I offer the following only as reference and suggestion; a person's ability to legally carry any sort of knife varies greatly due location, circumstances, attitude of the individual law officer, etc.
Texas Penal Code 46.01 defines "illegal knife" as having a blade over 5.5 inches, hand instrument designed to cut or stab another by being thrown, dagger, bowie knife, sword, or spear. Carrying the aforementioned is an offense; be aware that the terms "bowie", "dagger", etc. are not cleary explained in the PC.
I suggest obtaining a copy of the Penal Code (university bookstores will have it) and speaking with a lawyer familiar with these sections of the code to get more info.
Hope this helps.
------------------
Condition Yellow: for a longer, happier life.