diff --git a/LuaLibs/WProcessLapJoint.lua b/LuaLibs/WProcessLapJoint.lua
index 8889c17..a8936ab 100644
--- a/LuaLibs/WProcessLapJoint.lua
+++ b/LuaLibs/WProcessLapJoint.lua
@@ -1385,8 +1385,8 @@ local function MakeSideGrooveByMill( Proc, nFacet, nRawId, b3Raw, sCustomMach, d
    local nOtherFacet = abs( nFacet - 1)
    local vtN2 = EgtSurfTmFacetNormVersor( Proc.Id, nOtherFacet, GDB_ID.ROOT)
    local dElevOtherFacet = WL.GetFaceElevation( Proc.Id, nOtherFacet, nRawId)
-   -- se lap joint 2 facce dal basso e angolo più di 90°
-   local bExcludeSideMill = Proc.Fct == 2 and dAng and dAng > -90 + 10 * GEO.EPS_SMALL and vtN2:getZ() < -0.99 and vtN2:getZ() > -1.01
+   -- se lap joint 2 facce dal basso e angolo negativo
+   local bExcludeSideMill = Proc.Fct == 2 and vtN:getZ() < -0.01 and vtN2:getZ() < -0.01
    -- dimensioni della faccia principale
    local _, dH, dV = EgtSurfTmFacetMinAreaRectangle( Proc.Id, nFacet, GDB_ID.ROOT)
    local dThick = min( dH, dV)
@@ -2039,8 +2039,11 @@ local function MakeSideGrooveByMill( Proc, nFacet, nRawId, b3Raw, sCustomMach, d
          EgtSetOperationMode( nMchFId, false)
          return false, sErr
       end
+   elseif bExcludeSideMill then
+      local sErr = 'Feature not machinable by orientation'
+      EgtOutLog( sErr)
+      return false, sErr
    end
-
    return true, sWarn
 end
 
@@ -2345,11 +2348,12 @@ local function MakeTwoFaces( Proc, nRawId, b3Raw)
          EgtOutLog( sErr)
          return false, sErr
       end
-      local vtN = EgtSurfTmFacetNormVersor( Proc.Id, nFacInd, GDB_ID.ROOT)
+      local vtNTemp = EgtSurfTmFacetNormVersor( Proc.Id, nFacInd, GDB_ID.ROOT)
       local dSideDist
       local ptMid = ( ptP1 + ptP2) / 2
       -- faccia orizzontale
-      local nFacet = EgtIf( vtN:getZ() >= WD.NZ_MINA, nFacInd, nFacInd2)
+      local nFacet = EgtIf( vtNTemp:getZ() >= WD.NZ_MINA, nFacInd, nFacInd2)
+      local vtN = EgtSurfTmFacetNormVersor( Proc.Id, nFacet, GDB_ID.ROOT)
       -- faccia verticale
       local nFacetVert = EgtIf( nFacet == nFacInd, nFacInd2, nFacInd)
       local vtNV = EgtSurfTmFacetNormVersor( Proc.Id, nFacetVert, GDB_ID.ROOT)
@@ -2593,7 +2597,6 @@ local function MakeMoreFaces( Proc, nRawId, b3Raw)
          local sErr = 'Side milling not possible'
          EgtOutLog( sErr)
          return true, sErr
-
       end
    -- fessura verticale
    elseif Proc.Stype == 3 then