diff --git a/nc_files/remap_lib/python-stdglue/stdglue.py b/nc_files/remap_lib/python-stdglue/stdglue.py
index 73b937aaad9..c7914f97280 100644
--- a/nc_files/remap_lib/python-stdglue/stdglue.py
+++ b/nc_files/remap_lib/python-stdglue/stdglue.py
@@ -210,7 +210,7 @@ def change_epilog(self, **words):
             if self.return_value > 0.0:
                 # commit change
                 self.selected_pocket =  int(self.params["selected_pocket"])
-                emccanon.CHANGE_TOOL(self.selected_pocket)
+                emccanon.CHANGE_TOOL()
                 self.current_pocket = self.selected_pocket
                 self.selected_pocket = -1
                 self.selected_tool = -1
@@ -476,7 +476,7 @@ def index_lathe_tool_with_wear(self,**words):
         # change tool
         try:
             self.selected_pocket =  int(self.params["selected_pocket"])
-            emccanon.CHANGE_TOOL(self.selected_pocket)
+            emccanon.CHANGE_TOOL()
             self.current_pocket = self.selected_pocket
             self.selected_pocket = -1
             self.selected_tool = -1
@@ -572,7 +572,7 @@ def tool_probe_m6(self, **words):
 
         try:
             self.selected_pocket =  int(self.params["selected_pocket"])
-            emccanon.CHANGE_TOOL(self.selected_pocket)
+            emccanon.CHANGE_TOOL()
             self.current_pocket = self.selected_pocket
             self.selected_pocket = -1
             self.selected_tool = -1
diff --git a/src/emc/canterp/canterp.cc b/src/emc/canterp/canterp.cc
index a759caf94a0..f336a05ddac 100644
--- a/src/emc/canterp/canterp.cc
+++ b/src/emc/canterp/canterp.cc
@@ -424,10 +424,7 @@ int Canterp::execute(const char *line) {
     }
 
     if (!strcmp(the_command_name, "CHANGE_TOOL")) {
-	if (1 != sscanf(the_command_args, "%d", &i1)) {
-	    return INTERP_ERROR;
-	}
-	CHANGE_TOOL(i1);
+	CHANGE_TOOL();
 	return 0;
     }
 
diff --git a/src/emc/nml_intf/canon.hh b/src/emc/nml_intf/canon.hh
index dd44a11b6ef..885f1e732fb 100644
--- a/src/emc/nml_intf/canon.hh
+++ b/src/emc/nml_intf/canon.hh
@@ -635,7 +635,7 @@ extern void SET_TOOL_TABLE_ENTRY(int pocket, int toolno, EmcPose offset, double
                                  double frontangle, double backangle, int orientation);
 extern void USE_TOOL_LENGTH_OFFSET(EmcPose offset);
 
-extern void CHANGE_TOOL(int slot);	/* slot is slot number */
+extern void CHANGE_TOOL();
 
 /* It is assumed that each cutting tool in the machine is assigned to a
 slot (intended to correspond to a slot number in a tool carousel).
diff --git a/src/emc/rs274ngc/gcodemodule.cc b/src/emc/rs274ngc/gcodemodule.cc
index fe2a8aa8337..cb6de60c52d 100644
--- a/src/emc/rs274ngc/gcodemodule.cc
+++ b/src/emc/rs274ngc/gcodemodule.cc
@@ -167,6 +167,7 @@ static PyTypeObject LineCodeType = {
 static PyObject *callback;
 static int interp_error;
 static int last_sequence_number;
+static int selected_tool = 0;
 static bool metric;
 static double _pos_x, _pos_y, _pos_z, _pos_a, _pos_b, _pos_c, _pos_u, _pos_v, _pos_w;
 EmcPose tool_offset;
@@ -427,11 +428,11 @@ void SET_FEED_MODE(int spindle, int mode) {
 #endif
 }
 
