diff --git a/MachMgr.h b/MachMgr.h
index e2be4a6..26913a8 100644
--- a/MachMgr.h
+++ b/MachMgr.h
@@ -488,7 +488,7 @@ class MachMgr : public IMachMgr
       bool ShowRootParts( bool bShow) ;
      // Tools DataBase
       bool UpdateAllToolDraws( void) const ;
-      bool UpdateToolDraw( const EgtUUID& UuidTool, double& dTHoldLen, double& dTHoldDiam) const ;
+      bool UpdateToolDraw( const EgtUUID& UuidTool, double& dTHoldBase, double& dTHoldLen, double& dTHoldDiam) const ;
       int  UpdateStandardToolDraw( const ToolData* pTdata, int nGenCtx, int nToolCtx, bool bToSave) const ;
       int  UpdateCustomToolDraw( const ToolData* pTdata, int nGenCtx, int nToolCtx, bool bToSave) const ;
       std::string GetToolMakerKeyFromType( int nType) const ;
diff --git a/MachMgrDBTools.cpp b/MachMgrDBTools.cpp
index 6b07f3c..2a45433 100644
--- a/MachMgrDBTools.cpp
+++ b/MachMgrDBTools.cpp
@@ -528,10 +528,10 @@ MachMgr::UpdateAllToolDraws( void) const
       bool bNoDraw = ( ! sDraw.empty()  &&  ! ExistsFile( sToolDir + "\\" + sDraw)) ;
      // se modificato o senza disegno, ne lancio la creazione e aggiorno dati portautensile
       if ( bModif  ||  bNoDraw) {
-         double dTHoldLen = 0, dTHoldDiam = 0 ;
-         UpdateToolDraw( UuidTool, dTHoldLen, dTHoldDiam) ;
+         double dTHoldBase = 0,  dTHoldLen = 0, dTHoldDiam = 0 ;
+         UpdateToolDraw( UuidTool, dTHoldBase, dTHoldLen, dTHoldDiam) ;
          pTsMgr->SetCurrTool( sName) ;
-         pTsMgr->UpdateCurrToolHolderData( dTHoldLen, dTHoldDiam) ;
+         pTsMgr->UpdateCurrToolHolderData( dTHoldBase, dTHoldLen, dTHoldDiam) ;
          pTsMgr->SaveCurrTool() ;
          pTsMgr->SetCurrTool( "") ;
       }
@@ -548,7 +548,7 @@ MachMgr::UpdateAllToolDraws( void) const
 
 //----------------------------------------------------------------------------
 bool
-MachMgr::UpdateToolDraw( const EgtUUID& UuidTool, double& dTHoldLen, double& dTHoldDiam) const
+MachMgr::UpdateToolDraw( const EgtUUID& UuidTool, double& dTHoldBase, double& dTHoldLen, double& dTHoldDiam) const
 {
   // recupero il gestore di utensili della macchina corrente
    ToolsMgr* pTsMgr = GetCurrToolsMgr() ;
@@ -589,6 +589,8 @@ MachMgr::UpdateToolDraw( const EgtUUID& UuidTool, double& dTHoldLen, double& dTH
    bOk = bOk && ExeSaveFile( sDrawPath, GDB_SV_BIN) ;
   // Recupero i dati del portautensile
    int nToolId = ExeGetFirstGroupInGroup( GDB_ID_ROOT) ;
+   if ( ! ExeGetInfo( nToolId, TTH_BASE, dTHoldBase))
+      dTHoldBase = 0 ;
    if ( ! ExeGetInfo( nToolId, TTH_LEN, dTHoldLen))
       dTHoldLen = 0 ;
    if ( ! ExeGetInfo( nToolId, TTH_DIAM, dTHoldDiam))
diff --git a/MachineHeads.cpp b/MachineHeads.cpp
index 5059b15..565f8bb 100644
--- a/MachineHeads.cpp
+++ b/MachineHeads.cpp
@@ -171,6 +171,8 @@ Machine::LoadTool( Exit* pExit, const string& sTool)
       return false ;
   // sposto eventuali info relative al porta utensile (ToolHolder) nel gruppo SOLID
    double dVal ;
