May I draw everyone's attention to 110.14 (A)?
As I read this, machine screws, even with a washer, would not be equivalent to the permitted "wire binding" head. Oddly enough, a "washer head," such as found on many teks screws, would.
110.14 already requires a "thoroughly good connection." I suggest the more specific ban on "sheet metal screws" serves only to muddy the issue, and should be dropped.
