Thanks! I'm not too worried about targeting the steel. With a good magnet or stud finder I think I can find it OK.
I'm planning to hang a few heavy tools like a chainsaw so I probably do need to go into the steel tubing, but maybe self-tapping screws are good enough for this.
I'm looking to install E-Track in my cargo trailer that has 3/8" OSB sidewalls over steel structural members (1x1 16 gauge tube). It seems people often use self-drilling screws for this but I'm worried about them weakening under vibration and load over time.
I don't want to put bolts through to...