diff --git a/FlatCAMApp.py b/FlatCAMApp.py
index 22428809..c598bfda 100644
--- a/FlatCAMApp.py
+++ b/FlatCAMApp.py
@@ -729,6 +729,7 @@ class App(QtCore.QObject):
             "tools_ncccutz": self.ui.tools_defaults_form.tools_ncc_group.cutz_entry,
             "tools_ncctipdia": self.ui.tools_defaults_form.tools_ncc_group.tipdia_entry,
             "tools_ncctipangle": self.ui.tools_defaults_form.tools_ncc_group.tipangle_entry,
+            "tools_nccnewdia": self.ui.tools_defaults_form.tools_ncc_group.newdia_entry,
 
             # CutOut Tool
             "tools_cutouttooldia": self.ui.tools_defaults_form.tools_cutout_group.cutout_tooldia_entry,
@@ -1205,6 +1206,7 @@ class App(QtCore.QObject):
             "tools_ncccutz": -0.001968504,
             "tools_ncctipdia": 0.00393701,
             "tools_ncctipangle": 30,
+            "tools_nccnewdia": 0.0393701,
 
             # Cutout Tool
             "tools_cutouttooldia": 0.0944882,
@@ -5811,6 +5813,7 @@ class App(QtCore.QObject):
 
                       'tools_paintmargin', 'tools_painttooldia', 'tools_paintoverlap',
                       "tools_ncctools", "tools_nccoverlap", "tools_nccmargin", "tools_ncccutz", "tools_ncctipdia",
+                      "tools_nccnewdia",
                       "tools_2sided_drilldia", "tools_film_boundary",
                       "tools_cutouttooldia", 'tools_cutoutmargin', 'tools_cutoutgapsize',
                       "tools_panelize_constrainx", "tools_panelize_constrainy",
diff --git a/README.md b/README.md
index 641a987b..d0c20cf6 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,11 @@ CAD program, and create G-Code for Isolation routing.
 
 =================================================
 
+3.11.2019
+
+- fixed the V-shape tool diameter calculation in NCC Tool
+- in NCC Tool made the new tool dia (circular type) a parameter in Preferences
+
 30.10.2019
 
 - converted SolderPaste Tool to usage of SpinBoxes; changed the SolderPaste Tool UI in Preferences too
diff --git a/flatcamGUI/PreferencesUI.py b/flatcamGUI/PreferencesUI.py
index c87a4535..ec326c53 100644
--- a/flatcamGUI/PreferencesUI.py
+++ b/flatcamGUI/PreferencesUI.py
@@ -3712,6 +3712,7 @@ class ToolsNCCPrefGroupUI(OptionsGroupUI):
         super(ToolsNCCPrefGroupUI, self).__init__(self)
 
         self.setTitle(str(_("NCC Tool Options")))
+        self.decimals = 4
 
         # ## Clear non-copper regions
         self.clearcopper_label = QtWidgets.QLabel("<b>%s:</b>" % _("Parameters"))
@@ -3756,7 +3757,7 @@ class ToolsNCCPrefGroupUI(OptionsGroupUI):
         self.tipdialabel.setToolTip(
             _("The tip diameter for V-Shape Tool"))
         self.tipdia_entry = FCDoubleSpinner()
-        self.tipdia_entry.set_precision(4)
+        self.tipdia_entry.set_precision(self.decimals)
         self.tipdia_entry.set_range(0, 1000)
         self.tipdia_entry.setSingleStep(0.1)
 
@@ -3769,7 +3770,7 @@ class ToolsNCCPrefGroupUI(OptionsGroupUI):
             _("The tip angle for V-Shape Tool.\n"
               "In degree."))
         self.tipangle_entry = FCDoubleSpinner()
-        self.tipangle_entry.set_precision(4)
+        self.tipangle_entry.set_precision(self.decimals)
         self.tipangle_entry.set_range(-360, 360)
         self.tipangle_entry.setSingleStep(5)
         self.tipangle_entry.setWrapping(True)
@@ -3777,6 +3778,37 @@ class ToolsNCCPrefGroupUI(OptionsGroupUI):
         grid0.addWidget(self.tipanglelabel, 3, 0)
         grid0.addWidget(self.tipangle_entry, 3, 1)
 
