This is worth looking at, on the subject of torque wrenches. Keep a close eye on your reading and if the nut is turning but the torque isn't increasing you're starting to strip or stretch. If you don't stop you'll be sorry... Even if you're reading way under the target torque.
http://home.jtan.com/~joe/KIAT/kiat_3.htm
http://home.jtan.com/~joe/KIAT/kiat_3.htm