diff --git a/Drilling.cpp b/Drilling.cpp
index 0cf476d..d65cd58 100644
--- a/Drilling.cpp
+++ b/Drilling.cpp
@@ -2779,8 +2779,8 @@ Drilling::GenerateHoleCl( int nInd, const SelData& nCircId, const string& sPName
   // assegno l'elevazione massima
    m_pGeomDB->SetInfo( nPathId, KEY_ELEV, hole.dLen) ;
   // foro normale
-   if ( m_Params.m_dStep < EPS_SMALL  ||
-        m_Params.m_dStep > hole.dLen - EPS_SMALL) {
+   if ( ( m_Params.m_dStep < EPS_SMALL  ||  m_Params.m_dStep > hole.dLen - 10 * EPS_SMALL)  &&
+        GetDoubleLastStep() > hole.dLen - 10 * EPS_SMALL) {
       if ( DoStandardDrilling( hole, nCircId, nPathId, dMHOff, vtA, currToolData)) {
         // aggiorno numero forature
          ++ m_nDrillings ;
@@ -3572,25 +3572,20 @@ Drilling::DoPeckDrilling( const Hole& hole, SelData Id, int nPathId, double dMHO
       if ( AddRapidMove( ptP2, bSplitArcs) == GDB_ID_NULL)
          return false ;
    }
-  // determino se foro in doppio
-   bool bDouble = false ;
-   {  int nDouble = 0 ;
-      if ( GetValInNotes( m_Params.m_sUserNotes, UN_DOUBLE, nDouble)  &&
-           ( nDouble == 1  ||  nDouble == 2  ||  nDouble == 3))
-         bDouble = true ;
-   }
-
+  // parametri per foro in doppio
+   bool bDouble = ( GetDoubleType( m_Params.m_sUserNotes) != 0)  ;
+   double dDoubleLastStep = GetDoubleLastStep() ;
   // ciclo di affondamento a step
    const double MIN_STEP = 1 ;
    const double APPR_STEP = 1 ;
    const double MIN_MOVE = 1 ;
    double dOrigStep = max( m_Params.m_dStep, MIN_STEP) ;
-   double dSteppedLen = ( bDouble ? hole.dLen - dOrigStep : hole.dLen) ;
+   double dSteppedLen = ( bDouble ? hole.dLen - dDoubleLastStep : hole.dLen) ;
    int nStep = int( ceil( dSteppedLen / dOrigStep)) ;
    double dStep = dSteppedLen / nStep ;
    if ( bDouble)
       ++ nStep ;
-   double dLastStep = ( bDouble ? dOrigStep : dStep) ;
+   double dLastStep = ( bDouble ? dDoubleLastStep : dStep) ;
    if ( dReturnPos < - dStep + APPR_STEP + MIN_MOVE)
       dReturnPos = - dStep + APPR_STEP + MIN_MOVE ;
    double dCurrLen = 0 ;
@@ -3723,6 +3718,22 @@ Drilling::DoPeckDrilling( const Hole& hole, SelData Id, int nPathId, double dMHO
    return true ;
 }
 
+//----------------------------------------------------------------------------
+double
+Drilling::GetDoubleLastStep( void)
+{
+  // se non è foratura in doppio, restituisco valore molto grande
+   const double FALSE_LASTSTEP = 10000 ;
+   if ( GetDoubleType( m_Params.m_sUserNotes) == 0) 
+      return FALSE_LASTSTEP ;
+  // recupero valore
+   const double MIN_LASTSTEP = 15 ;
+   double dDoubleLastStep = m_Params.m_dStep ;
+   if ( GetValInNotes( m_Params.m_sUserNotes, UN_LASTSTEP, dDoubleLastStep))
+      dDoubleLastStep = max( dDoubleLastStep, MIN_LASTSTEP)  ;
+   return dDoubleLastStep ;
+}
+
 //----------------------------------------------------------------------------
 // Debug Functions
 //----------------------------------------------------------------------------
diff --git a/Drilling.h b/Drilling.h
index 822f5ab..9ba2ac6 100644
--- a/Drilling.h
+++ b/Drilling.h
@@ -128,6 +128,7 @@ class Drilling : public Machining
