Here is the whole article directly from the ILCS.
720 ILCS 5/33A‑1) (from Ch. 38, par. 33A‑1)
Sec. 33A‑1. Legislative intent and definitions.
(a) Legislative findings. The legislature finds and declares the following:
(1) The use of a dangerous weapon in the commission
of a felony offense poses a much greater threat to the public health, safety, and general welfare, than when a weapon is not used in the commission of the offense.
(2) Further, the use of a firearm greatly
facilitates the commission of a criminal offense because of the more lethal nature of a firearm and the greater perceived threat produced in those confronted by a person wielding a firearm. Unlike other dangerous weapons such as knives and clubs, the use of a firearm in the commission of a criminal felony offense significantly escalates the threat and the potential for bodily harm, and the greater range of the firearm increases the potential for harm to more persons. Not only are the victims and bystanders at greater risk when a firearm is used, but also the law enforcement officers whose duty is to confront and apprehend the armed suspect.
(3) Current law does contain offenses involving the
use or discharge of a gun toward or against a person, such as aggravated battery with a firearm, aggravated discharge of a firearm, and reckless discharge of a firearm; however, the General Assembly has legislated greater penalties for the commission of a felony while in possession of a firearm because it deems such acts as more serious.
(b) Legislative intent.
(1) In order to deter the use of firearms in the
commission of a felony offense, the General Assembly deems it appropriate for a greater penalty to be imposed when a firearm is used or discharged in the commission of an offense than the penalty imposed for using other types of weapons and for the penalty to increase on more serious offenses.
(2) With the additional elements of the discharge of
a firearm and great bodily harm inflicted by a firearm being added to armed violence and other serious felony offenses, it is the intent of the General Assembly to punish those elements more severely during commission of a felony offense than when those elements stand alone as the act of the offender.
(3) It is the intent of the 91st General Assembly
that should Public Act 88‑680 be declared unconstitutional for a violation of Article 4, Section 8 of the 1970 Constitution of the State of Illinois, the amendatory changes made by Public Act 88‑680 to Article 33A of the Criminal Code of 1961 and which are set forth as law in this amendatory Act of the 91st General Assembly are hereby reenacted by this amendatory Act of the 91st General Assembly.
(c) Definitions.
(1) "Armed with a dangerous weapon". A person is
considered armed with a dangerous weapon for purposes of this Article, when he or she carries on or about his or her person or is otherwise armed with a Category I, Category II, or Category III weapon.
(2) A Category I weapon is a handgun, sawed‑off
shotgun, sawed‑off rifle, any other firearm small enough to be concealed upon the person, semiautomatic firearm, or machine gun. A Category II weapon is any other rifle, shotgun, spring gun, other firearm, stun gun or taser as defined in paragraph (a) of Section 24‑1 of this Code, knife with a blade of at least 3 inches in length, dagger, dirk, switchblade knife, stiletto, axe, hatchet, or other deadly or dangerous weapon or instrument of like character. As used in this subsection (b) "semiautomatic firearm" means a repeating firearm that utilizes a portion of the energy of a firing cartridge to extract the fired cartridge case and chamber the next round and that requires a separate pull of the trigger to fire each cartridge.
(3) A Category III weapon is a bludgeon, black‑jack,
slungshot, sand‑bag, sand‑club, metal knuckles, billy, or other dangerous weapon of like character.
(Source: P.A. 91‑404, eff. 1‑1‑00; 91‑696, eff. 4‑13‑00.)
Now if you are looking for the statute that outlaws weapons. then you need this one.
(720 ILCS 5/24‑1) (from Ch. 38, par. 24‑1)
(Text of Section from P.A. 94‑72)
Sec. 24‑1. Unlawful Use of Weapons.