+   if ( m_pGeomDB->GetInfo( nTGrpId, TTH_BASE, dVal))
+      m_pGeomDB->SetInfo( nSolidId, TTH_BASE, dVal) ;
    if ( m_pGeomDB->GetInfo( nTGrpId, TTH_LEN, dVal))
       m_pGeomDB->SetInfo( nSolidId, TTH_LEN, dVal) ;
    if ( m_pGeomDB->GetInfo( nTGrpId, TTH_DIAM, dVal))
diff --git a/Milling.cpp b/Milling.cpp
index 3df5088..b2dd76a 100644
--- a/Milling.cpp
+++ b/Milling.cpp
@@ -109,6 +109,7 @@ Milling::Clone( void) const
          pMill->m_nPhase = m_nPhase ;
          pMill->m_Params = m_Params ;
          pMill->m_TParams = m_TParams ;
+         pMill->m_dTHoldBase = m_dTHoldBase ;
          pMill->m_dTHoldLen = m_dTHoldLen ;
          pMill->m_dTHoldDiam = m_dTHoldDiam ;
          pMill->m_nStatus = m_nStatus ;
@@ -232,6 +233,7 @@ Milling::Milling( void)
    m_Params.m_sToolName = "*" ;
    m_TParams.m_sName = "*" ;
    m_TParams.m_sHead = "*" ;
+   m_dTHoldBase = 0 ;
    m_dTHoldLen = 0 ;
    m_dTHoldDiam = 0 ;
    m_nStatus = MCH_ST_TO_VERIFY ;
@@ -652,6 +654,8 @@ Milling::Preview( bool bRecalc)
    }
   // recupero i dati del portautensile
    int nToolId = m_pMchMgr->GetCalcTool() ;
+   m_dTHoldBase = 0 ;
+   m_pGeomDB->GetInfo( nToolId, TTH_BASE, m_dTHoldBase) ;
    m_dTHoldLen = 0 ;
    m_pGeomDB->GetInfo( nToolId, TTH_LEN, m_dTHoldLen) ;
    m_dTHoldDiam = 0 ;
@@ -757,6 +761,8 @@ Milling::Apply( bool bRecalc, bool bPostApply)
    }
   // recupero i dati del portautensile
    int nToolId = m_pMchMgr->GetCalcTool() ;
+   m_dTHoldBase = 0 ;
+   m_pGeomDB->GetInfo( nToolId, TTH_BASE, m_dTHoldBase) ;
    m_dTHoldLen = 0 ;
    m_pGeomDB->GetInfo( nToolId, TTH_LEN, m_dTHoldLen) ;
    m_dTHoldDiam = 0 ;
@@ -1800,7 +1806,7 @@ Milling::ProcessPath( int nPathId, int nPvId, int nClId)
       else {
         // massimo affondamento dell'utensile
          double dSafe = m_pMchMgr->GetCurrMachiningsMgr()->GetMaxDepthSafe() ;
-         double dMaxDepth = m_TParams.m_dLen - ( m_TParams.m_dDiam > m_dTHoldDiam ? 0 : m_dTHoldLen) - dSafe ;
+         double dMaxDepth = m_TParams.m_dLen - ( m_TParams.m_dDiam > m_dTHoldDiam ? m_dTHoldBase : m_dTHoldLen) - dSafe ;
         // se c'è oscillazione e l'elevazione complessiva supera la capacità dell'utensile, annullo l'oscillazione
          if ( bPathOscEnable  &&  dElev + dAddElev > dMaxDepth + EPS_SMALL) {
             bPathOscEnable = false ;
diff --git a/Milling.h b/Milling.h
index 57b83c8..be6e851 100644
--- a/Milling.h
+++ b/Milling.h
@@ -149,6 +149,7 @@ class Milling : public Machining
       SELVECTOR     m_vId ;             // identificativi entità geometriche da lavorare
       MillingData   m_Params ;          // parametri lavorazione
       ToolData      m_TParams ;         // parametri utensile
+      double        m_dTHoldBase ;      // posizione base del porta-utensile
       double        m_dTHoldLen ;       // lunghezza del porta-utensile
       double        m_dTHoldDiam ;      // diametro del porta-utensile
       int           m_nStatus ;         // stato di aggiornamento della lavorazione
