fix: make tripod case dovetail connector fit

hardware/README.md

@@ -105,8 +105,8 @@ The ESP8266 and GoPro talk over Wi-Fi — **no data cable between them**. The on
 
 | | W × D × H (mm) |
 |---|---|
-| Case body external | ~56.8 × 36.9 × 19.0 |
+| Case body external | ~56.8 × 38.2 × 19.0 |
 | Lid external | ~56.8 × 32.8 × 4.0 |
-| Tripod clamp | ~43.0 × 54.3 × 16.0 |
+| Tripod clamp | ~43.0 × 56.9 × 16.0 |
 | Clamp pole fit | Nominal 35mm; smaller poles TBD / may need inserts |
 | Total weight | TBD after prototype print |

hardware/case/tripod-case-v3.scad

@@ -29,12 +29,15 @@ mouth_width   = 13.0;     // clamp opening
 m3_clearance  = 3.4;      // M3 screw clearance
 nut_flat      = 6.4;      // M3 nut trap flat-to-flat
 
-// Dovetail interface
+// Dovetail slide interface
+// Male rail is on the case; matching female socket is on the tripod clamp.
+// This is easier to inspect and avoids the previous mismatched "two lips + tab" geometry.
 rail_z         = outer_h * 0.78;
 rail_depth     = 5.0;
-rail_open_w   = 12.0;
-rail_back_w   = 18.0;
-rail_clearance = 0.35;
+rail_neck_w    = 12.0;   // narrow width at case wall / slot opening
+rail_outer_w   = 18.0;   // wider retained edge
+rail_clearance = 0.45;   // FDM sliding clearance per side-ish
+socket_wall    = 2.2;
 
 // Cable ports
 usb_port_w = 12; usb_port_h = 6;
@@ -104,17 +107,15 @@ module screw_post(x, y) {
     }
 }
 
-module dovetail_socket_rails() {
-    // Female-ish dovetail receiver on the case back. The clamp's male dovetail slides vertically.
-    // Two angled lips are intentionally proud of the rear wall for printability and strength.
-    for (side = [-1, 1]) {
-        translate([side*(rail_open_w/2 + 1.3), outer_d/2 + 0.9, outer_h/2])
-            rotate([0, 0, side*8])
-                cube([3.0, rail_depth + 1.0, rail_z], center=true);
-    }
-    // Bottom stop so clamp cannot slide all the way through.
-    translate([0, outer_d/2 + 1.3, outer_h*0.12])
-        cube([rail_back_w + 2, rail_depth, 2.4], center=true);
+module case_male_dovetail_rail() {
+    // Positive tapered rail on the case back. Cross-section is narrow at the
+    // wall and wider at the outside, so the clamp socket captures it.
+    translate([0, outer_d/2 - 0.15, outer_h/2])
+        dovetail_prism(rail_z, rail_neck_w, rail_outer_w, rail_depth);
+
+    // Bottom stop so the clamp socket cannot slide past the case.
+    translate([0, outer_d/2 + rail_depth/2, outer_h*0.12])
+        rounded_cube_centered(rail_outer_w + 3.0, rail_depth + 0.8, 2.4, 0.8);
 }
 
 module case_body() {
@@ -122,7 +123,7 @@ module case_body() {
         case_shell();
         for (x = [-1, 1], y = [-1, 1])
             screw_post(x*(outer_w/2 - 5), y*(outer_d/2 - 5));
-        dovetail_socket_rails();
+        case_male_dovetail_rail();
     }
 }
 
@@ -173,18 +174,33 @@ module clamp_ears() {
     }
 }
 
-module male_dovetail_tab() {
+module clamp_dovetail_socket() {
     outer_r = pole_dia/2 + clamp_thick;
-    // Tab on rear of clamp, opposite the mouth. Slides into case rails.
-    translate([0, -outer_r - rail_depth + 0.4, 0])
-        dovetail_prism(clamp_width, rail_open_w - rail_clearance, rail_back_w - rail_clearance, rail_depth);
+    socket_outer_w = rail_outer_w + socket_wall*2;
+    socket_depth   = rail_depth + socket_wall*2;
+
+    // Solid boss on the rear of the clamp, opposite the tightening mouth.
+    // A matching dovetail void is cut through it along Z so the case rail
+    // slides in from the top/bottom with practical FDM clearance.
+    difference() {
+        translate([0, -outer_r - socket_depth/2 + socket_wall, 0])
+            rounded_cube_centered(socket_outer_w, socket_depth, clamp_width, 1.2);
+
+        translate([0, -outer_r - 0.15, 0])
+            dovetail_prism(
+                clamp_width + 1.0,
+                rail_neck_w + rail_clearance,
+                rail_outer_w + rail_clearance,
+                rail_depth + 0.6
+            );
+    }
 }
 
 module tripod_clamp() {
     union() {
         clamp_ring_with_mouth();
         clamp_ears();
-        male_dovetail_tab();
+        clamp_dovetail_socket();
     }
 }