I have purchased an M-10 X 1.0 to 1/8 NPT 27 adapter for installing my
oil pressure gauge extension hose which is similiar to the one in this link:

http://www.egauges.com/vdo_acce.asp?Subgroup=Mech_Temp_Adapters

That way I'll keep my engine's threads stock.

Mike

Kenneth Lewis wrote:
>  FYI. The oil pressure switch has metric threads. NPT pipe thread is a
> conical hole, which is how the seal is made. The metric hole has parallel
> sides. The seal is made at the shoulder, not in the threads. The thread
> pitch is also slightly different.
>   This has always bothered me about the remote oil pressure switch extender
> hose, which is also NPT.
> Ken Lewis
> http://neksiwel.20m.com/
>