diff --git a/app/services/danger_zone.py b/app/services/danger_zone.py
index 8309591..b44bf91 100644
--- a/app/services/danger_zone.py
+++ b/app/services/danger_zone.py
@@ -16,12 +16,9 @@ from app.models.fit import Fit, FitNote
 from app.models.imported_part import ImportedPart
 from app.models.iso_thread import IsoThread
 from app.models.manufacturer import Manufacturer
-from app.models.part_colour import PartColour
-from app.models.part_type import PartType
 from app.models.scope_info import ScopeInfo
 from app.models.scope_model import ScopeModel
 from app.models.static_connection import StaticConnection
-from app.models.sub_part_type import SubPartType
 from app.models.unc_thread import UncThread
 
 # Children before the RESTRICT-protected reference tables they point to.
diff --git a/app/templates/admin/danger_zone.html b/app/templates/admin/danger_zone.html
index 7ed5d6d..30e2724 100644
--- a/app/templates/admin/danger_zone.html
+++ b/app/templates/admin/danger_zone.html
@@ -8,15 +8,15 @@
   <div class="card" style="border: 1px solid var(--color-danger, #c00)">
     <h2>Purge database</h2>
     <p>
-      Permanently deletes every part, taxonomy entry, attachment point, fit,
-      and imported part in the database — manufacturers, part colours, part
-      types, sub part types, scope models, ISO/UNC threads, clamp/static
-      connections, attachment point names, augmented parts, scope info,
-      attachment points, fits, fit notes, and imported parts.
+      Permanently deletes every part, attachment point, fit, and imported
+      part in the database — manufacturers, scope models, ISO/UNC threads,
+      clamp/static connections, attachment point names, augmented parts,
+      scope info, attachment points, fits, fit notes, and imported parts.
     </p>
     <p>
       <strong>Not</strong> deleted: users, roles &amp; permissions, refresh
-      tokens, the audit log, and the OData connection configuration.
+      tokens, the audit log, the OData connection configuration, and part
+      taxonomy (part colours, part types, sub part types).
     </p>
     <p class="muted">This cannot be undone. Take a database backup first if you might need this data again.</p>
     <button class="btn btn-danger"
diff --git a/tests/test_danger_zone.py b/tests/test_danger_zone.py
index ca4e21b..5edd2ad 100644
--- a/tests/test_danger_zone.py
+++ b/tests/test_danger_zone.py
@@ -132,20 +132,17 @@ async def test_purge_wipes_domain_data_but_keeps_users_and_odata_config(
             FitNote,
             ImportedPart,
             ScopeModel,
-            SubPartType,
-            PartType,
             AttachmentPointName,
             IsoThread,
             UncThread,
             ClampConnection,
             StaticConnection,
-            PartColour,
             Manufacturer,
         ):
             rows = (await db.execute(Model.__table__.select())).all()
             assert rows == [], f"{Model.__name__} should be empty after purge"
 
-        # Kept: users, RBAC, and the OData connection config.
+        # Kept: users, RBAC, the OData connection config, and part taxonomy.
         from app.crud import user as user_crud
 
         assert await user_crud.get_by_email(db, "root@example.com") is not None
@@ -153,5 +150,9 @@ async def test_purge_wipes_domain_data_but_keeps_users_and_odata_config(
         assert config is not None
         assert config.odata_url == "https://example.test/odata"
 
+        for Model in (PartColour, PartType, SubPartType):
+            rows = (await db.execute(Model.__table__.select())).all()
+            assert rows != [], f"{Model.__name__} should survive the purge"
+
         entries = await audit_crud.list_recent(db)
         assert any("Purged all domain data" in e.description for e in entries)
diff --git a/tests/test_scope_guide.py b/tests/test_scope_guide.py
index e073c6b..305f7b5 100644
--- a/tests/test_scope_guide.py
+++ b/tests/test_scope_guide.py
@@ -275,7 +275,7 @@ async def test_scopes_page_renders_objective_attachment_point_thread(
     assert resp.status_code == 200
     body = resp.text
     # The attachment point's thread spec wins over ScopeInfo.objective_thread_pitch.
-    assert "M44×0.5" in body
+    assert "M44.0×0.5" in body
     assert "M52x0.75" not in body