diff --git a/LuaLibs/BeamLib.lua b/LuaLibs/BeamLib.lua
index 616a7e5..0c19524 100644
--- a/LuaLibs/BeamLib.lua
+++ b/LuaLibs/BeamLib.lua
@@ -588,7 +588,7 @@ function BeamLib.GetFaceWithMostAdj( Proc, nPartId, bCompare3Fc, dCosSideAng)
    end
    local bEveryFaceHasUndercut = ( nFacesWithUnderCut == nFacCnt)
    -- tunnel o assimilabile
-   if Proc.Topology == 'Tunnel' or ( bCompare3Fc and Proc.Topology == 'Groove' and Proc.IsThrough and not (Proc.AffectedFaces.Left or Proc.AffectedFaces.Right)) or ( Proc.Topology == 'Strip' and bEveryFaceHasUndercut) then
+   if Proc.Topology == 'Tunnel' or ( bCompare3Fc and Proc.Topology == 'Groove' and Proc.IsThrough) or ( Proc.Topology == 'Strip' and bEveryFaceHasUndercut) then
       if Proc.IsParallel or Proc.AllRightAngles then
          return -1, GEO.INFINITO, true
       else
diff --git a/LuaLibs/ProcessLapJoint.lua b/LuaLibs/ProcessLapJoint.lua
index 4143ff2..fea7633 100644
--- a/LuaLibs/ProcessLapJoint.lua
+++ b/LuaLibs/ProcessLapJoint.lua
@@ -3408,7 +3408,9 @@ local function MakeByChainOrSaw( Proc, nPhase, nRawId, nPartId, nFacInd,
             bGoFromHead = false
          -- continuo di testa se fessura con tre facce o non è tunnel
          else
-            bGoFromHead = (( bIs3Faces and dMaxElev) or not bOrthoFaces)
+            bGoFromHead = (( bIs3Faces and ( dMaxElev 
+                           or ( Proc.Topology == 'Groove' and Proc.IsThrough and (Proc.AffectedFaces.Left or Proc.AffectedFaces.Right) and not Proc.IsParallel))) 
+                           or not bOrthoFaces)
          end
       end
       -- se continuo a lavorare di testa
@@ -3477,7 +3479,7 @@ local function MakeByChainOrSaw( Proc, nPhase, nRawId, nPartId, nFacInd,
             local dToolEntryAngle, _, _, dTanToolEntryAngle = GetToolEntryAngle( Proc, rfFac:getVersZ())
             -- se necessario, avverto limitazione dell'affondamento
             if dElev > dMaxDepth + 10 * GEO.EPS_SMALL then
-               if Proc.Fct == 3 and Proc.Topology == 'Groove' and Proc.IsThrough and (Proc.AffectedFaces.Left or Proc.AffectedFaces.Right) then
+               if Proc.Fct == 3 and Proc.Topology == 'Groove' and Proc.IsThrough and (Proc.AffectedFaces.Left or Proc.AffectedFaces.Right) and not Proc.IsParallel then
                   local Edges = BL.GetEdgesInfo( Proc, Proc.Face[nFacAdj+1])
                   local dWorkEdgeWidth
                   for i = 1, #Edges do