Compression fittings/ferrule on the new ones on both ends.
So let's back up.... you have a legit point....... you say "the other end" is cut off. I will assume it's copper line that was cut. It's tubing with oil in it, goes up the line to the gauge. Since there is no "sender" on a mechanical oil pressure gauge, it's just a pipe fitting/adapter/bushing/whatever, screwed into a place on motor where oil pressure is present. Usually there are several places that can be used. Maybe you can get a compression fitting on that end. That would work. Leave the gauge end alone because it's soldered. Don't know if that end is salvageable if broken, maybe so. Gotta see some pix. Clean up the cut end, chamfer/deburr it and slip a fitting and ferrule onto it and adapt it up to another fiting that fits the motor hole.
You are rightly speaking of parts like
THIS.You can use an electrical gauge that does have a sender. Good ol resistance signal again. Maybe you have an electrical gauge, You say a "solid wire" is soldered to the gauge. I'm thinking that is tubing.