diff --git a/Pocketing.cpp b/Pocketing.cpp
index c6a48ad..019e5f2 100644
--- a/Pocketing.cpp
+++ b/Pocketing.cpp
@@ -110,6 +110,9 @@ Pocketing::Clone( void) const
          pPock->m_nPhase = m_nPhase ;
          pPock->m_Params = m_Params ;
          pPock->m_TParams = m_TParams ;
+         pPock->m_dTHoldBase = m_dTHoldBase ;
+         pPock->m_dTHoldLen = m_dTHoldLen ;
+         pPock->m_dTHoldDiam = m_dTHoldDiam ;
          pPock->m_nStatus = m_nStatus ;
          pPock->m_nPockets = m_nPockets ;
          pPock->m_bTiltingTab = m_bTiltingTab ;
@@ -231,6 +234,7 @@ Pocketing::Pocketing( void)
    m_Params.m_sToolName = "*" ;
    m_TParams.m_sName = "*" ;
    m_TParams.m_sHead = "*" ;
+   m_dTHoldBase = 0 ;
    m_dTHoldLen = 0 ;
    m_dTHoldDiam = 0 ;
    m_dMaxHelixRad = INFINITO ;
@@ -552,6 +556,8 @@ Pocketing::Preview( bool bRecalc)
    }
   // recupero i dati del portautensile
    int nToolId = m_pMchMgr->GetCalcTool() ;
+   m_dTHoldBase = 0 ;
+   m_pGeomDB->GetInfo( nToolId, TTH_BASE, m_dTHoldBase) ;
    m_dTHoldLen = 0 ;
    m_pGeomDB->GetInfo( nToolId, TTH_LEN, m_dTHoldLen) ;
    m_dTHoldDiam = 0 ;
@@ -643,6 +649,8 @@ Pocketing::Apply( bool bRecalc, bool bPostApply)
    }
   // recupero i dati del portautensile
    int nToolId = m_pMchMgr->GetCalcTool() ;
+   m_dTHoldBase = 0 ;
+   m_pGeomDB->GetInfo( nToolId, TTH_BASE, m_dTHoldBase) ;
    m_dTHoldLen = 0 ;
    m_pGeomDB->GetInfo( nToolId, TTH_LEN, m_dTHoldLen) ;
    m_dTHoldDiam = 0 ;
@@ -1585,7 +1593,7 @@ Pocketing::ProcessPath( int nPathId, int nPvId, int nClId)
    else {
      // se l'elevazione supera il massimo affondamento dell'utensile
       double dSafe = m_pMchMgr->GetCurrMachiningsMgr()->GetMaxDepthSafe() ;
-      double dMaxDepth = m_TParams.m_dLen - ( m_TParams.m_dDiam > m_dTHoldDiam ? 0 : m_dTHoldLen) - dSafe ;
+      double dMaxDepth = m_TParams.m_dLen - ( m_TParams.m_dDiam > m_dTHoldDiam ? m_dTHoldBase : m_dTHoldLen) - dSafe ;
       if ( dElev > dMaxDepth + EPS_SMALL) {
         // segnalo, riduco e continuo
          string sInfo = "Warning in Pocketing : machining depth (" + ToString( dElev, 1) +
diff --git a/Pocketing.h b/Pocketing.h
index c50d1a6..f5a01ed 100644
--- a/Pocketing.h
+++ b/Pocketing.h
@@ -171,6 +171,7 @@ class Pocketing : public Machining
       SELVECTOR     m_vId ;             // identificativi entità geometriche da lavorare
       PocketingData m_Params ;          // parametri lavorazione
       ToolData      m_TParams ;         // parametri utensile
+      double        m_dTHoldBase ;      // posizione base del porta-utensile
       double        m_dTHoldLen ;       // lunghezza del porta-utensile
       double        m_dTHoldDiam ;      // diametro del porta-utensile
       double        m_dMaxHelixRad ;    // raggio massimo attacco ad elica nel caso di cerchi
diff --git a/SurfFinishing.cpp b/SurfFinishing.cpp
index 720f875..90ba460 100644
--- a/SurfFinishing.cpp
+++ b/SurfFinishing.cpp
