diff --git a/VolZmapVolume.cpp b/VolZmapVolume.cpp
index 0f238e3..d778a17 100644
--- a/VolZmapVolume.cpp
+++ b/VolZmapVolume.cpp
@@ -2610,7 +2610,14 @@ VolZmap::MillingGeneralMotionStep( const Point3d& ptPs, const Vector3d& vtDs, co
 
   // Calcolo angoli di rotazione utensile longitudinale e trasversale rispetto al movimento per eventuale suddivisione
    double dAlongAngDeg, dAcrossAngDeg ;
-   GetAlongAcrossRotation( vtDs, vtDe, ptPe - ptPs, dAlongAngDeg, dAcrossAngDeg) ;
+   if ( m_vTool[m_nCurrTool].GetRadius() < 40)
+      GetAlongAcrossRotation( vtDs, vtDe, ptPe - ptPs, dAlongAngDeg, dAcrossAngDeg) ;
+   else {
+      Vector3d vtAxis = vtDs ^ vtDe ;
+      GetAlongAcrossRotation( vtDs, vtDe, vtAxis, dAlongAngDeg, dAcrossAngDeg) ;
+      swap( dAlongAngDeg, dAcrossAngDeg) ;
+   }
+
 
   // Calcolo numero degli step di movimento
    int nStepCnt = int( max( { abs( dAlongAngDeg) / ANG_ALONG_STEP, abs( dAcrossAngDeg) / ANG_ACROSS_STEP, 1.})) ;
@@ -2719,7 +2726,7 @@ VolZmap::MillingGeneralMotionStep( const Point3d& ptPs, const Vector3d& vtDs, co
       InitializePointsAndVectors( ptSti, ptEni, vtDSi, vtDEi, ptLs, ptLe, vtLs, vtLe) ;
 
       // Standard è multithread
-      constexpr bool MULTITHREAD = false ;
+      constexpr bool MULTITHREAD = true ;
       if ( MULTITHREAD) {
          // Ciclo sulle mappe
          vector<future<bool>> vRes( m_nMapNum) ;