Finished off the reinforcement studs/bolts for the head.
Found a pair of good somewhat stronger aluminium alloy rods and turned them on the lathe.
Used aluminium instead so I can choose whether I wanna TIG weld them in place or just use loctite to seal them so coolant wont come out through the holes, since they are in the large cooling cavities between every combustion chamber.
Threaded them in M14 x 2mm.
I also wanted to make it easy to screw them in and torque them properly with a torque wrench.
So the idea of perfect hexagon shaped 13mm bolt head came to life.
I took the half finished bolts and moved them to the Wire cut EDM machine. Mounted them in the fourth axle that rotates 360°, did some testing and programming. Programmed it to between every cut to rotate 60° for each corner, took about 15min for each bolt.
However the outcome was much better than expected, but left it with a quite rough surface finish. The wire cutter takes quite some time otherwise.