My girlfriend just moved into a new apartment and her front door is 17/8" thick hollow steel, with a hollow steel frame in concrete. This door has a combination knob/deadbolt and a 1 3/8" hole for mounting a vertical deadbolt rimlock. She was told by the building management that she is responsible for purchasing and installing that lock. So that job falls in my lap.
My issue is that this is a hollow door made of sheet steel. The segal lock we bought is good for mounting in both metal and wood doors, but the instructions show wood only, and it comes with coarse threaded #12 screws.
My first issue is that the holes in the door, where a lock of this type was previously mounted, are too large, and my second is that even if they weren't (or if i purchased larger screws), a screw through sheet steel is not a secure mount for a lock. I am thinking maybe I am supposed to use some type of toggling anchor but the holes do not look large enough for that. Can somebody point me in the right direction, please?