{HEAD ~ The burnishing section} is operative to upset the material around the hole, so as to result in {TAIL ~ a residual stress} beneficial to the hole 
{ HEAD ~ The burnishing section } is operative to upset the material around the hole , so as to result in { TAIL ~ a residual stress } beneficial to the hole
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH