diff --git a/LuaLibs/ProcessHeadCut.lua b/LuaLibs/ProcessHeadCut.lua
index b6671f4..67a3465 100644
--- a/LuaLibs/ProcessHeadCut.lua
+++ b/LuaLibs/ProcessHeadCut.lua
@@ -254,7 +254,8 @@ local function MakeHeadChamfer( idProc, nPartId)
    EgtSetMachiningParam( MCH_MP.DEPTH, dDepthHeadChamfer + dExtra)
    EgtSetMachiningParam( MCH_MP.OFFSR, dExtra)
    -- assegno lato di lavoro
-   EgtSetMachiningParam( MCH_MP.WORKSIDE, MCH_MILL_WS.RIGHT)
+   EgtSetMachiningParam( MCH_MP.WORKSIDE, MCH_MILL_WS.LEFT)
+   EgtSetMachiningParam( MCH_MP.INVERT, true)
    -- eseguo
    if not ML.ApplyMachining( true, false) then
       local _, sErr = EgtGetLastMachMgrError()
diff --git a/LuaLibs/ProcessSplit.lua b/LuaLibs/ProcessSplit.lua
index 5f8a800..58f393b 100644
--- a/LuaLibs/ProcessSplit.lua
+++ b/LuaLibs/ProcessSplit.lua
@@ -258,7 +258,8 @@ local function MakeTailChamfer( idProc, nPartId, dDepthTailChamfer)
    EgtSetMachiningParam( MCH_MP.DEPTH, dDepthTailChamfer + dExtra)
    EgtSetMachiningParam( MCH_MP.OFFSR, dExtra)
    -- assegno lato di lavoro
-   EgtSetMachiningParam( MCH_MP.WORKSIDE, MCH_MILL_WS.RIGHT)
+   EgtSetMachiningParam( MCH_MP.WORKSIDE, MCH_MILL_WS.LEFT)
+   EgtSetMachiningParam( MCH_MP.INVERT, true)
    -- eseguo
    if not ML.ApplyMachining( true, false) then
       local _, sErr = EgtGetLastMachMgrError()