diff --git a/LuaLibs/ProcessTenon.lua b/LuaLibs/ProcessTenon.lua
index 3ea367e..170dbfc 100644
--- a/LuaLibs/ProcessTenon.lua
+++ b/LuaLibs/ProcessTenon.lua
@@ -321,9 +321,9 @@ function ProcessTenon.Make( Proc, nPhase, nRawId, nPartId, dOvmHead)
       -- se contorno aperto, cambio parametri di attacco/uscita
       if not bClosed then
          EgtSetMachiningParam( MCH_MP.LITANG, 0.7 * dMillDiam)
-         EgtSetMachiningParam( MCH_MP.LIPERP, 0)
+         EgtSetMachiningParam( MCH_MP.LIPERP, 20)
          EgtSetMachiningParam( MCH_MP.LOTANG, 0.7 * dMillDiam)
-         EgtSetMachiningParam( MCH_MP.LOPERP, 0)
+         EgtSetMachiningParam( MCH_MP.LOPERP, 20)
       end
       -- imposto posizione braccio porta testa
       local nSCC = MCH_SCC.NONE