+        # Cut Z entry
+        cutzlabel = QtWidgets.QLabel('%s:' % _('Cut Z'))
+        cutzlabel.setToolTip(
+           _("Depth of cut into material. Negative value.\n"
+             "In FlatCAM units.")
+        )
+        self.cutz_entry = FCDoubleSpinner()
+        self.cutz_entry.set_precision(self.decimals)
+        self.cutz_entry.set_range(-9999.9999, -0.000001)
+        self.cutz_entry.setSingleStep(0.1)
+
+        self.cutz_entry.setToolTip(
+           _("Depth of cut into material. Negative value.\n"
+             "In FlatCAM units.")
+        )
+
+        grid0.addWidget(cutzlabel, 4, 0)
+        grid0.addWidget(self.cutz_entry, 4, 1)
+
+        # New Diameter
+        self.newdialabel = QtWidgets.QLabel('%s:' % _('New Tool Dia'))
+        self.newdialabel.setToolTip(
+            _("The new tool diameter (cut width) to add in the tool table."))
+        self.newdia_entry = FCDoubleSpinner()
+        self.newdia_entry.set_precision(self.decimals)
+        self.newdia_entry.set_range(0.0001, 9999.9999)
+        self.newdia_entry.setSingleStep(0.1)
+
+        grid0.addWidget(self.newdialabel, 5, 0)
+        grid0.addWidget(self.newdia_entry, 5, 1)
+
         # Milling Type Radio Button
         self.milling_type_label = QtWidgets.QLabel('%s:' % _('Milling Type'))
         self.milling_type_label.setToolTip(
@@ -3793,8 +3825,8 @@ class ToolsNCCPrefGroupUI(OptionsGroupUI):
               "- conventional / useful when there is no backlash compensation")
         )
 
-        grid0.addWidget(self.milling_type_label, 4, 0)
-        grid0.addWidget(self.milling_type_radio, 4, 1)
+        grid0.addWidget(self.milling_type_label, 6, 0)
+        grid0.addWidget(self.milling_type_radio, 6, 1)
 
         # Tool order Radio Button
         self.ncc_order_label = QtWidgets.QLabel('%s:' % _('Tool order'))
@@ -3814,27 +3846,8 @@ class ToolsNCCPrefGroupUI(OptionsGroupUI):
                                           "'Reverse' --> menas that the tools will ordered from big to small\n\n"
                                           "WARNING: using rest machining will automatically set the order\n"
                                           "in reverse and disable this control."))
-        grid0.addWidget(self.ncc_order_label, 5, 0)
-        grid0.addWidget(self.ncc_order_radio, 5, 1)
-
-        # Cut Z entry
-        cutzlabel = QtWidgets.QLabel('%s:' % _('Cut Z'))
-        cutzlabel.setToolTip(
-           _("Depth of cut into material. Negative value.\n"
-             "In FlatCAM units.")
-        )
-        self.cutz_entry = FCDoubleSpinner()
-        self.cutz_entry.set_precision(4)
-        self.cutz_entry.set_range(-1000, -0.000001)
-        self.cutz_entry.setSingleStep(0.1)
-
-        self.cutz_entry.setToolTip(
-           _("Depth of cut into material. Negative value.\n"
-             "In FlatCAM units.")
-        )
-
-        grid0.addWidget(cutzlabel, 6, 0)
-        grid0.addWidget(self.cutz_entry, 6, 1)
+        grid0.addWidget(self.ncc_order_label, 7, 0)
+        grid0.addWidget(self.ncc_order_radio, 7, 1)
 
         # Overlap Entry
         nccoverlabel = QtWidgets.QLabel('%s:' % _('Overlap Rate'))
@@ -3850,25 +3863,25 @@ class ToolsNCCPrefGroupUI(OptionsGroupUI):
              "due of too many paths.")
         )
         self.ncc_overlap_entry = FCDoubleSpinner()
-        self.ncc_overlap_entry.set_precision(3)
+        self.ncc_overlap_entry.set_precision(self.decimals)
         self.ncc_overlap_entry.setWrapping(True)
         self.ncc_overlap_entry.setRange(0.000, 0.999)
         self.ncc_overlap_entry.setSingleStep(0.1)
-        grid0.addWidget(nccoverlabel, 7, 0)
-        grid0.addWidget(self.ncc_overlap_entry, 7, 1)
+        grid0.addWidget(nccoverlabel, 8, 0)
+        grid0.addWidget(self.ncc_overlap_entry, 8, 1)
 
