diff --git a/doc/changelog.txt b/doc/changelog.txt
index 1b400bfb..ac9bb8a4 100644
--- a/doc/changelog.txt
+++ b/doc/changelog.txt
@@ -13,6 +13,7 @@ Fixes:
 
 Changes:
 - gui: Use Alt-key shortcuts for menu entries.
+- checking: Improved thread locking and reduce calls to time.sleep().
 
 Features:
 - checking: Added support for Google Chrome bookmark files.
diff --git a/linkcheck/director/__init__.py b/linkcheck/director/__init__.py
index aabaed3f..1ba215ad 100644
--- a/linkcheck/director/__init__.py
+++ b/linkcheck/director/__init__.py
@@ -1,5 +1,5 @@
 # -*- coding: iso-8859-1 -*-
-# Copyright (C) 2006-2010 Bastian Kleineidam
+# Copyright (C) 2006-2011 Bastian Kleineidam
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -17,7 +17,6 @@
 """
 Management of checking a queue of links with several threads.
 """
-import time
 import os
 import thread
 import urlparse
@@ -158,18 +157,13 @@ def check_url (aggregate):
     """Helper function waiting for URL queue."""
     while True:
         try:
-            aggregate.urlqueue.join(timeout=0.5)
+            aggregate.urlqueue.join(timeout=30)
             break
         except urlqueue.Timeout:
-            # Since urlqueue.join() is not interruptable, add a timeout
-            # and a one-second slumber.
-            time.sleep(1)
+            # Cleanup threads every 30 seconds
             aggregate.remove_stopped_threads()
             if not aggregate.threads:
                 break
-            if aggregate.wanted_stop:
-                # some other thread wants us to stop
-                raise KeyboardInterrupt
 
 
 def interrupt (aggregate):
diff --git a/linkcheck/director/checker.py b/linkcheck/director/checker.py
index 47120025..05182a3c 100644
--- a/linkcheck/director/checker.py
+++ b/linkcheck/director/checker.py
@@ -1,5 +1,5 @@
 # -*- coding: iso-8859-1 -*-
-# Copyright (C) 2006-2010 Bastian Kleineidam
+# Copyright (C) 2006-2011 Bastian Kleineidam
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -45,10 +45,8 @@ class Checker (task.CheckedTask):
 
     def run_checked (self):
         """Check URLs in the queue."""
-        while True:
+        while not self.stopped(0):
             self.check_url()
-            if self.stopped():
-                break
 
     def check_url (self):
         """Try to get URL data from queue and check it."""
diff --git a/linkcheck/director/cleanup.py b/linkcheck/director/cleanup.py
index 7be5f4ec..5fcd87d5 100644
--- a/linkcheck/director/cleanup.py
+++ b/linkcheck/director/cleanup.py
@@ -1,5 +1,5 @@
 # -*- coding: iso-8859-1 -*-
-# Copyright (C) 2007-2010 Bastian Kleineidam
+# Copyright (C) 2007-2011 Bastian Kleineidam
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -32,11 +32,5 @@ class Cleanup (task.CheckedTask):
         self.start_time = time.time()
         self.setName("Cleanup")
         # clean every 15 seconds
-        wait_seconds = 15
-        waitfor = range(wait_seconds*10)
-        while True:
-            for dummy in waitfor:
-                time.sleep(0.1)
-                if self.stopped():
-                    return
+        while not self.stopped(15):
             self.connections.remove_expired()
diff --git a/linkcheck/director/status.py b/linkcheck/director/status.py
index 8bd4cc7c..1f749b97 100644
--- a/linkcheck/director/status.py
+++ b/linkcheck/director/status.py
@@ -1,5 +1,5 @@
 # -*- coding: iso-8859-1 -*-
-# Copyright (C) 2006-2010 Bastian Kleineidam
+# Copyright (C) 2006-2011 Bastian Kleineidam
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -33,12 +33,7 @@ class Status (task.CheckedTask):
         """Print periodic status messages."""
         self.start_time = time.time()
         self.setName("Status")
-        waitfor = range(self.wait_seconds*10)
-        while True:
-            for dummy in waitfor:
-                time.sleep(0.1)
-                if self.stopped():
-                    return
+        while not self.stopped(self.wait_seconds):
             self.log_status()
 
     def log_status (self):
diff --git a/linkcheck/threader.py b/linkcheck/threader.py
index ea68a764..ff0bf0e1 100644
--- a/linkcheck/threader.py
+++ b/linkcheck/threader.py
@@ -78,6 +78,9 @@ class StoppableThread (threading.Thread):
         """Set stop event."""
         self._stop.set()
 
-    def stopped (self):
+    def stopped (self, timeout=None):
         """Return True if stop event is set."""
-        return self._stop.isSet()
+        self._stop.wait(timeout)
+        # XXX on Python >= 2.7 the result from wait() can be returned
+        # directly.
+        return self._stop.is_set()