Add 2in_core

2 inch core for 16mm film, can be made into arbitrary sizes by changing
oW parameter.

models/2in_core/2in_core.scad

@@ -0,0 +1,83 @@
+module core (oW, decoy = false) {
+	coreH = 16;
+	iW = 15.3;
+	oW = oW / 2;
+     $fn = 100;
+    
+	module cyl (R) {
+		cylinder(r = R, h = coreH, center = true);
+	}
+
+	module inner_core_shape (coreR, trans, cubeW, cubeL) {
+		union () {
+			cyl(coreR);
+			translate([trans, 0, 0]) {
+				cube([cubeW, cubeL, coreH], center = true);
+			}
+		}
+	}
+
+	module inner_core () {
+		difference () {
+			inner_core_shape(iW, iW + .5, 6, 7);
+			inner_core_shape(iW - 2, iW - .5, 4, 4);
+		}
+	}
+	module clip () {
+		translate([oW - 2, 0, 0]) {
+			rotate(45, [0, 0, 1]){
+				cube([6, 1, coreH], center = true);
+			}
+		}
+	}
+
+	module outer_clip () {
+		translate([oW - 2, 0, 0]) {
+			difference() {
+				rotate(45, [0, 0, 1]){
+					cube([8, 4, coreH], center = true);
+				}
+				translate([3.9, 0, 0]) {
+					cube([6, 8, coreH], center = true);
+				}
+			}
+		}
+	}
+
+	module outer_core () {
+		difference () {
+			union () {
+				difference () {
+					cyl(oW);
+					cyl(oW - 2);
+				}
+				outer_clip();
+			}
+			clip();
+		}
+	}
+
+	module supports (x) {
+		for (i = [0 : x]) {
+			rotate ([0, 0, i * 360 / (x + 1)]) {
+				if (i == 0) {
+					translate ([iW + ((oW - iW) / 2) - 1, 0, 0]) {
+						cube([oW - iW - 5.7, 2, coreH] ,center = true);
+					}
+				} else {
+					translate ([iW + ((oW - iW) / 2) - 1, 0, 0]) {
+						cube([oW - iW - 1, 2, coreH] ,center = true);
+					}
+				}
+			}
+		}
+	}
+
+	union () {
+		inner_core();
+		outer_core();
+		supports(6);
+	}	
+}
+
+core(50, true);