(With apologies for drifting thread)...no need to comment on the fact that knife laws pretty much everywhere are vague and confusing.

Regarding Chicago, there are armchair attorneys on bladeforums.com that tend to agree with kmcrawford III's belief that 8-24-20, para. 5 does limit to 2.5", to wit:

"No person shall carry concealed on or about his person a pistol, revolver, derringer or other firearm or dagger, dirk, stiletto, bowie knife, commando knife, any blade of which is released by a spring mechanism, including known knives as "switch-blades" or any other type or kind of knife, any blade of which is more than two and one-half inches in length, ordinary razor or other dangerous weapon except that no person 18 years of age or under shall carry concealed on or about his person, any knife, the blade of which is two inches in length or longer."

Key words being "concealed on or about." Does that mean a folder with just the clip showing outside pocket, as in some jurisdictions, removes knife from "concealed" category?"