         # Margin entry
         nccmarginlabel = QtWidgets.QLabel('%s:' % _('Margin'))
         nccmarginlabel.setToolTip(
             _("Bounding box margin.")
         )
-        grid0.addWidget(nccmarginlabel, 8, 0)
         self.ncc_margin_entry = FCDoubleSpinner()
-        self.ncc_margin_entry.set_precision(4)
+        self.ncc_margin_entry.set_precision(self.decimals)
         self.ncc_margin_entry.set_range(-10000, 10000)
         self.ncc_margin_entry.setSingleStep(0.1)
 
-        grid0.addWidget(self.ncc_margin_entry, 8, 1)
+        grid0.addWidget(nccmarginlabel, 9, 0)
+        grid0.addWidget(self.ncc_margin_entry, 9, 1)
 
         # Method
         methodlabel = QtWidgets.QLabel('%s:' % _('Method'))
@@ -3878,13 +3891,15 @@ class ToolsNCCPrefGroupUI(OptionsGroupUI):
               "<B>Seed-based</B>: Outwards from seed.<BR>"
               "<B>Line-based</B>: Parallel lines.")
         )
-        grid0.addWidget(methodlabel, 9, 0)
+
         self.ncc_method_radio = RadioSet([
             {"label": _("Standard"), "value": "standard"},
             {"label": _("Seed-based"), "value": "seed"},
             {"label": _("Straight lines"), "value": "lines"}
         ], orientation='vertical', stretch=False)
-        grid0.addWidget(self.ncc_method_radio, 9, 1)
+
+        grid0.addWidget(methodlabel, 10, 0)
+        grid0.addWidget(self.ncc_method_radio, 10, 1)
 
         # Connect lines
         pathconnectlabel = QtWidgets.QLabel('%s:' % _("Connect"))
@@ -3892,9 +3907,10 @@ class ToolsNCCPrefGroupUI(OptionsGroupUI):
             _("Draw lines between resulting\n"
               "segments to minimize tool lifts.")
         )
-        grid0.addWidget(pathconnectlabel, 10, 0)
         self.ncc_connect_cb = FCCheckBox()
-        grid0.addWidget(self.ncc_connect_cb, 10, 1)
+
+        grid0.addWidget(pathconnectlabel, 11, 0)
+        grid0.addWidget(self.ncc_connect_cb, 11, 1)
 
         # Contour Checkbox
         contourlabel = QtWidgets.QLabel('%s:' % _("Contour"))
@@ -3902,9 +3918,10 @@ class ToolsNCCPrefGroupUI(OptionsGroupUI):
            _("Cut around the perimeter of the polygon\n"
              "to trim rough edges.")
         )
-        grid0.addWidget(contourlabel, 11, 0)
         self.ncc_contour_cb = FCCheckBox()
-        grid0.addWidget(self.ncc_contour_cb, 11, 1)
+
+        grid0.addWidget(contourlabel, 12, 0)
+        grid0.addWidget(self.ncc_contour_cb, 12, 1)
 
         # Rest machining CheckBox
         restlabel = QtWidgets.QLabel('%s:' % _("Rest M."))
@@ -3917,9 +3934,10 @@ class ToolsNCCPrefGroupUI(OptionsGroupUI):
               "no more copper to clear or there are no more tools.\n"
               "If not checked, use the standard algorithm.")
         )
-        grid0.addWidget(restlabel, 12, 0)
         self.ncc_rest_cb = FCCheckBox()
-        grid0.addWidget(self.ncc_rest_cb, 12, 1)
+
+        grid0.addWidget(restlabel, 13, 0)
+        grid0.addWidget(self.ncc_rest_cb, 13, 1)
 