-void CHANGE_TOOL(int pocket) {
+void CHANGE_TOOL() {
     maybe_new_line();
     if(interp_error) return;
     PyObject *result = 
-        callmethod(callback, "change_tool", "i", pocket);
+        callmethod(callback, "change_tool", "i", selected_tool);
     if(result == NULL) interp_error ++;
     Py_XDECREF(result);
 }
@@ -528,7 +529,7 @@ void PROGRAM_END() {}
 void FINISH() {}
 void ON_RESET() {}
 void PALLET_SHUTTLE() {}
-void SELECT_TOOL(int tool) {}
+void SELECT_TOOL(int tool) {selected_tool = tool;}
 void UPDATE_TAG(StateTag tag) {}
 void OPTIONAL_PROGRAM_STOP() {}
 int  GET_EXTERNAL_TC_FAULT() {return 0;}
diff --git a/src/emc/rs274ngc/interp_convert.cc b/src/emc/rs274ngc/interp_convert.cc
index 57003c0f85b..c915638b755 100644
--- a/src/emc/rs274ngc/interp_convert.cc
+++ b/src/emc/rs274ngc/interp_convert.cc
@@ -6149,7 +6149,7 @@ int Interp::convert_tool_change(setup_pointer settings)  //!< pointer to machine
       settings->w_current = w_end;
   }
 
-  CHANGE_TOOL(settings->selected_pocket);
+  CHANGE_TOOL();
 
   settings->current_pocket = settings->selected_pocket;
   // tool change can move the controlled point.  reread it:
diff --git a/src/emc/sai/saicanon.cc b/src/emc/sai/saicanon.cc
index 38cfdfb6e15..de4d3448c0e 100644
--- a/src/emc/sai/saicanon.cc
+++ b/src/emc/sai/saicanon.cc
@@ -552,15 +552,15 @@ void USE_TOOL_LENGTH_OFFSET(EmcPose offset)
          offset.tran.x, offset.tran.y, offset.tran.z, offset.a, offset.b, offset.c, offset.u, offset.v, offset.w);
 }
 
-void CHANGE_TOOL(int slot)
+void CHANGE_TOOL()
 {
-  PRINT("CHANGE_TOOL(%d)\n", slot);
-  _sai._active_slot = slot;
+  PRINT("CHANGE_TOOL()\n");
+  _sai._active_slot = _sai._selected_tool;
 #ifdef TOOL_NML //{
   _sai._tools[0] = _sai._tools[slot];
 #else //}{
     CANON_TOOL_TABLE tdata;
-    if (tooldata_get(&tdata,slot) != IDX_OK) {
+    if (tooldata_get(&tdata,_sai._selected_tool) != IDX_OK) {
         UNEXPECTED_MSG;
     }
     _sai._tools[0] = tdata;
@@ -571,7 +571,10 @@ void CHANGE_TOOL(int slot)
 }
 
 void SELECT_TOOL(int tool)//TODO: fix slot number
-{PRINT("SELECT_TOOL(%d)\n", tool);}
+{
+  PRINT("SELECT_TOOL(%d)\n", tool);
+  _sai._selected_tool = tool;
+}
 
 void CHANGE_TOOL_NUMBER(int tool)
 {
@@ -1136,6 +1139,7 @@ void reset_internals()
 StandaloneInterpInternals::StandaloneInterpInternals() :
   _active_plane(CANON_PLANE::XY),
   _active_slot(1),
+  _selected_tool(0),
   _feed_mode(0),
   _feed_rate(0.0),
   _flood(0),
diff --git a/src/emc/sai/saicanon.hh b/src/emc/sai/saicanon.hh
index 902cec460fe..43450d38547 100644
--- a/src/emc/sai/saicanon.hh
+++ b/src/emc/sai/saicanon.hh
@@ -21,6 +21,7 @@ struct StandaloneInterpInternals
 
   CANON_PLANE _active_plane;
   int _active_slot;
+  int _selected_tool;
   int _feed_mode;
   double _feed_rate;
   int _flood;
diff --git a/src/emc/task/emccanon.cc b/src/emc/task/emccanon.cc
index bf5741f8b24..0f32a94ca1f 100644
--- a/src/emc/task/emccanon.cc
+++ b/src/emc/task/emccanon.cc
@@ -2900,7 +2900,7 @@ void USE_TOOL_LENGTH_OFFSET(EmcPose offset)
 }
 
