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CADAM-master/benchmarks/03-hex-bolt-and-nut.md

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+# 3 — Hex bolt & nut — real threads
+
+> **Prompt**
+>
+> Create an M12 hex bolt 45 mm long with a real threaded shaft and a standard hex head, plus its matching hex nut, placed side by side.
+
+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="03-hex-bolt-and-nut.gif" alt="Hex bolt & nut — real threads — orbiting render" width="380"></p>
+
+**Parametric controls:** 3 dimensions · 2 colours
+
+**What it demonstrates**
+
+- **Real ISO metric threads** via BOSL2 `screw()` / `nut()` (spec `"M12x1.75"`) — not faked with stacked cylinders
+- A complete fastener set: hex bolt + matching hex nut
+- Standard spec string drives pitch, head, and thread profile
+
+**Editable parameters**
+
+| Parameter | Default | Range / options | Description |
+| --- | --- | --- | --- |
+| `screw_length` | `45` | `[10:1:100]` | Length of the screw shaft |
+
+<details>
+<summary>OpenSCAD source — <code>03-hex-bolt-and-nut.scad</code></summary>
+
+```scad
+include <BOSL2/std.scad>
+include <BOSL2/screws.scad>
+
+/* [Screw Parameters] */
+// The screw size and pitch specification
+screw_spec = "M12x1.75"; 
+
+// Length of the screw shaft
+screw_length = 45;      // [10:1:100]
+
+/* [Colors] */
+bolt_color = "LightSlateGray";
+nut_color = "LightSlateGray";
+
+$fn = 64;
+
+// Place bolt on the left
+translate([-15, 0, 0])
+color(bolt_color)
+screw(spec=screw_spec, l=screw_length, head="hex");
+
+// Place nut on the right
+translate([15, 0, 0])
+color(nut_color)
+nut(spec=screw_spec);
+```
+
+</details>