@@ -88,6 +88,9 @@ SurfFinishing::Clone( void) const
          pSrF->m_nPhase = m_nPhase ;
          pSrF->m_Params = m_Params ;
          pSrF->m_TParams = m_TParams ;
+         pSrF->m_dTHoldBase = m_dTHoldBase ;
+         pSrF->m_dTHoldLen = m_dTHoldLen ;
+         pSrF->m_dTHoldDiam = m_dTHoldDiam ;
          pSrF->m_nStatus = m_nStatus ;
          pSrF->m_nPaths = m_nPaths ;
       }
@@ -201,6 +204,7 @@ SurfFinishing::SurfFinishing( void)
    m_Params.m_sToolName = "*" ;
    m_TParams.m_sName = "*" ;
    m_TParams.m_sHead = "*" ;
+   m_dTHoldBase = 0 ;
    m_dTHoldLen = 0 ;
    m_dTHoldDiam = 0 ;
    m_nStatus = MCH_ST_TO_VERIFY ;
@@ -528,6 +532,8 @@ SurfFinishing::Apply( bool bRecalc, bool bPostApply)
    }
   // recupero i dati del portautensile
    int nToolId = m_pMchMgr->GetCalcTool() ;
+   m_dTHoldBase = 0 ;
+   m_pGeomDB->GetInfo( nToolId, TTH_BASE, m_dTHoldBase) ;
    m_dTHoldLen = 0 ;
    m_pGeomDB->GetInfo( nToolId, TTH_LEN, m_dTHoldLen) ;
    m_dTHoldDiam = 0 ;
diff --git a/SurfFinishing.h b/SurfFinishing.h
index b1a2185..7bd4048 100644
--- a/SurfFinishing.h
+++ b/SurfFinishing.h
@@ -113,6 +113,7 @@ class SurfFinishing : public Machining
       SELVECTOR         m_vId ;             // identificativi entità geometriche da lavorare
       SurfFinishingData m_Params ;          // parametri lavorazione
       ToolData          m_TParams ;         // parametri utensile
+      double            m_dTHoldBase ;      // posizione base del porta-utensile
       double            m_dTHoldLen ;       // lunghezza del porta-utensile
       double            m_dTHoldDiam ;      // diametro del porta-utensile
       int               m_nStatus ;         // stato di aggiornamento della lavorazione
diff --git a/ToolsMgr.cpp b/ToolsMgr.cpp
index e2a7261..ae7e129 100644
--- a/ToolsMgr.cpp
+++ b/ToolsMgr.cpp
@@ -561,12 +561,13 @@ ToolsMgr::SaveCurrTool( void)
 
 //----------------------------------------------------------------------------
 bool
-ToolsMgr::UpdateCurrToolHolderData( double dTHoldLen, double dTHoldDiam)
+ToolsMgr::UpdateCurrToolHolderData( double dTHoldBase, double dTHoldLen, double dTHoldDiam)
 {
   // verifico validità utensile corrente
    if ( ! m_bCurrTool)
       return false ;
   // Aggiorno i dati nelle note di sistema
+   SetValInNotes( TSI_THBASE, dTHoldBase, m_tdCurrTool.m_sSysNotes) ;
    SetValInNotes( TSI_THLEN, dTHoldLen, m_tdCurrTool.m_sSysNotes) ;
    SetValInNotes( TSI_THDIAM, dTHoldDiam, m_tdCurrTool.m_sSysNotes) ;
    return true ;
@@ -679,21 +680,24 @@ ToolsMgr::GetCurrToolMaxDepth( double dSafe, double& dMaxDepth) const
   // se fresa
    else if ( ( m_tdCurrTool.m_nType & TF_MILL) != 0) {
      // recupero le dimensioni del porta utensili
+      double dTHoldBase = 0 ;
       double dTHoldLen = 0 ;
       double dTHoldDiam = 0 ;
-      if ( ! GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THLEN, dTHoldLen)  ||
+      if ( ! GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THBASE, dTHoldBase)  ||
