TracTuff -8 ORB to M10 x 1.25 Bleed Bolt Adapter
$14.95
The -8 ORB to M10 x 1.25 Bleed Bolt Adapter was originally made to convert the -8 ORB port on the H22 Thermostat Housing Delete to a Bleed Bolt... but M10 x 1.25 is so close to 1/8" NPT that you can effectively drill through this adapter and start a 1/8" NPT tap very easily.
I recommend a thread sealant after you tap this part being there will now be multiple threads in the part.