// --- NEW CALIBRATION TRIO (TIGHTER RANGE) ---
$fn = 100;

pvc_od = 33.4; 
wall = 4;
height = 10; // 10mm tall for speed

// New tighter offsets
offsets = [0.05, 0.15, 0.25]; 

module test_ring(offset, index) {
    id = pvc_od + offset;
    od = id + (wall * 2);
    
    translate([index * (od + 10), 0, 0]) {
        difference() {
            cylinder(d = od, h = height);
            
            // Clean hole through
            translate([0, 0, -1])
                cylinder(d = id, h = height + 2);
            
            // Identification Notches
            for (n = [0 : index]) {
                rotate([0, 0, n * 20])
                translate([od/2, 0, height/2])
                cube([4, 2, height + 1], center=true);
            }
        }
    }
}

test_ring(offsets[0], 0); // 1 Notch  (0.05)
test_ring(offsets[1], 1); // 2 Notches (0.15)
test_ring(offsets[2], 2); // 3 Notches (0.25)