diff --git a/LuaLibs/BeamExec.lua b/LuaLibs/BeamExec.lua
index 9e47bc1..5d16f02 100644
--- a/LuaLibs/BeamExec.lua
+++ b/LuaLibs/BeamExec.lua
@@ -1333,8 +1333,9 @@ end
 
 -------------------------------------------------------------------------------------------------------------
 function BeamExec.ProcessFeatures()
-   -- default per costanti qualora non definite
-   BD.IMPROVE_HEAD_TAIL_DRILLINGS = ( BD.IMPROVE_HEAD_TAIL_DRILLINGS or true)
+   if BD.IMPROVE_HEAD_TAIL_DRILLINGS == nil then
+      BD.IMPROVE_HEAD_TAIL_DRILLINGS = true
+   end
    -- verifica se possibile rotazione di 90 gradi
    BD.ROT90 = BD.ROT90 and Verify90DegRotation( EgtGetFirstRawPart())
    -- ciclo sui pezzi