       bool MultiHeadOrderConfig( TABMHDRILL& tabDrills, const VECTORHOLE& vHoles, const Vector3d& vtTool, const Vector3d& vtAux) ;
       bool MultiHeadHoleToolsConfig( const VECTORHOLE& vHoles, int nConfig, INTINTVECTOR& vConfMask) ;
       int  VerifyMultiParallelDrills( void) ;
+      double GetDoubleLastStep( void) ;
 
     /* debug functions */
      void PrintConfigs( const VECTORHOLE& vHoles) ;
diff --git a/EgtMachKernel.rc b/EgtMachKernel.rc
index dc42c73..7773a2b 100644
Binary files a/EgtMachKernel.rc and b/EgtMachKernel.rc differ
diff --git a/MachMgr.h b/MachMgr.h
index e3a1c0c..bdee15b 100644
--- a/MachMgr.h
+++ b/MachMgr.h
@@ -488,11 +488,15 @@ class MachMgr : public IMachMgr
       bool GetOperationNewName( std::string& sName) const ;
       const ToolData* GetMachiningToolData( void) const ;
      // Simulation
-      bool SimAddCollisionObj( int nInd, bool bToolOn, int nFrameId, int nType, const Vector3d& vtMove, double dPar1, double dPar2, double dPar3) ;
+      bool SimAddCollisionObj( int nInd, bool bToolOn, int nFrameId, int nType,
+                               const Vector3d& vtMove, double dPar1, double dPar2, double dPar3) ;
+      bool SimRemoveCollisionObj( int nFrameId) ;
+      bool SimGetCollisionObj( int nPos, int& nInd, bool& bToolOn, int& nFrameId, int& nType,
+                               Vector3d& vtMove, double& dPar1, double& dPar2, double& dPar3) const ;
       bool SimExecCollisionCheck( int& nCdInd, int& nObjInd, int nMoveType) ;
       bool SimOnCollision(  int nCdInd, int nObjInd, int& nErr) ;
-      bool SimSetToolForVmill( const std::string& sTool, const std::string& sHead, int nExit, int nFlag, double dPar1, double dPar2,
-                               const INTVECTOR& vVmill, bool bFirst) ;
+      bool SimSetToolForVmill( const std::string& sTool, const std::string& sHead, int nExit, int nFlag,
+                               double dPar1, double dPar2, const INTVECTOR& vVmill, bool bFirst) ;
       bool SimEnableToolsForVmill( bool bEnable) ;
       int  SimMoveAxes( int nMoveType, const SAMVECTOR& vAxNaEpSt) ;
       bool SimSaveCmd( int nType, int nPar, const std::string& sPar, const std::string& sPar2) ;
diff --git a/MachMgrSimulation.cpp b/MachMgrSimulation.cpp
index 3ded32a..35e1cef 100644
--- a/MachMgrSimulation.cpp
+++ b/MachMgrSimulation.cpp
@@ -176,6 +176,29 @@ MachMgr::SimAddCollisionObj( int nInd, bool bToolOn, int nFrameId, int nType, co
    return m_pSimul->AddCollisionObj( nInd, bToolOn, nFrameId, nType, vtMove, dPar1, dPar2, dPar3) ;
 }
 
+//----------------------------------------------------------------------------
+bool
+MachMgr::SimRemoveCollisionObj( int nFrameId)
+{
+  // verifico simulatore
+   if ( m_pSimul == nullptr)
+      return false ;
+  // rimuovo gli oggetti da verificare per la collisione con il grezzo con FrameId indicato
+   return m_pSimul->RemoveCollisionObj( nFrameId) ;
+}
+
+//----------------------------------------------------------------------------
+bool
+MachMgr::SimGetCollisionObj( int nPos, int& nInd, bool& bToolOn, int& nFrameId, int& nType,
+                             Vector3d& vtMove, double& dPar1, double& dPar2, double& dPar3) const
