diff --git a/EMkMachiningGeoConst.h b/EMkMachiningGeoConst.h
index 9439ca3..3feb3b7 100644
--- a/EMkMachiningGeoConst.h
+++ b/EMkMachiningGeoConst.h
@@ -34,6 +34,7 @@ static std::string MCH_AUXVIEW = "AVIEW" ;
 static std::string MCH_TABS = "TABS" ;
 static std::string MCH_PV = "PV" ;
 static std::string MCH_ST = "ST" ;
+static std::string MCH_ST_DBL = "STDBL" ;
 static std::string MCH_CL = "CL" ;
 static std::string MCH_DBL = "DBL" ;
 static std::string MCH_PATH = "P" ;