@
Jerr I think your problem lies in the difference between how you are using the port and how most people have used it on this forum.
Most people who use the oil galley location actually incorporate a pressure sensor & gauge (not temperature). The pressure sensor cavity is flush and doesn't need to probe through like a temperature sensor.
- The car already has built-in oil temperature. You can pull it up via OBD.
People link 1/8" BSPT adapters because the majority of non-US made gauge/sensor kits popular on import platforms actually use BSPT (think Blitz, HKS, Defi, Greddy, Apexi, TRD, Pivot, Revel, etc.)
If you want to make this easy on yourself and you want to press on with an NPT temperature gauge, get a sandwich plate from a US make. Mishimoto has one that utilizes 1/8" NPT.
I don't see any problem boring out the BSPT to NPT adapter as long as you feel comfortable with the amount of material left over for the threads. The engine oil system only goes up to ~200 psi. Metal fittings are plenty strong for that