diff --git a/hkl/diffract.py b/hkl/diffract.py
index dfeed1e2..5ae8108c 100644
--- a/hkl/diffract.py
+++ b/hkl/diffract.py
@@ -42,11 +42,11 @@ class Diffractometer(PseudoPositioner):
         ~engine
         ~forward
         ~inverse
-        ~forwardSolutionsTable
-        ~applyConstraints
-        ~resetConstraints
-        ~showConstraints
-        ~undoLastConstraints
+        ~forward_solutions_table
+        ~apply_constraints
+        ~reset_constraints
+        ~show_constraints
+        ~undo_last_constraints
         ~pa
         ~wh
         ~_energy_changed
@@ -395,7 +395,7 @@ def check_value(self, pos):
             pos = [pos.get(p.attr_name, p.position) for p in self.pseudo_positioners]
         super().check_value(pos)
 
-    def applyConstraints(self, constraints):
+    def apply_constraints(self, constraints):
         """
         Constrain the diffractometer's motions.
 
@@ -405,13 +405,13 @@ def applyConstraints(self, constraints):
         self._push_current_constraints()
         self._set_constraints(constraints)
 
-    def resetConstraints(self):
+    def reset_constraints(self):
         """Set constraints back to initial settings."""
         if len(self._constraints_stack) > 0:
             self._set_constraints(self._constraints_stack[0])
             self._constraints_stack = []
 
-    def showConstraints(self, fmt="simple", printing=True):
+    def show_constraints(self, fmt="simple", printing=True):
         """Print the current constraints in a table."""
         tbl = pyRestTable.Table()
         tbl.labels = "axis low_limit high_limit value fit".split()
@@ -432,7 +432,7 @@ def showConstraints(self, fmt="simple", printing=True):
 
         return tbl
 
-    def undoLastConstraints(self):
+    def undo_last_constraints(self):
         """
         Remove the current constraints additions, restore previous.
         """
@@ -458,7 +458,7 @@ def _set_constraints(self, constraints):
             self.calc[axis].value = constraint.value
             self.calc[axis].fit = constraint.fit
 
-    def forwardSolutionsTable(self, reflections, full=False):
+    def forward_solutions_table(self, reflections, full=False):
         """
         Return table of computed solutions for each (hkl) in the supplied reflections list.
 
@@ -561,7 +561,7 @@ def Package(**kwargs):
             pt.addRow(row)
         table.addRow(("positions", addTable(pt)))
 
-        t = self.showConstraints(printing=False)
+        t = self.show_constraints(printing=False)
         table.addRow(("constraints", addTable(t)))
 
         if all_samples:
diff --git a/hkl/tests/test_diffract.py b/hkl/tests/test_diffract.py
index 83e2a183..ff2c327c 100644
--- a/hkl/tests/test_diffract.py
+++ b/hkl/tests/test_diffract.py
@@ -145,7 +145,7 @@ def test_names(fourc):
     assert fourc.class_name.get() == "Fourc"
 
 
-def test_forwardSolutionsTable(fourc):
+def test_forward_solutions_table(fourc):
     fourc.energy.put(A_KEV / 1.54)
 
     # (100) has chi ~ 0 which poses occasional roundoff errors
@@ -156,7 +156,7 @@ def test_forwardSolutionsTable(fourc):
     assert pytest.approx(sol.phi, 1e-5) == -90
     assert pytest.approx(sol.tth, 1e-5) == -60
 
-    tbl = fourc.forwardSolutionsTable(
+    tbl = fourc.forward_solutions_table(
         # fmt: off
         [
             [1, 1, 0],
@@ -261,8 +261,8 @@ def test_wh(fourc, capsys):
     assert out == expected
 
 
-def test_showConstraints(fourc, capsys):
-    fourc.showConstraints()
+def test_show_constraints(fourc, capsys):
+    fourc.show_constraints()
     out, err = capsys.readouterr()
     assert len(out) > 0
     assert err == ""
@@ -281,10 +281,10 @@ def test_showConstraints(fourc, capsys):
         assert r.rstrip() == e.rstrip()
 
 
-def test_applyConstraints(fourc):
+def test_apply_constraints(fourc):
     fourc.energy.put(A_KEV / 1.54)
     # fmt: off
-    fourc.applyConstraints(
+    fourc.apply_constraints(
         {
             "tth": Constraint(0, 180, 0, True),
             "chi": Constraint(0, 180, 0, True),