Some friendly thoughts for your NEXT adventure -
Obtain a few M6 x 18 grouphead screws (p/n 00300021) and drill them in a lathe like a friend did for his Rancilio Silvia:
Now use the screw as a "jig" for drilling the grouphead:

The hole in the grouphead can now be enlarged and tapped for an adaptor to fit a thermocouple. Possibly the easiest path would be to drill it out to 5.0 mm and continue the M6 threads all the way out the top. You could adjust the thermocouple depth as to your liking. My friend chose this:

On a separate subject, Ian (CafeIke) is very correct about that high boiler pressure. While it is true that 1.40 bar provides enough power for a small steam turbine