+           ! GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THLEN, dTHoldLen)  ||
            ! GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THDIAM, dTHoldDiam)) {
          (const_cast<ToolsMgr*>(this))->SaveCurrTool() ;
          Save() ;  
+         GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THBASE, dTHoldBase) ;
          GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THLEN, dTHoldLen) ;
          GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THDIAM, dTHoldDiam) ;
       }
-     // calcolo il massimo affondamento (lunghezza TH negativa significa che TH è parte della testa)
+     // calcolo il massimo affondamento
       dMaxDepth = m_tdCurrTool.m_dLen - dSafe ;
       if ( m_tdCurrTool.m_dDiam > dTHoldDiam)
-         dMaxDepth -= min( 0., dTHoldLen) ;
+         dMaxDepth -= dTHoldBase ;
       else
-         dMaxDepth -= max( 0., dTHoldLen) ;
+         dMaxDepth -= dTHoldLen ;
       return true ;
    }
   // se mortasatrice o sega a catena
@@ -734,12 +738,15 @@ ToolsMgr::GetCurrToolThDiam( double& dThDiam) const
         ( m_tdCurrTool.m_nType & TF_MILL) != 0  ||
         ( m_tdCurrTool.m_nType & TF_CHISEL) != 0) {
      // recupero le dimensioni del porta utensili
+      double dTHoldBase = 0 ;
       double dTHoldLen = 0 ;
       double dTHoldDiam = 0 ;
-      if ( ! GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THLEN, dTHoldLen)  ||
+      if ( ! GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THBASE, dTHoldBase)  ||
+           ! GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THLEN, dTHoldLen)  ||
            ! GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THDIAM, dTHoldDiam)) {
          (const_cast<ToolsMgr*>(this))->SaveCurrTool() ;
          Save() ;  
+         GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THBASE, dTHoldBase) ;
          GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THLEN, dTHoldLen) ;
          GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THDIAM, dTHoldDiam) ;
       }
@@ -770,12 +777,15 @@ ToolsMgr::GetCurrToolThLength( double& dThLen) const
         ( m_tdCurrTool.m_nType & TF_MILL) != 0  ||
         ( m_tdCurrTool.m_nType & TF_CHISEL) != 0) {
      // recupero le dimensioni del porta utensili
+      double dTHoldBase = 0 ;
       double dTHoldLen = 0 ;
       double dTHoldDiam = 0 ;
-      if ( ! GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THLEN, dTHoldLen)  ||
+      if ( ! GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THBASE, dTHoldBase)  ||
+           ! GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THLEN, dTHoldLen)  ||
            ! GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THDIAM, dTHoldDiam)) {
          (const_cast<ToolsMgr*>(this))->SaveCurrTool() ;
          Save() ;  
+         GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THBASE, dTHoldBase) ;
          GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THLEN, dTHoldLen) ;
