diff --git a/LuaLibs/ProcessTenon.lua b/LuaLibs/ProcessTenon.lua
index a278ab9..7aa3754 100644
--- a/LuaLibs/ProcessTenon.lua
+++ b/LuaLibs/ProcessTenon.lua
@@ -225,7 +225,7 @@ function ProcessTenon.Make( Proc, nPhase, nRawId, nPartId, dOvmHead)
    local OVERLAP_COEFF = 0.7
    -- porto inizio curva il più possibile sul bordo in alto o in basso
    local dMaxDist = OVERLAP_COEFF * dMillDiam * MAX_PASS
-   local bMyShortPart = ( bShortPart and abs( vtN:getX()) < 0.999 and abs( vtN:getY()) < 0.259)
+   local bMyShortPart = ( bShortPart and vtN:getX() < 0 and abs( vtN:getX()) < 0.999 and abs( vtN:getY()) < 0.259)
    BL.PutStartNearestToEdge( AuxId, b3Solid, dMaxDist, ( bH2 and bMillDown) ~= bMyShortPart)
    -- se elevazione superiore a massimo affondamento della fresa, riduco opportunamente
    local sWarn