         # ## NCC Offset choice
         self.ncc_offset_choice_label = QtWidgets.QLabel('%s:' % _("Offset"))
@@ -3929,9 +3947,10 @@ class ToolsNCCPrefGroupUI(OptionsGroupUI):
               "from the copper features.\n"
               "The value can be between 0 and 10 FlatCAM units.")
         )
-        grid0.addWidget(self.ncc_offset_choice_label, 13, 0)
         self.ncc_choice_offset_cb = FCCheckBox()
-        grid0.addWidget(self.ncc_choice_offset_cb, 13, 1)
+
+        grid0.addWidget(self.ncc_offset_choice_label, 14, 0)
+        grid0.addWidget(self.ncc_choice_offset_cb, 14, 1)
 
         # ## NCC Offset value
         self.ncc_offset_label = QtWidgets.QLabel('%s:' % _("Offset value"))
@@ -3939,16 +3958,16 @@ class ToolsNCCPrefGroupUI(OptionsGroupUI):
             _("If used, it will add an offset to the copper features.\n"
               "The copper clearing will finish to a distance\n"
               "from the copper features.\n"
-              "The value can be between 0 and 10 FlatCAM units.")
+              "The value can be between 0.0 and 9999.9 FlatCAM units.")
         )
-        grid0.addWidget(self.ncc_offset_label, 14, 0)
         self.ncc_offset_spinner = FCDoubleSpinner()
-        self.ncc_offset_spinner.set_range(0.00, 10.00)
-        self.ncc_offset_spinner.set_precision(4)
+        self.ncc_offset_spinner.set_range(0.00, 9999.9999)
+        self.ncc_offset_spinner.set_precision(self.decimals)
         self.ncc_offset_spinner.setWrapping(True)
         self.ncc_offset_spinner.setSingleStep(0.1)
 
-        grid0.addWidget(self.ncc_offset_spinner, 14, 1)
+        grid0.addWidget(self.ncc_offset_label, 15, 0)
+        grid0.addWidget(self.ncc_offset_spinner, 15, 1)
 
         # ## Reference
         self.reference_radio = RadioSet([{'label': _('Itself'), 'value': 'itself'},
@@ -3963,8 +3982,9 @@ class ToolsNCCPrefGroupUI(OptionsGroupUI):
               "- 'Reference Object' -  will do non copper clearing within the area\n"
               "specified by another object.")
         )
-        grid0.addWidget(reference_label, 15, 0)
-        grid0.addWidget(self.reference_radio, 15, 1)
+
+        grid0.addWidget(reference_label, 16, 0)
+        grid0.addWidget(self.reference_radio, 16, 1)
 
         # ## Plotting type
         self.ncc_plotting_radio = RadioSet([{'label': _('Normal'), 'value': 'normal'},
@@ -3974,8 +3994,8 @@ class ToolsNCCPrefGroupUI(OptionsGroupUI):
             _("- 'Normal' -  normal plotting, done at the end of the NCC job\n"
               "- 'Progressive' - after each shape is generated it will be plotted.")
         )
-        grid0.addWidget(plotting_label, 16, 0)
-        grid0.addWidget(self.ncc_plotting_radio, 16, 1)
+        grid0.addWidget(plotting_label, 17, 0)
+        grid0.addWidget(self.ncc_plotting_radio, 17, 1)
 
         self.layout.addStretch()
 
diff --git a/flatcamTools/ToolCalculators.py b/flatcamTools/ToolCalculators.py
index 032ef5a7..6a43a3aa 100644
--- a/flatcamTools/ToolCalculators.py
+++ b/flatcamTools/ToolCalculators.py
@@ -325,8 +325,7 @@ class ToolCalculator(FlatCAMTool):
 
         tip_diameter = float(self.tipDia_entry.get_value())
 
-        half_tip_angle = float(self.tipAngle_entry.get_value())
-        half_tip_angle /= 2
+        half_tip_angle = float(self.tipAngle_entry.get_value()) / 2.0
 
         cut_depth = float(self.cutDepth_entry.get_value())
         cut_depth = -cut_depth if cut_depth < 0 else cut_depth
diff --git a/flatcamTools/ToolNonCopperClear.py b/flatcamTools/ToolNonCopperClear.py
index b29203e3..835eb926 100644
--- a/flatcamTools/ToolNonCopperClear.py
+++ b/flatcamTools/ToolNonCopperClear.py
@@ -153,8 +153,10 @@ class NonCopperClear(FlatCAMTool, Gerber):
               "If it's not successful then the non-copper clearing will fail, too.\n"
               "- Clear -> the regular non-copper clearing."))
 