 /* CHANGE_TOOL results from M6 */
-void CHANGE_TOOL(int slot)
+void CHANGE_TOOL()
 {
     EMC_TRAJ_LINEAR_MOVE linearMoveMsg;
     linearMoveMsg.feed_mode = canon.feed_mode;
diff --git a/tests/ccomp/lathe-comp/expected b/tests/ccomp/lathe-comp/expected
index 627b2427c5a..4fabddb4b79 100644
--- a/tests/ccomp/lathe-comp/expected
+++ b/tests/ccomp/lathe-comp/expected
@@ -12,7 +12,7 @@
  N..... USE_TOOL_LENGTH_OFFSET(0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000)
  N..... SELECT_TOOL(0)
  N..... STOP_SPINDLE_TURNING(0)
- N..... CHANGE_TOOL(0)
+ N..... CHANGE_TOOL()
  N..... STRAIGHT_TRAVERSE(0.3000, 0.0000, 0.0000, 0.0000, 0.0000, 0.0000)
  N..... COMMENT("interpreter: cutter radius compensation off")
  N..... STRAIGHT_FEED(0.1000, 0.0000, 0.0000, 0.0000, 0.0000, 0.0000)
@@ -24,7 +24,7 @@
  N..... STRAIGHT_TRAVERSE(0.3000, 0.0000, 1.7500, 0.0000, 0.0000, 0.0000)
  N..... SELECT_TOOL(2)
  N..... STOP_SPINDLE_TURNING(0)
- N..... CHANGE_TOOL(2)
+ N..... CHANGE_TOOL()
  N..... USE_TOOL_LENGTH_OFFSET(0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000)
  N..... STRAIGHT_TRAVERSE(0.3000, 0.0000, 0.0000, 0.0000, 0.0000, 0.0000)
  N..... COMMENT("interpreter: cutter radius compensation on left")
@@ -38,7 +38,7 @@
  N..... STRAIGHT_TRAVERSE(0.3000, 0.0000, 1.7500, 0.0000, 0.0000, 0.0000)
  N..... SELECT_TOOL(7)
  N..... STOP_SPINDLE_TURNING(0)
- N..... CHANGE_TOOL(7)
+ N..... CHANGE_TOOL()
  N..... USE_TOOL_LENGTH_OFFSET(0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000)
  N..... STRAIGHT_TRAVERSE(0.3000, 0.0000, 1.8500, 0.0000, 0.0000, 0.0000)
  N..... STRAIGHT_TRAVERSE(-0.3000, 0.0000, 1.8500, 0.0000, 0.0000, 0.0000)
@@ -55,7 +55,7 @@
  N..... USE_TOOL_LENGTH_OFFSET(0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000)
  N..... SELECT_TOOL(0)
  N..... STOP_SPINDLE_TURNING(0)
- N..... CHANGE_TOOL(0)
+ N..... CHANGE_TOOL()
  N..... SET_G5X_OFFSET(1, 0.0000, 0.0000, 0.0000, 0.0000, 0.0000, 0.0000)
  N..... SET_XY_ROTATION(0.0000)
  N..... SELECT_PLANE(CANON_PLANE_XY)
diff --git a/tests/ccomp/mill-g90g91g92/expected b/tests/ccomp/mill-g90g91g92/expected
index 4ec880bacc2..f58e4008429 100644
--- a/tests/ccomp/mill-g90g91g92/expected
+++ b/tests/ccomp/mill-g90g91g92/expected
@@ -7,7 +7,7 @@
  N..... USE_LENGTH_UNITS(CANON_UNITS_INCHES)
  N..... SELECT_TOOL(3)
  N..... STOP_SPINDLE_TURNING(0)
- N..... CHANGE_TOOL(3)
+ N..... CHANGE_TOOL()
  N..... STRAIGHT_TRAVERSE(0.0000, 0.0000, 0.0000, 0.0000, 0.0000, 0.0000)
  N..... SET_FEED_RATE(100.0000)
  N..... STRAIGHT_TRAVERSE(0.0000, 0.0000, 1.0000, 0.0000, 0.0000, 0.0000)
diff --git a/tests/ccomp/mill-line-arc-entry/expected b/tests/ccomp/mill-line-arc-entry/expected
index f99aafe4e6e..ab893c5e6e7 100644
--- a/tests/ccomp/mill-line-arc-entry/expected
+++ b/tests/ccomp/mill-line-arc-entry/expected
@@ -23,7 +23,7 @@
  N..... COMMENT("with compensation")
  N..... SELECT_TOOL(4)
  N..... STOP_SPINDLE_TURNING(0)
- N..... CHANGE_TOOL(4)
+ N..... CHANGE_TOOL()
  N..... STRAIGHT_TRAVERSE(1.0000, 5.0000, 0.0000, 0.0000, 0.0000, 0.0000)
  N..... COMMENT("interpreter: cutter radius compensation on left")
  N..... STRAIGHT_FEED(1.5000, 4.0000, 0.0000, 0.0000, 0.0000, 0.0000)