          GetValInNotes( m_tdCurrTool.m_sSysNotes, TSI_THDIAM, dTHoldDiam) ;
       }
diff --git a/ToolsMgr.h b/ToolsMgr.h
index cee6fb8..95899e5 100644
--- a/ToolsMgr.h
+++ b/ToolsMgr.h
@@ -56,7 +56,7 @@ class ToolsMgr
       bool GetCurrToolParam( int nType, double& dVal) const ;
       bool GetCurrToolParam( int nType, std::string& sVal) const ;
       template <class T> bool GetCurrToolValInNotes( int nType, const std::string& sKey, T& Val) const ;
-      bool UpdateCurrToolHolderData( double dTHoldLen, double dTHoldDiam) ;
+      bool UpdateCurrToolHolderData( double dTHoldBase, double dTHoldLen, double dTHoldDiam) ;
       bool GetCurrToolMaxDepth( double dSafe, double& dMaxDepth) const ;
       bool GetCurrToolThDiam( double& dThDiam) const ;
       bool GetCurrToolThLength( double& dThLen) const ;
diff --git a/WaterJetting.cpp b/WaterJetting.cpp
index e469ef9..09da63b 100644
--- a/WaterJetting.cpp
+++ b/WaterJetting.cpp
@@ -89,6 +89,7 @@ WaterJetting::Clone( void) const
          pWJ->m_nPhase = m_nPhase ;
          pWJ->m_Params = m_Params ;
          pWJ->m_TParams = m_TParams ;
+         pWJ->m_dTHoldBase = m_dTHoldBase ;
          pWJ->m_dTHoldLen = m_dTHoldLen ;
          pWJ->m_dTHoldDiam = m_dTHoldDiam ;
          pWJ->m_dElev = m_dElev ;
@@ -207,6 +208,7 @@ WaterJetting::WaterJetting( void)
    m_Params.m_sToolName = "*" ;
    m_TParams.m_sName = "*" ;
    m_TParams.m_sHead = "*" ;
+   m_dTHoldBase = 0 ;
    m_dTHoldLen = 0 ;
    m_dTHoldDiam = 0 ;
    m_dElev = 0 ;
@@ -563,6 +565,8 @@ WaterJetting::Preview( bool bRecalc)
    }
   // recupero i dati del portautensile
    int nToolId = m_pMchMgr->GetCalcTool() ;
+   m_dTHoldBase = 0 ;
+   m_pGeomDB->GetInfo( nToolId, TTH_BASE, m_dTHoldBase) ;
    m_dTHoldLen = 0 ;
    m_pGeomDB->GetInfo( nToolId, TTH_LEN, m_dTHoldLen) ;
    m_dTHoldDiam = 0 ;
@@ -656,6 +660,8 @@ WaterJetting::Apply( bool bRecalc, bool bPostApply)
    }
   // recupero i dati del portautensile
    int nToolId = m_pMchMgr->GetCalcTool() ;
+   m_dTHoldBase = 0 ;
+   m_pGeomDB->GetInfo( nToolId, TTH_BASE, m_dTHoldBase) ;
    m_dTHoldLen = 0 ;
    m_pGeomDB->GetInfo( nToolId, TTH_LEN, m_dTHoldLen) ;
    m_dTHoldDiam = 0 ;
diff --git a/WaterJetting.h b/WaterJetting.h
index 5fe5b05..5225649 100644
--- a/WaterJetting.h
+++ b/WaterJetting.h
@@ -121,6 +121,7 @@ class WaterJetting : public Machining
       SELVECTOR          m_vId ;             // identificativi entità geometriche da lavorare
       WaterJettingData   m_Params ;          // parametri lavorazione
       ToolData           m_TParams ;         // parametri utensile
+      double             m_dTHoldBase ;      // posizione base del porta-utensile
       double             m_dTHoldLen ;       // lunghezza del porta-utensile
       double             m_dTHoldDiam ;      // diametro del porta-utensile
       double             m_dElev ;           // elevazione del percorso tenendo conto dell'angolo di fianco