(a) A person commits the offense of unlawful use of weapons when he knowingly:
(1) Sells, manufactures, purchases, possesses or
carries any bludgeon, black‑jack, slung‑shot, sand‑club, sand‑bag, metal knuckles, throwing star, or any knife, commonly referred to as a switchblade knife, which has a blade that opens automatically by hand pressure applied to a button, spring or other device in the handle of the knife, or a ballistic knife, which is a device that propels a knifelike blade as a projectile by means of a coil spring, elastic material or compressed gas; or
(2) Carries or possesses with intent to use the same
unlawfully against another, a dagger, dirk, billy, dangerous knife, razor, stiletto, broken bottle or other piece of glass, stun gun or taser or any other dangerous or deadly weapon or instrument of like character; or
(3) Carries on or about his person or in any
vehicle, a tear gas gun projector or bomb or any object containing noxious liquid gas or substance, other than an object containing a non‑lethal noxious liquid gas or substance designed solely for personal defense carried by a person 18 years of age or older; or
(4) Carries or possesses in any vehicle or concealed
on or about his person except when on his land or in his own abode or fixed place of business any pistol, revolver, stun gun or taser or other firearm, except that this subsection (a) (4) does not apply to or affect transportation of weapons that meet one of the following conditions:
(i) are broken down in a non‑functioning state;
or
(ii) are not immediately accessible; or
(iii) are unloaded and enclosed in a case,
firearm carrying box, shipping box, or other container by a person who has been issued a currently valid Firearm Owner's Identification Card; or
(5) Sets a spring gun; or
(6) Possesses any device or attachment of any kind
designed, used or intended for use in silencing the report of any firearm; or
(7) Sells, manufactures, purchases, possesses or
carries:
(i) a machine gun, which shall be defined for
the purposes of this subsection as any weapon, which shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot without manually reloading by a single function of the trigger, including the frame or receiver of any such weapon, or sells, manufactures, purchases, possesses, or carries any combination of parts designed or intended for use in converting any weapon into a machine gun, or any combination or parts from which a machine gun can be assembled if such parts are in the possession or under the control of a person;
(ii) any rifle having one or more barrels less
than 16 inches in length or a shotgun having one or more barrels less than 18 inches in length or any weapon made from a rifle or shotgun, whether by alteration, modification, or otherwise, if such a weapon as modified has an overall length of less than 26 inches; or
(iii) any bomb, bomb‑shell, grenade, bottle or
other container containing an explosive substance of over one‑quarter ounce for like purposes, such as, but not limited to, black powder bombs and Molotov cocktails or artillery projectiles; or
(8) Carries or possesses any firearm, stun gun or
taser or other deadly weapon in any place which is licensed to sell intoxicating beverages, or at any public gathering held pursuant to a license issued by any governmental body or any public gathering at which an admission is charged, excluding a place where a showing, demonstration or lecture involving the exhibition of unloaded firearms is conducted.
This subsection (a)(8) does not apply to any auction
or raffle of a firearm held pursuant to a license or permit issued by a governmental body, nor does it apply to persons engaged in firearm safety training courses; or
(9) Carries or possesses in a vehicle or on or about
his person any pistol, revolver, stun gun or taser or firearm or ballistic knife, when he is hooded, robed or masked in such manner as to conceal his identity; or
(10) Carries or possesses on or about his person,
upon any public street, alley, or other public lands within the corporate limits of a city, village or incorporated town, except when an invitee thereon or therein, for the purpose of the display of such weapon or the lawful commerce in weapons, or except when on his land or in his own abode or fixed place of business, any pistol, revolver, stun gun or taser or other firearm, except that this subsection (a) (10) does not apply to or affect transportation of weapons that meet one of the following conditions:
(i) are broken down in a non‑functioning state;
or
(ii) are not immediately accessible; or
(iii) are unloaded and enclosed in a case,
firearm carrying box, shipping box, or other container by a person who has been issued a currently valid Firearm Owner's Identification Card.
A "stun gun or taser", as used in this paragraph (a)
means (i) any device which is powered by electrical charging units, such as, batteries, and which fires one or several barbs attached to a length of wire and which, upon hitting a human, can send out a current capable of disrupting the person's nervous system in such a manner as to render him incapable of normal functioning or (ii) any device which is powered by electrical charging units, such as batteries, and which, upon contact with a human or clothing worn by a human, can send out current capable of disrupting the person's nervous system in such a manner as to render him incapable of normal functioning; or
(11) Sells, manufactures or purchases any explosive
bullet. For purposes of this paragraph (a) "explosive bullet" means the projectile portion of an ammunition cartridge which contains or carries an explosive charge which will explode upon contact with the flesh of a human or an animal. "Cartridge" means a tubular metal case having a projectile affixed at the front thereof and a cap or primer at the rear end thereof, with the propellant contained in such tube between the projectile and the cap; or
No where in the Deadly weapons statute does it mention any legal or illegal length for a blade, nor does it mention fixed blades v. folders. As someone had mentioned in another thread, you could carry excaliber and not be breaking any laws. but if you carry it with the intent to commit a crime, you are then violating state law. Now in the Use of a Deadly weapon article, it does mention Dangerous knife(highlighted in red). But it says "with the intent to use". So again, as long as you are just carrying it as a pocket knife, and not to go to the stop-and-rob, to make a withdrawl, you are ok.