+{
+  // verifico simulatore
+   if ( m_pSimul == nullptr)
+      return false ;
+  // recupero i dati dell'oggetto di collisione di posizione indicata nel relativo vettore
+   return m_pSimul->GetCollisionObj( nPos, nInd, bToolOn, nFrameId, nType, vtMove, dPar1, dPar2, dPar3) ;
+}
+
 //----------------------------------------------------------------------------
 bool
 MachMgr::SimExecCollisionCheck( int& nCdInd, int& nObjInd, int nMoveType)
diff --git a/Machine.h b/Machine.h
index deb68c9..52b991e 100644
--- a/Machine.h
+++ b/Machine.h
@@ -402,6 +402,8 @@ class Machine
       static int LuaEmtSetWarning( lua_State* L) ;
       static int LuaEmtAddCollisionObj( lua_State* L) ;
       static int LuaEmtAddCollisionObjEx( lua_State* L) ;
+      static int LuaEmtRemoveCollisionObj( lua_State* L) ;
+      static int LuaEmtGetCollisionObj( lua_State* L) ;
       static int LuaEmtExecCollisionCheck( lua_State* L) ;
       static int LuaEmtOnCollision( lua_State* L) ;
       static int LuaEmtSetToolForVmill( lua_State* L) ;
diff --git a/MachineLua.cpp b/MachineLua.cpp
index 63edcc0..ba6c000 100644
--- a/MachineLua.cpp
+++ b/MachineLua.cpp
@@ -144,6 +144,10 @@ Machine::LuaInit( const string& sMachineName)
    m_LuaMgr.RegisterFunction( "EmtAddCollisionObj", Machine::LuaEmtAddCollisionObj) ;
   // registro la funzione estesa per aggiungere un oggetto da verificare per la collisione in simulazione
    m_LuaMgr.RegisterFunction( "EmtAddCollisionObjEx", Machine::LuaEmtAddCollisionObjEx) ;
+  // registro la funzione per rimuovere oggetti con dato FrameId da verificare per la collisione in simulazione
+   m_LuaMgr.RegisterFunction( "EmtRemoveCollisionObj", Machine::LuaEmtRemoveCollisionObj) ;
+  // registro la funzione per avere i dati dell'oggetto con posizione indicata nel vettore da verificare per la collisione in simulazione
+   m_LuaMgr.RegisterFunction( "EmtGetCollisionObj", Machine::LuaEmtGetCollisionObj) ;
   // registro la funzione di esecuzione della verifica di collisione in simulazione
    m_LuaMgr.RegisterFunction( "EmtExecCollisionCheck", Machine::LuaEmtExecCollisionCheck) ;
   // registro la funzione di gestione della collisione in simulazione
@@ -1428,6 +1432,65 @@ Machine::LuaEmtAddCollisionObjEx( lua_State* L)
    return 1 ;
 }
 
+//----------------------------------------------------------------------------
+int
+Machine::LuaEmtRemoveCollisionObj( lua_State* L)
+{
+  // 1 parametro : nFrameId 
+   int nFrameId ;
+   LuaCheckParam( L, 1, nFrameId)
+   LuaClearStack( L) ;
+  // verifico ci sia una macchina attiva
+   if ( m_pMchLua == nullptr)
+      return luaL_error( L, " Unknown Machine") ;
+  // assegno i dati
+   bool bOk = ( m_pMchLua->m_pMchMgr != nullptr && m_pMchLua->m_pMchMgr->SimRemoveCollisionObj( nFrameId)) ;
+  // assegno risultato
+   LuaSetParam( L, bOk) ;
+   return 1 ;
+}
+
+//----------------------------------------------------------------------------
+int
+Machine::LuaEmtGetCollisionObj( lua_State* L)
+{
+  // 1 parametro : nPos 
+   int nPos ;
+   LuaCheckParam( L, 1, nPos)
+   LuaClearStack( L) ;
+  // verifico ci sia una macchina attiva
