Bill Tindall, E.Tn.
I have cut timber and firewood for a long time. I have had a chain come off when it got tangled cutting brush but never cutting something large. I was cutting a large limb on a downed tree at chest height. As the limb dropped the chain came off and the loose end whacked me on the thigh hard enough to make a bruise through the padded chaps. The pointy chisel teeth wounded the chaps but I wasn't. Don't know why the chain got thrown as it was tight on the bar. Suspect the bar may be worn...will check and replace if necessary.