-        form = QtWidgets.QFormLayout()
-        self.tools_box.addLayout(form)
+        grid1 = QtWidgets.QGridLayout()
+        self.tools_box.addLayout(grid1)
+        grid1.setColumnStretch(0, 0)
+        grid1.setColumnStretch(1, 1)
 
         # Milling Type Radio Button
         self.milling_type_label = QtWidgets.QLabel('%s:' % _('Milling Type'))
@@ -172,6 +174,9 @@ class NonCopperClear(FlatCAMTool, Gerber):
               "- conventional / useful when there is no backlash compensation")
         )
 
+        grid1.addWidget(self.milling_type_label, 0, 0)
+        grid1.addWidget(self.milling_type_radio, 0, 1)
+
         # Tool order
         self.ncc_order_label = QtWidgets.QLabel('<b>%s:</b>' % _('Tool order'))
         self.ncc_order_label.setToolTip(_("This set the way that the tools in the tools table are used.\n"
@@ -191,9 +196,9 @@ class NonCopperClear(FlatCAMTool, Gerber):
                                           "WARNING: using rest machining will automatically set the order\n"
                                           "in reverse and disable this control."))
 
-        form.addRow(self.milling_type_label, self.milling_type_radio)
-        form.addRow(self.ncc_order_label, self.ncc_order_radio)
-        form.addRow(QtWidgets.QLabel(''))
+        grid1.addWidget(self.ncc_order_label, 1, 0)
+        grid1.addWidget(self.ncc_order_radio, 1, 1)
+        grid1.addWidget(QtWidgets.QLabel(''), 2, 0)
 
         self.milling_type_label.hide()
         self.milling_type_radio.hide()
@@ -202,7 +207,7 @@ class NonCopperClear(FlatCAMTool, Gerber):
         # ############### Tool selection ##############################
         # #############################################################
         self.tool_sel_label = QtWidgets.QLabel('<b>%s</b>' % _("Tool Selection"))
-        form.addRow(self.tool_sel_label)
+        grid1.addWidget(self.tool_sel_label, 3, 0, 1, 2)
 
         # Tool Type Radio Button
         self.tool_type_label = QtWidgets.QLabel('%s:' % _('Tool Type'))
@@ -219,17 +224,8 @@ class NonCopperClear(FlatCAMTool, Gerber):
               "- 'V-shape'\n"
               "- Circular")
         )
-        form.addRow(self.tool_type_label, self.tool_type_radio)
-
-        # ### Add a new Tool ####
-        self.addtool_entry_lbl = QtWidgets.QLabel('<b>%s:</b>' % _('Tool Dia'))
-        self.addtool_entry_lbl.setToolTip(
-            _("Diameter for the new tool to add in the Tool Table")
-        )
-        self.addtool_entry = FCDoubleSpinner()
-        self.addtool_entry.set_precision(self.decimals)
-
-        form.addRow(self.addtool_entry_lbl, self.addtool_entry)
+        grid1.addWidget(self.tool_type_label, 4, 0)
+        grid1.addWidget(self.tool_type_radio, 4, 1)
 
         # Tip Dia
         self.tipdialabel = QtWidgets.QLabel('%s:' % _('V-Tip Dia'))
@@ -239,7 +235,8 @@ class NonCopperClear(FlatCAMTool, Gerber):
         self.tipdia_entry.set_precision(self.decimals)
         self.tipdia_entry.setSingleStep(0.1)
 
-        form.addRow(self.tipdialabel, self.tipdia_entry)
+        grid1.addWidget(self.tipdialabel, 5, 0)
+        grid1.addWidget(self.tipdia_entry, 5, 1)
 
         # Tip Angle
         self.tipanglelabel = QtWidgets.QLabel('%s:' % _('V-Tip Angle'))
@@ -250,7 +247,38 @@ class NonCopperClear(FlatCAMTool, Gerber):
         self.tipangle_entry.set_precision(self.decimals)
         self.tipangle_entry.setSingleStep(5)
 