diff --git a/tests/interp/cam-nisley/expected b/tests/interp/cam-nisley/expected
index d8499dc2ea4..4bc9ee37531 100644
--- a/tests/interp/cam-nisley/expected
+++ b/tests/interp/cam-nisley/expected
@@ -50,7 +50,7 @@
  N..... COMMENT("set up the tool")
  N..... SELECT_TOOL(1)
  N..... STOP_SPINDLE_TURNING(0)
- N..... CHANGE_TOOL(1)
+ N..... CHANGE_TOOL()
  N..... COMMENT("-----------------")
  N..... MESSAGE("Verify METRIC Sherline.tbl file!")
  N..... MESSAGE("Align XY=0 at center, Z=0 at surface, spindle to match S value, hit [Run]")
diff --git a/tests/interp/compile/use-rs274.cc b/tests/interp/compile/use-rs274.cc
index 98d5021fc10..91ca5a058d9 100644
--- a/tests/interp/compile/use-rs274.cc
+++ b/tests/interp/compile/use-rs274.cc
@@ -146,7 +146,7 @@ void USE_NO_SPINDLE_FORCE() {}
 void SET_TOOL_TABLE_ENTRY(int pocket, int toolno, EmcPose offset, double diameter,
                                  double frontangle, double backangle, int orientation) {}
 void USE_TOOL_LENGTH_OFFSET(EmcPose offset) {}
-void CHANGE_TOOL(int slot) {}	
+void CHANGE_TOOL() {}	
 void SELECT_TOOL(int tool) {}	
 void CHANGE_TOOL_NUMBER(int number) {}
 void RELOAD_TOOLDATA() {}
diff --git a/tests/interp/g10/g10-l1-l10/expected b/tests/interp/g10/g10-l1-l10/expected
index 282b9d08517..0cad3409669 100644
--- a/tests/interp/g10/g10-l1-l10/expected
+++ b/tests/interp/g10/g10-l1-l10/expected
@@ -14,7 +14,7 @@
  N..... SET_TOOL_TABLE_ENTRY(0, 1, 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000, 0.0000, 0.0000, 0)
  N..... SELECT_TOOL(1)
  N..... STOP_SPINDLE_TURNING(0)
- N..... CHANGE_TOOL(1)
+ N..... CHANGE_TOOL()
  N..... USE_TOOL_LENGTH_OFFSET(0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000)
  N..... MESSAGE(" should be 0 0 0: 0.000000 0.000000 0.000000")
  N..... SET_TOOL_TABLE_ENTRY(1, 1, 1.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000, 0.0000, 0.0000, 0)
@@ -48,7 +48,7 @@
  N..... SET_TOOL_TABLE_ENTRY(0, 1, 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000, 0.0000, 0.0000, 0)
  N..... SELECT_TOOL(1)
  N..... STOP_SPINDLE_TURNING(0)
- N..... CHANGE_TOOL(1)
+ N..... CHANGE_TOOL()
  N..... USE_TOOL_LENGTH_OFFSET(0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000)
  N..... STRAIGHT_TRAVERSE(0.1000, 0.2000, 0.3000, 0.0000, 0.0000, 0.0000)
  N..... MESSAGE(" should be 0 0 0: 0.000000 0.000000 0.000000")
@@ -85,7 +85,7 @@
  N..... SET_TOOL_TABLE_ENTRY(0, 1, 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000, 0.0000, 0.0000, 0)
  N..... SELECT_TOOL(1)
  N..... STOP_SPINDLE_TURNING(0)
- N..... CHANGE_TOOL(1)
+ N..... CHANGE_TOOL()
  N..... USE_TOOL_LENGTH_OFFSET(0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000)
  N..... MESSAGE(" should be 0 0 0: 0.000000 0.000000 0.000000")
  N..... SET_TOOL_TABLE_ENTRY(1, 1, -0.7071 -0.7071 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000, 0.0000, 0.0000, 0)
@@ -108,7 +108,7 @@
  N..... SET_TOOL_TABLE_ENTRY(0, 1, 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000, 0.0000, 0.0000, 0)
  N..... SELECT_TOOL(1)
  N..... STOP_SPINDLE_TURNING(0)
- N..... CHANGE_TOOL(1)
+ N..... CHANGE_TOOL()
