SCAD (138 lines)
// ============================================================
// Small furniture butt hinge (180 deg open)
// - Left leaf : x < 0 (3 knuckles: outer 2 + center 1)
// - Right leaf : x > 0 (2 knuckles: intermediate)
// - Pin : along +Y axis, centered on Y axis
// ============================================================
$fn = 96;
// ---------- Parameters ----------
leaf_len = 30; // along Y (hinge axis)
leaf_wid = 25; // along X (opening direction)
leaf_thk = 2; // plate thickness (Z)
pin_dia = 4;
pin_len = 32; // 1 mm proud at each end
knuckle_od = 8;
pin_clear = 0.3;
knuckle_id = pin_dia + pin_clear; // 4.6
seg = leaf_len / 5; // 6 mm per segment
gap = 0.15; // small running clearance between knuckles
// countersunk screw holes (M3)
cs_top_dia = 6;
cs_depth = 1;
hole_dia = 3.2;
hole_pitch = 8;
hole_inset = 6; // distance from outer edge of leaf to hole centers
eps = 0.01;
// Segment centers along Y : -12, -6, 0, 6, 12
function seg_y(i) = -leaf_len/2 + seg/2 + i*seg; // i = 0..4
// ============================================================
// Modules
// ============================================================
// One knuckle (tube) segment centred on Y = yc
module knuckle(yc, h) {
translate([0, yc, 0])
rotate([-90, 0, 0])
difference() {
cylinder(h = h, d = knuckle_od, center = true);
cylinder(h = h + 1, d = knuckle_id, center = true);
}
}
// Countersunk hole, drilled from +Z down through the plate
module cs_hole() {
union() {
// through hole
translate([0, 0, -leaf_thk/2 - eps])
cylinder(h = leaf_thk + 2*eps, d = hole_dia);
// conical countersink at top face
translate([0, 0, leaf_thk/2 - cs_depth])
cylinder(h = cs_depth + eps, d1 = hole_dia, d2 = cs_top_dia);
}
}
// Plate body extending in +X from the knuckle axis, blended into knuckle OD
module leaf_plate() {
// main flat plate from x = knuckle_od/2 ... leaf_wid
translate([knuckle_od/2 - 0.5, -leaf_len/2, -leaf_thk/2])
cube([leaf_wid - knuckle_od/2 + 0.5, leaf_len, leaf_thk]);
}
// Web that ties the plate to its own knuckle segments
module leaf_web(yc, h) {
translate([0, yc - h/2, -leaf_thk/2])
cube([knuckle_od/2, h, leaf_thk]);
}
// Screw hole pattern for one leaf (in local +X leaf coordinates)
module leaf_holes() {
for (k = [-1, 0, 1])
translate([leaf_wid - hole_inset, k * hole_pitch, 0])
cs_hole();
}
// ---- Right leaf : plate in +X, knuckles at segments 1 and 3 ----
module right_leaf() {
color("Silver")
difference() {
union() {
leaf_plate();
for (i = [1, 3]) {
knuckle(seg_y(i), seg - gap);
leaf_web(seg_y(i), seg - gap);
}
}
leaf_holes();
// clear the pin bore through everything
rotate([-90, 0, 0])
cylinder(h = leaf_len + 20, d = knuckle_id, center = true);
}
}
// ---- Left leaf : mirrored, knuckles at segments 0, 2 and 4 ----
module left_leaf() {
color("Silver")
mirror([1, 0, 0])
difference() {
union() {
leaf_plate();
for (i = [0, 2, 4]) {
knuckle(seg_y(i), seg - gap);
leaf_web(seg_y(i), seg - gap);
}
}
leaf_holes();
rotate([-90, 0, 0])
cylinder(h = leaf_len + 20, d = knuckle_id, center = true);
}
}
// ---- Pin ----
module pin() {
color("DimGray")
rotate([-90, 0, 0])
union() {
cylinder(h = pin_len, d = pin_dia, center = true);
// small chamfered heads at both ends
translate([0, 0, pin_len/2 - 0.4])
cylinder(h = 0.4, d1 = pin_dia, d2 = pin_dia - 0.8);
translate([0, 0, -pin_len/2])
cylinder(h = 0.4, d1 = pin_dia - 0.8, d2 = pin_dia);
}
}
// ============================================================
// Assembly : 180 deg open
// ============================================================
left_leaf();
right_leaf();
pin();
