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+# 7 — Right-angle bevel gear drive
+
+> **Prompt**
+>
+> Build a right-angle bevel gear drive: a 24-tooth bevel gear on a vertical shaft meshing at 90 degrees with a 16-tooth bevel pinion on a horizontal shaft, each on a short stub shaft.
+
+Fully parametric OpenSCAD built from the prompt above — adjustable dimensions and colours, exported as `.SCAD` and rendered to the orbiting preview with [`render.sh`](render.sh).
+
+<p align="center"><img src="07-bevel-gear-drive.gif" alt="Right-angle bevel gear drive — orbiting render" width="380"></p>
+
+**Parametric controls:** 9 dimensions · 3 colours
+
+**What it demonstrates**
+
+- A meshing **bevel gear pair** at 90° via BOSL2 `bevel_gear()` with matched pitch cones
+- 24-tooth gear + 16-tooth pinion, each on a stub shaft
+- Three colours for gear / pinion / shafts
+
+**Editable parameters**
+
+| Parameter | Default | Range / options | Description |
+| --- | --- | --- | --- |
+| `gear1_teeth` | `24` | `[10:1:60]` |  |
+| `gear2_teeth` | `16` | `[10:1:60]` |  |
+| `circular_pitch` | `5` | `[2:0.5:10]` |  |
+| `face_width` | `8` | `[4:1:20]` |  |
+| `bore_diameter` | `5` | `[2:0.5:20]` |  |
+| `shaft_length` | `30` | `[10:1:50]` |  |
+| `shaft_diameter` | `5` | `[2:0.5:20]` |  |
+| `gear2_spin` | `11.25` | `[0:0.1:45]` |  |
+
+<details>
+<summary>OpenSCAD source — <code>07-bevel-gear-drive.scad</code></summary>
+
+```scad
+include <BOSL2/std.scad>
+include <BOSL2/gears.scad>
+
+/* [Gear Specifications] */
+gear1_teeth = 24;      // [10:1:60]
+gear2_teeth = 16;      // [10:1:60]
+circular_pitch = 5;    // [2:0.5:10]
+face_width = 8;        // [4:1:20]
+bore_diameter = 5;     // [2:0.5:20]
+shaft_length = 30;     // [10:1:50]
+shaft_diameter = 5;    // [2:0.5:20]
+gear2_spin = 11.25;    // [0:0.1:45]
+
+/* [Colors] */
+gear1_color = "SteelBlue";
+gear2_color = "DarkOrange";
+shaft_color = "Silver";
+
+$fn = 64;
+
+module gear_system() {
+    // Gear 1: Vertical (Z-axis)
+    color(gear1_color)
+    bevel_gear(
+        circ_pitch = circular_pitch,
+        teeth = gear1_teeth,
+        mate_teeth = gear2_teeth,
+        face_width = face_width,
+        bore = bore_diameter,
+        spiral = 0,
+        anchor = "apex"
+    );
+    
+    // Vertical Shaft
+    color(shaft_color)
+    translate([0, 0, -shaft_length/2])
+    cylinder(h=shaft_length, d=shaft_diameter, center=true);
+
+    // Gear 2: Horizontal (X-axis)
+    color(gear2_color)
+    rotate([0, 90, 0])
+    rotate([0, 0, gear2_spin]) // Fine-tune tooth meshing
+    bevel_gear(
+        circ_pitch = circular_pitch,
+        teeth = gear2_teeth,
+        mate_teeth = gear1_teeth,
+        face_width = face_width,
+        bore = bore_diameter,
+        spiral = 0,
+        anchor = "apex"
+    );
+    
+    // Horizontal Shaft
+    color(shaft_color)
+    rotate([0, 90, 0])
+    translate([0, 0, -shaft_length/2])
+    cylinder(h=shaft_length, d=shaft_diameter, center=true);
+}
+
+gear_system();
+```
+
+</details>