+   if ( m_pMchLua == nullptr)
+      return luaL_error( L, " Unknown Machine") ;
+  // recupero i dati
+   int nInd ;
+   bool bToolOn ;
+   int nFrameId ;
+   int nType ;
+   Vector3d vtMove ;
+   double dPar1 ;
+   double dPar2 ;
+   double dPar3 ;
+   bool bOk = ( m_pMchLua->m_pMchMgr != nullptr  &&
+                m_pMchLua->m_pMchMgr->SimGetCollisionObj( nPos, nInd, bToolOn, nFrameId, nType, vtMove, dPar1, dPar2, dPar3)) ;
+  // assegno risultato
+   if ( bOk) {
+      LuaSetParam( L, true) ;
+      LuaSetParam( L, nInd) ;
+      LuaSetParam( L, bToolOn) ;
+      LuaSetParam( L, nFrameId) ;
+      LuaSetParam( L, nType) ;
+      LuaSetParam( L, vtMove) ;
+      LuaSetParam( L, dPar1) ;
+      LuaSetParam( L, dPar2) ;
+      LuaSetParam( L, dPar3) ;
+      return 9 ;  
+   }
+   else {
+      LuaSetParam( L, false) ;
+      return 1 ;
+   }
+}
+
 //----------------------------------------------------------------------------
 int
 Machine::LuaEmtExecCollisionCheck( lua_State* L)
diff --git a/Machining.cpp b/Machining.cpp
index 0025672..f94bcdc 100644
--- a/Machining.cpp
+++ b/Machining.cpp
@@ -584,7 +584,7 @@ Machining::GetToolPreviewStepCount( void) const
          -- nCount ;
          nRiseId = m_pGeomDB->GetNextName( nRiseId, MCH_CL_RISE) ;
       }
-     // tolgo le entità di tipo HOME
+     // tolgo le entit� HOME
       int nHomeId = m_pGeomDB->GetFirstNameInGroup( nPxId, MCH_CL_HOME) ;
       while ( nHomeId != GDB_ID_NULL) {
          -- nCount ;
@@ -609,7 +609,7 @@ Machining::GetToolPreviewNext( int nEntId, int nParentId, int nStId) const
      // ciclo nel gruppo
       while ( nNewId != GDB_ID_NULL) {
          string sName ; m_pGeomDB->GetName( nNewId, sName) ;
-         if ( sName != MCH_CL_CLIMB  &&  sName != MCH_CL_RISE  && sName != MCH_CL_HOME)
+         if ( sName != MCH_CL_CLIMB  &&  sName != MCH_CL_RISE  &&  sName != MCH_CL_HOME)
             break ;
          nNewId = m_pGeomDB->GetNext( nNewId) ;
       }
diff --git a/OperUserNotesConst.h b/OperUserNotesConst.h
index a86b5af..28b8239 100644
--- a/OperUserNotesConst.h
+++ b/OperUserNotesConst.h
@@ -26,6 +26,9 @@ static const std::string UN_DOUBLE = "DOUBLE" ;
 static const std::string UN_MIRRORAX = "MirrorAx" ;
 static const std::string UN_DELTAZ = "DeltaZ" ;
 
+// Solo per Drilling
+static const std::string UN_LASTSTEP = "LastStep" ;
+
 // Solo per FiveAxisMilling
 static const std::string UN_SINGCONEANG = "SingConeAng" ;
 
diff --git a/Sawing.cpp b/Sawing.cpp
index a4db978..ad6ed75 100644
--- a/Sawing.cpp
+++ b/Sawing.cpp
@@ -1603,6 +1603,15 @@ Sawing::ProcessPath( int nPathId, int nPvId, int nClId)
    double dThick ;
    pCompo->GetThickness( dThick) ;
 
+  // aggiusto eventuali normali inverse di archi rispetto ad estrusione
+   const ICurve* pCrv = pCompo->GetFirstCurve() ;
+   while ( pCrv != nullptr) {
+      const ICurveArc* pArc = GetCurveArc( pCrv) ;
+      if ( pArc != nullptr  &&  pArc->GetNormVersor() * vtExtr < 0)
+         const_cast<ICurveArc*>(pArc)->InvertN() ;
+      pCrv = pCompo->GetNextCurve() ;
+   }
+
   // recupero distanza da fondo dei grezzi interessati dal percorso
    double dRbDist, dAllRbDist ;