-        form.addRow(self.tipanglelabel, self.tipangle_entry)
+        grid1.addWidget(self.tipanglelabel, 6, 0)
+        grid1.addWidget(self.tipangle_entry, 6 , 1)
+
+        # Cut Z entry
+        cutzlabel = QtWidgets.QLabel('%s:' % _('Cut Z'))
+        cutzlabel.setToolTip(
+           _("Depth of cut into material. Negative value.\n"
+             "In FlatCAM units.")
+        )
+        self.cutz_entry = FCDoubleSpinner()
+        self.cutz_entry.set_precision(self.decimals)
+        self.cutz_entry.set_range(-99999, -0.00000000000001)
+
+        self.cutz_entry.setToolTip(
+           _("Depth of cut into material. Negative value.\n"
+             "In FlatCAM units.")
+        )
+        grid1.addWidget(cutzlabel, 7, 0)
+        grid1.addWidget(self.cutz_entry, 7, 1)
+
+        # ### Tool Diameter ####
+        self.addtool_entry_lbl = QtWidgets.QLabel('<b>%s:</b>' % _('Tool Dia'))
+        self.addtool_entry_lbl.setToolTip(
+            _("Diameter for the new tool to add in the Tool Table.\n"
+              "If the tool is V-shape type then this value is automatically\n"
+              "calculated from the other parameters.")
+        )
+        self.addtool_entry = FCDoubleSpinner()
+        self.addtool_entry.set_precision(self.decimals)
+
+        grid1.addWidget(self.addtool_entry_lbl, 8, 0)
+        grid1.addWidget(self.addtool_entry, 8, 1)
 
         grid2 = QtWidgets.QGridLayout()
         self.tools_box.addLayout(grid2)
@@ -287,23 +315,6 @@ class NonCopperClear(FlatCAMTool, Gerber):
         e_lab_1 = QtWidgets.QLabel('<b>%s:</b>' % _("Parameters"))
         grid3.addWidget(e_lab_1, 0, 0)
 
-        # Cut Z entry
-        cutzlabel = QtWidgets.QLabel('%s:' % _('Cut Z'))
-        cutzlabel.setToolTip(
-           _("Depth of cut into material. Negative value.\n"
-             "In FlatCAM units.")
-        )
-        self.cutz_entry = FCDoubleSpinner()
-        self.cutz_entry.set_precision(self.decimals)
-        self.cutz_entry.set_range(-99999, -0.00000000000001)
-
-        self.cutz_entry.setToolTip(
-           _("Depth of cut into material. Negative value.\n"
-             "In FlatCAM units.")
-        )
-        grid3.addWidget(cutzlabel, 1, 0)
-        grid3.addWidget(self.cutz_entry, 1, 1)
-
         # Overlap Entry
         nccoverlabel = QtWidgets.QLabel('%s:' % _('Overlap Rate'))
         nccoverlabel.setToolTip(
@@ -535,6 +546,10 @@ class NonCopperClear(FlatCAMTool, Gerber):
         self.deltool_btn.clicked.connect(self.on_tool_delete)
         self.generate_ncc_button.clicked.connect(self.on_ncc_click)
 
+        self.tipdia_entry.returnPressed.connect(self.on_calculate_tooldia)
+        self.tipangle_entry.returnPressed.connect(self.on_calculate_tooldia)
+        self.cutz_entry.returnPressed.connect(self.on_calculate_tooldia)
+
         self.box_combo_type.currentIndexChanged.connect(self.on_combo_box_type)
         self.reference_radio.group_toggle_fn = self.on_toggle_reference
         self.ncc_choice_offset_cb.stateChanged.connect(self.on_offset_choice)
@@ -551,7 +566,7 @@ class NonCopperClear(FlatCAMTool, Gerber):
     def on_add_tool_by_key(self):
         tool_add_popup = FCInputDialog(title='%s...' % _("New Tool"),
                                        text='%s:' % _('Enter a Tool Diameter'),
-                                       min=0.0000, max=99.9999, decimals=4)
+                                       min=0.0001, max=9999.9999, decimals=self.decimals)
         tool_add_popup.setWindowIcon(QtGui.QIcon('share/letter_t_32.png'))
 
         val, ok = tool_add_popup.get_value()
@@ -624,6 +639,7 @@ class NonCopperClear(FlatCAMTool, Gerber):
         self.tool_type_radio.set_value(self.app.defaults["tools_ncctool_type"])
         self.tipdia_entry.set_value(self.app.defaults["tools_ncctipdia"])
         self.tipangle_entry.set_value(self.app.defaults["tools_ncctipangle"])
+        self.addtool_entry.set_value(self.app.defaults["tools_nccnewdia"])
 
         self.on_tool_type(val=self.tool_type_radio.get_value())
 
