[Half-Inch Stud]

Originally Posted by Goat-Racer

I would say that hard line would be a big no-no unless the filter housing was mounted to the engine directly and there was no flex to work harden and break the tube.
The other problem is that 1/2" tube is only 1/2" OD less twice the wall thickness. All of the hose is measured from the ID, and the typical-10 line is 5/8".
I know that you know this stuff, but I would hate to see anyone use hard line and eventually break it and blow oil underneath the tires.

Excellent. KNEW there were good reason to NOT do copper, just forgot, so I posted such.