Broken bolt in head

5-32" X-TRACTALLOY BROKEN BOLT EXTRACTION ELECTRODE - Partsmaster

use these , you can gently build the stud up with these rods or you can lay a nut over top and weld through the nut until filled with weld and turn out . even if a stud is broke off down deep in a hole you can still use these as the flux fills the threads and protects them from the filler . i use these now for 25 years and never had one defeat me yet . i just pulled 4 broken off flush exhaust manifold studs from a 4.8 dakota a few days ago .