@@ -707,11 +723,6 @@ class NonCopperClear(FlatCAMTool, Gerber):
         # updated units
         self.units = self.app.ui.general_defaults_form.general_app_group.units_radio.get_value().upper()
 
-        if self.units == "IN":
-            self.addtool_entry.set_value(0.039)
-        else:
-            self.addtool_entry.set_value(1)
-
         sorted_tools = []
         for k, v in self.ncc_tools.items():
             if self.units == "IN":
@@ -905,54 +916,50 @@ class NonCopperClear(FlatCAMTool, Gerber):
 
     def on_tool_type(self, val):
         if val == 'V':
-            self.addtool_entry_lbl.hide()
-            self.addtool_entry.hide()
+            self.addtool_entry_lbl.setDisabled(True)
+            self.addtool_entry.setDisabled(True)
             self.tipdialabel.show()
             self.tipdia_entry.show()
             self.tipanglelabel.show()
             self.tipangle_entry.show()
         else:
-            self.addtool_entry_lbl.show()
-            self.addtool_entry.show()
+            self.addtool_entry_lbl.setDisabled(False)
+            self.addtool_entry.setDisabled(False)
             self.tipdialabel.hide()
             self.tipdia_entry.hide()
             self.tipanglelabel.hide()
             self.tipangle_entry.hide()
 
+    def on_calculate_tooldia(self):
+        if self.tool_type_radio.get_value() == 'V':
+            tip_dia = float(self.tipdia_entry.get_value())
+            tip_angle = float(self.tipangle_entry.get_value()) / 2.0
+            cut_z = float(self.cutz_entry.get_value())
+            cut_z = -cut_z if cut_z < 0 else cut_z
+
+            # calculated tool diameter so the cut_z parameter is obeyed
+            tool_dia = tip_dia + (2 * cut_z * math.tan(math.radians(tip_angle)))
+
+            # update the default_data so it is used in the ncc_tools dict
+            self.default_data.update({
+                "vtipdia": tip_dia,
+                "vtipangle": (tip_angle * 2),
+            })
+
+            self.addtool_entry.set_value(tool_dia)
+
+            return tool_dia
+        else:
+            return float(self.addtool_entry.get_value())
+
     def on_tool_add(self, dia=None, muted=None):
-
         self.ui_disconnect()
-
         self.units = self.app.ui.general_defaults_form.general_app_group.units_radio.get_value().upper()
 
         if dia:
             tool_dia = dia
         else:
-            if self.tool_type_radio.get_value() == 'V':
-
-                tip_dia = float(self.tipdia_entry.get_value())
-                tip_angle = float(self.tipangle_entry.get_value()) / 2
-                cut_z = float(self.cutz_entry.get_value())
-
-                # calculated tool diameter so the cut_z parameter is obeyed
-                tool_dia = tip_dia + 2 * cut_z * math.tan(math.radians(tip_angle))
-
-                # update the default_data so it is used in the ncc_tools dict
-                self.default_data.update({
-                    "vtipdia": tip_dia,
-                    "vtipangle": (tip_angle * 2),
-                })
-            else:
-                try:
-                    tool_dia = float(self.addtool_entry.get_value())
-                except ValueError:
-                    # try to convert comma to decimal point. if it's still not working error message and return
-                    try:
-                        tool_dia = float(self.addtool_entry.get_value().replace(',', '.'))
-                    except ValueError:
-                        self.app.inform.emit('[ERROR_NOTCL] %s' % _("Wrong value format entered, use a number."))
-                        return
-
+            tool_dia = self.on_calculate_tooldia()
             if tool_dia is None:
                 self.build_ui()
                 self.app.inform.emit('[WARNING_NOTCL] %s' % _("Please enter a tool diameter to add, in Float format."))