diff --git a/camlib.py b/camlib.py
index 7c2b0204..434a5122 100644
--- a/camlib.py
+++ b/camlib.py
@@ -3109,6 +3109,8 @@ class CNCjob(Geometry):
         elif zcut == 0:
             self.app.inform.emit('[WARNING] %s.' % _("The Cut Z parameter is zero. There will be no cut, aborting"))
             return 'fail'
+        else:
+            return zcut
 
     # used in Tool Drilling
     def excellon_tool_gcode_gen(self, tool, points, tools, first_pt, is_first=False, is_last=False, opt_type='T',
diff --git a/tclCommands/TclCommandDrillcncjob.py b/tclCommands/TclCommandDrillcncjob.py
index efd90db4..e891163c 100644
--- a/tclCommands/TclCommandDrillcncjob.py
+++ b/tclCommands/TclCommandDrillcncjob.py
@@ -148,7 +148,8 @@ class TclCommandDrillcncjob(TclCommandSignaled):
                     req_tools = set()
                     for tool in obj.tools:
                         for req_dia in diameters:
-                            obj_dia_form = float('%.*f' % (obj.decimals, float(obj.tools[tool]["C"])))
+                            obj_dia_form = float(
+                                '%.*f' % (obj.decimals, float(obj.tools[tool]["tooldia"])))
                             req_dia_form = float('%.*f' % (obj.decimals, float(req_dia)))
 
                             if 'diatol' in args:
@@ -157,11 +158,11 @@ class TclCommandDrillcncjob(TclCommandSignaled):
                                 tolerance = 0.0 if tolerance < 0.0 else tolerance
                                 tolerance = 1.0 if tolerance > 1.0 else tolerance
                                 if math.isclose(obj_dia_form, req_dia_form, rel_tol=tolerance):
-                                    req_tools.add(tool)
+                                    req_tools.add(str(tool))
                                     nr_diameters -= 1
                             else:
                                 if obj_dia_form == req_dia_form:
-                                    req_tools.add(tool)
+                                    req_tools.add(str(tool))
                                     nr_diameters -= 1
 
                     if nr_diameters > 0:
@@ -174,10 +175,11 @@ class TclCommandDrillcncjob(TclCommandSignaled):
                     # make a string of diameters separated by comma; this is what generate_from_excellon_by_tool() is
                     # expecting as tools parameter
                     tools = ','.join(req_tools)
+                    tools += ','
 
                     # no longer needed
                     del args['drilled_dias']
-                    del args['diatol']
+                    args.pop('diatol', None)
 
                     # Split and put back. We are passing the whole dictionary later.
                     # args['milled_dias'] = [x.strip() for x in args['tools'].split(",")]