diff --git a/src/components/three/ModelViewer.tsx b/src/components/three/ModelViewer.tsx
index 8725376..2a1061e 100644
--- a/src/components/three/ModelViewer.tsx
+++ b/src/components/three/ModelViewer.tsx
@@ -596,8 +596,25 @@ function PositionDragHandler() {
             rotX: ft.rotX + dy * sens,
           });
         }
-      } else if (button === 1 || (button === 0 && shiftKey)) {
-        // Middle or Shift+left: depth (Z in camera space)
+      } else if (button === 1) {
+        // Middle button (wheel): roll around the piece's own longitudinal axis
+        const sens = 0.5;
+        let dominant: 'x' | 'y' | 'z' = 'x';
+        scene.traverse((o) => {
+          if (o.userData?.modelId === active.id && o.userData?.dominantAxis) {
+            dominant = o.userData.dominantAxis;
+          }
+        });
+        const delta = dx * sens;
+        if (dominant === 'x') {
+          useModelStore.getState().setFineTuning({ rotX: ft.rotX + delta });
+        } else if (dominant === 'y') {
+          useModelStore.getState().setFineTuning({ rotY: ft.rotY + delta });
+        } else {
+          useModelStore.getState().setFineTuning({ rotZ: ft.rotZ + delta });
+        }
+      } else if (button === 0 && shiftKey) {
+        // Shift+left: depth (Z in camera space)
         const worldDelta = dy * pixelsPerWorldUnit;
         const camDir = new THREE.Vector3();
         camera.getWorldDirection(camDir);