I recently took it upon myself to replace the brake line from the block splitter thing by the master cylinder to the rear brakes on a project I have been working on. After ordering brake fittings (14mm x 1.5mm) for 1/4' line. I found that they did not fit by a very thin margin, to remedy this I ran a 1/4' drill through it on my press to no avail, after this O repeated with 9/32' after which the brake line fit with a slight clearance.
My question being is this ok to use? the brakeline has a ISO flare so I figured it will crush and seal the line but I figured I should double check on here.
I included some photos for reference.