  N..... USE_TOOL_LENGTH_OFFSET(0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000)
  N..... MESSAGE(" should be 0 0 0: 0.000000 0.000000 0.000000")
  N..... SET_TOOL_TABLE_ENTRY(1, 1, -0.7071 -0.7071 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000, 0.0000, 0.0000, 0)
diff --git a/tests/interp/g10/g10-l11/expected b/tests/interp/g10/g10-l11/expected
index 376e847b383..867b9539c30 100644
--- a/tests/interp/g10/g10-l11/expected
+++ b/tests/interp/g10/g10-l11/expected
@@ -21,7 +21,7 @@
  N..... SET_TOOL_TABLE_ENTRY(0, 1, 0.0000 0.0000 -3.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000, 0.0000, 0.0000, 0)
  N..... SELECT_TOOL(1)
  N..... STOP_SPINDLE_TURNING(0)
- N..... CHANGE_TOOL(1)
+ N..... CHANGE_TOOL()
  N..... MESSAGE("-3.000000")
  N..... SET_G5X_OFFSET(2, 4.0000, 5.0000, -6.0000, 0.0000, 0.0000, 0.0000)
  N..... SET_G92_OFFSET(0.0000, 0.0000, 0.0000, 0.0000, 0.0000, 0.0000)
@@ -42,7 +42,7 @@
  N..... SET_TOOL_TABLE_ENTRY(0, 1, 0.0000 0.0000 -3.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000, 0.0000, 0.0000, 0)
  N..... SELECT_TOOL(1)
  N..... STOP_SPINDLE_TURNING(0)
- N..... CHANGE_TOOL(1)
+ N..... CHANGE_TOOL()
  N..... MESSAGE("-3.000000")
  N..... SET_G5X_OFFSET(2, 4.0000, 5.0000, -6.0000, 0.0000, 0.0000, 0.0000)
  N..... SET_G92_OFFSET(-43.0622, -47.4282, -76.0000, 0.0000, 0.0000, 0.0000)
diff --git a/tests/interp/g76/expected b/tests/interp/g76/expected
index 24963a4e299..c2c4921112c 100644
--- a/tests/interp/g76/expected
+++ b/tests/interp/g76/expected
@@ -12,7 +12,7 @@
  N..... COMMENT("thread")
  N..... SELECT_TOOL(4)
  N..... STOP_SPINDLE_TURNING(0)
- N..... CHANGE_TOOL(4)
+ N..... CHANGE_TOOL()
  N..... USE_TOOL_LENGTH_OFFSET(0.0000 0.0000 0.7000, 0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000)
  N..... SET_SPINDLE_SPEED(0, 800.0000)
  N..... START_SPINDLE_CLOCKWISE(0)
diff --git a/tests/remap/introspect/expected b/tests/remap/introspect/expected
index 724342b799c..4e6bd8af9d6 100644
--- a/tests/remap/introspect/expected
+++ b/tests/remap/introspect/expected
@@ -8,7 +8,7 @@ executing
     7 N..... MESSAGE(" before introspect: call_level= 0.000000")
     8 N..... SELECT_TOOL(3)
     9 N..... STOP_SPINDLE_TURNING(0)
-   10 N..... CHANGE_TOOL(3)
+   10 N..... CHANGE_TOOL()
    11 N..... SET_FEED_RATE(200.0000)
    12 N..... SET_SPINDLE_SPEED(0, 3000.0000)
    13 N..... START_SPINDLE_CLOCKWISE(0)
diff --git a/tests/remap/oword-pycall/expected b/tests/remap/oword-pycall/expected
index ee72a4a264d..a11f8e0c786 100644
--- a/tests/remap/oword-pycall/expected
+++ b/tests/remap/oword-pycall/expected
@@ -10,7 +10,7 @@ multiply: number of arguments= 3
     7 N..... USE_LENGTH_UNITS(CANON_UNITS_INCHES)
     8 N..... SELECT_TOOL(1)
     9 N..... STOP_SPINDLE_TURNING(0)
-   10 N..... CHANGE_TOOL(1)
+   10 N..... CHANGE_TOOL()
    11 N..... USE_TOOL_LENGTH_OFFSET(10.0000 0.0000 20.0000, 0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000)
    12 N..... USE_TOOL_LENGTH_OFFSET(0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000, 0.0000 0.0000 0.0000)
    13 N..... SET_TOOL_TABLE_ENTRY(1, 1, 20.0000 30.0000 40.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000, 0.0000, 0.0000, 0)