    double dToler = 2 * m_TParams.m_dThick + tan( abs( m_Params.m_dSideAngle) * DEGTORAD) * m_TParams.m_dMaxMat ;
diff --git a/Simulator.h b/Simulator.h
index 7c2ba80..2ce446d 100644
--- a/Simulator.h
+++ b/Simulator.h
@@ -53,6 +53,9 @@ class __declspec( novtable) ISimulator
       virtual bool GetMoveInfo( int& nGmove, double& dFeed) const = 0 ;
       virtual bool AddCollisionObj( int nInd, bool bToolOn, int nFrameId, int nType,
                                     const Vector3d& vtMove, double dPar1, double dPar2, double dPar3) = 0 ;
+      virtual bool RemoveCollisionObj( int nFrameId) = 0 ;
+      virtual bool GetCollisionObj( int nPos, int& nInd, bool& bToolOn, int& nFrameId, int& nType,
+                                    Vector3d& vtMove, double& dPar1, double& dPar2, double& dPar3) = 0 ;
       virtual bool ExecCollisionCheck( int& nCdInd, int& nObjInd, int nMoveType) = 0 ;
       virtual bool OnCollision( int nCdInd, int nObjInd, int& nErr) = 0 ;
       virtual bool SetToolForVmill( const std::string& sTool, const std::string& sHead, int nExit, int nFlag,
diff --git a/SimulatorMP.cpp b/SimulatorMP.cpp
index 199e4c8..2bcb705 100644
--- a/SimulatorMP.cpp
+++ b/SimulatorMP.cpp
@@ -2336,6 +2336,34 @@ SimulatorMP::AddCollisionObj( int nInd, bool bToolOn, int nFrameId, int nType, c
    return true ;
 }
 
+//----------------------------------------------------------------------------
+bool
+SimulatorMP::RemoveCollisionObj( int nFrameId)
+{
+   erase_if( m_CollObj, [nFrameId]( CollObj Item) { return ( Item.nFrameId == nFrameId) ; }) ;
+   return true ;
+}
+
+//----------------------------------------------------------------------------
+bool
+SimulatorMP::GetCollisionObj( int nPos, int& nInd, bool& bToolOn, int& nFrameId, int& nType,
+                              Vector3d& vtMove, double& dPar1, double& dPar2, double& dPar3)
+{
+  // posizione nel vettore non valida
+   if ( nPos < 0  ||  nPos >= ssize( m_CollObj))
+      return false ;
+  // assegno i dati
+   nInd = m_CollObj[nPos].nInd ;
+   bToolOn = m_CollObj[nPos].bToolOn ;
+   nFrameId = m_CollObj[nPos].nFrameId ;
+   nType = m_CollObj[nPos].nType ;
+   vtMove = m_CollObj[nPos].vtMove ;
+   dPar1 = m_CollObj[nPos].dPar1 ;
+   dPar2 = m_CollObj[nPos].dPar2 ;
+   dPar3 = m_CollObj[nPos].dPar3 ;
+   return true ;
+}
+
 //----------------------------------------------------------------------------
 bool
 SimulatorMP::SetToolForVmill( const string& sTool, const string& sHead, int nExit, int nFlag, double dPar1, double dPar2,
diff --git a/SimulatorMP.h b/SimulatorMP.h
index afb1f83..9635854 100644
--- a/SimulatorMP.h
+++ b/SimulatorMP.h
@@ -40,6 +40,9 @@ class SimulatorMP : public ISimulator
       bool GetMoveInfo( int& nGmove, double& dFeed) const override ;
       bool AddCollisionObj( int nInd, bool bToolOn, int nFrameId, int nType,
                             const Vector3d& vtMove, double dPar1, double dPar2, double dPar3) override ;
+      bool RemoveCollisionObj( int nFrameId) override ;
+      bool GetCollisionObj( int nPos, int& nInd, bool& bToolOn, int& nFrameId, int& nType,
+                            Vector3d& vtMove, double& dPar1, double& dPar2, double& dPar3) override ;
