Taken from the Old Discussion Forum:
Re: straightening bent drill stem
From: Tim Munsterman – firstname.lastname@example.org
Date: 11 Jun 2002
Hi John, You might try using heat to straighten the drill stem. By taking a large oxy-fuel rosebud torch and heating 3X18 inch long rectangles at various locations along the outside radius (extrados) of the bent pipe, thermal expansion and contraction will move the pipe back into position. I would use an IR gun to monitor temperature, don’t heat any location more than 1000F (if it glows it’s too hot). Heat the rectangle to temperature and allow to cool. The heat will initially cause the bend to look worse, then it will pull the pipe back past its original bent position. This is an old trick used on I-beams where heat shapes of rectangles and triangles can be used to curve an I-beam around to a desired shape. You might have your welder practice on a 20 foot length of pipe.
Call me if this sounds too confusing. Take care, Tim. Capstone Engineering 281-493-2236 x 212 or Cell phone at 281-414-2136