Broken Exhaust stud removal

After finding out I ordered the wrong crank bearings (bought standard, need .020 over ID).  I decided I should probably get the head back together.  It started with removing the two broken exhaust studs.

I apparently didnt take a before pic.  So this is the second one I drilled and tapped.

Ran a small drill thru the center, the stud hole goes completely thru the head.

The drill set in my tap and die kit.  Started with the 1/8" drill, then worked up to 15/64".  Broke one of the bits on the second stud.  opps.


Here is the final drill out

Start of the tap, I find I run it 2-3 turns and back it out and clean the tap, and repeat until I run it completely through the hole.

Voila, two new studs and copper nuts.  I found the copper nuts didn't easily thread down the studs, so I ran the tap through them.  It looks like these are copper coated and the coating was a tad thick on the top end for it to thread.  Now they run easy, I just hope that they don't seize like the old ones did.

The other side I managed not to break, so I ran the die over them to clean up the threads.

Will have to wait on the new bearings before the engine case can go back together, in the mean time the other head has 3 broken studs that need attention.