       bool ExecCollisionCheck( int& nCdInd, int& nObjInd, int nMoveType) override ;
       bool OnCollision( int nCdInd, int nObjInd, int& nErr) override ;
       bool SetToolForVmill( const std::string& sTool, const std::string& sHead, int nExit, int nFlag,
diff --git a/SimulatorSP.cpp b/SimulatorSP.cpp
index f2e1e92..f3572fc 100644
--- a/SimulatorSP.cpp
+++ b/SimulatorSP.cpp
@@ -2343,7 +2343,8 @@ SimulatorSP::OnResetMachine( void)
 
 //----------------------------------------------------------------------------
 bool
-SimulatorSP::AddCollisionObj( int nInd, bool bToolOn, int nFrameId, int nType, const Vector3d& vtMove, double dPar1, double dPar2, double dPar3)
+SimulatorSP::AddCollisionObj( int nInd, bool bToolOn, int nFrameId, int nType,
+                              const Vector3d& vtMove, double dPar1, double dPar2, double dPar3)
 {
   // verifiche sui parametri
    if ( nInd <= 0  ||  nFrameId <= GDB_ID_NULL)
@@ -2374,6 +2375,35 @@ SimulatorSP::AddCollisionObj( int nInd, bool bToolOn, int nFrameId, int nType, c
    }
   // aggiungo al vettore
    m_CollObj.emplace_back( nInd, bToolOn, nFrameId, nType, vtMove, dPar1, dPar2, dPar3) ;
+
+   return true ;
+}
+
+//----------------------------------------------------------------------------
+bool
+SimulatorSP::RemoveCollisionObj( int nFrameId)
+{
+   erase_if( m_CollObj, [nFrameId]( CollObj Item) { return ( Item.nFrameId == nFrameId) ; }) ;
+   return true ;
+}
+
+//----------------------------------------------------------------------------
+bool
+SimulatorSP::GetCollisionObj( int nPos, int& nInd, bool& bToolOn, int& nFrameId, int& nType,
+                              Vector3d& vtMove, double& dPar1, double& dPar2, double& dPar3)
+{
+  // posizione nel vettore non valida
+   if ( nPos < 0  ||  nPos >= ssize( m_CollObj))
+      return false ;
+  // assegno i dati
+   nInd = m_CollObj[nPos].nInd ;
+   bToolOn = m_CollObj[nPos].bToolOn ;
+   nFrameId = m_CollObj[nPos].nFrameId ;
+   nType = m_CollObj[nPos].nType ;
+   vtMove = m_CollObj[nPos].vtMove ;
+   dPar1 = m_CollObj[nPos].dPar1 ;
+   dPar2 = m_CollObj[nPos].dPar2 ;
+   dPar3 = m_CollObj[nPos].dPar3 ;
    return true ;
 }
 
diff --git a/SimulatorSP.h b/SimulatorSP.h
index 983c3f6..ae54298 100644
--- a/SimulatorSP.h
+++ b/SimulatorSP.h
@@ -40,6 +40,9 @@ class SimulatorSP : public ISimulator
       bool GetMoveInfo( int& nGmove, double& dFeed) const override ;
       bool AddCollisionObj( int nInd, bool bToolOn, int nFrameId, int nType,
                             const Vector3d& vtMove, double dPar1, double dPar2, double dPar3) override ;
+      bool RemoveCollisionObj( int nFrameId) override ;
+      bool GetCollisionObj( int nPos, int& nInd, bool& bToolOn, int& nFrameId, int& nType,
+                            Vector3d& vtMove, double& dPar1, double& dPar2, double& dPar3) override ;
       bool ExecCollisionCheck( int& nCdInd, int& nObjInd, int nMoveType) override ;
       bool OnCollision( int nCdInd, int nObjInd, int& nErr) override ;
       bool SetToolForVmill( const std::string& sTool, const std::string& sHead, int nExit, int nFlag,