Then I lightly center punch, and check again with the magnifier to make certain that I really punched in the right place. You may be able to get Kroil from a shooting supply place. The shear plane should go through the unthreaded shank of a bolt if not than the root area of the thread must be used in the calculation. During the drilling, they may actually twist the bolt out. I am still asked the two nut question but I always tend to recommend other more modern ways of locking the threads. Usually, there is some open space under it. If the extractor starts to twist, pull it out with Vise Grips, and drill the fastener to the minor thread diameter.
Research indicates that the reason why fasteners come loose is usually caused by transverse loadings causing slippage of the joint.
Removing Seized, Broken, Frozen or Stuck Threaded Fasteners
Instead of using washers however the trend as been to the use of flanged fasteners. The preload is related to the applied torque by friction that is present under the nut face and in the threads. It is normally calculated as preload divided by the stress area of the thread. The shear plane should go through the unthreaded shank of a bolt if not than the root area of the thread must be used in the calculation. My reasoning was that nut heights had been decided by establishing the least height that would ensure that the bolt would break before the threads started to shear.