diff --git a/Mortising.cpp b/Mortising.cpp
index b160acc..15f915a 100644
--- a/Mortising.cpp
+++ b/Mortising.cpp
@@ -1345,7 +1345,7 @@ Mortising::ProcessPath( int nPathId, int nPvId, int nClId)
    GetValInNotes( m_Params.m_sUserNotes, "Plunge", nPlunge) ;
 
   // verifico che lo step dell'utensile sia sensato
-   double dOkStep = ( nPlunge == MORTISE_PLUNGE_STEP ? m_Params.m_dStep : 0) ;
+   double dOkStep = ( nPlunge == MORTISE_PLUNGE_STEP  ||  nPlunge == MORTISE_PLUNGE_STEP_NO_SAFEZ ? m_Params.m_dStep : 0) ;
    const double MIN_ZSTEP = 1.0 ;
    if ( dOkStep >= EPS_SMALL  &&  dOkStep < MIN_ZSTEP) {
       dOkStep = MIN_ZSTEP ;
@@ -1567,6 +1567,15 @@ Mortising::GenerateOnePlungeCl( const Point3d& ptStart, const Point3d& ptEnd, co
 {
   // compensazione elevazione/affondamento
    double dDelta = dElev - dDepth ;
+  // pre-calcolo step per modalità con step
+   int nStep = 1 ;
+   double dStep = dElev ;
+   if ( nPlunge == MORTISE_PLUNGE_STEP  ||  nPlunge == MORTISE_PLUNGE_STEP_NO_SAFEZ) {
+      if ( dOkStep < EPS_SMALL)
+         dOkStep = dElev ;
+      nStep = max( 1, static_cast<int>( ceil( ( dElev - 10 * EPS_SMALL) / dOkStep))) ;
+      dStep = dElev / nStep ;
+   }
 
   // determino se l'inizio dell'attacco è esattamente sotto il grezzo, nel qual caso ricalcolo l'elevazione
    double dSafeZ = GetSafeZ() + GetDeltaSafeZ( vtTool) ;
@@ -1578,17 +1587,26 @@ Mortising::GenerateOnePlungeCl( const Point3d& ptStart, const Point3d& ptEnd, co
    if ( ! bUnderStart)
       GetElevation( m_nPhase, ptLi, vtTool, GetRadiusForStartEndElevation(), vtTool, dStartElev) ;
 
+  // sicurezza su punto iniziale
+   double dAppr = dStartElev + dSafeZ ;
+   if ( nPlunge == MORTISE_PLUNGE_STEP_NO_SAFEZ) {
+      double dStartDownElev ;
+      if ( ! GetElevation( m_nPhase, ptStart, vtTool, GetRadiusForStartEndElevation(), vtTool, dStartDownElev))
+         dStartDownElev = dDelta ;
+      if ( dStartDownElev < EPS_SMALL)
+         dAppr = -dStep ;
+   }
+
   // 1 -> punto approccio
    int nFirstFlag = ( bFirst ? 1 : 0) ; 
    SetFlag( nFirstFlag) ;
-   Point3d ptP1 = ( nPlunge != MORTISE_PLUNGE_END ? ptStart : ptEnd) + vtTool * ( dDelta + dStartElev + dSafeZ) ;
-   int nStart = AddRapidStartOrMove( ptP1, bFirst) ;
-   if ( nStart == GDB_ID_NULL)
+   Point3d ptP1 = ( nPlunge != MORTISE_PLUNGE_END ? ptStart : ptEnd) + vtTool * ( dDelta + dAppr) ;
+   if ( AddRapidStartOrMove( ptP1, bFirst) == GDB_ID_NULL)
       return false ;
    SetFlag( 0) ;
 
   // 2 -> punto fuori (se diverso dal precedente)
-   if ( m_Params.m_dStartPos < dSafeZ - 10 * EPS_SMALL) {
+   if ( m_Params.m_dStartPos < dAppr - 10 * EPS_SMALL) {
       Point3d ptP2 = ( nPlunge != MORTISE_PLUNGE_END ? ptStart : ptEnd) + vtTool * ( dDelta + m_Params.m_dStartPos) ;
       if ( AddRapidMove( ptP2) == GDB_ID_NULL)
          return false ;
@@ -1616,10 +1634,6 @@ Mortising::GenerateOnePlungeCl( const Point3d& ptStart, const Point3d& ptEnd, co
    }
    else {
      // determino numero e affondamento degli step
-      if ( dOkStep < EPS_SMALL)
-         dOkStep = dElev ;
-      int nStep = max( 1, static_cast<int>( ceil( ( dElev - 10 * EPS_SMALL) / dOkStep))) ;
-      double dStep = dElev / nStep ;
       const double RETURN_DIST = 10 ;
      // a seconda del tipo
       switch ( m_Params.m_nStepType) {
@@ -1629,7 +1643,7 @@ Mortising::GenerateOnePlungeCl( const Point3d& ptStart, const Point3d& ptEnd, co
             SetFeed( GetStartFeed()) ;
             SetFlag( 0) ;
             Point3d ptP3 = (( i % 2 == 1) ? ptStart : ptEnd) + ( dDelta - i * dStep) * vtTool ;
-            if ( AddLinearMove( ptP3) == GDB_ID_NULL)
+            if ( AddLinearMove( ptP3) == GDB_ID_NULL  &&  ! ( i == 1  &&  nPlunge == MORTISE_PLUNGE_STEP_NO_SAFEZ))
                return false ;
            // 4 -> punto termine
             SetFeed( GetFeed()) ;
@@ -1683,11 +1697,21 @@ Mortising::GenerateOnePlungeCl( const Point3d& ptStart, const Point3d& ptEnd, co
   // altrimenti ridetermino elevazione su fine percorso di lavoro
    if ( ! bUnderEnd)
       GetElevation( m_nPhase, ptLo, vtTool, GetRadiusForStartEndElevation(), vtTool, dEndElev) ;
+
+  // sicurezza su punto finale
+   double dRetr = dEndElev + dSafeZ ;
+   if ( nPlunge == MORTISE_PLUNGE_STEP_NO_SAFEZ) {
+      double dEndDownElev ;
+      if ( ! GetElevation( m_nPhase, ptStart, vtTool, GetRadiusForStartEndElevation(), vtTool, dEndDownElev))
+         dEndDownElev = dDelta ;
+      if ( dEndDownElev < EPS_SMALL)
+         dRetr = dEndElev - dStep ;
+   }
    
   // 6 -> ritorno all'approccio
    SetFeed( GetEndFeed()) ;
    SetFlag( 104) ;            // risalita sopra la fine
-   Point3d ptP6 = ptLast + vtTool * ( dDelta + dEndElev + dSafeZ) ;
+   Point3d ptP6 = ptLast + vtTool * ( dDelta + dRetr) ;
    if ( AddLinearMove( ptP6) == GDB_ID_NULL)
       return false ;