {
// through hole + countersink on top face (+Z)
union() {
translate([0, 0, -1])
cylinder(d = hole_d, h = leaf_t + 2);
translate([0, 0, leaf_t - csk_depth])
cylinder(d1 = hole_d, d2 = csk_d, h = csk_depth + 0.01);
translate([0, 0, leaf_t - 0.001])
cylinder(d = csk_d, h = 1);
}
}
// Generic leaf; sgn = -1 for left (x<0), +1 for right (x>0)
// segs = list of knuckle segment indices (0..4)
module leaf(sgn, segs) {
difference() {
union() {
// plate: from knuckle to outer edge, top face at Z=leaf_t/2
translate([sgn > 0 ? 0 : -leaf_w, 0, -leaf_t / 2])
cube([leaf_w, leaf_len, leaf_t]);
// knuckles
for (i = segs)
knuckle(i * kn_seg, (i + 1) * kn_seg);
}
// pin bore
pin_bore();
// gap cuts between knuckles (so adjacent segments don't touch)
for (i = [0 : 4])
if (len(search(i, segs)) == 0)
translate([-kn_od, i * kn_seg - 0.15, -kn_od])
cube([2 * kn_od, kn_seg + 0.3, 2 * kn_od]);
// screw holes
for (j = [-1, 0, 1])
translate([sgn * hole_x, leaf_len / 2 + j * hole_pitch, -leaf_t / 2])
screw_hole();
}
}
module pin() {
translate([0, -1, 0])
rotate([-90, 0, 0])
cylinder(d = pin_d, h = pin_len);
}
// ---------- assembly (open 180°) ----------
color("silver") leaf(-1, [0, 2, 4]); // left leaf: outer 2 + center
color("lightgray") leaf( 1, [1, 3]); // right leaf: middle 2
color("gold") pin();