$fn = 64;

// --- Parameters ---
rail_length = 300;
rail_height = 10;
base_width = 20;
top_width = 32;

hole_spacing = 50;
hole_diameter = 4.5;
countersink_diameter = 9.5;
countersink_depth = 3.5;

// --- Main Model ---
difference() {
    // Dovetail rail body
    translate([0, rail_length / 2, 0])
    rotate([90, 0, 0])
    linear_extrude(height = rail_length)
    polygon(points = [
        [-base_width / 2, 0],
        [base_width / 2, 0],
        [top_width / 2, rail_height],
        [-top_width / 2, rail_height]
    ]);
    
    // Mounting holes
    num_holes = floor(rail_length / hole_spacing);
    start_y = -((num_holes - 1) * hole_spacing) / 2;
    
    for (i = [0 : num_holes - 1]) {
        translate([0, start_y + (i * hole_spacing), 0]) {
            // Through hole
            translate([0, 0, -1])
            cylinder(h = rail_height + 2, d = hole_diameter);
            
            // Countersink cone
            translate([0, 0, rail_height - countersink_depth])
            cylinder(h = countersink_depth, d1 = hole_diameter, d2 = countersink_diameter);
            
            // Top clearance to ensure clean manifold cut
            translate([0, 0, rail_height - 0.01])
            cylinder(h = 1, d = countersink_diameter);
        }
    }
}