diff --git a/gerbview/gerbview_frame.cpp b/gerbview/gerbview_frame.cpp
index 0dc0a2f027..d2e5f1178f 100644
--- a/gerbview/gerbview_frame.cpp
+++ b/gerbview/gerbview_frame.cpp
@@ -303,11 +303,12 @@ bool GERBVIEW_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
             SetActiveLayer( layer );
 
             // Try to guess the type of file by its ext
-            // if it is .drl (Kicad files), it is a drill file
+            // if it is .drl (Kicad files), .nc or .xnc it is a drill file
             wxFileName fn( aFileSet[i] );
             wxString ext = fn.GetExt();
 
-            if( ext == DrillFileExtension )     // In Excellon format
+            if( ext == DrillFileExtension ||    // our Excellon format
+                ext == "nc" || ext == "xnc" )   // alternate ext for Excellon format
                 LoadExcellonFiles( aFileSet[i] );
             else if( ext == GerberJobFileExtension )
                 LoadGerberJobFile( aFileSet[i] );
diff --git a/kicad/files-io.cpp b/kicad/files-io.cpp
index 3ac2cbb3b5..15b420a29f 100644
--- a/kicad/files-io.cpp
+++ b/kicad/files-io.cpp
@@ -41,7 +41,7 @@
 #include "kicad.h"
 
 
-#define     ZipFileExtension    wxT( "zip" )
+#define ZipFileExtension wxT( "zip" )
 
 
 void KICAD_MANAGER_FRAME::OnFileHistory( wxCommandEvent& event )
@@ -148,7 +148,7 @@ void KICAD_MANAGER_FRAME::OnArchiveFiles( wxCommandEvent& event )
         wxT( "*.gp1" ), wxT( "*.gp2" ),
         wxT( "*.gpb" ), wxT( "*.gpt" ),
         wxT( "*.gt?" ),
-        wxT( "*.pos" ), wxT( "*.drl" ),         // Fab files
+        wxT( "*.pos" ), wxT( "*.drl" ), wxT( "*.nc" ), wxT( "*.xnc" ),  // Fab files
         wxT( "*.d356" ), wxT( "*.rpt" ),
         wxT( "*.stp" ), wxT( "*.step" ),        // 3d files
         wxT( "*.wrl" ),
diff --git a/kicad/kicad.h b/kicad/kicad.h
index 803dcc314d..79b47195f7 100644
--- a/kicad/kicad.h
+++ b/kicad/kicad.h
@@ -65,6 +65,8 @@ enum TreeFileType {
     TREE_REPORT,            // report file (.rpt)
     TREE_FP_PLACE,          // fooprints position (place) file (.pos)
     TREE_DRILL,             // Excellon drill file (.drl)
+    TREE_DRILL_NC,          // Similar Excellon drill file (.nc)
+    TREE_DRILL_XNC,         // Similar Excellon drill file (.xnc)
     TREE_SVG,               // SVG file (.svg)
     TREE_PAGE_LAYOUT_DESCR, // Page layout and title block descr file (.kicad_wks)
     TREE_FOOTPRINT_FILE,    // footprint file (.kicad_mod)
diff --git a/kicad/tree_project_frame.cpp b/kicad/tree_project_frame.cpp
index b466640958..2bb7a03df1 100644
--- a/kicad/tree_project_frame.cpp
+++ b/kicad/tree_project_frame.cpp
@@ -88,6 +88,8 @@ static const wxChar* s_allowedExtensionsToList[] =
     wxT( "^.*\\.pos$" ),            // Footprint position files
     wxT( "^.*\\.cmp$" ),            // Cvpcb cmp/footprint link files
     wxT( "^.*\\.drl$" ),            // Excellon drill files
+    wxT( "^.*\\.nc$" ),             // Excellon NC drill files (alternate file ext)
+    wxT( "^.*\\.xnc$" ),            // Excellon NC drill files (alternate file ext)
     wxT( "^.*\\.svg$" ),            // SVG print/plot files
     NULL                            // end of list
 };
@@ -306,6 +308,14 @@ wxString TREE_PROJECT_FRAME::GetFileExt( TreeFileType type )
         ext = DrillFileExtension;
         break;
 
+    case TREE_DRILL_NC:
+        ext = "nc";
+        break;
+
+    case TREE_DRILL_XNC:
+        ext = "xnc";
+        break;
+
     case TREE_SVG:
         ext = SVGFileExtension;
         break;
@@ -385,6 +395,8 @@ wxString TREE_PROJECT_FRAME::GetFileWildcard( TreeFileType type )
         break;
 
     case TREE_DRILL:
+    case TREE_DRILL_NC:
+    case TREE_DRILL_XNC:
         ext = DrillFileWildcard();
         break;
 
diff --git a/kicad/treeproject_item.cpp b/kicad/treeproject_item.cpp
index 5bdc75646c..e7ed9c9132 100644
--- a/kicad/treeproject_item.cpp
+++ b/kicad/treeproject_item.cpp
@@ -224,6 +224,8 @@ void TREEPROJECT_ITEM::Activate( TREE_PROJECT_FRAME* aTreePrjFrame )
 
     case TREE_GERBER:
     case TREE_DRILL:
+    case TREE_DRILL_NC:
+    case TREE_DRILL_XNC:
         frame->Execute( m_parent, GERBVIEW_EXE, fullFileName );
         break;
 
diff --git a/kicad/treeprojectfiles.cpp b/kicad/treeprojectfiles.cpp
index 57b07c5488..fc2d1ef47c 100644
--- a/kicad/treeprojectfiles.cpp
+++ b/kicad/treeprojectfiles.cpp
@@ -72,6 +72,8 @@ TREEPROJECTFILES::TREEPROJECTFILES( TREE_PROJECT_FRAME* parent ) :
     m_ImageList->Add( KiBitmap( tools_xpm ) );                  // TREE_REPORT
     m_ImageList->Add( KiBitmap( post_compo_xpm ) );             // TREE_POS
     m_ImageList->Add( KiBitmap( post_drill_xpm ) );             // TREE_DRILL
+    m_ImageList->Add( KiBitmap( post_drill_xpm ) );             // TREE_DRILL_NC (similar TREE_DRILL)
+    m_ImageList->Add( KiBitmap( post_drill_xpm ) );             // TREE_DRILL_XNC (similar TREE_DRILL)
     m_ImageList->Add( KiBitmap( svg_file_xpm ) );               // TREE_SVG
     m_ImageList->Add( KiBitmap( pagelayout_load_xpm ) );        // TREE_PAGE_LAYOUT_DESCR
     m_ImageList->Add( KiBitmap( module_xpm ) );                 // TREE_FOOTPRINT_FILE